[v4,3/6] drm/bridge/synopsys: Add MIPI DSI host controller bridge

Commit Message

Philippe CORNU June 19, 2017, 4:28 p.m. UTC

Add a Synopsys Designware MIPI DSI host DRM bridge driver, based on the
Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.

Signed-off-by: Philippe CORNU <[e-mail]>
---
 drivers/gpu/drm/bridge/synopsys/Kconfig       |   6 +
 drivers/gpu/drm/bridge/synopsys/Makefile      |   2 +
 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 976 ++++++++++++++++++++++++++
 include/drm/bridge/dw_mipi_dsi.h              |  39 +
 4 files changed, 1023 insertions(+)
 create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
 create mode 100644 include/drm/bridge/dw_mipi_dsi.h

Comments

Archit Taneja June 28, 2017, 6:44 a.m. UTC | #1

On 06/19/2017 09:58 PM, Philippe CORNU wrote:
> Add a Synopsys Designware MIPI DSI host DRM bridge driver, based on the
> Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
> 
> Signed-off-by: Philippe CORNU <[e-mail]>
> ---
>   drivers/gpu/drm/bridge/synopsys/Kconfig       |   6 +
>   drivers/gpu/drm/bridge/synopsys/Makefile      |   2 +
>   drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 976 ++++++++++++++++++++++++++
>   include/drm/bridge/dw_mipi_dsi.h              |  39 +
>   4 files changed, 1023 insertions(+)
>   create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>   create mode 100644 include/drm/bridge/dw_mipi_dsi.h
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig b/drivers/gpu/drm/bridge/synopsys/Kconfig
> index 40d2827..f00ee26 100644
> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
> @@ -21,3 +21,9 @@ config DRM_DW_HDMI_I2S_AUDIO
>   	help
>   	  Support the I2S Audio interface which is part of the Synopsys
>   	  Designware HDMI block.
> +
> +config DRM_DW_MIPI_DSI
> +	tristate
> +	select DRM_KMS_HELPER
> +	select DRM_MIPI_DSI
> +	select DRM_PANEL_BRIDGE
> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile b/drivers/gpu/drm/bridge/synopsys/Makefile
> index 17aa7a6..5f57d36 100644
> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
> @@ -3,3 +3,5 @@
>   obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>   obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>   obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
> +
> +obj-$(CONFIG_DRM_DW_MIPI_DSI) += dw-mipi-dsi.o
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> new file mode 100644
> index 0000000..416ed7f
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -0,0 +1,976 @@
> +/*
> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
> + * Copyright (C) STMicroelectronics SA 2017
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * Modified by Philippe Cornu <[e-mail]>
> + * This generic Synopsys DesignWare MIPI DSI host driver is based on the
> + * Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/component.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> +#include <drm/drmP.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_of.h>
> +#include <drm/bridge/dw_mipi_dsi.h>
> +#include <video/mipi_display.h>
> +
> +#define DSI_VERSION			0x00
> +#define DSI_PWR_UP			0x04
> +#define RESET				0
> +#define POWERUP				BIT(0)
> +
> +#define DSI_CLKMGR_CFG			0x08
> +#define TO_CLK_DIVIDSION(div)		(((div) & 0xff) << 8)
> +#define TX_ESC_CLK_DIVIDSION(div)	(((div) & 0xff) << 0)
> +
> +#define DSI_DPI_VCID			0x0c
> +#define DPI_VID(vid)			(((vid) & 0x3) << 0)
> +
> +#define DSI_DPI_COLOR_CODING		0x10
> +#define EN18_LOOSELY			BIT(8)
> +#define DPI_COLOR_CODING_16BIT_1	0x0
> +#define DPI_COLOR_CODING_16BIT_2	0x1
> +#define DPI_COLOR_CODING_16BIT_3	0x2
> +#define DPI_COLOR_CODING_18BIT_1	0x3
> +#define DPI_COLOR_CODING_18BIT_2	0x4
> +#define DPI_COLOR_CODING_24BIT		0x5
> +
> +#define DSI_DPI_CFG_POL			0x14
> +#define COLORM_ACTIVE_LOW		BIT(4)
> +#define SHUTD_ACTIVE_LOW		BIT(3)
> +#define HSYNC_ACTIVE_LOW		BIT(2)
> +#define VSYNC_ACTIVE_LOW		BIT(1)
> +#define DATAEN_ACTIVE_LOW		BIT(0)
> +
> +#define DSI_DPI_LP_CMD_TIM		0x18
> +#define OUTVACT_LPCMD_TIME(p)		(((p) & 0xff) << 16)
> +#define INVACT_LPCMD_TIME(p)		((p) & 0xff)
> +
> +#define DSI_DBI_CFG			0x20
> +#define DSI_DBI_CMDSIZE			0x28
> +
> +#define DSI_PCKHDL_CFG			0x2c
> +#define EN_CRC_RX			BIT(4)
> +#define EN_ECC_RX			BIT(3)
> +#define EN_BTA				BIT(2)
> +#define EN_EOTP_RX			BIT(1)
> +#define EN_EOTP_TX			BIT(0)
> +
> +#define DSI_MODE_CFG			0x34
> +#define ENABLE_VIDEO_MODE		0
> +#define ENABLE_CMD_MODE			BIT(0)
> +
> +#define DSI_VID_MODE_CFG		0x38
> +#define FRAME_BTA_ACK			BIT(14)
> +#define ENABLE_LOW_POWER		(0x3f << 8)
> +#define ENABLE_LOW_POWER_MASK		(0x3f << 8)
> +#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES	0x0
> +#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS	0x1
> +#define VID_MODE_TYPE_BURST			0x2
> +#define VID_MODE_TYPE_MASK			0x3
> +
> +#define DSI_VID_PKT_SIZE		0x3c
> +#define VID_PKT_SIZE(p)			(((p) & 0x3fff) << 0)
> +#define VID_PKT_MAX_SIZE		0x3fff
> +
> +#define DSI_VID_HSA_TIME		0x48
> +#define DSI_VID_HBP_TIME		0x4c
> +#define DSI_VID_HLINE_TIME		0x50
> +#define DSI_VID_VSA_LINES		0x54
> +#define DSI_VID_VBP_LINES		0x58
> +#define DSI_VID_VFP_LINES		0x5c
> +#define DSI_VID_VACTIVE_LINES		0x60
> +#define DSI_CMD_MODE_CFG		0x68
> +#define MAX_RD_PKT_SIZE_LP		BIT(24)
> +#define DCS_LW_TX_LP			BIT(19)
> +#define DCS_SR_0P_TX_LP			BIT(18)
> +#define DCS_SW_1P_TX_LP			BIT(17)
> +#define DCS_SW_0P_TX_LP			BIT(16)
> +#define GEN_LW_TX_LP			BIT(14)
> +#define GEN_SR_2P_TX_LP			BIT(13)
> +#define GEN_SR_1P_TX_LP			BIT(12)
> +#define GEN_SR_0P_TX_LP			BIT(11)
> +#define GEN_SW_2P_TX_LP			BIT(10)
> +#define GEN_SW_1P_TX_LP			BIT(9)
> +#define GEN_SW_0P_TX_LP			BIT(8)
> +#define EN_ACK_RQST			BIT(1)
> +#define EN_TEAR_FX			BIT(0)
> +
> +#define CMD_MODE_ALL_LP			(MAX_RD_PKT_SIZE_LP | \
> +					 DCS_LW_TX_LP | \
> +					 DCS_SR_0P_TX_LP | \
> +					 DCS_SW_1P_TX_LP | \
> +					 DCS_SW_0P_TX_LP | \
> +					 GEN_LW_TX_LP | \
> +					 GEN_SR_2P_TX_LP | \
> +					 GEN_SR_1P_TX_LP | \
> +					 GEN_SR_0P_TX_LP | \
> +					 GEN_SW_2P_TX_LP | \
> +					 GEN_SW_1P_TX_LP | \
> +					 GEN_SW_0P_TX_LP)
> +
> +#define DSI_GEN_HDR			0x6c
> +#define GEN_HDATA(data)			(((data) & 0xffff) << 8)
> +#define GEN_HDATA_MASK			(0xffff << 8)
> +#define GEN_HTYPE(type)			(((type) & 0xff) << 0)
> +#define GEN_HTYPE_MASK			0xff
> +
> +#define DSI_GEN_PLD_DATA		0x70
> +
> +#define DSI_CMD_PKT_STATUS		0x74
> +#define GEN_CMD_EMPTY			BIT(0)
> +#define GEN_CMD_FULL			BIT(1)
> +#define GEN_PLD_W_EMPTY			BIT(2)
> +#define GEN_PLD_W_FULL			BIT(3)
> +#define GEN_PLD_R_EMPTY			BIT(4)
> +#define GEN_PLD_R_FULL			BIT(5)
> +#define GEN_RD_CMD_BUSY			BIT(6)
> +
> +#define DSI_TO_CNT_CFG			0x78
> +#define HSTX_TO_CNT(p)			(((p) & 0xffff) << 16)
> +#define LPRX_TO_CNT(p)			((p) & 0xffff)
> +
> +#define DSI_BTA_TO_CNT			0x8c
> +#define DSI_LPCLK_CTRL			0x94
> +#define AUTO_CLKLANE_CTRL		BIT(1)
> +#define PHY_TXREQUESTCLKHS		BIT(0)
> +
> +#define DSI_PHY_TMR_LPCLK_CFG		0x98
> +#define PHY_CLKHS2LP_TIME(lbcc)		(((lbcc) & 0x3ff) << 16)
> +#define PHY_CLKLP2HS_TIME(lbcc)		((lbcc) & 0x3ff)
> +
> +#define DSI_PHY_TMR_CFG			0x9c
> +#define PHY_HS2LP_TIME(lbcc)		(((lbcc) & 0xff) << 24)
> +#define PHY_LP2HS_TIME(lbcc)		(((lbcc) & 0xff) << 16)
> +#define MAX_RD_TIME(lbcc)		((lbcc) & 0x7fff)
> +
> +#define DSI_PHY_RSTZ			0xa0
> +#define PHY_DISFORCEPLL			0
> +#define PHY_ENFORCEPLL			BIT(3)
> +#define PHY_DISABLECLK			0
> +#define PHY_ENABLECLK			BIT(2)
> +#define PHY_RSTZ			0
> +#define PHY_UNRSTZ			BIT(1)
> +#define PHY_SHUTDOWNZ			0
> +#define PHY_UNSHUTDOWNZ			BIT(0)
> +
> +#define DSI_PHY_IF_CFG			0xa4
> +#define N_LANES(n)			((((n) - 1) & 0x3) << 0)
> +#define PHY_STOP_WAIT_TIME(cycle)	(((cycle) & 0xff) << 8)
> +
> +#define DSI_PHY_STATUS			0xb0
> +#define LOCK				BIT(0)
> +#define STOP_STATE_CLK_LANE		BIT(2)
> +
> +#define DSI_PHY_TST_CTRL0		0xb4
> +#define PHY_TESTCLK			BIT(1)
> +#define PHY_UNTESTCLK			0
> +#define PHY_TESTCLR			BIT(0)
> +#define PHY_UNTESTCLR			0
> +
> +#define DSI_PHY_TST_CTRL1		0xb8
> +#define PHY_TESTEN			BIT(16)
> +#define PHY_UNTESTEN			0
> +#define PHY_TESTDOUT(n)			(((n) & 0xff) << 8)
> +#define PHY_TESTDIN(n)			(((n) & 0xff) << 0)
> +
> +#define DSI_INT_ST0			0xbc
> +#define DSI_INT_ST1			0xc0
> +#define DSI_INT_MSK0			0xc4
> +#define DSI_INT_MSK1			0xc8
> +
> +#define PHY_STATUS_TIMEOUT_US		10000
> +#define CMD_PKT_STATUS_TIMEOUT_US	20000
> +
> +struct dw_mipi_dsi {
> +	struct drm_bridge bridge;
> +	struct mipi_dsi_host dsi_host;
> +	struct drm_bridge *panel_bridge;
> +	bool is_panel_bridge;
> +	struct device *dev;
> +	void __iomem *base;
> +
> +	struct clk *pclk;
> +
> +	unsigned int lane_mbps; /* per lane */
> +	u32 channel;
> +	u32 lanes;
> +	u32 format;
> +	unsigned long mode_flags;
> +
> +	const struct dw_mipi_dsi_plat_data *plat_data;
> +};
> +
> +/*
> + * The controller should generate 2 frames before
> + * preparing the peripheral.
> + */
> +static void dw_mipi_dsi_wait_for_two_frames(struct drm_display_mode *mode)
> +{
> +	int refresh, two_frames;
> +
> +	refresh = drm_mode_vrefresh(mode);
> +	two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
> +	msleep(two_frames);
> +}
> +
> +static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host *host)
> +{
> +	return container_of(host, struct dw_mipi_dsi, dsi_host);
> +}
> +
> +static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge *bridge)
> +{
> +	return container_of(bridge, struct dw_mipi_dsi, bridge);
> +}
> +
> +static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val)
> +{
> +	writel(val, dsi->base + reg);
> +}
> +
> +static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
> +{
> +	return readl(dsi->base + reg);
> +}
> +
> +static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
> +				   struct mipi_dsi_device *device)
> +{
> +	struct dw_mipi_dsi *dsi = host_to_dsi(host);
> +	struct drm_bridge *bridge;
> +	struct drm_panel *panel;
> +	int ret;
> +
> +	if (device->lanes > dsi->plat_data->max_data_lanes) {
> +		dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
> +			device->lanes);
> +		return -EINVAL;
> +	}
> +
> +	dsi->lanes = device->lanes;
> +	dsi->channel = device->channel;
> +	dsi->format = device->format;
> +	dsi->mode_flags = device->mode_flags;
> +
> +	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
> +					  &panel, &bridge);
> +	if (ret)
> +		return ret;
> +
> +	if (panel) {
> +		bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DSI);
> +		if (IS_ERR(bridge))
> +			return PTR_ERR(bridge);
> +		dsi->is_panel_bridge = true;
> +	}
> +
> +	dsi->panel_bridge = bridge;
> +
> +	return drm_bridge_add(&dsi->bridge);
> +}
> +
> +static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
> +				   struct mipi_dsi_device *device)
> +{
> +	struct dw_mipi_dsi *dsi = host_to_dsi(host);
> +
> +	if (dsi->is_panel_bridge)
> +		drm_panel_bridge_remove(dsi->panel_bridge);
> +
> +	drm_bridge_remove(&dsi->bridge);
> +
> +	return 0;
> +}
> +
> +static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
> +				   const struct mipi_dsi_msg *msg)
> +{
> +	bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
> +	u32 val = 0;
> +
> +	if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
> +		val |= EN_ACK_RQST;
> +	if (lpm)
> +		val |= CMD_MODE_ALL_LP;
> +
> +	dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
> +	dsi_write(dsi, DSI_CMD_MODE_CFG, val);
> +}
> +
> +static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
> +{
> +	int ret;
> +	u32 val, mask;
> +
> +	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +				 val, !(val & GEN_CMD_FULL), 1000,
> +				 CMD_PKT_STATUS_TIMEOUT_US);
> +	if (ret < 0) {
> +		dev_err(dsi->dev, "failed to get available command FIFO\n");
> +		return ret;
> +	}
> +
> +	dsi_write(dsi, DSI_GEN_HDR, hdr_val);
> +
> +	mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
> +	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +				 val, (val & mask) == mask,
> +				 1000, CMD_PKT_STATUS_TIMEOUT_US);
> +	if (ret < 0) {
> +		dev_err(dsi->dev, "failed to write command FIFO\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
> +				       const struct mipi_dsi_msg *msg)
> +{
> +	const u8 *tx_buf = msg->tx_buf;
> +	u16 data = 0;
> +	u32 val;
> +
> +	if (msg->tx_len > 0)
> +		data |= tx_buf[0];
> +	if (msg->tx_len > 1)
> +		data |= tx_buf[1] << 8;
> +
> +	if (msg->tx_len > 2) {
> +		dev_err(dsi->dev, "too long tx buf length %zu for short write\n",
> +			msg->tx_len);
> +		return -EINVAL;
> +	}
> +
> +	val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
> +	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
> +}
> +
> +static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
> +				      const struct mipi_dsi_msg *msg)
> +{
> +	const u8 *tx_buf = msg->tx_buf;
> +	int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
> +	u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
> +	u32 remainder;
> +	u32 val;
> +
> +	if (msg->tx_len < 3) {
> +		dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
> +			msg->tx_len);
> +		return -EINVAL;
> +	}
> +
> +	while (DIV_ROUND_UP(len, pld_data_bytes)) {
> +		if (len < pld_data_bytes) {
> +			remainder = 0;
> +			memcpy(&remainder, tx_buf, len);
> +			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
> +			len = 0;
> +		} else {
> +			memcpy(&remainder, tx_buf, pld_data_bytes);
> +			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
> +			tx_buf += pld_data_bytes;
> +			len -= pld_data_bytes;
> +		}
> +
> +		ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
> +					 val, !(val & GEN_PLD_W_FULL), 1000,
> +					 CMD_PKT_STATUS_TIMEOUT_US);
> +		if (ret < 0) {
> +			dev_err(dsi->dev,
> +				"failed to get available write payload FIFO\n");
> +			return ret;
> +		}
> +	}
> +
> +	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
> +}
> +
> +static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
> +					 const struct mipi_dsi_msg *msg)
> +{
> +	struct dw_mipi_dsi *dsi = host_to_dsi(host);
> +	int ret;
> +
> +	/*
> +	 * TODO dw drv improvements
> +	 * use mipi_dsi_create_packet() instead of all following
> +	 * functions and code (no switch cases, no
> +	 * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
> +	 * and use packet.header...
> +	 */
> +	dw_mipi_message_config(dsi, msg);
> +
> +	switch (msg->type) {
> +	case MIPI_DSI_DCS_SHORT_WRITE:
> +	case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
> +	case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
> +		ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
> +		break;
> +	case MIPI_DSI_DCS_LONG_WRITE:
> +		ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
> +		break;
> +	default:
> +		dev_err(dsi->dev, "unsupported message type 0x%02x\n",
> +			msg->type);
> +		ret = -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
> +	.attach = dw_mipi_dsi_host_attach,
> +	.detach = dw_mipi_dsi_host_detach,
> +	.transfer = dw_mipi_dsi_host_transfer,
> +};
> +
> +static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
> +{
> +	u32 val;
> +
> +	/*
> +	 * TODO dw drv improvements
> +	 * enabling low power is panel-dependent, we should use the
> +	 * panel configuration here...
> +	 */
> +	val = ENABLE_LOW_POWER;
> +
> +	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
> +		val |= VID_MODE_TYPE_BURST;
> +	else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> +		val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
> +	else
> +		val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
> +
> +	dsi_write(dsi, DSI_VID_MODE_CFG, val);
> +}
> +
> +static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
> +				 unsigned long mode_flags)
> +{
> +	dsi_write(dsi, DSI_PWR_UP, RESET);
> +
> +	if (mode_flags & MIPI_DSI_MODE_VIDEO) {
> +		dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
> +		dw_mipi_dsi_video_mode_config(dsi);
> +		dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
> +	} else {
> +		dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
> +	}
> +
> +	dsi_write(dsi, DSI_PWR_UP, POWERUP);
> +}
> +
> +static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
> +{
> +	dsi_write(dsi, DSI_PWR_UP, RESET);
> +	dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
> +}
> +
> +static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
> +{
> +	/*
> +	 * The maximum permitted escape clock is 20MHz and it is derived from
> +	 * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
> +	 *
> +	 *     (lane_mbps >> 3) / esc_clk_division < 20
> +	 * which is:
> +	 *     (lane_mbps >> 3) / 20 > esc_clk_division
> +	 */
> +	u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
> +
> +	dsi_write(dsi, DSI_PWR_UP, RESET);
> +
> +	/*
> +	 * TODO dw drv improvements
> +	 * timeout clock division should be computed with the
> +	 * high speed transmission counter timeout and byte lane...
> +	 */
> +	dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
> +		  TX_ESC_CLK_DIVIDSION(esc_clk_division));
> +}
> +
> +static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
> +				   struct drm_display_mode *mode)
> +{
> +	u32 val = 0, color = 0;
> +
> +	switch (dsi->format) {
> +	case MIPI_DSI_FMT_RGB888:
> +		color = DPI_COLOR_CODING_24BIT;
> +		break;
> +	case MIPI_DSI_FMT_RGB666:
> +		color = DPI_COLOR_CODING_18BIT_2 | EN18_LOOSELY;
> +		break;
> +	case MIPI_DSI_FMT_RGB666_PACKED:
> +		color = DPI_COLOR_CODING_18BIT_1;
> +		break;
> +	case MIPI_DSI_FMT_RGB565:
> +		color = DPI_COLOR_CODING_16BIT_1;
> +		break;
> +	}
> +
> +	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
> +		val |= VSYNC_ACTIVE_LOW;
> +	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
> +		val |= HSYNC_ACTIVE_LOW;
> +
> +	dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));
> +	dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
> +	dsi_write(dsi, DSI_DPI_CFG_POL, val);
> +	/*
> +	 * TODO dw drv improvements
> +	 * largest packet sizes during hfp or during vsa/vpb/vfp
> +	 * should be computed according to byte lane, lane number and only
> +	 * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
> +	 */
> +	dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
> +		  | INVACT_LPCMD_TIME(4));
> +}
> +
> +static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
> +{
> +	dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
> +}
> +
> +static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
> +					    struct drm_display_mode *mode)
> +{
> +	/*
> +	 * TODO dw drv improvements
> +	 * only burst mode is supported here. For non-burst video modes,
> +	 * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
> +	 * DSI_VNPCR.NPSIZE... especially because this driver supports
> +	 * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
> +	 */
> +	dsi_write(dsi, DSI_VID_PKT_SIZE, VID_PKT_SIZE(mode->hdisplay));
> +}
> +
> +static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
> +{
> +	/*
> +	 * TODO dw drv improvements
> +	 * compute high speed transmission counter timeout according
> +	 * to the timeout clock division (TO_CLK_DIVIDSION) and byte lane...
> +	 */
> +	dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) | LPRX_TO_CNT(1000));
> +	/*
> +	 * TODO dw drv improvements
> +	 * the Bus-Turn-Around Timeout Counter should be computed
> +	 * according to byte lane...
> +	 */
> +	dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
> +	dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
> +}
> +
> +/* Get lane byte clock cycles. */
> +static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
> +					   struct drm_display_mode *mode,
> +					   u32 hcomponent)
> +{
> +	u32 frac, lbcc;
> +
> +	lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
> +
> +	frac = lbcc % mode->clock;
> +	lbcc = lbcc / mode->clock;
> +	if (frac)
> +		lbcc++;
> +
> +	return lbcc;
> +}
> +
> +static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
> +					  struct drm_display_mode *mode)
> +{
> +	u32 htotal, hsa, hbp, lbcc;
> +
> +	htotal = mode->htotal;
> +	hsa = mode->hsync_end - mode->hsync_start;
> +	hbp = mode->htotal - mode->hsync_end;
> +
> +	/*
> +	 * TODO dw drv improvements
> +	 * computations below may be improved...
> +	 */
> +	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
> +	dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);
> +
> +	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
> +	dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);
> +
> +	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
> +	dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
> +}
> +
> +static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi *dsi,
> +					       struct drm_display_mode *mode)
> +{
> +	u32 vactive, vsa, vfp, vbp;
> +
> +	vactive = mode->vdisplay;
> +	vsa = mode->vsync_end - mode->vsync_start;
> +	vfp = mode->vsync_start - mode->vdisplay;
> +	vbp = mode->vtotal - mode->vsync_end;
> +
> +	dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
> +	dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
> +	dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
> +	dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
> +}
> +
> +static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
> +{
> +	/*
> +	 * TODO dw drv improvements
> +	 * data & clock lane timers should be computed according to panel
> +	 * blankings and to the automatic clock lane control mode...
> +	 * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
> +	 * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
> +	 */
> +	dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
> +		  | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
> +
> +	dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
> +		  | PHY_CLKLP2HS_TIME(0x40));
> +}
> +
> +static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
> +{
> +	/*
> +	 * TODO dw drv improvements
> +	 * stop wait time should be the maximum between host dsi
> +	 * and panel stop wait times
> +	 */
> +	dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
> +		  N_LANES(dsi->lanes));
> +}
> +
> +static void dw_mipi_dsi_dphy_init(struct dw_mipi_dsi *dsi)
> +{
> +	/* Clear PHY state */
> +	dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
> +		  | PHY_RSTZ | PHY_SHUTDOWNZ);
> +	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
> +	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLR);
> +	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
> +}
> +
> +static void dw_mipi_dsi_dphy_enable(struct dw_mipi_dsi *dsi)
> +{
> +	u32 val;
> +	int ret;
> +
> +	dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
> +		  PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
> +
> +	ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
> +				 val, val & LOCK, 1000, PHY_STATUS_TIMEOUT_US);
> +	if (ret < 0)
> +		DRM_DEBUG_DRIVER("failed to wait phy lock state\n");
> +
> +	ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
> +				 val, val & STOP_STATE_CLK_LANE, 1000,
> +				 PHY_STATUS_TIMEOUT_US);
> +	if (ret < 0)
> +		DRM_DEBUG_DRIVER("failed to wait phy clk lane stop state\n");
> +}
> +
> +static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
> +{
> +	dsi_read(dsi, DSI_INT_ST0);
> +	dsi_read(dsi, DSI_INT_ST1);
> +	dsi_write(dsi, DSI_INT_MSK0, 0);
> +	dsi_write(dsi, DSI_INT_MSK1, 0);
> +}
> +
> +static void dw_mipi_dsi_bridge_post_disable(struct drm_bridge *bridge)
> +{
> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
> +
> +	/*
> +	 * Switch to cmd mode before panel-bridge disable & panel unprepare.
> +	 * Note: panel-bridge disable & panel disable has been called
> +	 * before by the drm framework.

I don't think that's exactly the case. I think the sequence should be as in the
call chain below.

> +	 */
> +	dw_mipi_dsi_set_mode(dsi, 0);
> +
> +	/*
> +	 * TODO Only way found to call panel-bridge disable & panel unprepare
> +	 * before the dsi "final" disable... can we do better?

I agree, this is a problem. More below.

> +	 */
> +	drm_bridge_post_disable(dsi->panel_bridge);
> +

I'm guessing our display chain is something like:

KMS_encoder -> DW_DSI_bridge -> Panel_bridge -> Panel

The order in which the disable ops are called:

drm_bridge_disable(Panel_bridge)
   - drm_panel_disable(Panel)
drm_bridge_disable(DW_DSI_bridge)
encoder_funcs->prepare(KMS_encoder)
drm_bridge_post_disable(DW_DSI_bridge)
drm_bridge_post_disable(Panel_bridge)
   - drm_panel_unprepare(Panel)

Assuming that only drm_panel_unprepare() requires sending DSI commands, you could have
switched to command mode in DW_DSI_bridge's disable() op, and do the "final" DSI disable
in DW_DSI_bridge's post_disable(), but that would still result in drm_panel_unprepare()
being called with the DSI host dead.

The existing call chain of consecutive bridges is the most symmetric one, and the one
expected to work in most cases, but it clearly doesn't work in your use case.

We have a few options:

- Undo the drm-panel-bridge stuff, and have the freedom of calling drm_panel ops in
whatever order we want.

- Put a big TODO/HACK comment here, saying that this needs to be fixed in the drm_bridge
framework and the API needs to be updated to manage our own call chains. Also,
instead of calling "drm_bridge_post_disable(dsi->panel_bridge);" explicitly, we
can manually call panel_bridge->post_disable() op directly. This avoids us doing
things recursively.

We would implement the TODO task in drm_bridges only when there are more people
desperately in the need to have customizable call chains of bridge ops for long
display chains, so I don't see it being implemented in the near future, but I don't
think there should be any problem keeping this hack in the dw dsi driver for now.

What choice do you prefer?

Eric, Daniel,

Fyi, this is another case where the panel-bridge stuff doesn't work so well. Not
criticizing or anything, just pointing out :)

Archit


> +	dw_mipi_dsi_disable(dsi);
> +	clk_disable_unprepare(dsi->pclk);
> +	pm_runtime_put(dsi->dev);
> +}
> +
> +void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
> +				 struct drm_display_mode *mode,
> +				 struct drm_display_mode *adjusted_mode)
> +{
> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
> +	const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
> +	void *priv_data = dsi->plat_data->priv_data;
> +	int ret;
> +
> +	clk_prepare_enable(dsi->pclk);
> +
> +	ret = phy_ops->get_lane_mbps(priv_data, mode, dsi->mode_flags,
> +				     dsi->lanes, dsi->format, &dsi->lane_mbps);
> +	if (ret)
> +		DRM_DEBUG_DRIVER("Phy get_lane_mbps() failed\n");
> +
> +	pm_runtime_get_sync(dsi->dev);
> +	dw_mipi_dsi_init(dsi);
> +	dw_mipi_dsi_dpi_config(dsi, mode);
> +	dw_mipi_dsi_packet_handler_config(dsi);
> +	dw_mipi_dsi_video_mode_config(dsi);
> +	dw_mipi_dsi_video_packet_config(dsi, mode);
> +	dw_mipi_dsi_command_mode_config(dsi);
> +	dw_mipi_dsi_line_timer_config(dsi, mode);
> +	dw_mipi_dsi_vertical_timing_config(dsi, mode);
> +
> +	dw_mipi_dsi_dphy_init(dsi);
> +	dw_mipi_dsi_dphy_timing_config(dsi);
> +	dw_mipi_dsi_dphy_interface_config(dsi);
> +
> +	dw_mipi_dsi_clear_err(dsi);
> +
> +	ret = phy_ops->init(priv_data);
> +	if (ret)
> +		DRM_DEBUG_DRIVER("Phy init() failed\n");
> +
> +	dw_mipi_dsi_dphy_enable(dsi);
> +
> +	dw_mipi_dsi_wait_for_two_frames(mode);
> +
> +	/* Switch to cmd mode for panel-bridge pre_enable & panel prepare */
> +	dw_mipi_dsi_set_mode(dsi, 0);
> +}
> +
> +static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge)
> +{
> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
> +
> +	/* Switch to video mode for panel-bridge enable & panel enable */
> +	dw_mipi_dsi_set_mode(dsi, MIPI_DSI_MODE_VIDEO);
> +}
> +
> +static enum drm_mode_status
> +dw_mipi_dsi_bridge_mode_valid(struct drm_bridge *bridge,
> +			      const struct drm_display_mode *mode)
> +{
> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
> +	const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
> +	enum drm_mode_status mode_status = MODE_OK;
> +
> +	if (pdata->mode_valid)
> +		mode_status = pdata->mode_valid(pdata->priv_data, mode);
> +
> +	return mode_status;
> +}
> +
> +static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge)
> +{
> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
> +
> +	if (!bridge->encoder) {
> +		DRM_ERROR("Parent encoder object not found\n");
> +		return -ENODEV;
> +	}
> +
> +	/* Set the encoder type as caller does not know it */
> +	bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
> +
> +	/* Attach the panel-bridge to the dsi bridge */
> +	return drm_bridge_attach(bridge->encoder, dsi->panel_bridge, bridge);
> +}
> +
> +static struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
> +	.mode_set     = dw_mipi_dsi_bridge_mode_set,
> +	.enable	      = dw_mipi_dsi_bridge_enable,
> +	.post_disable = dw_mipi_dsi_bridge_post_disable,
> +	.mode_valid   = dw_mipi_dsi_bridge_mode_valid,
> +	.attach	      = dw_mipi_dsi_bridge_attach,
> +};
> +
> +static struct dw_mipi_dsi *
> +__dw_mipi_dsi_probe(struct platform_device *pdev,
> +		    const struct dw_mipi_dsi_plat_data *plat_data)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct reset_control *apb_rst;
> +	struct dw_mipi_dsi *dsi;
> +	struct resource *res;
> +	int ret;
> +
> +	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> +	if (!dsi)
> +		return ERR_PTR(-ENOMEM);
> +
> +	dsi->dev = dev;
> +	dsi->plat_data = plat_data;
> +
> +	if (!plat_data->phy_ops->init || !plat_data->phy_ops->get_lane_mbps) {
> +		DRM_ERROR("Phy not properly configured\n");
> +		return ERR_PTR(-ENODEV);
> +	}
> +
> +	if (!plat_data->base) {
> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +		if (!res)
> +			return ERR_PTR(-ENODEV);
> +
> +		dsi->base = devm_ioremap_resource(dev, res);
> +		if (IS_ERR(dsi->base))
> +			return ERR_PTR(-ENODEV);
> +
> +	} else {
> +		dsi->base = plat_data->base;
> +	}
> +
> +	dsi->pclk = devm_clk_get(dev, "pclk");
> +	if (IS_ERR(dsi->pclk)) {
> +		ret = PTR_ERR(dsi->pclk);
> +		dev_err(dev, "Unable to get pclk: %d\n", ret);
> +		return ERR_PTR(ret);
> +	}
> +
> +	/*
> +	 * Note that the reset was not defined in the initial device tree, so
> +	 * we have to be prepared for it not being found.
> +	 */
> +	apb_rst = devm_reset_control_get(dev, "apb");
> +	if (IS_ERR(apb_rst)) {
> +		ret = PTR_ERR(apb_rst);
> +		if (ret == -ENOENT) {
> +			apb_rst = NULL;
> +		} else {
> +			dev_err(dev, "Unable to get reset control: %d\n", ret);
> +			return ERR_PTR(ret);
> +		}
> +	}
> +
> +	if (apb_rst) {
> +		ret = clk_prepare_enable(dsi->pclk);
> +		if (ret) {
> +			dev_err(dev, "%s: Failed to enable pclk\n", __func__);
> +			return ERR_PTR(ret);
> +		}
> +
> +		reset_control_assert(apb_rst);
> +		usleep_range(10, 20);
> +		reset_control_deassert(apb_rst);
> +
> +		clk_disable_unprepare(dsi->pclk);
> +	}
> +
> +	pm_runtime_enable(dev);
> +
> +	dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
> +	dsi->dsi_host.dev = dev;
> +	ret = mipi_dsi_host_register(&dsi->dsi_host);
> +	if (ret) {
> +		dev_err(dev, "Failed to register MIPI host: %d\n", ret);
> +		return ERR_PTR(ret);
> +	}
> +
> +	dsi->bridge.driver_private = dsi;
> +	dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
> +#ifdef CONFIG_OF
> +	dsi->bridge.of_node = pdev->dev.of_node;
> +#endif
> +
> +	dev_set_drvdata(dev, dsi);
> +
> +	return dsi;
> +}
> +
> +static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
> +{
> +	pm_runtime_disable(dsi->dev);
> +}
> +
> +/*
> + * Probe/remove API, used from platforms based on the DRM bridge API.
> + */
> +int dw_mipi_dsi_probe(struct platform_device *pdev,
> +		      const struct dw_mipi_dsi_plat_data *plat_data)
> +{
> +	struct dw_mipi_dsi *dsi;
> +
> +	dsi = __dw_mipi_dsi_probe(pdev, plat_data);
> +	if (IS_ERR(dsi))
> +		return PTR_ERR(dsi);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_probe);
> +
> +void dw_mipi_dsi_remove(struct platform_device *pdev)
> +{
> +	struct dw_mipi_dsi *dsi = platform_get_drvdata(pdev);
> +
> +	mipi_dsi_host_unregister(&dsi->dsi_host);
> +
> +	__dw_mipi_dsi_remove(dsi);
> +}
> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_remove);
> +
> +/*
> + * Bind/unbind API, used from platforms based on the component framework.
> + */
> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder *encoder,
> +		     const struct dw_mipi_dsi_plat_data *plat_data)
> +{
> +	struct dw_mipi_dsi *dsi;
> +	int ret;
> +
> +	dsi = __dw_mipi_dsi_probe(pdev, plat_data);
> +	if (IS_ERR(dsi))
> +		return PTR_ERR(dsi);
> +
> +	ret = drm_bridge_attach(encoder, &dsi->bridge, NULL);
> +	if (ret) {
> +		dw_mipi_dsi_remove(pdev);
> +		DRM_ERROR("Failed to initialize bridge with drm\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_bind);
> +
> +void dw_mipi_dsi_unbind(struct device *dev)
> +{
> +	struct dw_mipi_dsi *dsi = dev_get_drvdata(dev);
> +
> +	__dw_mipi_dsi_remove(dsi);
> +}
> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_unbind);
> +
> +MODULE_AUTHOR("Chris Zhong <[e-mail]>");
> +MODULE_AUTHOR("Philippe Cornu <[e-mail]>");
> +MODULE_DESCRIPTION("DW MIPI DSI host controller driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:dw-mipi-dsi");
> diff --git a/include/drm/bridge/dw_mipi_dsi.h b/include/drm/bridge/dw_mipi_dsi.h
> new file mode 100644
> index 0000000..9b30fec
> --- /dev/null
> +++ b/include/drm/bridge/dw_mipi_dsi.h
> @@ -0,0 +1,39 @@
> +/*
> + * Copyright (C) STMicroelectronics SA 2017
> + *
> + * Authors: Philippe Cornu <[e-mail]>
> + *          Yannick Fertre <[e-mail]>
> + *
> + * License terms:  GNU General Public License (GPL), version 2
> + */
> +
> +#ifndef __DW_MIPI_DSI__
> +#define __DW_MIPI_DSI__
> +
> +struct dw_mipi_dsi_phy_ops {
> +	int (*init)(void *priv_data);
> +	int (*get_lane_mbps)(void *priv_data, struct drm_display_mode *mode,
> +			     unsigned long mode_flags, u32 lanes, u32 format,
> +			     unsigned int *lane_mbps);
> +};
> +
> +struct dw_mipi_dsi_plat_data {
> +	void __iomem *base;
> +	unsigned int max_data_lanes;
> +
> +	enum drm_mode_status (*mode_valid)(void *priv_data,
> +					   const struct drm_display_mode *mode);
> +
> +	const struct dw_mipi_dsi_phy_ops *phy_ops;
> +
> +	void *priv_data;
> +};
> +
> +int dw_mipi_dsi_probe(struct platform_device *pdev,
> +		      const struct dw_mipi_dsi_plat_data *plat_data);
> +void dw_mipi_dsi_remove(struct platform_device *pdev);
> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder *encoder,
> +		     const struct dw_mipi_dsi_plat_data *plat_data);
> +void dw_mipi_dsi_unbind(struct device *dev);
> +
> +#endif /* __DW_MIPI_DSI__ */
>

Andrzej Hajda June 28, 2017, 9:05 a.m. UTC | #2

On 28.06.2017 08:44, Archit Taneja wrote:
>
> On 06/19/2017 09:58 PM, Philippe CORNU wrote:
>> Add a Synopsys Designware MIPI DSI host DRM bridge driver, based on the
>> Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
>>
>> Signed-off-by: Philippe CORNU <[e-mail]>
>> ---
>>   drivers/gpu/drm/bridge/synopsys/Kconfig       |   6 +
>>   drivers/gpu/drm/bridge/synopsys/Makefile      |   2 +
>>   drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 976 ++++++++++++++++++++++++++
>>   include/drm/bridge/dw_mipi_dsi.h              |  39 +
>>   4 files changed, 1023 insertions(+)
>>   create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>   create mode 100644 include/drm/bridge/dw_mipi_dsi.h
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig b/drivers/gpu/drm/bridge/synopsys/Kconfig
>> index 40d2827..f00ee26 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
>> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
>> @@ -21,3 +21,9 @@ config DRM_DW_HDMI_I2S_AUDIO
>>   	help
>>   	  Support the I2S Audio interface which is part of the Synopsys
>>   	  Designware HDMI block.
>> +
>> +config DRM_DW_MIPI_DSI
>> +	tristate
>> +	select DRM_KMS_HELPER
>> +	select DRM_MIPI_DSI
>> +	select DRM_PANEL_BRIDGE
>> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile b/drivers/gpu/drm/bridge/synopsys/Makefile
>> index 17aa7a6..5f57d36 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
>> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
>> @@ -3,3 +3,5 @@
>>   obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>   obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>   obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
>> +
>> +obj-$(CONFIG_DRM_DW_MIPI_DSI) += dw-mipi-dsi.o
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> new file mode 100644
>> index 0000000..416ed7f
>> --- /dev/null
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> @@ -0,0 +1,976 @@
>> +/*
>> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
>> + * Copyright (C) STMicroelectronics SA 2017
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * Modified by Philippe Cornu <[e-mail]>
>> + * This generic Synopsys DesignWare MIPI DSI host driver is based on the
>> + * Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/component.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/reset.h>
>> +#include <drm/drmP.h>
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_crtc.h>
>> +#include <drm/drm_crtc_helper.h>
>> +#include <drm/drm_mipi_dsi.h>
>> +#include <drm/drm_of.h>
>> +#include <drm/bridge/dw_mipi_dsi.h>
>> +#include <video/mipi_display.h>
>> +
>> +#define DSI_VERSION			0x00
>> +#define DSI_PWR_UP			0x04
>> +#define RESET				0
>> +#define POWERUP				BIT(0)
>> +
>> +#define DSI_CLKMGR_CFG			0x08
>> +#define TO_CLK_DIVIDSION(div)		(((div) & 0xff) << 8)
>> +#define TX_ESC_CLK_DIVIDSION(div)	(((div) & 0xff) << 0)
>> +
>> +#define DSI_DPI_VCID			0x0c
>> +#define DPI_VID(vid)			(((vid) & 0x3) << 0)
>> +
>> +#define DSI_DPI_COLOR_CODING		0x10
>> +#define EN18_LOOSELY			BIT(8)
>> +#define DPI_COLOR_CODING_16BIT_1	0x0
>> +#define DPI_COLOR_CODING_16BIT_2	0x1
>> +#define DPI_COLOR_CODING_16BIT_3	0x2
>> +#define DPI_COLOR_CODING_18BIT_1	0x3
>> +#define DPI_COLOR_CODING_18BIT_2	0x4
>> +#define DPI_COLOR_CODING_24BIT		0x5
>> +
>> +#define DSI_DPI_CFG_POL			0x14
>> +#define COLORM_ACTIVE_LOW		BIT(4)
>> +#define SHUTD_ACTIVE_LOW		BIT(3)
>> +#define HSYNC_ACTIVE_LOW		BIT(2)
>> +#define VSYNC_ACTIVE_LOW		BIT(1)
>> +#define DATAEN_ACTIVE_LOW		BIT(0)
>> +
>> +#define DSI_DPI_LP_CMD_TIM		0x18
>> +#define OUTVACT_LPCMD_TIME(p)		(((p) & 0xff) << 16)
>> +#define INVACT_LPCMD_TIME(p)		((p) & 0xff)
>> +
>> +#define DSI_DBI_CFG			0x20
>> +#define DSI_DBI_CMDSIZE			0x28
>> +
>> +#define DSI_PCKHDL_CFG			0x2c
>> +#define EN_CRC_RX			BIT(4)
>> +#define EN_ECC_RX			BIT(3)
>> +#define EN_BTA				BIT(2)
>> +#define EN_EOTP_RX			BIT(1)
>> +#define EN_EOTP_TX			BIT(0)
>> +
>> +#define DSI_MODE_CFG			0x34
>> +#define ENABLE_VIDEO_MODE		0
>> +#define ENABLE_CMD_MODE			BIT(0)
>> +
>> +#define DSI_VID_MODE_CFG		0x38
>> +#define FRAME_BTA_ACK			BIT(14)
>> +#define ENABLE_LOW_POWER		(0x3f << 8)
>> +#define ENABLE_LOW_POWER_MASK		(0x3f << 8)
>> +#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES	0x0
>> +#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS	0x1
>> +#define VID_MODE_TYPE_BURST			0x2
>> +#define VID_MODE_TYPE_MASK			0x3
>> +
>> +#define DSI_VID_PKT_SIZE		0x3c
>> +#define VID_PKT_SIZE(p)			(((p) & 0x3fff) << 0)
>> +#define VID_PKT_MAX_SIZE		0x3fff
>> +
>> +#define DSI_VID_HSA_TIME		0x48
>> +#define DSI_VID_HBP_TIME		0x4c
>> +#define DSI_VID_HLINE_TIME		0x50
>> +#define DSI_VID_VSA_LINES		0x54
>> +#define DSI_VID_VBP_LINES		0x58
>> +#define DSI_VID_VFP_LINES		0x5c
>> +#define DSI_VID_VACTIVE_LINES		0x60
>> +#define DSI_CMD_MODE_CFG		0x68
>> +#define MAX_RD_PKT_SIZE_LP		BIT(24)
>> +#define DCS_LW_TX_LP			BIT(19)
>> +#define DCS_SR_0P_TX_LP			BIT(18)
>> +#define DCS_SW_1P_TX_LP			BIT(17)
>> +#define DCS_SW_0P_TX_LP			BIT(16)
>> +#define GEN_LW_TX_LP			BIT(14)
>> +#define GEN_SR_2P_TX_LP			BIT(13)
>> +#define GEN_SR_1P_TX_LP			BIT(12)
>> +#define GEN_SR_0P_TX_LP			BIT(11)
>> +#define GEN_SW_2P_TX_LP			BIT(10)
>> +#define GEN_SW_1P_TX_LP			BIT(9)
>> +#define GEN_SW_0P_TX_LP			BIT(8)
>> +#define EN_ACK_RQST			BIT(1)
>> +#define EN_TEAR_FX			BIT(0)
>> +
>> +#define CMD_MODE_ALL_LP			(MAX_RD_PKT_SIZE_LP | \
>> +					 DCS_LW_TX_LP | \
>> +					 DCS_SR_0P_TX_LP | \
>> +					 DCS_SW_1P_TX_LP | \
>> +					 DCS_SW_0P_TX_LP | \
>> +					 GEN_LW_TX_LP | \
>> +					 GEN_SR_2P_TX_LP | \
>> +					 GEN_SR_1P_TX_LP | \
>> +					 GEN_SR_0P_TX_LP | \
>> +					 GEN_SW_2P_TX_LP | \
>> +					 GEN_SW_1P_TX_LP | \
>> +					 GEN_SW_0P_TX_LP)
>> +
>> +#define DSI_GEN_HDR			0x6c
>> +#define GEN_HDATA(data)			(((data) & 0xffff) << 8)
>> +#define GEN_HDATA_MASK			(0xffff << 8)
>> +#define GEN_HTYPE(type)			(((type) & 0xff) << 0)
>> +#define GEN_HTYPE_MASK			0xff
>> +
>> +#define DSI_GEN_PLD_DATA		0x70
>> +
>> +#define DSI_CMD_PKT_STATUS		0x74
>> +#define GEN_CMD_EMPTY			BIT(0)
>> +#define GEN_CMD_FULL			BIT(1)
>> +#define GEN_PLD_W_EMPTY			BIT(2)
>> +#define GEN_PLD_W_FULL			BIT(3)
>> +#define GEN_PLD_R_EMPTY			BIT(4)
>> +#define GEN_PLD_R_FULL			BIT(5)
>> +#define GEN_RD_CMD_BUSY			BIT(6)
>> +
>> +#define DSI_TO_CNT_CFG			0x78
>> +#define HSTX_TO_CNT(p)			(((p) & 0xffff) << 16)
>> +#define LPRX_TO_CNT(p)			((p) & 0xffff)
>> +
>> +#define DSI_BTA_TO_CNT			0x8c
>> +#define DSI_LPCLK_CTRL			0x94
>> +#define AUTO_CLKLANE_CTRL		BIT(1)
>> +#define PHY_TXREQUESTCLKHS		BIT(0)
>> +
>> +#define DSI_PHY_TMR_LPCLK_CFG		0x98
>> +#define PHY_CLKHS2LP_TIME(lbcc)		(((lbcc) & 0x3ff) << 16)
>> +#define PHY_CLKLP2HS_TIME(lbcc)		((lbcc) & 0x3ff)
>> +
>> +#define DSI_PHY_TMR_CFG			0x9c
>> +#define PHY_HS2LP_TIME(lbcc)		(((lbcc) & 0xff) << 24)
>> +#define PHY_LP2HS_TIME(lbcc)		(((lbcc) & 0xff) << 16)
>> +#define MAX_RD_TIME(lbcc)		((lbcc) & 0x7fff)
>> +
>> +#define DSI_PHY_RSTZ			0xa0
>> +#define PHY_DISFORCEPLL			0
>> +#define PHY_ENFORCEPLL			BIT(3)
>> +#define PHY_DISABLECLK			0
>> +#define PHY_ENABLECLK			BIT(2)
>> +#define PHY_RSTZ			0
>> +#define PHY_UNRSTZ			BIT(1)
>> +#define PHY_SHUTDOWNZ			0
>> +#define PHY_UNSHUTDOWNZ			BIT(0)
>> +
>> +#define DSI_PHY_IF_CFG			0xa4
>> +#define N_LANES(n)			((((n) - 1) & 0x3) << 0)
>> +#define PHY_STOP_WAIT_TIME(cycle)	(((cycle) & 0xff) << 8)
>> +
>> +#define DSI_PHY_STATUS			0xb0
>> +#define LOCK				BIT(0)
>> +#define STOP_STATE_CLK_LANE		BIT(2)
>> +
>> +#define DSI_PHY_TST_CTRL0		0xb4
>> +#define PHY_TESTCLK			BIT(1)
>> +#define PHY_UNTESTCLK			0
>> +#define PHY_TESTCLR			BIT(0)
>> +#define PHY_UNTESTCLR			0
>> +
>> +#define DSI_PHY_TST_CTRL1		0xb8
>> +#define PHY_TESTEN			BIT(16)
>> +#define PHY_UNTESTEN			0
>> +#define PHY_TESTDOUT(n)			(((n) & 0xff) << 8)
>> +#define PHY_TESTDIN(n)			(((n) & 0xff) << 0)
>> +
>> +#define DSI_INT_ST0			0xbc
>> +#define DSI_INT_ST1			0xc0
>> +#define DSI_INT_MSK0			0xc4
>> +#define DSI_INT_MSK1			0xc8
>> +
>> +#define PHY_STATUS_TIMEOUT_US		10000
>> +#define CMD_PKT_STATUS_TIMEOUT_US	20000
>> +
>> +struct dw_mipi_dsi {
>> +	struct drm_bridge bridge;
>> +	struct mipi_dsi_host dsi_host;
>> +	struct drm_bridge *panel_bridge;
>> +	bool is_panel_bridge;
>> +	struct device *dev;
>> +	void __iomem *base;
>> +
>> +	struct clk *pclk;
>> +
>> +	unsigned int lane_mbps; /* per lane */
>> +	u32 channel;
>> +	u32 lanes;
>> +	u32 format;
>> +	unsigned long mode_flags;
>> +
>> +	const struct dw_mipi_dsi_plat_data *plat_data;
>> +};
>> +
>> +/*
>> + * The controller should generate 2 frames before
>> + * preparing the peripheral.
>> + */
>> +static void dw_mipi_dsi_wait_for_two_frames(struct drm_display_mode *mode)
>> +{
>> +	int refresh, two_frames;
>> +
>> +	refresh = drm_mode_vrefresh(mode);
>> +	two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
>> +	msleep(two_frames);
>> +}
>> +
>> +static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host *host)
>> +{
>> +	return container_of(host, struct dw_mipi_dsi, dsi_host);
>> +}
>> +
>> +static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge *bridge)
>> +{
>> +	return container_of(bridge, struct dw_mipi_dsi, bridge);
>> +}
>> +
>> +static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val)
>> +{
>> +	writel(val, dsi->base + reg);
>> +}
>> +
>> +static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
>> +{
>> +	return readl(dsi->base + reg);
>> +}
>> +
>> +static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
>> +				   struct mipi_dsi_device *device)
>> +{
>> +	struct dw_mipi_dsi *dsi = host_to_dsi(host);
>> +	struct drm_bridge *bridge;
>> +	struct drm_panel *panel;
>> +	int ret;
>> +
>> +	if (device->lanes > dsi->plat_data->max_data_lanes) {
>> +		dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
>> +			device->lanes);
>> +		return -EINVAL;
>> +	}
>> +
>> +	dsi->lanes = device->lanes;
>> +	dsi->channel = device->channel;
>> +	dsi->format = device->format;
>> +	dsi->mode_flags = device->mode_flags;
>> +
>> +	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
>> +					  &panel, &bridge);
>> +	if (ret)
>> +		return ret;
>> +
>> +	if (panel) {
>> +		bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DSI);
>> +		if (IS_ERR(bridge))
>> +			return PTR_ERR(bridge);
>> +		dsi->is_panel_bridge = true;
>> +	}
>> +
>> +	dsi->panel_bridge = bridge;
>> +
>> +	return drm_bridge_add(&dsi->bridge);
>> +}
>> +
>> +static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
>> +				   struct mipi_dsi_device *device)
>> +{
>> +	struct dw_mipi_dsi *dsi = host_to_dsi(host);
>> +
>> +	if (dsi->is_panel_bridge)
>> +		drm_panel_bridge_remove(dsi->panel_bridge);
>> +
>> +	drm_bridge_remove(&dsi->bridge);
>> +
>> +	return 0;
>> +}
>> +
>> +static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
>> +				   const struct mipi_dsi_msg *msg)
>> +{
>> +	bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
>> +	u32 val = 0;
>> +
>> +	if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
>> +		val |= EN_ACK_RQST;
>> +	if (lpm)
>> +		val |= CMD_MODE_ALL_LP;
>> +
>> +	dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
>> +	dsi_write(dsi, DSI_CMD_MODE_CFG, val);
>> +}
>> +
>> +static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
>> +{
>> +	int ret;
>> +	u32 val, mask;
>> +
>> +	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> +				 val, !(val & GEN_CMD_FULL), 1000,
>> +				 CMD_PKT_STATUS_TIMEOUT_US);
>> +	if (ret < 0) {
>> +		dev_err(dsi->dev, "failed to get available command FIFO\n");
>> +		return ret;
>> +	}
>> +
>> +	dsi_write(dsi, DSI_GEN_HDR, hdr_val);
>> +
>> +	mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
>> +	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> +				 val, (val & mask) == mask,
>> +				 1000, CMD_PKT_STATUS_TIMEOUT_US);
>> +	if (ret < 0) {
>> +		dev_err(dsi->dev, "failed to write command FIFO\n");
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
>> +				       const struct mipi_dsi_msg *msg)
>> +{
>> +	const u8 *tx_buf = msg->tx_buf;
>> +	u16 data = 0;
>> +	u32 val;
>> +
>> +	if (msg->tx_len > 0)
>> +		data |= tx_buf[0];
>> +	if (msg->tx_len > 1)
>> +		data |= tx_buf[1] << 8;
>> +
>> +	if (msg->tx_len > 2) {
>> +		dev_err(dsi->dev, "too long tx buf length %zu for short write\n",
>> +			msg->tx_len);
>> +		return -EINVAL;
>> +	}
>> +
>> +	val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
>> +	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
>> +}
>> +
>> +static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
>> +				      const struct mipi_dsi_msg *msg)
>> +{
>> +	const u8 *tx_buf = msg->tx_buf;
>> +	int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
>> +	u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
>> +	u32 remainder;
>> +	u32 val;
>> +
>> +	if (msg->tx_len < 3) {
>> +		dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
>> +			msg->tx_len);
>> +		return -EINVAL;
>> +	}
>> +
>> +	while (DIV_ROUND_UP(len, pld_data_bytes)) {
>> +		if (len < pld_data_bytes) {
>> +			remainder = 0;
>> +			memcpy(&remainder, tx_buf, len);
>> +			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>> +			len = 0;
>> +		} else {
>> +			memcpy(&remainder, tx_buf, pld_data_bytes);
>> +			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>> +			tx_buf += pld_data_bytes;
>> +			len -= pld_data_bytes;
>> +		}
>> +
>> +		ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> +					 val, !(val & GEN_PLD_W_FULL), 1000,
>> +					 CMD_PKT_STATUS_TIMEOUT_US);
>> +		if (ret < 0) {
>> +			dev_err(dsi->dev,
>> +				"failed to get available write payload FIFO\n");
>> +			return ret;
>> +		}
>> +	}
>> +
>> +	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
>> +}
>> +
>> +static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>> +					 const struct mipi_dsi_msg *msg)
>> +{
>> +	struct dw_mipi_dsi *dsi = host_to_dsi(host);
>> +	int ret;
>> +
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * use mipi_dsi_create_packet() instead of all following
>> +	 * functions and code (no switch cases, no
>> +	 * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
>> +	 * and use packet.header...
>> +	 */
>> +	dw_mipi_message_config(dsi, msg);
>> +
>> +	switch (msg->type) {
>> +	case MIPI_DSI_DCS_SHORT_WRITE:
>> +	case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
>> +	case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
>> +		ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
>> +		break;
>> +	case MIPI_DSI_DCS_LONG_WRITE:
>> +		ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
>> +		break;
>> +	default:
>> +		dev_err(dsi->dev, "unsupported message type 0x%02x\n",
>> +			msg->type);
>> +		ret = -EINVAL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
>> +	.attach = dw_mipi_dsi_host_attach,
>> +	.detach = dw_mipi_dsi_host_detach,
>> +	.transfer = dw_mipi_dsi_host_transfer,
>> +};
>> +
>> +static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
>> +{
>> +	u32 val;
>> +
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * enabling low power is panel-dependent, we should use the
>> +	 * panel configuration here...
>> +	 */
>> +	val = ENABLE_LOW_POWER;
>> +
>> +	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
>> +		val |= VID_MODE_TYPE_BURST;
>> +	else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
>> +		val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
>> +	else
>> +		val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
>> +
>> +	dsi_write(dsi, DSI_VID_MODE_CFG, val);
>> +}
>> +
>> +static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
>> +				 unsigned long mode_flags)
>> +{
>> +	dsi_write(dsi, DSI_PWR_UP, RESET);
>> +
>> +	if (mode_flags & MIPI_DSI_MODE_VIDEO) {
>> +		dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
>> +		dw_mipi_dsi_video_mode_config(dsi);
>> +		dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
>> +	} else {
>> +		dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>> +	}
>> +
>> +	dsi_write(dsi, DSI_PWR_UP, POWERUP);
>> +}
>> +
>> +static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
>> +{
>> +	dsi_write(dsi, DSI_PWR_UP, RESET);
>> +	dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
>> +}
>> +
>> +static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
>> +{
>> +	/*
>> +	 * The maximum permitted escape clock is 20MHz and it is derived from
>> +	 * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
>> +	 *
>> +	 *     (lane_mbps >> 3) / esc_clk_division < 20
>> +	 * which is:
>> +	 *     (lane_mbps >> 3) / 20 > esc_clk_division
>> +	 */
>> +	u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
>> +
>> +	dsi_write(dsi, DSI_PWR_UP, RESET);
>> +
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * timeout clock division should be computed with the
>> +	 * high speed transmission counter timeout and byte lane...
>> +	 */
>> +	dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
>> +		  TX_ESC_CLK_DIVIDSION(esc_clk_division));
>> +}
>> +
>> +static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
>> +				   struct drm_display_mode *mode)
>> +{
>> +	u32 val = 0, color = 0;
>> +
>> +	switch (dsi->format) {
>> +	case MIPI_DSI_FMT_RGB888:
>> +		color = DPI_COLOR_CODING_24BIT;
>> +		break;
>> +	case MIPI_DSI_FMT_RGB666:
>> +		color = DPI_COLOR_CODING_18BIT_2 | EN18_LOOSELY;
>> +		break;
>> +	case MIPI_DSI_FMT_RGB666_PACKED:
>> +		color = DPI_COLOR_CODING_18BIT_1;
>> +		break;
>> +	case MIPI_DSI_FMT_RGB565:
>> +		color = DPI_COLOR_CODING_16BIT_1;
>> +		break;
>> +	}
>> +
>> +	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
>> +		val |= VSYNC_ACTIVE_LOW;
>> +	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
>> +		val |= HSYNC_ACTIVE_LOW;
>> +
>> +	dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));
>> +	dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
>> +	dsi_write(dsi, DSI_DPI_CFG_POL, val);
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * largest packet sizes during hfp or during vsa/vpb/vfp
>> +	 * should be computed according to byte lane, lane number and only
>> +	 * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
>> +	 */
>> +	dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
>> +		  | INVACT_LPCMD_TIME(4));
>> +}
>> +
>> +static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
>> +{
>> +	dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
>> +}
>> +
>> +static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
>> +					    struct drm_display_mode *mode)
>> +{
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * only burst mode is supported here. For non-burst video modes,
>> +	 * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
>> +	 * DSI_VNPCR.NPSIZE... especially because this driver supports
>> +	 * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
>> +	 */
>> +	dsi_write(dsi, DSI_VID_PKT_SIZE, VID_PKT_SIZE(mode->hdisplay));
>> +}
>> +
>> +static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
>> +{
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * compute high speed transmission counter timeout according
>> +	 * to the timeout clock division (TO_CLK_DIVIDSION) and byte lane...
>> +	 */
>> +	dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) | LPRX_TO_CNT(1000));
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * the Bus-Turn-Around Timeout Counter should be computed
>> +	 * according to byte lane...
>> +	 */
>> +	dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
>> +	dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>> +}
>> +
>> +/* Get lane byte clock cycles. */
>> +static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
>> +					   struct drm_display_mode *mode,
>> +					   u32 hcomponent)
>> +{
>> +	u32 frac, lbcc;
>> +
>> +	lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
>> +
>> +	frac = lbcc % mode->clock;
>> +	lbcc = lbcc / mode->clock;
>> +	if (frac)
>> +		lbcc++;
>> +
>> +	return lbcc;
>> +}
>> +
>> +static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
>> +					  struct drm_display_mode *mode)
>> +{
>> +	u32 htotal, hsa, hbp, lbcc;
>> +
>> +	htotal = mode->htotal;
>> +	hsa = mode->hsync_end - mode->hsync_start;
>> +	hbp = mode->htotal - mode->hsync_end;
>> +
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * computations below may be improved...
>> +	 */
>> +	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
>> +	dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);
>> +
>> +	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
>> +	dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);
>> +
>> +	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
>> +	dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
>> +}
>> +
>> +static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi *dsi,
>> +					       struct drm_display_mode *mode)
>> +{
>> +	u32 vactive, vsa, vfp, vbp;
>> +
>> +	vactive = mode->vdisplay;
>> +	vsa = mode->vsync_end - mode->vsync_start;
>> +	vfp = mode->vsync_start - mode->vdisplay;
>> +	vbp = mode->vtotal - mode->vsync_end;
>> +
>> +	dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
>> +	dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
>> +	dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
>> +	dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
>> +}
>> +
>> +static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
>> +{
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * data & clock lane timers should be computed according to panel
>> +	 * blankings and to the automatic clock lane control mode...
>> +	 * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
>> +	 * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
>> +	 */
>> +	dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
>> +		  | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
>> +
>> +	dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
>> +		  | PHY_CLKLP2HS_TIME(0x40));
>> +}
>> +
>> +static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
>> +{
>> +	/*
>> +	 * TODO dw drv improvements
>> +	 * stop wait time should be the maximum between host dsi
>> +	 * and panel stop wait times
>> +	 */
>> +	dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
>> +		  N_LANES(dsi->lanes));
>> +}
>> +
>> +static void dw_mipi_dsi_dphy_init(struct dw_mipi_dsi *dsi)
>> +{
>> +	/* Clear PHY state */
>> +	dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
>> +		  | PHY_RSTZ | PHY_SHUTDOWNZ);
>> +	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>> +	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLR);
>> +	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>> +}
>> +
>> +static void dw_mipi_dsi_dphy_enable(struct dw_mipi_dsi *dsi)
>> +{
>> +	u32 val;
>> +	int ret;
>> +
>> +	dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
>> +		  PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
>> +
>> +	ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>> +				 val, val & LOCK, 1000, PHY_STATUS_TIMEOUT_US);
>> +	if (ret < 0)
>> +		DRM_DEBUG_DRIVER("failed to wait phy lock state\n");
>> +
>> +	ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>> +				 val, val & STOP_STATE_CLK_LANE, 1000,
>> +				 PHY_STATUS_TIMEOUT_US);
>> +	if (ret < 0)
>> +		DRM_DEBUG_DRIVER("failed to wait phy clk lane stop state\n");
>> +}
>> +
>> +static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
>> +{
>> +	dsi_read(dsi, DSI_INT_ST0);
>> +	dsi_read(dsi, DSI_INT_ST1);
>> +	dsi_write(dsi, DSI_INT_MSK0, 0);
>> +	dsi_write(dsi, DSI_INT_MSK1, 0);
>> +}
>> +
>> +static void dw_mipi_dsi_bridge_post_disable(struct drm_bridge *bridge)
>> +{
>> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +
>> +	/*
>> +	 * Switch to cmd mode before panel-bridge disable & panel unprepare.
>> +	 * Note: panel-bridge disable & panel disable has been called
>> +	 * before by the drm framework.
> I don't think that's exactly the case. I think the sequence should be as in the
> call chain below.
>
>> +	 */
>> +	dw_mipi_dsi_set_mode(dsi, 0);
>> +
>> +	/*
>> +	 * TODO Only way found to call panel-bridge disable & panel unprepare
>> +	 * before the dsi "final" disable... can we do better?
> I agree, this is a problem. More below.
>
>> +	 */
>> +	drm_bridge_post_disable(dsi->panel_bridge);
>> +
> I'm guessing our display chain is something like:
>
> KMS_encoder -> DW_DSI_bridge -> Panel_bridge -> Panel
>
> The order in which the disable ops are called:
>
> drm_bridge_disable(Panel_bridge)
>    - drm_panel_disable(Panel)
> drm_bridge_disable(DW_DSI_bridge)
> encoder_funcs->prepare(KMS_encoder)
> drm_bridge_post_disable(DW_DSI_bridge)
> drm_bridge_post_disable(Panel_bridge)
>    - drm_panel_unprepare(Panel)
>
> Assuming that only drm_panel_unprepare() requires sending DSI commands, you could have
> switched to command mode in DW_DSI_bridge's disable() op, and do the "final" DSI disable
> in DW_DSI_bridge's post_disable(), but that would still result in drm_panel_unprepare()
> being called with the DSI host dead.
>
> The existing call chain of consecutive bridges is the most symmetric one, and the one
> expected to work in most cases, but it clearly doesn't work in your use case.
>
> We have a few options:
>
> - Undo the drm-panel-bridge stuff, and have the freedom of calling drm_panel ops in
> whatever order we want.
>
> - Put a big TODO/HACK comment here, saying that this needs to be fixed in the drm_bridge
> framework and the API needs to be updated to manage our own call chains. Also,
> instead of calling "drm_bridge_post_disable(dsi->panel_bridge);" explicitly, we
> can manually call panel_bridge->post_disable() op directly. This avoids us doing
> things recursively.
>
> We would implement the TODO task in drm_bridges only when there are more people
> desperately in the need to have customizable call chains of bridge ops for long
> display chains, so I don't see it being implemented in the near future, but I don't
> think there should be any problem keeping this hack in the dw dsi driver for now.
>
> What choice do you prefer?
>
> Eric, Daniel,
>
> Fyi, this is another case where the panel-bridge stuff doesn't work so well. Not
> criticizing or anything, just pointing out :)

I have just looked at existing panel drivers, most of them (probably all
supporting DCS commands) sends commands to the panel in unprepare
callback, and it looks correct.

I am not sure what should be fixed in the framework, some alternatives I
see:
1. change order of disable callbacks, usually it should be reverse of
order of enable callbacks,
    but I guess it could break other devices with different requirements,
2. do not use call-chain, instead every bridge will be responsible to
call attached sink's callbacks, this way dsi bridge can turn off dsi
bus, after calling panel_bridge.post_disable,
it looks for me the most flexible solution, but it leaves the
responsibility to the drivers.
3. move DSI host power management to mipi_dsi bus, ie it should be
enabled on dsi device request, and disabled after dsi device does not
need power anymore.

Regards
Andrzej

>
> Archit
>
>
>> +	dw_mipi_dsi_disable(dsi);
>> +	clk_disable_unprepare(dsi->pclk);
>> +	pm_runtime_put(dsi->dev);
>> +}
>> +
>> +void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
>> +				 struct drm_display_mode *mode,
>> +				 struct drm_display_mode *adjusted_mode)
>> +{
>> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +	const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
>> +	void *priv_data = dsi->plat_data->priv_data;
>> +	int ret;
>> +
>> +	clk_prepare_enable(dsi->pclk);
>> +
>> +	ret = phy_ops->get_lane_mbps(priv_data, mode, dsi->mode_flags,
>> +				     dsi->lanes, dsi->format, &dsi->lane_mbps);
>> +	if (ret)
>> +		DRM_DEBUG_DRIVER("Phy get_lane_mbps() failed\n");
>> +
>> +	pm_runtime_get_sync(dsi->dev);
>> +	dw_mipi_dsi_init(dsi);
>> +	dw_mipi_dsi_dpi_config(dsi, mode);
>> +	dw_mipi_dsi_packet_handler_config(dsi);
>> +	dw_mipi_dsi_video_mode_config(dsi);
>> +	dw_mipi_dsi_video_packet_config(dsi, mode);
>> +	dw_mipi_dsi_command_mode_config(dsi);
>> +	dw_mipi_dsi_line_timer_config(dsi, mode);
>> +	dw_mipi_dsi_vertical_timing_config(dsi, mode);
>> +
>> +	dw_mipi_dsi_dphy_init(dsi);
>> +	dw_mipi_dsi_dphy_timing_config(dsi);
>> +	dw_mipi_dsi_dphy_interface_config(dsi);
>> +
>> +	dw_mipi_dsi_clear_err(dsi);
>> +
>> +	ret = phy_ops->init(priv_data);
>> +	if (ret)
>> +		DRM_DEBUG_DRIVER("Phy init() failed\n");
>> +
>> +	dw_mipi_dsi_dphy_enable(dsi);
>> +
>> +	dw_mipi_dsi_wait_for_two_frames(mode);
>> +
>> +	/* Switch to cmd mode for panel-bridge pre_enable & panel prepare */
>> +	dw_mipi_dsi_set_mode(dsi, 0);
>> +}
>> +
>> +static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge)
>> +{
>> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +
>> +	/* Switch to video mode for panel-bridge enable & panel enable */
>> +	dw_mipi_dsi_set_mode(dsi, MIPI_DSI_MODE_VIDEO);
>> +}
>> +
>> +static enum drm_mode_status
>> +dw_mipi_dsi_bridge_mode_valid(struct drm_bridge *bridge,
>> +			      const struct drm_display_mode *mode)
>> +{
>> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +	const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
>> +	enum drm_mode_status mode_status = MODE_OK;
>> +
>> +	if (pdata->mode_valid)
>> +		mode_status = pdata->mode_valid(pdata->priv_data, mode);
>> +
>> +	return mode_status;
>> +}
>> +
>> +static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge)
>> +{
>> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +
>> +	if (!bridge->encoder) {
>> +		DRM_ERROR("Parent encoder object not found\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	/* Set the encoder type as caller does not know it */
>> +	bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
>> +
>> +	/* Attach the panel-bridge to the dsi bridge */
>> +	return drm_bridge_attach(bridge->encoder, dsi->panel_bridge, bridge);
>> +}
>> +
>> +static struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
>> +	.mode_set     = dw_mipi_dsi_bridge_mode_set,
>> +	.enable	      = dw_mipi_dsi_bridge_enable,
>> +	.post_disable = dw_mipi_dsi_bridge_post_disable,
>> +	.mode_valid   = dw_mipi_dsi_bridge_mode_valid,
>> +	.attach	      = dw_mipi_dsi_bridge_attach,
>> +};
>> +
>> +static struct dw_mipi_dsi *
>> +__dw_mipi_dsi_probe(struct platform_device *pdev,
>> +		    const struct dw_mipi_dsi_plat_data *plat_data)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct reset_control *apb_rst;
>> +	struct dw_mipi_dsi *dsi;
>> +	struct resource *res;
>> +	int ret;
>> +
>> +	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
>> +	if (!dsi)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	dsi->dev = dev;
>> +	dsi->plat_data = plat_data;
>> +
>> +	if (!plat_data->phy_ops->init || !plat_data->phy_ops->get_lane_mbps) {
>> +		DRM_ERROR("Phy not properly configured\n");
>> +		return ERR_PTR(-ENODEV);
>> +	}
>> +
>> +	if (!plat_data->base) {
>> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +		if (!res)
>> +			return ERR_PTR(-ENODEV);
>> +
>> +		dsi->base = devm_ioremap_resource(dev, res);
>> +		if (IS_ERR(dsi->base))
>> +			return ERR_PTR(-ENODEV);
>> +
>> +	} else {
>> +		dsi->base = plat_data->base;
>> +	}
>> +
>> +	dsi->pclk = devm_clk_get(dev, "pclk");
>> +	if (IS_ERR(dsi->pclk)) {
>> +		ret = PTR_ERR(dsi->pclk);
>> +		dev_err(dev, "Unable to get pclk: %d\n", ret);
>> +		return ERR_PTR(ret);
>> +	}
>> +
>> +	/*
>> +	 * Note that the reset was not defined in the initial device tree, so
>> +	 * we have to be prepared for it not being found.
>> +	 */
>> +	apb_rst = devm_reset_control_get(dev, "apb");
>> +	if (IS_ERR(apb_rst)) {
>> +		ret = PTR_ERR(apb_rst);
>> +		if (ret == -ENOENT) {
>> +			apb_rst = NULL;
>> +		} else {
>> +			dev_err(dev, "Unable to get reset control: %d\n", ret);
>> +			return ERR_PTR(ret);
>> +		}
>> +	}
>> +
>> +	if (apb_rst) {
>> +		ret = clk_prepare_enable(dsi->pclk);
>> +		if (ret) {
>> +			dev_err(dev, "%s: Failed to enable pclk\n", __func__);
>> +			return ERR_PTR(ret);
>> +		}
>> +
>> +		reset_control_assert(apb_rst);
>> +		usleep_range(10, 20);
>> +		reset_control_deassert(apb_rst);
>> +
>> +		clk_disable_unprepare(dsi->pclk);
>> +	}
>> +
>> +	pm_runtime_enable(dev);
>> +
>> +	dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
>> +	dsi->dsi_host.dev = dev;
>> +	ret = mipi_dsi_host_register(&dsi->dsi_host);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to register MIPI host: %d\n", ret);
>> +		return ERR_PTR(ret);
>> +	}
>> +
>> +	dsi->bridge.driver_private = dsi;
>> +	dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
>> +#ifdef CONFIG_OF
>> +	dsi->bridge.of_node = pdev->dev.of_node;
>> +#endif
>> +
>> +	dev_set_drvdata(dev, dsi);
>> +
>> +	return dsi;
>> +}
>> +
>> +static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
>> +{
>> +	pm_runtime_disable(dsi->dev);
>> +}
>> +
>> +/*
>> + * Probe/remove API, used from platforms based on the DRM bridge API.
>> + */
>> +int dw_mipi_dsi_probe(struct platform_device *pdev,
>> +		      const struct dw_mipi_dsi_plat_data *plat_data)
>> +{
>> +	struct dw_mipi_dsi *dsi;
>> +
>> +	dsi = __dw_mipi_dsi_probe(pdev, plat_data);
>> +	if (IS_ERR(dsi))
>> +		return PTR_ERR(dsi);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_probe);
>> +
>> +void dw_mipi_dsi_remove(struct platform_device *pdev)
>> +{
>> +	struct dw_mipi_dsi *dsi = platform_get_drvdata(pdev);
>> +
>> +	mipi_dsi_host_unregister(&dsi->dsi_host);
>> +
>> +	__dw_mipi_dsi_remove(dsi);
>> +}
>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_remove);
>> +
>> +/*
>> + * Bind/unbind API, used from platforms based on the component framework.
>> + */
>> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder *encoder,
>> +		     const struct dw_mipi_dsi_plat_data *plat_data)
>> +{
>> +	struct dw_mipi_dsi *dsi;
>> +	int ret;
>> +
>> +	dsi = __dw_mipi_dsi_probe(pdev, plat_data);
>> +	if (IS_ERR(dsi))
>> +		return PTR_ERR(dsi);
>> +
>> +	ret = drm_bridge_attach(encoder, &dsi->bridge, NULL);
>> +	if (ret) {
>> +		dw_mipi_dsi_remove(pdev);
>> +		DRM_ERROR("Failed to initialize bridge with drm\n");
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_bind);
>> +
>> +void dw_mipi_dsi_unbind(struct device *dev)
>> +{
>> +	struct dw_mipi_dsi *dsi = dev_get_drvdata(dev);
>> +
>> +	__dw_mipi_dsi_remove(dsi);
>> +}
>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_unbind);
>> +
>> +MODULE_AUTHOR("Chris Zhong <[e-mail]>");
>> +MODULE_AUTHOR("Philippe Cornu <[e-mail]>");
>> +MODULE_DESCRIPTION("DW MIPI DSI host controller driver");
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:dw-mipi-dsi");
>> diff --git a/include/drm/bridge/dw_mipi_dsi.h b/include/drm/bridge/dw_mipi_dsi.h
>> new file mode 100644
>> index 0000000..9b30fec
>> --- /dev/null
>> +++ b/include/drm/bridge/dw_mipi_dsi.h
>> @@ -0,0 +1,39 @@
>> +/*
>> + * Copyright (C) STMicroelectronics SA 2017
>> + *
>> + * Authors: Philippe Cornu <[e-mail]>
>> + *          Yannick Fertre <[e-mail]>
>> + *
>> + * License terms:  GNU General Public License (GPL), version 2
>> + */
>> +
>> +#ifndef __DW_MIPI_DSI__
>> +#define __DW_MIPI_DSI__
>> +
>> +struct dw_mipi_dsi_phy_ops {
>> +	int (*init)(void *priv_data);
>> +	int (*get_lane_mbps)(void *priv_data, struct drm_display_mode *mode,
>> +			     unsigned long mode_flags, u32 lanes, u32 format,
>> +			     unsigned int *lane_mbps);
>> +};
>> +
>> +struct dw_mipi_dsi_plat_data {
>> +	void __iomem *base;
>> +	unsigned int max_data_lanes;
>> +
>> +	enum drm_mode_status (*mode_valid)(void *priv_data,
>> +					   const struct drm_display_mode *mode);
>> +
>> +	const struct dw_mipi_dsi_phy_ops *phy_ops;
>> +
>> +	void *priv_data;
>> +};
>> +
>> +int dw_mipi_dsi_probe(struct platform_device *pdev,
>> +		      const struct dw_mipi_dsi_plat_data *plat_data);
>> +void dw_mipi_dsi_remove(struct platform_device *pdev);
>> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder *encoder,
>> +		     const struct dw_mipi_dsi_plat_data *plat_data);
>> +void dw_mipi_dsi_unbind(struct device *dev);
>> +
>> +#endif /* __DW_MIPI_DSI__ */
>>

Philippe CORNU June 29, 2017, 2:43 p.m. UTC | #3

On 06/28/2017 08:44 AM, Archit Taneja wrote:
> 
> 
> On 06/19/2017 09:58 PM, Philippe CORNU wrote:
>> Add a Synopsys Designware MIPI DSI host DRM bridge driver, based on the
>> Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
>>
>> Signed-off-by: Philippe CORNU <[e-mail]>
>> ---
>>   drivers/gpu/drm/bridge/synopsys/Kconfig       |   6 +
>>   drivers/gpu/drm/bridge/synopsys/Makefile      |   2 +
>>   drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 976 
>> ++++++++++++++++++++++++++
>>   include/drm/bridge/dw_mipi_dsi.h              |  39 +
>>   4 files changed, 1023 insertions(+)
>>   create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>   create mode 100644 include/drm/bridge/dw_mipi_dsi.h
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig 
>> b/drivers/gpu/drm/bridge/synopsys/Kconfig
>> index 40d2827..f00ee26 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
>> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
>> @@ -21,3 +21,9 @@ config DRM_DW_HDMI_I2S_AUDIO
>>       help
>>         Support the I2S Audio interface which is part of the Synopsys
>>         Designware HDMI block.
>> +
>> +config DRM_DW_MIPI_DSI
>> +    tristate
>> +    select DRM_KMS_HELPER
>> +    select DRM_MIPI_DSI
>> +    select DRM_PANEL_BRIDGE
>> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile 
>> b/drivers/gpu/drm/bridge/synopsys/Makefile
>> index 17aa7a6..5f57d36 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
>> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
>> @@ -3,3 +3,5 @@
>>   obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>   obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>   obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
>> +
>> +obj-$(CONFIG_DRM_DW_MIPI_DSI) += dw-mipi-dsi.o
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c 
>> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> new file mode 100644
>> index 0000000..416ed7f
>> --- /dev/null
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> @@ -0,0 +1,976 @@
>> +/*
>> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
>> + * Copyright (C) STMicroelectronics SA 2017
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License as published by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * Modified by Philippe Cornu <[e-mail]>
>> + * This generic Synopsys DesignWare MIPI DSI host driver is based on the
>> + * Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/component.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/reset.h>
>> +#include <drm/drmP.h>
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_bridge.h>
>> +#include <drm/drm_crtc.h>
>> +#include <drm/drm_crtc_helper.h>
>> +#include <drm/drm_mipi_dsi.h>
>> +#include <drm/drm_of.h>
>> +#include <drm/bridge/dw_mipi_dsi.h>
>> +#include <video/mipi_display.h>
>> +
>> +#define DSI_VERSION            0x00
>> +#define DSI_PWR_UP            0x04
>> +#define RESET                0
>> +#define POWERUP                BIT(0)
>> +
>> +#define DSI_CLKMGR_CFG            0x08
>> +#define TO_CLK_DIVIDSION(div)        (((div) & 0xff) << 8)
>> +#define TX_ESC_CLK_DIVIDSION(div)    (((div) & 0xff) << 0)
>> +
>> +#define DSI_DPI_VCID            0x0c
>> +#define DPI_VID(vid)            (((vid) & 0x3) << 0)
>> +
>> +#define DSI_DPI_COLOR_CODING        0x10
>> +#define EN18_LOOSELY            BIT(8)
>> +#define DPI_COLOR_CODING_16BIT_1    0x0
>> +#define DPI_COLOR_CODING_16BIT_2    0x1
>> +#define DPI_COLOR_CODING_16BIT_3    0x2
>> +#define DPI_COLOR_CODING_18BIT_1    0x3
>> +#define DPI_COLOR_CODING_18BIT_2    0x4
>> +#define DPI_COLOR_CODING_24BIT        0x5
>> +
>> +#define DSI_DPI_CFG_POL            0x14
>> +#define COLORM_ACTIVE_LOW        BIT(4)
>> +#define SHUTD_ACTIVE_LOW        BIT(3)
>> +#define HSYNC_ACTIVE_LOW        BIT(2)
>> +#define VSYNC_ACTIVE_LOW        BIT(1)
>> +#define DATAEN_ACTIVE_LOW        BIT(0)
>> +
>> +#define DSI_DPI_LP_CMD_TIM        0x18
>> +#define OUTVACT_LPCMD_TIME(p)        (((p) & 0xff) << 16)
>> +#define INVACT_LPCMD_TIME(p)        ((p) & 0xff)
>> +
>> +#define DSI_DBI_CFG            0x20
>> +#define DSI_DBI_CMDSIZE            0x28
>> +
>> +#define DSI_PCKHDL_CFG            0x2c
>> +#define EN_CRC_RX            BIT(4)
>> +#define EN_ECC_RX            BIT(3)
>> +#define EN_BTA                BIT(2)
>> +#define EN_EOTP_RX            BIT(1)
>> +#define EN_EOTP_TX            BIT(0)
>> +
>> +#define DSI_MODE_CFG            0x34
>> +#define ENABLE_VIDEO_MODE        0
>> +#define ENABLE_CMD_MODE            BIT(0)
>> +
>> +#define DSI_VID_MODE_CFG        0x38
>> +#define FRAME_BTA_ACK            BIT(14)
>> +#define ENABLE_LOW_POWER        (0x3f << 8)
>> +#define ENABLE_LOW_POWER_MASK        (0x3f << 8)
>> +#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES    0x0
>> +#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS    0x1
>> +#define VID_MODE_TYPE_BURST            0x2
>> +#define VID_MODE_TYPE_MASK            0x3
>> +
>> +#define DSI_VID_PKT_SIZE        0x3c
>> +#define VID_PKT_SIZE(p)            (((p) & 0x3fff) << 0)
>> +#define VID_PKT_MAX_SIZE        0x3fff
>> +
>> +#define DSI_VID_HSA_TIME        0x48
>> +#define DSI_VID_HBP_TIME        0x4c
>> +#define DSI_VID_HLINE_TIME        0x50
>> +#define DSI_VID_VSA_LINES        0x54
>> +#define DSI_VID_VBP_LINES        0x58
>> +#define DSI_VID_VFP_LINES        0x5c
>> +#define DSI_VID_VACTIVE_LINES        0x60
>> +#define DSI_CMD_MODE_CFG        0x68
>> +#define MAX_RD_PKT_SIZE_LP        BIT(24)
>> +#define DCS_LW_TX_LP            BIT(19)
>> +#define DCS_SR_0P_TX_LP            BIT(18)
>> +#define DCS_SW_1P_TX_LP            BIT(17)
>> +#define DCS_SW_0P_TX_LP            BIT(16)
>> +#define GEN_LW_TX_LP            BIT(14)
>> +#define GEN_SR_2P_TX_LP            BIT(13)
>> +#define GEN_SR_1P_TX_LP            BIT(12)
>> +#define GEN_SR_0P_TX_LP            BIT(11)
>> +#define GEN_SW_2P_TX_LP            BIT(10)
>> +#define GEN_SW_1P_TX_LP            BIT(9)
>> +#define GEN_SW_0P_TX_LP            BIT(8)
>> +#define EN_ACK_RQST            BIT(1)
>> +#define EN_TEAR_FX            BIT(0)
>> +
>> +#define CMD_MODE_ALL_LP            (MAX_RD_PKT_SIZE_LP | \
>> +                     DCS_LW_TX_LP | \
>> +                     DCS_SR_0P_TX_LP | \
>> +                     DCS_SW_1P_TX_LP | \
>> +                     DCS_SW_0P_TX_LP | \
>> +                     GEN_LW_TX_LP | \
>> +                     GEN_SR_2P_TX_LP | \
>> +                     GEN_SR_1P_TX_LP | \
>> +                     GEN_SR_0P_TX_LP | \
>> +                     GEN_SW_2P_TX_LP | \
>> +                     GEN_SW_1P_TX_LP | \
>> +                     GEN_SW_0P_TX_LP)
>> +
>> +#define DSI_GEN_HDR            0x6c
>> +#define GEN_HDATA(data)            (((data) & 0xffff) << 8)
>> +#define GEN_HDATA_MASK            (0xffff << 8)
>> +#define GEN_HTYPE(type)            (((type) & 0xff) << 0)
>> +#define GEN_HTYPE_MASK            0xff
>> +
>> +#define DSI_GEN_PLD_DATA        0x70
>> +
>> +#define DSI_CMD_PKT_STATUS        0x74
>> +#define GEN_CMD_EMPTY            BIT(0)
>> +#define GEN_CMD_FULL            BIT(1)
>> +#define GEN_PLD_W_EMPTY            BIT(2)
>> +#define GEN_PLD_W_FULL            BIT(3)
>> +#define GEN_PLD_R_EMPTY            BIT(4)
>> +#define GEN_PLD_R_FULL            BIT(5)
>> +#define GEN_RD_CMD_BUSY            BIT(6)
>> +
>> +#define DSI_TO_CNT_CFG            0x78
>> +#define HSTX_TO_CNT(p)            (((p) & 0xffff) << 16)
>> +#define LPRX_TO_CNT(p)            ((p) & 0xffff)
>> +
>> +#define DSI_BTA_TO_CNT            0x8c
>> +#define DSI_LPCLK_CTRL            0x94
>> +#define AUTO_CLKLANE_CTRL        BIT(1)
>> +#define PHY_TXREQUESTCLKHS        BIT(0)
>> +
>> +#define DSI_PHY_TMR_LPCLK_CFG        0x98
>> +#define PHY_CLKHS2LP_TIME(lbcc)        (((lbcc) & 0x3ff) << 16)
>> +#define PHY_CLKLP2HS_TIME(lbcc)        ((lbcc) & 0x3ff)
>> +
>> +#define DSI_PHY_TMR_CFG            0x9c
>> +#define PHY_HS2LP_TIME(lbcc)        (((lbcc) & 0xff) << 24)
>> +#define PHY_LP2HS_TIME(lbcc)        (((lbcc) & 0xff) << 16)
>> +#define MAX_RD_TIME(lbcc)        ((lbcc) & 0x7fff)
>> +
>> +#define DSI_PHY_RSTZ            0xa0
>> +#define PHY_DISFORCEPLL            0
>> +#define PHY_ENFORCEPLL            BIT(3)
>> +#define PHY_DISABLECLK            0
>> +#define PHY_ENABLECLK            BIT(2)
>> +#define PHY_RSTZ            0
>> +#define PHY_UNRSTZ            BIT(1)
>> +#define PHY_SHUTDOWNZ            0
>> +#define PHY_UNSHUTDOWNZ            BIT(0)
>> +
>> +#define DSI_PHY_IF_CFG            0xa4
>> +#define N_LANES(n)            ((((n) - 1) & 0x3) << 0)
>> +#define PHY_STOP_WAIT_TIME(cycle)    (((cycle) & 0xff) << 8)
>> +
>> +#define DSI_PHY_STATUS            0xb0
>> +#define LOCK                BIT(0)
>> +#define STOP_STATE_CLK_LANE        BIT(2)
>> +
>> +#define DSI_PHY_TST_CTRL0        0xb4
>> +#define PHY_TESTCLK            BIT(1)
>> +#define PHY_UNTESTCLK            0
>> +#define PHY_TESTCLR            BIT(0)
>> +#define PHY_UNTESTCLR            0
>> +
>> +#define DSI_PHY_TST_CTRL1        0xb8
>> +#define PHY_TESTEN            BIT(16)
>> +#define PHY_UNTESTEN            0
>> +#define PHY_TESTDOUT(n)            (((n) & 0xff) << 8)
>> +#define PHY_TESTDIN(n)            (((n) & 0xff) << 0)
>> +
>> +#define DSI_INT_ST0            0xbc
>> +#define DSI_INT_ST1            0xc0
>> +#define DSI_INT_MSK0            0xc4
>> +#define DSI_INT_MSK1            0xc8
>> +
>> +#define PHY_STATUS_TIMEOUT_US        10000
>> +#define CMD_PKT_STATUS_TIMEOUT_US    20000
>> +
>> +struct dw_mipi_dsi {
>> +    struct drm_bridge bridge;
>> +    struct mipi_dsi_host dsi_host;
>> +    struct drm_bridge *panel_bridge;
>> +    bool is_panel_bridge;
>> +    struct device *dev;
>> +    void __iomem *base;
>> +
>> +    struct clk *pclk;
>> +
>> +    unsigned int lane_mbps; /* per lane */
>> +    u32 channel;
>> +    u32 lanes;
>> +    u32 format;
>> +    unsigned long mode_flags;
>> +
>> +    const struct dw_mipi_dsi_plat_data *plat_data;
>> +};
>> +
>> +/*
>> + * The controller should generate 2 frames before
>> + * preparing the peripheral.
>> + */
>> +static void dw_mipi_dsi_wait_for_two_frames(struct drm_display_mode 
>> *mode)
>> +{
>> +    int refresh, two_frames;
>> +
>> +    refresh = drm_mode_vrefresh(mode);
>> +    two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
>> +    msleep(two_frames);
>> +}
>> +
>> +static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host 
>> *host)
>> +{
>> +    return container_of(host, struct dw_mipi_dsi, dsi_host);
>> +}
>> +
>> +static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge 
>> *bridge)
>> +{
>> +    return container_of(bridge, struct dw_mipi_dsi, bridge);
>> +}
>> +
>> +static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val)
>> +{
>> +    writel(val, dsi->base + reg);
>> +}
>> +
>> +static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
>> +{
>> +    return readl(dsi->base + reg);
>> +}
>> +
>> +static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
>> +                   struct mipi_dsi_device *device)
>> +{
>> +    struct dw_mipi_dsi *dsi = host_to_dsi(host);
>> +    struct drm_bridge *bridge;
>> +    struct drm_panel *panel;
>> +    int ret;
>> +
>> +    if (device->lanes > dsi->plat_data->max_data_lanes) {
>> +        dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
>> +            device->lanes);
>> +        return -EINVAL;
>> +    }
>> +
>> +    dsi->lanes = device->lanes;
>> +    dsi->channel = device->channel;
>> +    dsi->format = device->format;
>> +    dsi->mode_flags = device->mode_flags;
>> +
>> +    ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
>> +                      &panel, &bridge);
>> +    if (ret)
>> +        return ret;
>> +
>> +    if (panel) {
>> +        bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DSI);
>> +        if (IS_ERR(bridge))
>> +            return PTR_ERR(bridge);
>> +        dsi->is_panel_bridge = true;
>> +    }
>> +
>> +    dsi->panel_bridge = bridge;
>> +
>> +    return drm_bridge_add(&dsi->bridge);
>> +}
>> +
>> +static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
>> +                   struct mipi_dsi_device *device)
>> +{
>> +    struct dw_mipi_dsi *dsi = host_to_dsi(host);
>> +
>> +    if (dsi->is_panel_bridge)
>> +        drm_panel_bridge_remove(dsi->panel_bridge);
>> +
>> +    drm_bridge_remove(&dsi->bridge);
>> +
>> +    return 0;
>> +}
>> +
>> +static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
>> +                   const struct mipi_dsi_msg *msg)
>> +{
>> +    bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
>> +    u32 val = 0;
>> +
>> +    if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
>> +        val |= EN_ACK_RQST;
>> +    if (lpm)
>> +        val |= CMD_MODE_ALL_LP;
>> +
>> +    dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
>> +    dsi_write(dsi, DSI_CMD_MODE_CFG, val);
>> +}
>> +
>> +static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 
>> hdr_val)
>> +{
>> +    int ret;
>> +    u32 val, mask;
>> +
>> +    ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> +                 val, !(val & GEN_CMD_FULL), 1000,
>> +                 CMD_PKT_STATUS_TIMEOUT_US);
>> +    if (ret < 0) {
>> +        dev_err(dsi->dev, "failed to get available command FIFO\n");
>> +        return ret;
>> +    }
>> +
>> +    dsi_write(dsi, DSI_GEN_HDR, hdr_val);
>> +
>> +    mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
>> +    ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> +                 val, (val & mask) == mask,
>> +                 1000, CMD_PKT_STATUS_TIMEOUT_US);
>> +    if (ret < 0) {
>> +        dev_err(dsi->dev, "failed to write command FIFO\n");
>> +        return ret;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
>> +                       const struct mipi_dsi_msg *msg)
>> +{
>> +    const u8 *tx_buf = msg->tx_buf;
>> +    u16 data = 0;
>> +    u32 val;
>> +
>> +    if (msg->tx_len > 0)
>> +        data |= tx_buf[0];
>> +    if (msg->tx_len > 1)
>> +        data |= tx_buf[1] << 8;
>> +
>> +    if (msg->tx_len > 2) {
>> +        dev_err(dsi->dev, "too long tx buf length %zu for short 
>> write\n",
>> +            msg->tx_len);
>> +        return -EINVAL;
>> +    }
>> +
>> +    val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
>> +    return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
>> +}
>> +
>> +static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
>> +                      const struct mipi_dsi_msg *msg)
>> +{
>> +    const u8 *tx_buf = msg->tx_buf;
>> +    int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
>> +    u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
>> +    u32 remainder;
>> +    u32 val;
>> +
>> +    if (msg->tx_len < 3) {
>> +        dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
>> +            msg->tx_len);
>> +        return -EINVAL;
>> +    }
>> +
>> +    while (DIV_ROUND_UP(len, pld_data_bytes)) {
>> +        if (len < pld_data_bytes) {
>> +            remainder = 0;
>> +            memcpy(&remainder, tx_buf, len);
>> +            dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>> +            len = 0;
>> +        } else {
>> +            memcpy(&remainder, tx_buf, pld_data_bytes);
>> +            dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>> +            tx_buf += pld_data_bytes;
>> +            len -= pld_data_bytes;
>> +        }
>> +
>> +        ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> +                     val, !(val & GEN_PLD_W_FULL), 1000,
>> +                     CMD_PKT_STATUS_TIMEOUT_US);
>> +        if (ret < 0) {
>> +            dev_err(dsi->dev,
>> +                "failed to get available write payload FIFO\n");
>> +            return ret;
>> +        }
>> +    }
>> +
>> +    return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
>> +}
>> +
>> +static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>> +                     const struct mipi_dsi_msg *msg)
>> +{
>> +    struct dw_mipi_dsi *dsi = host_to_dsi(host);
>> +    int ret;
>> +
>> +    /*
>> +     * TODO dw drv improvements
>> +     * use mipi_dsi_create_packet() instead of all following
>> +     * functions and code (no switch cases, no
>> +     * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
>> +     * and use packet.header...
>> +     */
>> +    dw_mipi_message_config(dsi, msg);
>> +
>> +    switch (msg->type) {
>> +    case MIPI_DSI_DCS_SHORT_WRITE:
>> +    case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
>> +    case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
>> +        ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
>> +        break;
>> +    case MIPI_DSI_DCS_LONG_WRITE:
>> +        ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
>> +        break;
>> +    default:
>> +        dev_err(dsi->dev, "unsupported message type 0x%02x\n",
>> +            msg->type);
>> +        ret = -EINVAL;
>> +    }
>> +
>> +    return ret;
>> +}
>> +
>> +static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
>> +    .attach = dw_mipi_dsi_host_attach,
>> +    .detach = dw_mipi_dsi_host_detach,
>> +    .transfer = dw_mipi_dsi_host_transfer,
>> +};
>> +
>> +static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
>> +{
>> +    u32 val;
>> +
>> +    /*
>> +     * TODO dw drv improvements
>> +     * enabling low power is panel-dependent, we should use the
>> +     * panel configuration here...
>> +     */
>> +    val = ENABLE_LOW_POWER;
>> +
>> +    if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
>> +        val |= VID_MODE_TYPE_BURST;
>> +    else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
>> +        val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
>> +    else
>> +        val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
>> +
>> +    dsi_write(dsi, DSI_VID_MODE_CFG, val);
>> +}
>> +
>> +static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
>> +                 unsigned long mode_flags)
>> +{
>> +    dsi_write(dsi, DSI_PWR_UP, RESET);
>> +
>> +    if (mode_flags & MIPI_DSI_MODE_VIDEO) {
>> +        dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
>> +        dw_mipi_dsi_video_mode_config(dsi);
>> +        dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
>> +    } else {
>> +        dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>> +    }
>> +
>> +    dsi_write(dsi, DSI_PWR_UP, POWERUP);
>> +}
>> +
>> +static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
>> +{
>> +    dsi_write(dsi, DSI_PWR_UP, RESET);
>> +    dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
>> +}
>> +
>> +static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
>> +{
>> +    /*
>> +     * The maximum permitted escape clock is 20MHz and it is derived 
>> from
>> +     * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
>> +     *
>> +     *     (lane_mbps >> 3) / esc_clk_division < 20
>> +     * which is:
>> +     *     (lane_mbps >> 3) / 20 > esc_clk_division
>> +     */
>> +    u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
>> +
>> +    dsi_write(dsi, DSI_PWR_UP, RESET);
>> +
>> +    /*
>> +     * TODO dw drv improvements
>> +     * timeout clock division should be computed with the
>> +     * high speed transmission counter timeout and byte lane...
>> +     */
>> +    dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
>> +          TX_ESC_CLK_DIVIDSION(esc_clk_division));
>> +}
>> +
>> +static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
>> +                   struct drm_display_mode *mode)
>> +{
>> +    u32 val = 0, color = 0;
>> +
>> +    switch (dsi->format) {
>> +    case MIPI_DSI_FMT_RGB888:
>> +        color = DPI_COLOR_CODING_24BIT;
>> +        break;
>> +    case MIPI_DSI_FMT_RGB666:
>> +        color = DPI_COLOR_CODING_18BIT_2 | EN18_LOOSELY;
>> +        break;
>> +    case MIPI_DSI_FMT_RGB666_PACKED:
>> +        color = DPI_COLOR_CODING_18BIT_1;
>> +        break;
>> +    case MIPI_DSI_FMT_RGB565:
>> +        color = DPI_COLOR_CODING_16BIT_1;
>> +        break;
>> +    }
>> +
>> +    if (mode->flags & DRM_MODE_FLAG_NVSYNC)
>> +        val |= VSYNC_ACTIVE_LOW;
>> +    if (mode->flags & DRM_MODE_FLAG_NHSYNC)
>> +        val |= HSYNC_ACTIVE_LOW;
>> +
>> +    dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));
>> +    dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
>> +    dsi_write(dsi, DSI_DPI_CFG_POL, val);
>> +    /*
>> +     * TODO dw drv improvements
>> +     * largest packet sizes during hfp or during vsa/vpb/vfp
>> +     * should be computed according to byte lane, lane number and only
>> +     * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
>> +     */
>> +    dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
>> +          | INVACT_LPCMD_TIME(4));
>> +}
>> +
>> +static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
>> +{
>> +    dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
>> +}
>> +
>> +static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
>> +                        struct drm_display_mode *mode)
>> +{
>> +    /*
>> +     * TODO dw drv improvements
>> +     * only burst mode is supported here. For non-burst video modes,
>> +     * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
>> +     * DSI_VNPCR.NPSIZE... especially because this driver supports
>> +     * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
>> +     */
>> +    dsi_write(dsi, DSI_VID_PKT_SIZE, VID_PKT_SIZE(mode->hdisplay));
>> +}
>> +
>> +static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
>> +{
>> +    /*
>> +     * TODO dw drv improvements
>> +     * compute high speed transmission counter timeout according
>> +     * to the timeout clock division (TO_CLK_DIVIDSION) and byte lane...
>> +     */
>> +    dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) | 
>> LPRX_TO_CNT(1000));
>> +    /*
>> +     * TODO dw drv improvements
>> +     * the Bus-Turn-Around Timeout Counter should be computed
>> +     * according to byte lane...
>> +     */
>> +    dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
>> +    dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>> +}
>> +
>> +/* Get lane byte clock cycles. */
>> +static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
>> +                       struct drm_display_mode *mode,
>> +                       u32 hcomponent)
>> +{
>> +    u32 frac, lbcc;
>> +
>> +    lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
>> +
>> +    frac = lbcc % mode->clock;
>> +    lbcc = lbcc / mode->clock;
>> +    if (frac)
>> +        lbcc++;
>> +
>> +    return lbcc;
>> +}
>> +
>> +static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
>> +                      struct drm_display_mode *mode)
>> +{
>> +    u32 htotal, hsa, hbp, lbcc;
>> +
>> +    htotal = mode->htotal;
>> +    hsa = mode->hsync_end - mode->hsync_start;
>> +    hbp = mode->htotal - mode->hsync_end;
>> +
>> +    /*
>> +     * TODO dw drv improvements
>> +     * computations below may be improved...
>> +     */
>> +    lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
>> +    dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);
>> +
>> +    lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
>> +    dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);
>> +
>> +    lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
>> +    dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
>> +}
>> +
>> +static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi *dsi,
>> +                           struct drm_display_mode *mode)
>> +{
>> +    u32 vactive, vsa, vfp, vbp;
>> +
>> +    vactive = mode->vdisplay;
>> +    vsa = mode->vsync_end - mode->vsync_start;
>> +    vfp = mode->vsync_start - mode->vdisplay;
>> +    vbp = mode->vtotal - mode->vsync_end;
>> +
>> +    dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
>> +    dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
>> +    dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
>> +    dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
>> +}
>> +
>> +static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
>> +{
>> +    /*
>> +     * TODO dw drv improvements
>> +     * data & clock lane timers should be computed according to panel
>> +     * blankings and to the automatic clock lane control mode...
>> +     * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
>> +     * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
>> +     */
>> +    dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
>> +          | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
>> +
>> +    dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
>> +          | PHY_CLKLP2HS_TIME(0x40));
>> +}
>> +
>> +static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
>> +{
>> +    /*
>> +     * TODO dw drv improvements
>> +     * stop wait time should be the maximum between host dsi
>> +     * and panel stop wait times
>> +     */
>> +    dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
>> +          N_LANES(dsi->lanes));
>> +}
>> +
>> +static void dw_mipi_dsi_dphy_init(struct dw_mipi_dsi *dsi)
>> +{
>> +    /* Clear PHY state */
>> +    dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
>> +          | PHY_RSTZ | PHY_SHUTDOWNZ);
>> +    dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>> +    dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLR);
>> +    dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>> +}
>> +
>> +static void dw_mipi_dsi_dphy_enable(struct dw_mipi_dsi *dsi)
>> +{
>> +    u32 val;
>> +    int ret;
>> +
>> +    dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
>> +          PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
>> +
>> +    ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>> +                 val, val & LOCK, 1000, PHY_STATUS_TIMEOUT_US);
>> +    if (ret < 0)
>> +        DRM_DEBUG_DRIVER("failed to wait phy lock state\n");
>> +
>> +    ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>> +                 val, val & STOP_STATE_CLK_LANE, 1000,
>> +                 PHY_STATUS_TIMEOUT_US);
>> +    if (ret < 0)
>> +        DRM_DEBUG_DRIVER("failed to wait phy clk lane stop state\n");
>> +}
>> +
>> +static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
>> +{
>> +    dsi_read(dsi, DSI_INT_ST0);
>> +    dsi_read(dsi, DSI_INT_ST1);
>> +    dsi_write(dsi, DSI_INT_MSK0, 0);
>> +    dsi_write(dsi, DSI_INT_MSK1, 0);
>> +}
>> +
>> +static void dw_mipi_dsi_bridge_post_disable(struct drm_bridge *bridge)
>> +{
>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +
>> +    /*
>> +     * Switch to cmd mode before panel-bridge disable & panel unprepare.
>> +     * Note: panel-bridge disable & panel disable has been called
>> +     * before by the drm framework.
> 
> I don't think that's exactly the case. I think the sequence should be as 
> in the
> call chain below.
> 

Hi Archit,
And many thanks for your comments :-)
the word "post_" is missing in the above comment, sorry for that. I 
should have written "Switch to cmd mode before panel-bridge post_disable 
& ..." that is much more correct I think, I will update this comment for 
v5 : )


>> +     */
>> +    dw_mipi_dsi_set_mode(dsi, 0);
>> +
>> +    /*
>> +     * TODO Only way found to call panel-bridge disable & panel 
>> unprepare
>> +     * before the dsi "final" disable... can we do better?
> 
> I agree, this is a problem. More below.

Same remark here, I forgot "post_" in the above comment.

> 
>> +     */
>> +    drm_bridge_post_disable(dsi->panel_bridge);
>> +
> 
> I'm guessing our display chain is something like:
> 
> KMS_encoder -> DW_DSI_bridge -> Panel_bridge -> Panel
> 
> The order in which the disable ops are called:
> 
> drm_bridge_disable(Panel_bridge)
>    - drm_panel_disable(Panel)
> drm_bridge_disable(DW_DSI_bridge)
> encoder_funcs->prepare(KMS_encoder)
> drm_bridge_post_disable(DW_DSI_bridge)
> drm_bridge_post_disable(Panel_bridge)
>    - drm_panel_unprepare(Panel)
> 

100%-perfect sequence, I do agree with you : )

> Assuming that only drm_panel_unprepare() requires sending DSI commands, 

Well, it really depends on DSI panels. For instance, panel drivers can 
send DCS/Generic DSI commands:
* in drm_panel_disable(): then these commands are sent during blankings, 
many lcds allow that. This is the proper place for backlight through DSI 
(dimming or off), for sleep mode DCS commands...

or/and

* in drm_panel_unprepare(): then these commands are sent during a 
"command mode" phase. This is the proper place for many things, from 
backlight off through DSI, sleep mode DCS commands... to a full power 
off (voltage regulators are switched off).

 From my pov, both drm_panel_disable() & drm_panel_unprepare() may send 
DSI commands... but it is not a real problem in fact as DSI commands can 
be sent through blankings in video mode or can be sent in "command mode"...

> you could have
> switched to command mode in DW_DSI_bridge's disable() op, and do the 
> "final" DSI disable
> in DW_DSI_bridge's post_disable(), but that would still result in 
> drm_panel_unprepare()
> being called with the DSI host dead.
> 
> The existing call chain of consecutive bridges is the most symmetric 
> one, and the one
> expected to work in most cases, but it clearly doesn't work in your use 
> case.
> 
> We have a few options:
> 
> - Undo the drm-panel-bridge stuff, and have the freedom of calling 
> drm_panel ops in
> whatever order we want.
> 
> - Put a big TODO/HACK comment here, saying that this needs to be fixed 
> in the drm_bridge
> framework and the API needs to be updated to manage our own call chains. 
> Also,
> instead of calling "drm_bridge_post_disable(dsi->panel_bridge);" 
> explicitly, we
> can manually call panel_bridge->post_disable() op directly. This avoids 
> us doing
> things recursively.
> 
> We would implement the TODO task in drm_bridges only when there are more 
> people
> desperately in the need to have customizable call chains of bridge ops 
> for long
> display chains, so I don't see it being implemented in the near future, 
> but I don't
> think there should be any problem keeping this hack in the dw dsi driver 
> for now.
> 
> What choice do you prefer?

Well, not so easy to decide what could be the best solution...

For the time being, I think I prefer keeping the panel bridge proposal 
(the v4 one), for several reasons in fact:

* It saves "many" lines of code, and supporting *both* panels & bridges 
(homogeneous approach).

* It helps reducing explicit calls like drm_panel_() or drm_bridge_() 
letting the drm framework doing its job :-)

* It is not an issue to have a TODO/HACK for the only remaining function 
call (drm_bridge_post_disable() here). I mean many others drivers calls 
directly these panel & bridge functions and this forces panel drivers to 
have in many places in their code "if (enabled) return;" or "if 
(prepared) return;" and we should work in the future to improve that 
(ie. Let's drm framework doing its job).

* It covers/offers the 3 important "hw disable" phases:
	- panel sends DCS/Generic DSI commands during its blankings in a video 
mode phase (most of the times, these commands are short, for backlight 
updates or sleep for instance...), it's correspond to panel_disable().
	- panel sends DCS/Generic DSI commands in a command mode phase (sleep, 
power off...), it's correspond to panel_unprepare().
	- the dsi IP is stopped after the 2 previous phases.

So, for all these reasons, I prefer the "Put a big TODO/HACK" option :)

Thank you,
Philippe

> 
> Eric, Daniel,
> 
> Fyi, this is another case where the panel-bridge stuff doesn't work so 
> well. Not
> criticizing or anything, just pointing out :)
> 
> Archit
> 
> 
>> +    dw_mipi_dsi_disable(dsi);
>> +    clk_disable_unprepare(dsi->pclk);
>> +    pm_runtime_put(dsi->dev);
>> +}
>> +
>> +void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
>> +                 struct drm_display_mode *mode,
>> +                 struct drm_display_mode *adjusted_mode)
>> +{
>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +    const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
>> +    void *priv_data = dsi->plat_data->priv_data;
>> +    int ret;
>> +
>> +    clk_prepare_enable(dsi->pclk);
>> +
>> +    ret = phy_ops->get_lane_mbps(priv_data, mode, dsi->mode_flags,
>> +                     dsi->lanes, dsi->format, &dsi->lane_mbps);
>> +    if (ret)
>> +        DRM_DEBUG_DRIVER("Phy get_lane_mbps() failed\n");
>> +
>> +    pm_runtime_get_sync(dsi->dev);
>> +    dw_mipi_dsi_init(dsi);
>> +    dw_mipi_dsi_dpi_config(dsi, mode);
>> +    dw_mipi_dsi_packet_handler_config(dsi);
>> +    dw_mipi_dsi_video_mode_config(dsi);
>> +    dw_mipi_dsi_video_packet_config(dsi, mode);
>> +    dw_mipi_dsi_command_mode_config(dsi);
>> +    dw_mipi_dsi_line_timer_config(dsi, mode);
>> +    dw_mipi_dsi_vertical_timing_config(dsi, mode);
>> +
>> +    dw_mipi_dsi_dphy_init(dsi);
>> +    dw_mipi_dsi_dphy_timing_config(dsi);
>> +    dw_mipi_dsi_dphy_interface_config(dsi);
>> +
>> +    dw_mipi_dsi_clear_err(dsi);
>> +
>> +    ret = phy_ops->init(priv_data);
>> +    if (ret)
>> +        DRM_DEBUG_DRIVER("Phy init() failed\n");
>> +
>> +    dw_mipi_dsi_dphy_enable(dsi);
>> +
>> +    dw_mipi_dsi_wait_for_two_frames(mode);
>> +
>> +    /* Switch to cmd mode for panel-bridge pre_enable & panel prepare */
>> +    dw_mipi_dsi_set_mode(dsi, 0);
>> +}
>> +
>> +static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge)
>> +{
>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +
>> +    /* Switch to video mode for panel-bridge enable & panel enable */
>> +    dw_mipi_dsi_set_mode(dsi, MIPI_DSI_MODE_VIDEO);
>> +}
>> +
>> +static enum drm_mode_status
>> +dw_mipi_dsi_bridge_mode_valid(struct drm_bridge *bridge,
>> +                  const struct drm_display_mode *mode)
>> +{
>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +    const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
>> +    enum drm_mode_status mode_status = MODE_OK;
>> +
>> +    if (pdata->mode_valid)
>> +        mode_status = pdata->mode_valid(pdata->priv_data, mode);
>> +
>> +    return mode_status;
>> +}
>> +
>> +static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge)
>> +{
>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>> +
>> +    if (!bridge->encoder) {
>> +        DRM_ERROR("Parent encoder object not found\n");
>> +        return -ENODEV;
>> +    }
>> +
>> +    /* Set the encoder type as caller does not know it */
>> +    bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
>> +
>> +    /* Attach the panel-bridge to the dsi bridge */
>> +    return drm_bridge_attach(bridge->encoder, dsi->panel_bridge, 
>> bridge);
>> +}
>> +
>> +static struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
>> +    .mode_set     = dw_mipi_dsi_bridge_mode_set,
>> +    .enable          = dw_mipi_dsi_bridge_enable,
>> +    .post_disable = dw_mipi_dsi_bridge_post_disable,
>> +    .mode_valid   = dw_mipi_dsi_bridge_mode_valid,
>> +    .attach          = dw_mipi_dsi_bridge_attach,
>> +};
>> +
>> +static struct dw_mipi_dsi *
>> +__dw_mipi_dsi_probe(struct platform_device *pdev,
>> +            const struct dw_mipi_dsi_plat_data *plat_data)
>> +{
>> +    struct device *dev = &pdev->dev;
>> +    struct reset_control *apb_rst;
>> +    struct dw_mipi_dsi *dsi;
>> +    struct resource *res;
>> +    int ret;
>> +
>> +    dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
>> +    if (!dsi)
>> +        return ERR_PTR(-ENOMEM);
>> +
>> +    dsi->dev = dev;
>> +    dsi->plat_data = plat_data;
>> +
>> +    if (!plat_data->phy_ops->init || 
>> !plat_data->phy_ops->get_lane_mbps) {
>> +        DRM_ERROR("Phy not properly configured\n");
>> +        return ERR_PTR(-ENODEV);
>> +    }
>> +
>> +    if (!plat_data->base) {
>> +        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +        if (!res)
>> +            return ERR_PTR(-ENODEV);
>> +
>> +        dsi->base = devm_ioremap_resource(dev, res);
>> +        if (IS_ERR(dsi->base))
>> +            return ERR_PTR(-ENODEV);
>> +
>> +    } else {
>> +        dsi->base = plat_data->base;
>> +    }
>> +
>> +    dsi->pclk = devm_clk_get(dev, "pclk");
>> +    if (IS_ERR(dsi->pclk)) {
>> +        ret = PTR_ERR(dsi->pclk);
>> +        dev_err(dev, "Unable to get pclk: %d\n", ret);
>> +        return ERR_PTR(ret);
>> +    }
>> +
>> +    /*
>> +     * Note that the reset was not defined in the initial device 
>> tree, so
>> +     * we have to be prepared for it not being found.
>> +     */
>> +    apb_rst = devm_reset_control_get(dev, "apb");
>> +    if (IS_ERR(apb_rst)) {
>> +        ret = PTR_ERR(apb_rst);
>> +        if (ret == -ENOENT) {
>> +            apb_rst = NULL;
>> +        } else {
>> +            dev_err(dev, "Unable to get reset control: %d\n", ret);
>> +            return ERR_PTR(ret);
>> +        }
>> +    }
>> +
>> +    if (apb_rst) {
>> +        ret = clk_prepare_enable(dsi->pclk);
>> +        if (ret) {
>> +            dev_err(dev, "%s: Failed to enable pclk\n", __func__);
>> +            return ERR_PTR(ret);
>> +        }
>> +
>> +        reset_control_assert(apb_rst);
>> +        usleep_range(10, 20);
>> +        reset_control_deassert(apb_rst);
>> +
>> +        clk_disable_unprepare(dsi->pclk);
>> +    }
>> +
>> +    pm_runtime_enable(dev);
>> +
>> +    dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
>> +    dsi->dsi_host.dev = dev;
>> +    ret = mipi_dsi_host_register(&dsi->dsi_host);
>> +    if (ret) {
>> +        dev_err(dev, "Failed to register MIPI host: %d\n", ret);
>> +        return ERR_PTR(ret);
>> +    }
>> +
>> +    dsi->bridge.driver_private = dsi;
>> +    dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
>> +#ifdef CONFIG_OF
>> +    dsi->bridge.of_node = pdev->dev.of_node;
>> +#endif
>> +
>> +    dev_set_drvdata(dev, dsi);
>> +
>> +    return dsi;
>> +}
>> +
>> +static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
>> +{
>> +    pm_runtime_disable(dsi->dev);
>> +}
>> +
>> +/*
>> + * Probe/remove API, used from platforms based on the DRM bridge API.
>> + */
>> +int dw_mipi_dsi_probe(struct platform_device *pdev,
>> +              const struct dw_mipi_dsi_plat_data *plat_data)
>> +{
>> +    struct dw_mipi_dsi *dsi;
>> +
>> +    dsi = __dw_mipi_dsi_probe(pdev, plat_data);
>> +    if (IS_ERR(dsi))
>> +        return PTR_ERR(dsi);
>> +
>> +    return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_probe);
>> +
>> +void dw_mipi_dsi_remove(struct platform_device *pdev)
>> +{
>> +    struct dw_mipi_dsi *dsi = platform_get_drvdata(pdev);
>> +
>> +    mipi_dsi_host_unregister(&dsi->dsi_host);
>> +
>> +    __dw_mipi_dsi_remove(dsi);
>> +}
>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_remove);
>> +
>> +/*
>> + * Bind/unbind API, used from platforms based on the component 
>> framework.
>> + */
>> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder 
>> *encoder,
>> +             const struct dw_mipi_dsi_plat_data *plat_data)
>> +{
>> +    struct dw_mipi_dsi *dsi;
>> +    int ret;
>> +
>> +    dsi = __dw_mipi_dsi_probe(pdev, plat_data);
>> +    if (IS_ERR(dsi))
>> +        return PTR_ERR(dsi);
>> +
>> +    ret = drm_bridge_attach(encoder, &dsi->bridge, NULL);
>> +    if (ret) {
>> +        dw_mipi_dsi_remove(pdev);
>> +        DRM_ERROR("Failed to initialize bridge with drm\n");
>> +        return ret;
>> +    }
>> +
>> +    return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_bind);
>> +
>> +void dw_mipi_dsi_unbind(struct device *dev)
>> +{
>> +    struct dw_mipi_dsi *dsi = dev_get_drvdata(dev);
>> +
>> +    __dw_mipi_dsi_remove(dsi);
>> +}
>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_unbind);
>> +
>> +MODULE_AUTHOR("Chris Zhong <[e-mail]>");
>> +MODULE_AUTHOR("Philippe Cornu <[e-mail]>");
>> +MODULE_DESCRIPTION("DW MIPI DSI host controller driver");
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:dw-mipi-dsi");
>> diff --git a/include/drm/bridge/dw_mipi_dsi.h 
>> b/include/drm/bridge/dw_mipi_dsi.h
>> new file mode 100644
>> index 0000000..9b30fec
>> --- /dev/null
>> +++ b/include/drm/bridge/dw_mipi_dsi.h
>> @@ -0,0 +1,39 @@
>> +/*
>> + * Copyright (C) STMicroelectronics SA 2017
>> + *
>> + * Authors: Philippe Cornu <[e-mail]>
>> + *          Yannick Fertre <[e-mail]>
>> + *
>> + * License terms:  GNU General Public License (GPL), version 2
>> + */
>> +
>> +#ifndef __DW_MIPI_DSI__
>> +#define __DW_MIPI_DSI__
>> +
>> +struct dw_mipi_dsi_phy_ops {
>> +    int (*init)(void *priv_data);
>> +    int (*get_lane_mbps)(void *priv_data, struct drm_display_mode *mode,
>> +                 unsigned long mode_flags, u32 lanes, u32 format,
>> +                 unsigned int *lane_mbps);
>> +};
>> +
>> +struct dw_mipi_dsi_plat_data {
>> +    void __iomem *base;
>> +    unsigned int max_data_lanes;
>> +
>> +    enum drm_mode_status (*mode_valid)(void *priv_data,
>> +                       const struct drm_display_mode *mode);
>> +
>> +    const struct dw_mipi_dsi_phy_ops *phy_ops;
>> +
>> +    void *priv_data;
>> +};
>> +
>> +int dw_mipi_dsi_probe(struct platform_device *pdev,
>> +              const struct dw_mipi_dsi_plat_data *plat_data);
>> +void dw_mipi_dsi_remove(struct platform_device *pdev);
>> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder 
>> *encoder,
>> +             const struct dw_mipi_dsi_plat_data *plat_data);
>> +void dw_mipi_dsi_unbind(struct device *dev);
>> +
>> +#endif /* __DW_MIPI_DSI__ */
>>
>

Archit Taneja July 3, 2017, 6:21 a.m. UTC | #4

On 06/28/2017 02:35 PM, Andrzej Hajda wrote:
> On 28.06.2017 08:44, Archit Taneja wrote:
>>
>> On 06/19/2017 09:58 PM, Philippe CORNU wrote:
>>> Add a Synopsys Designware MIPI DSI host DRM bridge driver, based on the
>>> Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
>>>
>>> Signed-off-by: Philippe CORNU <[e-mail]>
>>> ---
>>>    drivers/gpu/drm/bridge/synopsys/Kconfig       |   6 +
>>>    drivers/gpu/drm/bridge/synopsys/Makefile      |   2 +
>>>    drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 976 ++++++++++++++++++++++++++
>>>    include/drm/bridge/dw_mipi_dsi.h              |  39 +
>>>    4 files changed, 1023 insertions(+)
>>>    create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>>    create mode 100644 include/drm/bridge/dw_mipi_dsi.h
>>>
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> index 40d2827..f00ee26 100644
>>> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> @@ -21,3 +21,9 @@ config DRM_DW_HDMI_I2S_AUDIO
>>>    	help
>>>    	  Support the I2S Audio interface which is part of the Synopsys
>>>    	  Designware HDMI block.
>>> +
>>> +config DRM_DW_MIPI_DSI
>>> +	tristate
>>> +	select DRM_KMS_HELPER
>>> +	select DRM_MIPI_DSI
>>> +	select DRM_PANEL_BRIDGE
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile b/drivers/gpu/drm/bridge/synopsys/Makefile
>>> index 17aa7a6..5f57d36 100644
>>> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
>>> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
>>> @@ -3,3 +3,5 @@
>>>    obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>>    obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>>    obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
>>> +
>>> +obj-$(CONFIG_DRM_DW_MIPI_DSI) += dw-mipi-dsi.o
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>> new file mode 100644
>>> index 0000000..416ed7f
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>> @@ -0,0 +1,976 @@
>>> +/*
>>> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
>>> + * Copyright (C) STMicroelectronics SA 2017
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License as published by
>>> + * the Free Software Foundation; either version 2 of the License, or
>>> + * (at your option) any later version.
>>> + *
>>> + * Modified by Philippe Cornu <[e-mail]>
>>> + * This generic Synopsys DesignWare MIPI DSI host driver is based on the
>>> + * Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
>>> + */
>>> +
>>> +#include <linux/clk.h>
>>> +#include <linux/component.h>
>>> +#include <linux/iopoll.h>
>>> +#include <linux/module.h>
>>> +#include <linux/of_device.h>
>>> +#include <linux/pm_runtime.h>
>>> +#include <linux/reset.h>
>>> +#include <drm/drmP.h>
>>> +#include <drm/drm_atomic_helper.h>
>>> +#include <drm/drm_bridge.h>
>>> +#include <drm/drm_crtc.h>
>>> +#include <drm/drm_crtc_helper.h>
>>> +#include <drm/drm_mipi_dsi.h>
>>> +#include <drm/drm_of.h>
>>> +#include <drm/bridge/dw_mipi_dsi.h>
>>> +#include <video/mipi_display.h>
>>> +
>>> +#define DSI_VERSION			0x00
>>> +#define DSI_PWR_UP			0x04
>>> +#define RESET				0
>>> +#define POWERUP				BIT(0)
>>> +
>>> +#define DSI_CLKMGR_CFG			0x08
>>> +#define TO_CLK_DIVIDSION(div)		(((div) & 0xff) << 8)
>>> +#define TX_ESC_CLK_DIVIDSION(div)	(((div) & 0xff) << 0)
>>> +
>>> +#define DSI_DPI_VCID			0x0c
>>> +#define DPI_VID(vid)			(((vid) & 0x3) << 0)
>>> +
>>> +#define DSI_DPI_COLOR_CODING		0x10
>>> +#define EN18_LOOSELY			BIT(8)
>>> +#define DPI_COLOR_CODING_16BIT_1	0x0
>>> +#define DPI_COLOR_CODING_16BIT_2	0x1
>>> +#define DPI_COLOR_CODING_16BIT_3	0x2
>>> +#define DPI_COLOR_CODING_18BIT_1	0x3
>>> +#define DPI_COLOR_CODING_18BIT_2	0x4
>>> +#define DPI_COLOR_CODING_24BIT		0x5
>>> +
>>> +#define DSI_DPI_CFG_POL			0x14
>>> +#define COLORM_ACTIVE_LOW		BIT(4)
>>> +#define SHUTD_ACTIVE_LOW		BIT(3)
>>> +#define HSYNC_ACTIVE_LOW		BIT(2)
>>> +#define VSYNC_ACTIVE_LOW		BIT(1)
>>> +#define DATAEN_ACTIVE_LOW		BIT(0)
>>> +
>>> +#define DSI_DPI_LP_CMD_TIM		0x18
>>> +#define OUTVACT_LPCMD_TIME(p)		(((p) & 0xff) << 16)
>>> +#define INVACT_LPCMD_TIME(p)		((p) & 0xff)
>>> +
>>> +#define DSI_DBI_CFG			0x20
>>> +#define DSI_DBI_CMDSIZE			0x28
>>> +
>>> +#define DSI_PCKHDL_CFG			0x2c
>>> +#define EN_CRC_RX			BIT(4)
>>> +#define EN_ECC_RX			BIT(3)
>>> +#define EN_BTA				BIT(2)
>>> +#define EN_EOTP_RX			BIT(1)
>>> +#define EN_EOTP_TX			BIT(0)
>>> +
>>> +#define DSI_MODE_CFG			0x34
>>> +#define ENABLE_VIDEO_MODE		0
>>> +#define ENABLE_CMD_MODE			BIT(0)
>>> +
>>> +#define DSI_VID_MODE_CFG		0x38
>>> +#define FRAME_BTA_ACK			BIT(14)
>>> +#define ENABLE_LOW_POWER		(0x3f << 8)
>>> +#define ENABLE_LOW_POWER_MASK		(0x3f << 8)
>>> +#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES	0x0
>>> +#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS	0x1
>>> +#define VID_MODE_TYPE_BURST			0x2
>>> +#define VID_MODE_TYPE_MASK			0x3
>>> +
>>> +#define DSI_VID_PKT_SIZE		0x3c
>>> +#define VID_PKT_SIZE(p)			(((p) & 0x3fff) << 0)
>>> +#define VID_PKT_MAX_SIZE		0x3fff
>>> +
>>> +#define DSI_VID_HSA_TIME		0x48
>>> +#define DSI_VID_HBP_TIME		0x4c
>>> +#define DSI_VID_HLINE_TIME		0x50
>>> +#define DSI_VID_VSA_LINES		0x54
>>> +#define DSI_VID_VBP_LINES		0x58
>>> +#define DSI_VID_VFP_LINES		0x5c
>>> +#define DSI_VID_VACTIVE_LINES		0x60
>>> +#define DSI_CMD_MODE_CFG		0x68
>>> +#define MAX_RD_PKT_SIZE_LP		BIT(24)
>>> +#define DCS_LW_TX_LP			BIT(19)
>>> +#define DCS_SR_0P_TX_LP			BIT(18)
>>> +#define DCS_SW_1P_TX_LP			BIT(17)
>>> +#define DCS_SW_0P_TX_LP			BIT(16)
>>> +#define GEN_LW_TX_LP			BIT(14)
>>> +#define GEN_SR_2P_TX_LP			BIT(13)
>>> +#define GEN_SR_1P_TX_LP			BIT(12)
>>> +#define GEN_SR_0P_TX_LP			BIT(11)
>>> +#define GEN_SW_2P_TX_LP			BIT(10)
>>> +#define GEN_SW_1P_TX_LP			BIT(9)
>>> +#define GEN_SW_0P_TX_LP			BIT(8)
>>> +#define EN_ACK_RQST			BIT(1)
>>> +#define EN_TEAR_FX			BIT(0)
>>> +
>>> +#define CMD_MODE_ALL_LP			(MAX_RD_PKT_SIZE_LP | \
>>> +					 DCS_LW_TX_LP | \
>>> +					 DCS_SR_0P_TX_LP | \
>>> +					 DCS_SW_1P_TX_LP | \
>>> +					 DCS_SW_0P_TX_LP | \
>>> +					 GEN_LW_TX_LP | \
>>> +					 GEN_SR_2P_TX_LP | \
>>> +					 GEN_SR_1P_TX_LP | \
>>> +					 GEN_SR_0P_TX_LP | \
>>> +					 GEN_SW_2P_TX_LP | \
>>> +					 GEN_SW_1P_TX_LP | \
>>> +					 GEN_SW_0P_TX_LP)
>>> +
>>> +#define DSI_GEN_HDR			0x6c
>>> +#define GEN_HDATA(data)			(((data) & 0xffff) << 8)
>>> +#define GEN_HDATA_MASK			(0xffff << 8)
>>> +#define GEN_HTYPE(type)			(((type) & 0xff) << 0)
>>> +#define GEN_HTYPE_MASK			0xff
>>> +
>>> +#define DSI_GEN_PLD_DATA		0x70
>>> +
>>> +#define DSI_CMD_PKT_STATUS		0x74
>>> +#define GEN_CMD_EMPTY			BIT(0)
>>> +#define GEN_CMD_FULL			BIT(1)
>>> +#define GEN_PLD_W_EMPTY			BIT(2)
>>> +#define GEN_PLD_W_FULL			BIT(3)
>>> +#define GEN_PLD_R_EMPTY			BIT(4)
>>> +#define GEN_PLD_R_FULL			BIT(5)
>>> +#define GEN_RD_CMD_BUSY			BIT(6)
>>> +
>>> +#define DSI_TO_CNT_CFG			0x78
>>> +#define HSTX_TO_CNT(p)			(((p) & 0xffff) << 16)
>>> +#define LPRX_TO_CNT(p)			((p) & 0xffff)
>>> +
>>> +#define DSI_BTA_TO_CNT			0x8c
>>> +#define DSI_LPCLK_CTRL			0x94
>>> +#define AUTO_CLKLANE_CTRL		BIT(1)
>>> +#define PHY_TXREQUESTCLKHS		BIT(0)
>>> +
>>> +#define DSI_PHY_TMR_LPCLK_CFG		0x98
>>> +#define PHY_CLKHS2LP_TIME(lbcc)		(((lbcc) & 0x3ff) << 16)
>>> +#define PHY_CLKLP2HS_TIME(lbcc)		((lbcc) & 0x3ff)
>>> +
>>> +#define DSI_PHY_TMR_CFG			0x9c
>>> +#define PHY_HS2LP_TIME(lbcc)		(((lbcc) & 0xff) << 24)
>>> +#define PHY_LP2HS_TIME(lbcc)		(((lbcc) & 0xff) << 16)
>>> +#define MAX_RD_TIME(lbcc)		((lbcc) & 0x7fff)
>>> +
>>> +#define DSI_PHY_RSTZ			0xa0
>>> +#define PHY_DISFORCEPLL			0
>>> +#define PHY_ENFORCEPLL			BIT(3)
>>> +#define PHY_DISABLECLK			0
>>> +#define PHY_ENABLECLK			BIT(2)
>>> +#define PHY_RSTZ			0
>>> +#define PHY_UNRSTZ			BIT(1)
>>> +#define PHY_SHUTDOWNZ			0
>>> +#define PHY_UNSHUTDOWNZ			BIT(0)
>>> +
>>> +#define DSI_PHY_IF_CFG			0xa4
>>> +#define N_LANES(n)			((((n) - 1) & 0x3) << 0)
>>> +#define PHY_STOP_WAIT_TIME(cycle)	(((cycle) & 0xff) << 8)
>>> +
>>> +#define DSI_PHY_STATUS			0xb0
>>> +#define LOCK				BIT(0)
>>> +#define STOP_STATE_CLK_LANE		BIT(2)
>>> +
>>> +#define DSI_PHY_TST_CTRL0		0xb4
>>> +#define PHY_TESTCLK			BIT(1)
>>> +#define PHY_UNTESTCLK			0
>>> +#define PHY_TESTCLR			BIT(0)
>>> +#define PHY_UNTESTCLR			0
>>> +
>>> +#define DSI_PHY_TST_CTRL1		0xb8
>>> +#define PHY_TESTEN			BIT(16)
>>> +#define PHY_UNTESTEN			0
>>> +#define PHY_TESTDOUT(n)			(((n) & 0xff) << 8)
>>> +#define PHY_TESTDIN(n)			(((n) & 0xff) << 0)
>>> +
>>> +#define DSI_INT_ST0			0xbc
>>> +#define DSI_INT_ST1			0xc0
>>> +#define DSI_INT_MSK0			0xc4
>>> +#define DSI_INT_MSK1			0xc8
>>> +
>>> +#define PHY_STATUS_TIMEOUT_US		10000
>>> +#define CMD_PKT_STATUS_TIMEOUT_US	20000
>>> +
>>> +struct dw_mipi_dsi {
>>> +	struct drm_bridge bridge;
>>> +	struct mipi_dsi_host dsi_host;
>>> +	struct drm_bridge *panel_bridge;
>>> +	bool is_panel_bridge;
>>> +	struct device *dev;
>>> +	void __iomem *base;
>>> +
>>> +	struct clk *pclk;
>>> +
>>> +	unsigned int lane_mbps; /* per lane */
>>> +	u32 channel;
>>> +	u32 lanes;
>>> +	u32 format;
>>> +	unsigned long mode_flags;
>>> +
>>> +	const struct dw_mipi_dsi_plat_data *plat_data;
>>> +};
>>> +
>>> +/*
>>> + * The controller should generate 2 frames before
>>> + * preparing the peripheral.
>>> + */
>>> +static void dw_mipi_dsi_wait_for_two_frames(struct drm_display_mode *mode)
>>> +{
>>> +	int refresh, two_frames;
>>> +
>>> +	refresh = drm_mode_vrefresh(mode);
>>> +	two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
>>> +	msleep(two_frames);
>>> +}
>>> +
>>> +static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host *host)
>>> +{
>>> +	return container_of(host, struct dw_mipi_dsi, dsi_host);
>>> +}
>>> +
>>> +static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge *bridge)
>>> +{
>>> +	return container_of(bridge, struct dw_mipi_dsi, bridge);
>>> +}
>>> +
>>> +static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val)
>>> +{
>>> +	writel(val, dsi->base + reg);
>>> +}
>>> +
>>> +static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
>>> +{
>>> +	return readl(dsi->base + reg);
>>> +}
>>> +
>>> +static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
>>> +				   struct mipi_dsi_device *device)
>>> +{
>>> +	struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>> +	struct drm_bridge *bridge;
>>> +	struct drm_panel *panel;
>>> +	int ret;
>>> +
>>> +	if (device->lanes > dsi->plat_data->max_data_lanes) {
>>> +		dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
>>> +			device->lanes);
>>> +		return -EINVAL;
>>> +	}
>>> +
>>> +	dsi->lanes = device->lanes;
>>> +	dsi->channel = device->channel;
>>> +	dsi->format = device->format;
>>> +	dsi->mode_flags = device->mode_flags;
>>> +
>>> +	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
>>> +					  &panel, &bridge);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	if (panel) {
>>> +		bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DSI);
>>> +		if (IS_ERR(bridge))
>>> +			return PTR_ERR(bridge);
>>> +		dsi->is_panel_bridge = true;
>>> +	}
>>> +
>>> +	dsi->panel_bridge = bridge;
>>> +
>>> +	return drm_bridge_add(&dsi->bridge);
>>> +}
>>> +
>>> +static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
>>> +				   struct mipi_dsi_device *device)
>>> +{
>>> +	struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>> +
>>> +	if (dsi->is_panel_bridge)
>>> +		drm_panel_bridge_remove(dsi->panel_bridge);
>>> +
>>> +	drm_bridge_remove(&dsi->bridge);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
>>> +				   const struct mipi_dsi_msg *msg)
>>> +{
>>> +	bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
>>> +	u32 val = 0;
>>> +
>>> +	if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
>>> +		val |= EN_ACK_RQST;
>>> +	if (lpm)
>>> +		val |= CMD_MODE_ALL_LP;
>>> +
>>> +	dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
>>> +	dsi_write(dsi, DSI_CMD_MODE_CFG, val);
>>> +}
>>> +
>>> +static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
>>> +{
>>> +	int ret;
>>> +	u32 val, mask;
>>> +
>>> +	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>>> +				 val, !(val & GEN_CMD_FULL), 1000,
>>> +				 CMD_PKT_STATUS_TIMEOUT_US);
>>> +	if (ret < 0) {
>>> +		dev_err(dsi->dev, "failed to get available command FIFO\n");
>>> +		return ret;
>>> +	}
>>> +
>>> +	dsi_write(dsi, DSI_GEN_HDR, hdr_val);
>>> +
>>> +	mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
>>> +	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>>> +				 val, (val & mask) == mask,
>>> +				 1000, CMD_PKT_STATUS_TIMEOUT_US);
>>> +	if (ret < 0) {
>>> +		dev_err(dsi->dev, "failed to write command FIFO\n");
>>> +		return ret;
>>> +	}
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
>>> +				       const struct mipi_dsi_msg *msg)
>>> +{
>>> +	const u8 *tx_buf = msg->tx_buf;
>>> +	u16 data = 0;
>>> +	u32 val;
>>> +
>>> +	if (msg->tx_len > 0)
>>> +		data |= tx_buf[0];
>>> +	if (msg->tx_len > 1)
>>> +		data |= tx_buf[1] << 8;
>>> +
>>> +	if (msg->tx_len > 2) {
>>> +		dev_err(dsi->dev, "too long tx buf length %zu for short write\n",
>>> +			msg->tx_len);
>>> +		return -EINVAL;
>>> +	}
>>> +
>>> +	val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
>>> +	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
>>> +}
>>> +
>>> +static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
>>> +				      const struct mipi_dsi_msg *msg)
>>> +{
>>> +	const u8 *tx_buf = msg->tx_buf;
>>> +	int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
>>> +	u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
>>> +	u32 remainder;
>>> +	u32 val;
>>> +
>>> +	if (msg->tx_len < 3) {
>>> +		dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
>>> +			msg->tx_len);
>>> +		return -EINVAL;
>>> +	}
>>> +
>>> +	while (DIV_ROUND_UP(len, pld_data_bytes)) {
>>> +		if (len < pld_data_bytes) {
>>> +			remainder = 0;
>>> +			memcpy(&remainder, tx_buf, len);
>>> +			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>>> +			len = 0;
>>> +		} else {
>>> +			memcpy(&remainder, tx_buf, pld_data_bytes);
>>> +			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>>> +			tx_buf += pld_data_bytes;
>>> +			len -= pld_data_bytes;
>>> +		}
>>> +
>>> +		ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>>> +					 val, !(val & GEN_PLD_W_FULL), 1000,
>>> +					 CMD_PKT_STATUS_TIMEOUT_US);
>>> +		if (ret < 0) {
>>> +			dev_err(dsi->dev,
>>> +				"failed to get available write payload FIFO\n");
>>> +			return ret;
>>> +		}
>>> +	}
>>> +
>>> +	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
>>> +}
>>> +
>>> +static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>>> +					 const struct mipi_dsi_msg *msg)
>>> +{
>>> +	struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>> +	int ret;
>>> +
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * use mipi_dsi_create_packet() instead of all following
>>> +	 * functions and code (no switch cases, no
>>> +	 * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
>>> +	 * and use packet.header...
>>> +	 */
>>> +	dw_mipi_message_config(dsi, msg);
>>> +
>>> +	switch (msg->type) {
>>> +	case MIPI_DSI_DCS_SHORT_WRITE:
>>> +	case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
>>> +	case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
>>> +		ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
>>> +		break;
>>> +	case MIPI_DSI_DCS_LONG_WRITE:
>>> +		ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
>>> +		break;
>>> +	default:
>>> +		dev_err(dsi->dev, "unsupported message type 0x%02x\n",
>>> +			msg->type);
>>> +		ret = -EINVAL;
>>> +	}
>>> +
>>> +	return ret;
>>> +}
>>> +
>>> +static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
>>> +	.attach = dw_mipi_dsi_host_attach,
>>> +	.detach = dw_mipi_dsi_host_detach,
>>> +	.transfer = dw_mipi_dsi_host_transfer,
>>> +};
>>> +
>>> +static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	u32 val;
>>> +
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * enabling low power is panel-dependent, we should use the
>>> +	 * panel configuration here...
>>> +	 */
>>> +	val = ENABLE_LOW_POWER;
>>> +
>>> +	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
>>> +		val |= VID_MODE_TYPE_BURST;
>>> +	else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
>>> +		val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
>>> +	else
>>> +		val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
>>> +
>>> +	dsi_write(dsi, DSI_VID_MODE_CFG, val);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
>>> +				 unsigned long mode_flags)
>>> +{
>>> +	dsi_write(dsi, DSI_PWR_UP, RESET);
>>> +
>>> +	if (mode_flags & MIPI_DSI_MODE_VIDEO) {
>>> +		dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
>>> +		dw_mipi_dsi_video_mode_config(dsi);
>>> +		dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
>>> +	} else {
>>> +		dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>>> +	}
>>> +
>>> +	dsi_write(dsi, DSI_PWR_UP, POWERUP);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	dsi_write(dsi, DSI_PWR_UP, RESET);
>>> +	dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	/*
>>> +	 * The maximum permitted escape clock is 20MHz and it is derived from
>>> +	 * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
>>> +	 *
>>> +	 *     (lane_mbps >> 3) / esc_clk_division < 20
>>> +	 * which is:
>>> +	 *     (lane_mbps >> 3) / 20 > esc_clk_division
>>> +	 */
>>> +	u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
>>> +
>>> +	dsi_write(dsi, DSI_PWR_UP, RESET);
>>> +
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * timeout clock division should be computed with the
>>> +	 * high speed transmission counter timeout and byte lane...
>>> +	 */
>>> +	dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
>>> +		  TX_ESC_CLK_DIVIDSION(esc_clk_division));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
>>> +				   struct drm_display_mode *mode)
>>> +{
>>> +	u32 val = 0, color = 0;
>>> +
>>> +	switch (dsi->format) {
>>> +	case MIPI_DSI_FMT_RGB888:
>>> +		color = DPI_COLOR_CODING_24BIT;
>>> +		break;
>>> +	case MIPI_DSI_FMT_RGB666:
>>> +		color = DPI_COLOR_CODING_18BIT_2 | EN18_LOOSELY;
>>> +		break;
>>> +	case MIPI_DSI_FMT_RGB666_PACKED:
>>> +		color = DPI_COLOR_CODING_18BIT_1;
>>> +		break;
>>> +	case MIPI_DSI_FMT_RGB565:
>>> +		color = DPI_COLOR_CODING_16BIT_1;
>>> +		break;
>>> +	}
>>> +
>>> +	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
>>> +		val |= VSYNC_ACTIVE_LOW;
>>> +	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
>>> +		val |= HSYNC_ACTIVE_LOW;
>>> +
>>> +	dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));
>>> +	dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
>>> +	dsi_write(dsi, DSI_DPI_CFG_POL, val);
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * largest packet sizes during hfp or during vsa/vpb/vfp
>>> +	 * should be computed according to byte lane, lane number and only
>>> +	 * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
>>> +	 */
>>> +	dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
>>> +		  | INVACT_LPCMD_TIME(4));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
>>> +					    struct drm_display_mode *mode)
>>> +{
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * only burst mode is supported here. For non-burst video modes,
>>> +	 * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
>>> +	 * DSI_VNPCR.NPSIZE... especially because this driver supports
>>> +	 * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
>>> +	 */
>>> +	dsi_write(dsi, DSI_VID_PKT_SIZE, VID_PKT_SIZE(mode->hdisplay));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * compute high speed transmission counter timeout according
>>> +	 * to the timeout clock division (TO_CLK_DIVIDSION) and byte lane...
>>> +	 */
>>> +	dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) | LPRX_TO_CNT(1000));
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * the Bus-Turn-Around Timeout Counter should be computed
>>> +	 * according to byte lane...
>>> +	 */
>>> +	dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
>>> +	dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>>> +}
>>> +
>>> +/* Get lane byte clock cycles. */
>>> +static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
>>> +					   struct drm_display_mode *mode,
>>> +					   u32 hcomponent)
>>> +{
>>> +	u32 frac, lbcc;
>>> +
>>> +	lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
>>> +
>>> +	frac = lbcc % mode->clock;
>>> +	lbcc = lbcc / mode->clock;
>>> +	if (frac)
>>> +		lbcc++;
>>> +
>>> +	return lbcc;
>>> +}
>>> +
>>> +static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
>>> +					  struct drm_display_mode *mode)
>>> +{
>>> +	u32 htotal, hsa, hbp, lbcc;
>>> +
>>> +	htotal = mode->htotal;
>>> +	hsa = mode->hsync_end - mode->hsync_start;
>>> +	hbp = mode->htotal - mode->hsync_end;
>>> +
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * computations below may be improved...
>>> +	 */
>>> +	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
>>> +	dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);
>>> +
>>> +	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
>>> +	dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);
>>> +
>>> +	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
>>> +	dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi *dsi,
>>> +					       struct drm_display_mode *mode)
>>> +{
>>> +	u32 vactive, vsa, vfp, vbp;
>>> +
>>> +	vactive = mode->vdisplay;
>>> +	vsa = mode->vsync_end - mode->vsync_start;
>>> +	vfp = mode->vsync_start - mode->vdisplay;
>>> +	vbp = mode->vtotal - mode->vsync_end;
>>> +
>>> +	dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
>>> +	dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
>>> +	dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
>>> +	dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * data & clock lane timers should be computed according to panel
>>> +	 * blankings and to the automatic clock lane control mode...
>>> +	 * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
>>> +	 * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
>>> +	 */
>>> +	dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
>>> +		  | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
>>> +
>>> +	dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
>>> +		  | PHY_CLKLP2HS_TIME(0x40));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	/*
>>> +	 * TODO dw drv improvements
>>> +	 * stop wait time should be the maximum between host dsi
>>> +	 * and panel stop wait times
>>> +	 */
>>> +	dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
>>> +		  N_LANES(dsi->lanes));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dphy_init(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	/* Clear PHY state */
>>> +	dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
>>> +		  | PHY_RSTZ | PHY_SHUTDOWNZ);
>>> +	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>>> +	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLR);
>>> +	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dphy_enable(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	u32 val;
>>> +	int ret;
>>> +
>>> +	dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
>>> +		  PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
>>> +
>>> +	ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>>> +				 val, val & LOCK, 1000, PHY_STATUS_TIMEOUT_US);
>>> +	if (ret < 0)
>>> +		DRM_DEBUG_DRIVER("failed to wait phy lock state\n");
>>> +
>>> +	ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>>> +				 val, val & STOP_STATE_CLK_LANE, 1000,
>>> +				 PHY_STATUS_TIMEOUT_US);
>>> +	if (ret < 0)
>>> +		DRM_DEBUG_DRIVER("failed to wait phy clk lane stop state\n");
>>> +}
>>> +
>>> +static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
>>> +{
>>> +	dsi_read(dsi, DSI_INT_ST0);
>>> +	dsi_read(dsi, DSI_INT_ST1);
>>> +	dsi_write(dsi, DSI_INT_MSK0, 0);
>>> +	dsi_write(dsi, DSI_INT_MSK1, 0);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_bridge_post_disable(struct drm_bridge *bridge)
>>> +{
>>> +	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>> +
>>> +	/*
>>> +	 * Switch to cmd mode before panel-bridge disable & panel unprepare.
>>> +	 * Note: panel-bridge disable & panel disable has been called
>>> +	 * before by the drm framework.
>> I don't think that's exactly the case. I think the sequence should be as in the
>> call chain below.
>>
>>> +	 */
>>> +	dw_mipi_dsi_set_mode(dsi, 0);
>>> +
>>> +	/*
>>> +	 * TODO Only way found to call panel-bridge disable & panel unprepare
>>> +	 * before the dsi "final" disable... can we do better?
>> I agree, this is a problem. More below.
>>
>>> +	 */
>>> +	drm_bridge_post_disable(dsi->panel_bridge);
>>> +
>> I'm guessing our display chain is something like:
>>
>> KMS_encoder -> DW_DSI_bridge -> Panel_bridge -> Panel
>>
>> The order in which the disable ops are called:
>>
>> drm_bridge_disable(Panel_bridge)
>>     - drm_panel_disable(Panel)
>> drm_bridge_disable(DW_DSI_bridge)
>> encoder_funcs->prepare(KMS_encoder)
>> drm_bridge_post_disable(DW_DSI_bridge)
>> drm_bridge_post_disable(Panel_bridge)
>>     - drm_panel_unprepare(Panel)
>>
>> Assuming that only drm_panel_unprepare() requires sending DSI commands, you could have
>> switched to command mode in DW_DSI_bridge's disable() op, and do the "final" DSI disable
>> in DW_DSI_bridge's post_disable(), but that would still result in drm_panel_unprepare()
>> being called with the DSI host dead.
>>
>> The existing call chain of consecutive bridges is the most symmetric one, and the one
>> expected to work in most cases, but it clearly doesn't work in your use case.
>>
>> We have a few options:
>>
>> - Undo the drm-panel-bridge stuff, and have the freedom of calling drm_panel ops in
>> whatever order we want.
>>
>> - Put a big TODO/HACK comment here, saying that this needs to be fixed in the drm_bridge
>> framework and the API needs to be updated to manage our own call chains. Also,
>> instead of calling "drm_bridge_post_disable(dsi->panel_bridge);" explicitly, we
>> can manually call panel_bridge->post_disable() op directly. This avoids us doing
>> things recursively.
>>
>> We would implement the TODO task in drm_bridges only when there are more people
>> desperately in the need to have customizable call chains of bridge ops for long
>> display chains, so I don't see it being implemented in the near future, but I don't
>> think there should be any problem keeping this hack in the dw dsi driver for now.
>>
>> What choice do you prefer?
>>
>> Eric, Daniel,
>>
>> Fyi, this is another case where the panel-bridge stuff doesn't work so well. Not
>> criticizing or anything, just pointing out :)
> 
> I have just looked at existing panel drivers, most of them (probably all
> supporting DCS commands) sends commands to the panel in unprepare
> callback, and it looks correct.
> 
> I am not sure what should be fixed in the framework, some alternatives I
> see:
> 1. change order of disable callbacks, usually it should be reverse of
> order of enable callbacks,
>      but I guess it could break other devices with different requirements,
> 2. do not use call-chain, instead every bridge will be responsible to
> call attached sink's callbacks, this way dsi bridge can turn off dsi
> bus, after calling panel_bridge.post_disable,
> it looks for me the most flexible solution, but it leaves the
> responsibility to the drivers.
> 3. move DSI host power management to mipi_dsi bus, ie it should be
> enabled on dsi device request, and disabled after dsi device does not
> need power anymore.

2) seems the most flexible to me too, it would result in a lot of boilerplate
code in the bridge drivers, 90% of which work with the existing code. We could
consider converting the bridge drivers to explicitly call sink callbacks as a
long term task, though.

3) sounds like a nice idea to abstract away this issue, but would probably be
hard to get right so that it works across multiple DSI controllers.

Thanks,
Archit

Archit Taneja July 3, 2017, 6:31 a.m. UTC | #5

On 06/29/2017 08:13 PM, Philippe CORNU wrote:
> 
> 
> On 06/28/2017 08:44 AM, Archit Taneja wrote:
>>
>>
>> On 06/19/2017 09:58 PM, Philippe CORNU wrote:
>>> Add a Synopsys Designware MIPI DSI host DRM bridge driver, based on the
>>> Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
>>>
>>> Signed-off-by: Philippe CORNU <[e-mail]>
>>> ---
>>>    drivers/gpu/drm/bridge/synopsys/Kconfig       |   6 +
>>>    drivers/gpu/drm/bridge/synopsys/Makefile      |   2 +
>>>    drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 976
>>> ++++++++++++++++++++++++++
>>>    include/drm/bridge/dw_mipi_dsi.h              |  39 +
>>>    4 files changed, 1023 insertions(+)
>>>    create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>>    create mode 100644 include/drm/bridge/dw_mipi_dsi.h
>>>
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> index 40d2827..f00ee26 100644
>>> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>> @@ -21,3 +21,9 @@ config DRM_DW_HDMI_I2S_AUDIO
>>>        help
>>>          Support the I2S Audio interface which is part of the Synopsys
>>>          Designware HDMI block.
>>> +
>>> +config DRM_DW_MIPI_DSI
>>> +    tristate
>>> +    select DRM_KMS_HELPER
>>> +    select DRM_MIPI_DSI
>>> +    select DRM_PANEL_BRIDGE
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile
>>> b/drivers/gpu/drm/bridge/synopsys/Makefile
>>> index 17aa7a6..5f57d36 100644
>>> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
>>> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
>>> @@ -3,3 +3,5 @@
>>>    obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>>    obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>>    obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
>>> +
>>> +obj-$(CONFIG_DRM_DW_MIPI_DSI) += dw-mipi-dsi.o
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>> new file mode 100644
>>> index 0000000..416ed7f
>>> --- /dev/null
>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>> @@ -0,0 +1,976 @@
>>> +/*
>>> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
>>> + * Copyright (C) STMicroelectronics SA 2017
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License as published by
>>> + * the Free Software Foundation; either version 2 of the License, or
>>> + * (at your option) any later version.
>>> + *
>>> + * Modified by Philippe Cornu <[e-mail]>
>>> + * This generic Synopsys DesignWare MIPI DSI host driver is based on the
>>> + * Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
>>> + */
>>> +
>>> +#include <linux/clk.h>
>>> +#include <linux/component.h>
>>> +#include <linux/iopoll.h>
>>> +#include <linux/module.h>
>>> +#include <linux/of_device.h>
>>> +#include <linux/pm_runtime.h>
>>> +#include <linux/reset.h>
>>> +#include <drm/drmP.h>
>>> +#include <drm/drm_atomic_helper.h>
>>> +#include <drm/drm_bridge.h>
>>> +#include <drm/drm_crtc.h>
>>> +#include <drm/drm_crtc_helper.h>
>>> +#include <drm/drm_mipi_dsi.h>
>>> +#include <drm/drm_of.h>
>>> +#include <drm/bridge/dw_mipi_dsi.h>
>>> +#include <video/mipi_display.h>
>>> +
>>> +#define DSI_VERSION            0x00
>>> +#define DSI_PWR_UP            0x04
>>> +#define RESET                0
>>> +#define POWERUP                BIT(0)
>>> +
>>> +#define DSI_CLKMGR_CFG            0x08
>>> +#define TO_CLK_DIVIDSION(div)        (((div) & 0xff) << 8)
>>> +#define TX_ESC_CLK_DIVIDSION(div)    (((div) & 0xff) << 0)
>>> +
>>> +#define DSI_DPI_VCID            0x0c
>>> +#define DPI_VID(vid)            (((vid) & 0x3) << 0)
>>> +
>>> +#define DSI_DPI_COLOR_CODING        0x10
>>> +#define EN18_LOOSELY            BIT(8)
>>> +#define DPI_COLOR_CODING_16BIT_1    0x0
>>> +#define DPI_COLOR_CODING_16BIT_2    0x1
>>> +#define DPI_COLOR_CODING_16BIT_3    0x2
>>> +#define DPI_COLOR_CODING_18BIT_1    0x3
>>> +#define DPI_COLOR_CODING_18BIT_2    0x4
>>> +#define DPI_COLOR_CODING_24BIT        0x5
>>> +
>>> +#define DSI_DPI_CFG_POL            0x14
>>> +#define COLORM_ACTIVE_LOW        BIT(4)
>>> +#define SHUTD_ACTIVE_LOW        BIT(3)
>>> +#define HSYNC_ACTIVE_LOW        BIT(2)
>>> +#define VSYNC_ACTIVE_LOW        BIT(1)
>>> +#define DATAEN_ACTIVE_LOW        BIT(0)
>>> +
>>> +#define DSI_DPI_LP_CMD_TIM        0x18
>>> +#define OUTVACT_LPCMD_TIME(p)        (((p) & 0xff) << 16)
>>> +#define INVACT_LPCMD_TIME(p)        ((p) & 0xff)
>>> +
>>> +#define DSI_DBI_CFG            0x20
>>> +#define DSI_DBI_CMDSIZE            0x28
>>> +
>>> +#define DSI_PCKHDL_CFG            0x2c
>>> +#define EN_CRC_RX            BIT(4)
>>> +#define EN_ECC_RX            BIT(3)
>>> +#define EN_BTA                BIT(2)
>>> +#define EN_EOTP_RX            BIT(1)
>>> +#define EN_EOTP_TX            BIT(0)
>>> +
>>> +#define DSI_MODE_CFG            0x34
>>> +#define ENABLE_VIDEO_MODE        0
>>> +#define ENABLE_CMD_MODE            BIT(0)
>>> +
>>> +#define DSI_VID_MODE_CFG        0x38
>>> +#define FRAME_BTA_ACK            BIT(14)
>>> +#define ENABLE_LOW_POWER        (0x3f << 8)
>>> +#define ENABLE_LOW_POWER_MASK        (0x3f << 8)
>>> +#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES    0x0
>>> +#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS    0x1
>>> +#define VID_MODE_TYPE_BURST            0x2
>>> +#define VID_MODE_TYPE_MASK            0x3
>>> +
>>> +#define DSI_VID_PKT_SIZE        0x3c
>>> +#define VID_PKT_SIZE(p)            (((p) & 0x3fff) << 0)
>>> +#define VID_PKT_MAX_SIZE        0x3fff
>>> +
>>> +#define DSI_VID_HSA_TIME        0x48
>>> +#define DSI_VID_HBP_TIME        0x4c
>>> +#define DSI_VID_HLINE_TIME        0x50
>>> +#define DSI_VID_VSA_LINES        0x54
>>> +#define DSI_VID_VBP_LINES        0x58
>>> +#define DSI_VID_VFP_LINES        0x5c
>>> +#define DSI_VID_VACTIVE_LINES        0x60
>>> +#define DSI_CMD_MODE_CFG        0x68
>>> +#define MAX_RD_PKT_SIZE_LP        BIT(24)
>>> +#define DCS_LW_TX_LP            BIT(19)
>>> +#define DCS_SR_0P_TX_LP            BIT(18)
>>> +#define DCS_SW_1P_TX_LP            BIT(17)
>>> +#define DCS_SW_0P_TX_LP            BIT(16)
>>> +#define GEN_LW_TX_LP            BIT(14)
>>> +#define GEN_SR_2P_TX_LP            BIT(13)
>>> +#define GEN_SR_1P_TX_LP            BIT(12)
>>> +#define GEN_SR_0P_TX_LP            BIT(11)
>>> +#define GEN_SW_2P_TX_LP            BIT(10)
>>> +#define GEN_SW_1P_TX_LP            BIT(9)
>>> +#define GEN_SW_0P_TX_LP            BIT(8)
>>> +#define EN_ACK_RQST            BIT(1)
>>> +#define EN_TEAR_FX            BIT(0)
>>> +
>>> +#define CMD_MODE_ALL_LP            (MAX_RD_PKT_SIZE_LP | \
>>> +                     DCS_LW_TX_LP | \
>>> +                     DCS_SR_0P_TX_LP | \
>>> +                     DCS_SW_1P_TX_LP | \
>>> +                     DCS_SW_0P_TX_LP | \
>>> +                     GEN_LW_TX_LP | \
>>> +                     GEN_SR_2P_TX_LP | \
>>> +                     GEN_SR_1P_TX_LP | \
>>> +                     GEN_SR_0P_TX_LP | \
>>> +                     GEN_SW_2P_TX_LP | \
>>> +                     GEN_SW_1P_TX_LP | \
>>> +                     GEN_SW_0P_TX_LP)
>>> +
>>> +#define DSI_GEN_HDR            0x6c
>>> +#define GEN_HDATA(data)            (((data) & 0xffff) << 8)
>>> +#define GEN_HDATA_MASK            (0xffff << 8)
>>> +#define GEN_HTYPE(type)            (((type) & 0xff) << 0)
>>> +#define GEN_HTYPE_MASK            0xff
>>> +
>>> +#define DSI_GEN_PLD_DATA        0x70
>>> +
>>> +#define DSI_CMD_PKT_STATUS        0x74
>>> +#define GEN_CMD_EMPTY            BIT(0)
>>> +#define GEN_CMD_FULL            BIT(1)
>>> +#define GEN_PLD_W_EMPTY            BIT(2)
>>> +#define GEN_PLD_W_FULL            BIT(3)
>>> +#define GEN_PLD_R_EMPTY            BIT(4)
>>> +#define GEN_PLD_R_FULL            BIT(5)
>>> +#define GEN_RD_CMD_BUSY            BIT(6)
>>> +
>>> +#define DSI_TO_CNT_CFG            0x78
>>> +#define HSTX_TO_CNT(p)            (((p) & 0xffff) << 16)
>>> +#define LPRX_TO_CNT(p)            ((p) & 0xffff)
>>> +
>>> +#define DSI_BTA_TO_CNT            0x8c
>>> +#define DSI_LPCLK_CTRL            0x94
>>> +#define AUTO_CLKLANE_CTRL        BIT(1)
>>> +#define PHY_TXREQUESTCLKHS        BIT(0)
>>> +
>>> +#define DSI_PHY_TMR_LPCLK_CFG        0x98
>>> +#define PHY_CLKHS2LP_TIME(lbcc)        (((lbcc) & 0x3ff) << 16)
>>> +#define PHY_CLKLP2HS_TIME(lbcc)        ((lbcc) & 0x3ff)
>>> +
>>> +#define DSI_PHY_TMR_CFG            0x9c
>>> +#define PHY_HS2LP_TIME(lbcc)        (((lbcc) & 0xff) << 24)
>>> +#define PHY_LP2HS_TIME(lbcc)        (((lbcc) & 0xff) << 16)
>>> +#define MAX_RD_TIME(lbcc)        ((lbcc) & 0x7fff)
>>> +
>>> +#define DSI_PHY_RSTZ            0xa0
>>> +#define PHY_DISFORCEPLL            0
>>> +#define PHY_ENFORCEPLL            BIT(3)
>>> +#define PHY_DISABLECLK            0
>>> +#define PHY_ENABLECLK            BIT(2)
>>> +#define PHY_RSTZ            0
>>> +#define PHY_UNRSTZ            BIT(1)
>>> +#define PHY_SHUTDOWNZ            0
>>> +#define PHY_UNSHUTDOWNZ            BIT(0)
>>> +
>>> +#define DSI_PHY_IF_CFG            0xa4
>>> +#define N_LANES(n)            ((((n) - 1) & 0x3) << 0)
>>> +#define PHY_STOP_WAIT_TIME(cycle)    (((cycle) & 0xff) << 8)
>>> +
>>> +#define DSI_PHY_STATUS            0xb0
>>> +#define LOCK                BIT(0)
>>> +#define STOP_STATE_CLK_LANE        BIT(2)
>>> +
>>> +#define DSI_PHY_TST_CTRL0        0xb4
>>> +#define PHY_TESTCLK            BIT(1)
>>> +#define PHY_UNTESTCLK            0
>>> +#define PHY_TESTCLR            BIT(0)
>>> +#define PHY_UNTESTCLR            0
>>> +
>>> +#define DSI_PHY_TST_CTRL1        0xb8
>>> +#define PHY_TESTEN            BIT(16)
>>> +#define PHY_UNTESTEN            0
>>> +#define PHY_TESTDOUT(n)            (((n) & 0xff) << 8)
>>> +#define PHY_TESTDIN(n)            (((n) & 0xff) << 0)
>>> +
>>> +#define DSI_INT_ST0            0xbc
>>> +#define DSI_INT_ST1            0xc0
>>> +#define DSI_INT_MSK0            0xc4
>>> +#define DSI_INT_MSK1            0xc8
>>> +
>>> +#define PHY_STATUS_TIMEOUT_US        10000
>>> +#define CMD_PKT_STATUS_TIMEOUT_US    20000
>>> +
>>> +struct dw_mipi_dsi {
>>> +    struct drm_bridge bridge;
>>> +    struct mipi_dsi_host dsi_host;
>>> +    struct drm_bridge *panel_bridge;
>>> +    bool is_panel_bridge;
>>> +    struct device *dev;
>>> +    void __iomem *base;
>>> +
>>> +    struct clk *pclk;
>>> +
>>> +    unsigned int lane_mbps; /* per lane */
>>> +    u32 channel;
>>> +    u32 lanes;
>>> +    u32 format;
>>> +    unsigned long mode_flags;
>>> +
>>> +    const struct dw_mipi_dsi_plat_data *plat_data;
>>> +};
>>> +
>>> +/*
>>> + * The controller should generate 2 frames before
>>> + * preparing the peripheral.
>>> + */
>>> +static void dw_mipi_dsi_wait_for_two_frames(struct drm_display_mode
>>> *mode)
>>> +{
>>> +    int refresh, two_frames;
>>> +
>>> +    refresh = drm_mode_vrefresh(mode);
>>> +    two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
>>> +    msleep(two_frames);
>>> +}
>>> +
>>> +static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host
>>> *host)
>>> +{
>>> +    return container_of(host, struct dw_mipi_dsi, dsi_host);
>>> +}
>>> +
>>> +static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge
>>> *bridge)
>>> +{
>>> +    return container_of(bridge, struct dw_mipi_dsi, bridge);
>>> +}
>>> +
>>> +static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val)
>>> +{
>>> +    writel(val, dsi->base + reg);
>>> +}
>>> +
>>> +static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
>>> +{
>>> +    return readl(dsi->base + reg);
>>> +}
>>> +
>>> +static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
>>> +                   struct mipi_dsi_device *device)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>> +    struct drm_bridge *bridge;
>>> +    struct drm_panel *panel;
>>> +    int ret;
>>> +
>>> +    if (device->lanes > dsi->plat_data->max_data_lanes) {
>>> +        dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
>>> +            device->lanes);
>>> +        return -EINVAL;
>>> +    }
>>> +
>>> +    dsi->lanes = device->lanes;
>>> +    dsi->channel = device->channel;
>>> +    dsi->format = device->format;
>>> +    dsi->mode_flags = device->mode_flags;
>>> +
>>> +    ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
>>> +                      &panel, &bridge);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    if (panel) {
>>> +        bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DSI);
>>> +        if (IS_ERR(bridge))
>>> +            return PTR_ERR(bridge);
>>> +        dsi->is_panel_bridge = true;
>>> +    }
>>> +
>>> +    dsi->panel_bridge = bridge;
>>> +
>>> +    return drm_bridge_add(&dsi->bridge);
>>> +}
>>> +
>>> +static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
>>> +                   struct mipi_dsi_device *device)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>> +
>>> +    if (dsi->is_panel_bridge)
>>> +        drm_panel_bridge_remove(dsi->panel_bridge);
>>> +
>>> +    drm_bridge_remove(&dsi->bridge);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
>>> +                   const struct mipi_dsi_msg *msg)
>>> +{
>>> +    bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
>>> +    u32 val = 0;
>>> +
>>> +    if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
>>> +        val |= EN_ACK_RQST;
>>> +    if (lpm)
>>> +        val |= CMD_MODE_ALL_LP;
>>> +
>>> +    dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
>>> +    dsi_write(dsi, DSI_CMD_MODE_CFG, val);
>>> +}
>>> +
>>> +static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32
>>> hdr_val)
>>> +{
>>> +    int ret;
>>> +    u32 val, mask;
>>> +
>>> +    ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>>> +                 val, !(val & GEN_CMD_FULL), 1000,
>>> +                 CMD_PKT_STATUS_TIMEOUT_US);
>>> +    if (ret < 0) {
>>> +        dev_err(dsi->dev, "failed to get available command FIFO\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    dsi_write(dsi, DSI_GEN_HDR, hdr_val);
>>> +
>>> +    mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
>>> +    ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>>> +                 val, (val & mask) == mask,
>>> +                 1000, CMD_PKT_STATUS_TIMEOUT_US);
>>> +    if (ret < 0) {
>>> +        dev_err(dsi->dev, "failed to write command FIFO\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
>>> +                       const struct mipi_dsi_msg *msg)
>>> +{
>>> +    const u8 *tx_buf = msg->tx_buf;
>>> +    u16 data = 0;
>>> +    u32 val;
>>> +
>>> +    if (msg->tx_len > 0)
>>> +        data |= tx_buf[0];
>>> +    if (msg->tx_len > 1)
>>> +        data |= tx_buf[1] << 8;
>>> +
>>> +    if (msg->tx_len > 2) {
>>> +        dev_err(dsi->dev, "too long tx buf length %zu for short
>>> write\n",
>>> +            msg->tx_len);
>>> +        return -EINVAL;
>>> +    }
>>> +
>>> +    val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
>>> +    return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
>>> +}
>>> +
>>> +static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
>>> +                      const struct mipi_dsi_msg *msg)
>>> +{
>>> +    const u8 *tx_buf = msg->tx_buf;
>>> +    int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
>>> +    u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
>>> +    u32 remainder;
>>> +    u32 val;
>>> +
>>> +    if (msg->tx_len < 3) {
>>> +        dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
>>> +            msg->tx_len);
>>> +        return -EINVAL;
>>> +    }
>>> +
>>> +    while (DIV_ROUND_UP(len, pld_data_bytes)) {
>>> +        if (len < pld_data_bytes) {
>>> +            remainder = 0;
>>> +            memcpy(&remainder, tx_buf, len);
>>> +            dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>>> +            len = 0;
>>> +        } else {
>>> +            memcpy(&remainder, tx_buf, pld_data_bytes);
>>> +            dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>>> +            tx_buf += pld_data_bytes;
>>> +            len -= pld_data_bytes;
>>> +        }
>>> +
>>> +        ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>>> +                     val, !(val & GEN_PLD_W_FULL), 1000,
>>> +                     CMD_PKT_STATUS_TIMEOUT_US);
>>> +        if (ret < 0) {
>>> +            dev_err(dsi->dev,
>>> +                "failed to get available write payload FIFO\n");
>>> +            return ret;
>>> +        }
>>> +    }
>>> +
>>> +    return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
>>> +}
>>> +
>>> +static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>>> +                     const struct mipi_dsi_msg *msg)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>> +    int ret;
>>> +
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * use mipi_dsi_create_packet() instead of all following
>>> +     * functions and code (no switch cases, no
>>> +     * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
>>> +     * and use packet.header...
>>> +     */
>>> +    dw_mipi_message_config(dsi, msg);
>>> +
>>> +    switch (msg->type) {
>>> +    case MIPI_DSI_DCS_SHORT_WRITE:
>>> +    case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
>>> +    case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
>>> +        ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
>>> +        break;
>>> +    case MIPI_DSI_DCS_LONG_WRITE:
>>> +        ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
>>> +        break;
>>> +    default:
>>> +        dev_err(dsi->dev, "unsupported message type 0x%02x\n",
>>> +            msg->type);
>>> +        ret = -EINVAL;
>>> +    }
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
>>> +    .attach = dw_mipi_dsi_host_attach,
>>> +    .detach = dw_mipi_dsi_host_detach,
>>> +    .transfer = dw_mipi_dsi_host_transfer,
>>> +};
>>> +
>>> +static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    u32 val;
>>> +
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * enabling low power is panel-dependent, we should use the
>>> +     * panel configuration here...
>>> +     */
>>> +    val = ENABLE_LOW_POWER;
>>> +
>>> +    if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
>>> +        val |= VID_MODE_TYPE_BURST;
>>> +    else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
>>> +        val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
>>> +    else
>>> +        val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
>>> +
>>> +    dsi_write(dsi, DSI_VID_MODE_CFG, val);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
>>> +                 unsigned long mode_flags)
>>> +{
>>> +    dsi_write(dsi, DSI_PWR_UP, RESET);
>>> +
>>> +    if (mode_flags & MIPI_DSI_MODE_VIDEO) {
>>> +        dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
>>> +        dw_mipi_dsi_video_mode_config(dsi);
>>> +        dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
>>> +    } else {
>>> +        dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>>> +    }
>>> +
>>> +    dsi_write(dsi, DSI_PWR_UP, POWERUP);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    dsi_write(dsi, DSI_PWR_UP, RESET);
>>> +    dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    /*
>>> +     * The maximum permitted escape clock is 20MHz and it is derived
>>> from
>>> +     * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
>>> +     *
>>> +     *     (lane_mbps >> 3) / esc_clk_division < 20
>>> +     * which is:
>>> +     *     (lane_mbps >> 3) / 20 > esc_clk_division
>>> +     */
>>> +    u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
>>> +
>>> +    dsi_write(dsi, DSI_PWR_UP, RESET);
>>> +
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * timeout clock division should be computed with the
>>> +     * high speed transmission counter timeout and byte lane...
>>> +     */
>>> +    dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
>>> +          TX_ESC_CLK_DIVIDSION(esc_clk_division));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
>>> +                   struct drm_display_mode *mode)
>>> +{
>>> +    u32 val = 0, color = 0;
>>> +
>>> +    switch (dsi->format) {
>>> +    case MIPI_DSI_FMT_RGB888:
>>> +        color = DPI_COLOR_CODING_24BIT;
>>> +        break;
>>> +    case MIPI_DSI_FMT_RGB666:
>>> +        color = DPI_COLOR_CODING_18BIT_2 | EN18_LOOSELY;
>>> +        break;
>>> +    case MIPI_DSI_FMT_RGB666_PACKED:
>>> +        color = DPI_COLOR_CODING_18BIT_1;
>>> +        break;
>>> +    case MIPI_DSI_FMT_RGB565:
>>> +        color = DPI_COLOR_CODING_16BIT_1;
>>> +        break;
>>> +    }
>>> +
>>> +    if (mode->flags & DRM_MODE_FLAG_NVSYNC)
>>> +        val |= VSYNC_ACTIVE_LOW;
>>> +    if (mode->flags & DRM_MODE_FLAG_NHSYNC)
>>> +        val |= HSYNC_ACTIVE_LOW;
>>> +
>>> +    dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));
>>> +    dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
>>> +    dsi_write(dsi, DSI_DPI_CFG_POL, val);
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * largest packet sizes during hfp or during vsa/vpb/vfp
>>> +     * should be computed according to byte lane, lane number and only
>>> +     * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
>>> +     */
>>> +    dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
>>> +          | INVACT_LPCMD_TIME(4));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
>>> +                        struct drm_display_mode *mode)
>>> +{
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * only burst mode is supported here. For non-burst video modes,
>>> +     * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
>>> +     * DSI_VNPCR.NPSIZE... especially because this driver supports
>>> +     * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
>>> +     */
>>> +    dsi_write(dsi, DSI_VID_PKT_SIZE, VID_PKT_SIZE(mode->hdisplay));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * compute high speed transmission counter timeout according
>>> +     * to the timeout clock division (TO_CLK_DIVIDSION) and byte lane...
>>> +     */
>>> +    dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) |
>>> LPRX_TO_CNT(1000));
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * the Bus-Turn-Around Timeout Counter should be computed
>>> +     * according to byte lane...
>>> +     */
>>> +    dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
>>> +    dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>>> +}
>>> +
>>> +/* Get lane byte clock cycles. */
>>> +static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
>>> +                       struct drm_display_mode *mode,
>>> +                       u32 hcomponent)
>>> +{
>>> +    u32 frac, lbcc;
>>> +
>>> +    lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
>>> +
>>> +    frac = lbcc % mode->clock;
>>> +    lbcc = lbcc / mode->clock;
>>> +    if (frac)
>>> +        lbcc++;
>>> +
>>> +    return lbcc;
>>> +}
>>> +
>>> +static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
>>> +                      struct drm_display_mode *mode)
>>> +{
>>> +    u32 htotal, hsa, hbp, lbcc;
>>> +
>>> +    htotal = mode->htotal;
>>> +    hsa = mode->hsync_end - mode->hsync_start;
>>> +    hbp = mode->htotal - mode->hsync_end;
>>> +
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * computations below may be improved...
>>> +     */
>>> +    lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
>>> +    dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);
>>> +
>>> +    lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
>>> +    dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);
>>> +
>>> +    lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
>>> +    dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi *dsi,
>>> +                           struct drm_display_mode *mode)
>>> +{
>>> +    u32 vactive, vsa, vfp, vbp;
>>> +
>>> +    vactive = mode->vdisplay;
>>> +    vsa = mode->vsync_end - mode->vsync_start;
>>> +    vfp = mode->vsync_start - mode->vdisplay;
>>> +    vbp = mode->vtotal - mode->vsync_end;
>>> +
>>> +    dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
>>> +    dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
>>> +    dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
>>> +    dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * data & clock lane timers should be computed according to panel
>>> +     * blankings and to the automatic clock lane control mode...
>>> +     * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
>>> +     * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
>>> +     */
>>> +    dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
>>> +          | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
>>> +
>>> +    dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
>>> +          | PHY_CLKLP2HS_TIME(0x40));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    /*
>>> +     * TODO dw drv improvements
>>> +     * stop wait time should be the maximum between host dsi
>>> +     * and panel stop wait times
>>> +     */
>>> +    dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
>>> +          N_LANES(dsi->lanes));
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dphy_init(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    /* Clear PHY state */
>>> +    dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
>>> +          | PHY_RSTZ | PHY_SHUTDOWNZ);
>>> +    dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>>> +    dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLR);
>>> +    dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_dphy_enable(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    u32 val;
>>> +    int ret;
>>> +
>>> +    dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
>>> +          PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
>>> +
>>> +    ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>>> +                 val, val & LOCK, 1000, PHY_STATUS_TIMEOUT_US);
>>> +    if (ret < 0)
>>> +        DRM_DEBUG_DRIVER("failed to wait phy lock state\n");
>>> +
>>> +    ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>>> +                 val, val & STOP_STATE_CLK_LANE, 1000,
>>> +                 PHY_STATUS_TIMEOUT_US);
>>> +    if (ret < 0)
>>> +        DRM_DEBUG_DRIVER("failed to wait phy clk lane stop state\n");
>>> +}
>>> +
>>> +static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    dsi_read(dsi, DSI_INT_ST0);
>>> +    dsi_read(dsi, DSI_INT_ST1);
>>> +    dsi_write(dsi, DSI_INT_MSK0, 0);
>>> +    dsi_write(dsi, DSI_INT_MSK1, 0);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_bridge_post_disable(struct drm_bridge *bridge)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>> +
>>> +    /*
>>> +     * Switch to cmd mode before panel-bridge disable & panel unprepare.
>>> +     * Note: panel-bridge disable & panel disable has been called
>>> +     * before by the drm framework.
>>
>> I don't think that's exactly the case. I think the sequence should be as
>> in the
>> call chain below.
>>
> 
> Hi Archit,
> And many thanks for your comments :-)
> the word "post_" is missing in the above comment, sorry for that. I
> should have written "Switch to cmd mode before panel-bridge post_disable
> & ..." that is much more correct I think, I will update this comment for
> v5 : )
> 
> 
>>> +     */
>>> +    dw_mipi_dsi_set_mode(dsi, 0);
>>> +
>>> +    /*
>>> +     * TODO Only way found to call panel-bridge disable & panel
>>> unprepare
>>> +     * before the dsi "final" disable... can we do better?
>>
>> I agree, this is a problem. More below.
> 
> Same remark here, I forgot "post_" in the above comment.
> 
>>
>>> +     */
>>> +    drm_bridge_post_disable(dsi->panel_bridge);
>>> +
>>
>> I'm guessing our display chain is something like:
>>
>> KMS_encoder -> DW_DSI_bridge -> Panel_bridge -> Panel
>>
>> The order in which the disable ops are called:
>>
>> drm_bridge_disable(Panel_bridge)
>>     - drm_panel_disable(Panel)
>> drm_bridge_disable(DW_DSI_bridge)
>> encoder_funcs->prepare(KMS_encoder)
>> drm_bridge_post_disable(DW_DSI_bridge)
>> drm_bridge_post_disable(Panel_bridge)
>>     - drm_panel_unprepare(Panel)
>>
> 
> 100%-perfect sequence, I do agree with you : )
> 
>> Assuming that only drm_panel_unprepare() requires sending DSI commands,
> 
> Well, it really depends on DSI panels. For instance, panel drivers can
> send DCS/Generic DSI commands:
> * in drm_panel_disable(): then these commands are sent during blankings,
> many lcds allow that. This is the proper place for backlight through DSI
> (dimming or off), for sleep mode DCS commands...
> 
> or/and
> 
> * in drm_panel_unprepare(): then these commands are sent during a
> "command mode" phase. This is the proper place for many things, from
> backlight off through DSI, sleep mode DCS commands... to a full power
> off (voltage regulators are switched off).
> 
>   From my pov, both drm_panel_disable() & drm_panel_unprepare() may send
> DSI commands... but it is not a real problem in fact as DSI commands can
> be sent through blankings in video mode or can be sent in "command mode"...
> 
>> you could have
>> switched to command mode in DW_DSI_bridge's disable() op, and do the
>> "final" DSI disable
>> in DW_DSI_bridge's post_disable(), but that would still result in
>> drm_panel_unprepare()
>> being called with the DSI host dead.
>>
>> The existing call chain of consecutive bridges is the most symmetric
>> one, and the one
>> expected to work in most cases, but it clearly doesn't work in your use
>> case.
>>
>> We have a few options:
>>
>> - Undo the drm-panel-bridge stuff, and have the freedom of calling
>> drm_panel ops in
>> whatever order we want.
>>
>> - Put a big TODO/HACK comment here, saying that this needs to be fixed
>> in the drm_bridge
>> framework and the API needs to be updated to manage our own call chains.
>> Also,
>> instead of calling "drm_bridge_post_disable(dsi->panel_bridge);"
>> explicitly, we
>> can manually call panel_bridge->post_disable() op directly. This avoids
>> us doing
>> things recursively.
>>
>> We would implement the TODO task in drm_bridges only when there are more
>> people
>> desperately in the need to have customizable call chains of bridge ops
>> for long
>> display chains, so I don't see it being implemented in the near future,
>> but I don't
>> think there should be any problem keeping this hack in the dw dsi driver
>> for now.
>>
>> What choice do you prefer?
> 
> Well, not so easy to decide what could be the best solution...
> 
> For the time being, I think I prefer keeping the panel bridge proposal
> (the v4 one), for several reasons in fact:
> 
> * It saves "many" lines of code, and supporting *both* panels & bridges
> (homogeneous approach).
> 
> * It helps reducing explicit calls like drm_panel_() or drm_bridge_()
> letting the drm framework doing its job :-)
> 
> * It is not an issue to have a TODO/HACK for the only remaining function
> call (drm_bridge_post_disable() here). I mean many others drivers calls
> directly these panel & bridge functions and this forces panel drivers to
> have in many places in their code "if (enabled) return;" or "if
> (prepared) return;" and we should work in the future to improve that
> (ie. Let's drm framework doing its job).
> 
> * It covers/offers the 3 important "hw disable" phases:
> 	- panel sends DCS/Generic DSI commands during its blankings in a video
> mode phase (most of the times, these commands are short, for backlight
> updates or sleep for instance...), it's correspond to panel_disable().
> 	- panel sends DCS/Generic DSI commands in a command mode phase (sleep,
> power off...), it's correspond to panel_unprepare().
> 	- the dsi IP is stopped after the 2 previous phases.
> 
> So, for all these reasons, I prefer the "Put a big TODO/HACK" option :)

Sure. For v5, could you consider calling
panel_bridge->funcs->post_disable() op directly instead of calling
"drm_bridge_post_disable(dsi->panel_bridge);"? The hack would be more legible,
and we'd avoid unnecessary recursive chains.

Thanks,
Archit

> 
> Thank you,
> Philippe
> 
>>
>> Eric, Daniel,
>>
>> Fyi, this is another case where the panel-bridge stuff doesn't work so
>> well. Not
>> criticizing or anything, just pointing out :)
>>
>> Archit
>>
>>
>>> +    dw_mipi_dsi_disable(dsi);
>>> +    clk_disable_unprepare(dsi->pclk);
>>> +    pm_runtime_put(dsi->dev);
>>> +}
>>> +
>>> +void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
>>> +                 struct drm_display_mode *mode,
>>> +                 struct drm_display_mode *adjusted_mode)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>> +    const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
>>> +    void *priv_data = dsi->plat_data->priv_data;
>>> +    int ret;
>>> +
>>> +    clk_prepare_enable(dsi->pclk);
>>> +
>>> +    ret = phy_ops->get_lane_mbps(priv_data, mode, dsi->mode_flags,
>>> +                     dsi->lanes, dsi->format, &dsi->lane_mbps);
>>> +    if (ret)
>>> +        DRM_DEBUG_DRIVER("Phy get_lane_mbps() failed\n");
>>> +
>>> +    pm_runtime_get_sync(dsi->dev);
>>> +    dw_mipi_dsi_init(dsi);
>>> +    dw_mipi_dsi_dpi_config(dsi, mode);
>>> +    dw_mipi_dsi_packet_handler_config(dsi);
>>> +    dw_mipi_dsi_video_mode_config(dsi);
>>> +    dw_mipi_dsi_video_packet_config(dsi, mode);
>>> +    dw_mipi_dsi_command_mode_config(dsi);
>>> +    dw_mipi_dsi_line_timer_config(dsi, mode);
>>> +    dw_mipi_dsi_vertical_timing_config(dsi, mode);
>>> +
>>> +    dw_mipi_dsi_dphy_init(dsi);
>>> +    dw_mipi_dsi_dphy_timing_config(dsi);
>>> +    dw_mipi_dsi_dphy_interface_config(dsi);
>>> +
>>> +    dw_mipi_dsi_clear_err(dsi);
>>> +
>>> +    ret = phy_ops->init(priv_data);
>>> +    if (ret)
>>> +        DRM_DEBUG_DRIVER("Phy init() failed\n");
>>> +
>>> +    dw_mipi_dsi_dphy_enable(dsi);
>>> +
>>> +    dw_mipi_dsi_wait_for_two_frames(mode);
>>> +
>>> +    /* Switch to cmd mode for panel-bridge pre_enable & panel prepare */
>>> +    dw_mipi_dsi_set_mode(dsi, 0);
>>> +}
>>> +
>>> +static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>> +
>>> +    /* Switch to video mode for panel-bridge enable & panel enable */
>>> +    dw_mipi_dsi_set_mode(dsi, MIPI_DSI_MODE_VIDEO);
>>> +}
>>> +
>>> +static enum drm_mode_status
>>> +dw_mipi_dsi_bridge_mode_valid(struct drm_bridge *bridge,
>>> +                  const struct drm_display_mode *mode)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>> +    const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
>>> +    enum drm_mode_status mode_status = MODE_OK;
>>> +
>>> +    if (pdata->mode_valid)
>>> +        mode_status = pdata->mode_valid(pdata->priv_data, mode);
>>> +
>>> +    return mode_status;
>>> +}
>>> +
>>> +static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>> +
>>> +    if (!bridge->encoder) {
>>> +        DRM_ERROR("Parent encoder object not found\n");
>>> +        return -ENODEV;
>>> +    }
>>> +
>>> +    /* Set the encoder type as caller does not know it */
>>> +    bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
>>> +
>>> +    /* Attach the panel-bridge to the dsi bridge */
>>> +    return drm_bridge_attach(bridge->encoder, dsi->panel_bridge,
>>> bridge);
>>> +}
>>> +
>>> +static struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
>>> +    .mode_set     = dw_mipi_dsi_bridge_mode_set,
>>> +    .enable          = dw_mipi_dsi_bridge_enable,
>>> +    .post_disable = dw_mipi_dsi_bridge_post_disable,
>>> +    .mode_valid   = dw_mipi_dsi_bridge_mode_valid,
>>> +    .attach          = dw_mipi_dsi_bridge_attach,
>>> +};
>>> +
>>> +static struct dw_mipi_dsi *
>>> +__dw_mipi_dsi_probe(struct platform_device *pdev,
>>> +            const struct dw_mipi_dsi_plat_data *plat_data)
>>> +{
>>> +    struct device *dev = &pdev->dev;
>>> +    struct reset_control *apb_rst;
>>> +    struct dw_mipi_dsi *dsi;
>>> +    struct resource *res;
>>> +    int ret;
>>> +
>>> +    dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
>>> +    if (!dsi)
>>> +        return ERR_PTR(-ENOMEM);
>>> +
>>> +    dsi->dev = dev;
>>> +    dsi->plat_data = plat_data;
>>> +
>>> +    if (!plat_data->phy_ops->init ||
>>> !plat_data->phy_ops->get_lane_mbps) {
>>> +        DRM_ERROR("Phy not properly configured\n");
>>> +        return ERR_PTR(-ENODEV);
>>> +    }
>>> +
>>> +    if (!plat_data->base) {
>>> +        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>> +        if (!res)
>>> +            return ERR_PTR(-ENODEV);
>>> +
>>> +        dsi->base = devm_ioremap_resource(dev, res);
>>> +        if (IS_ERR(dsi->base))
>>> +            return ERR_PTR(-ENODEV);
>>> +
>>> +    } else {
>>> +        dsi->base = plat_data->base;
>>> +    }
>>> +
>>> +    dsi->pclk = devm_clk_get(dev, "pclk");
>>> +    if (IS_ERR(dsi->pclk)) {
>>> +        ret = PTR_ERR(dsi->pclk);
>>> +        dev_err(dev, "Unable to get pclk: %d\n", ret);
>>> +        return ERR_PTR(ret);
>>> +    }
>>> +
>>> +    /*
>>> +     * Note that the reset was not defined in the initial device
>>> tree, so
>>> +     * we have to be prepared for it not being found.
>>> +     */
>>> +    apb_rst = devm_reset_control_get(dev, "apb");
>>> +    if (IS_ERR(apb_rst)) {
>>> +        ret = PTR_ERR(apb_rst);
>>> +        if (ret == -ENOENT) {
>>> +            apb_rst = NULL;
>>> +        } else {
>>> +            dev_err(dev, "Unable to get reset control: %d\n", ret);
>>> +            return ERR_PTR(ret);
>>> +        }
>>> +    }
>>> +
>>> +    if (apb_rst) {
>>> +        ret = clk_prepare_enable(dsi->pclk);
>>> +        if (ret) {
>>> +            dev_err(dev, "%s: Failed to enable pclk\n", __func__);
>>> +            return ERR_PTR(ret);
>>> +        }
>>> +
>>> +        reset_control_assert(apb_rst);
>>> +        usleep_range(10, 20);
>>> +        reset_control_deassert(apb_rst);
>>> +
>>> +        clk_disable_unprepare(dsi->pclk);
>>> +    }
>>> +
>>> +    pm_runtime_enable(dev);
>>> +
>>> +    dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
>>> +    dsi->dsi_host.dev = dev;
>>> +    ret = mipi_dsi_host_register(&dsi->dsi_host);
>>> +    if (ret) {
>>> +        dev_err(dev, "Failed to register MIPI host: %d\n", ret);
>>> +        return ERR_PTR(ret);
>>> +    }
>>> +
>>> +    dsi->bridge.driver_private = dsi;
>>> +    dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
>>> +#ifdef CONFIG_OF
>>> +    dsi->bridge.of_node = pdev->dev.of_node;
>>> +#endif
>>> +
>>> +    dev_set_drvdata(dev, dsi);
>>> +
>>> +    return dsi;
>>> +}
>>> +
>>> +static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
>>> +{
>>> +    pm_runtime_disable(dsi->dev);
>>> +}
>>> +
>>> +/*
>>> + * Probe/remove API, used from platforms based on the DRM bridge API.
>>> + */
>>> +int dw_mipi_dsi_probe(struct platform_device *pdev,
>>> +              const struct dw_mipi_dsi_plat_data *plat_data)
>>> +{
>>> +    struct dw_mipi_dsi *dsi;
>>> +
>>> +    dsi = __dw_mipi_dsi_probe(pdev, plat_data);
>>> +    if (IS_ERR(dsi))
>>> +        return PTR_ERR(dsi);
>>> +
>>> +    return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_probe);
>>> +
>>> +void dw_mipi_dsi_remove(struct platform_device *pdev)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = platform_get_drvdata(pdev);
>>> +
>>> +    mipi_dsi_host_unregister(&dsi->dsi_host);
>>> +
>>> +    __dw_mipi_dsi_remove(dsi);
>>> +}
>>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_remove);
>>> +
>>> +/*
>>> + * Bind/unbind API, used from platforms based on the component
>>> framework.
>>> + */
>>> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder
>>> *encoder,
>>> +             const struct dw_mipi_dsi_plat_data *plat_data)
>>> +{
>>> +    struct dw_mipi_dsi *dsi;
>>> +    int ret;
>>> +
>>> +    dsi = __dw_mipi_dsi_probe(pdev, plat_data);
>>> +    if (IS_ERR(dsi))
>>> +        return PTR_ERR(dsi);
>>> +
>>> +    ret = drm_bridge_attach(encoder, &dsi->bridge, NULL);
>>> +    if (ret) {
>>> +        dw_mipi_dsi_remove(pdev);
>>> +        DRM_ERROR("Failed to initialize bridge with drm\n");
>>> +        return ret;
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_bind);
>>> +
>>> +void dw_mipi_dsi_unbind(struct device *dev)
>>> +{
>>> +    struct dw_mipi_dsi *dsi = dev_get_drvdata(dev);
>>> +
>>> +    __dw_mipi_dsi_remove(dsi);
>>> +}
>>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_unbind);
>>> +
>>> +MODULE_AUTHOR("Chris Zhong <[e-mail]>");
>>> +MODULE_AUTHOR("Philippe Cornu <[e-mail]>");
>>> +MODULE_DESCRIPTION("DW MIPI DSI host controller driver");
>>> +MODULE_LICENSE("GPL");
>>> +MODULE_ALIAS("platform:dw-mipi-dsi");
>>> diff --git a/include/drm/bridge/dw_mipi_dsi.h
>>> b/include/drm/bridge/dw_mipi_dsi.h
>>> new file mode 100644
>>> index 0000000..9b30fec
>>> --- /dev/null
>>> +++ b/include/drm/bridge/dw_mipi_dsi.h
>>> @@ -0,0 +1,39 @@
>>> +/*
>>> + * Copyright (C) STMicroelectronics SA 2017
>>> + *
>>> + * Authors: Philippe Cornu <[e-mail]>
>>> + *          Yannick Fertre <[e-mail]>
>>> + *
>>> + * License terms:  GNU General Public License (GPL), version 2
>>> + */
>>> +
>>> +#ifndef __DW_MIPI_DSI__
>>> +#define __DW_MIPI_DSI__
>>> +
>>> +struct dw_mipi_dsi_phy_ops {
>>> +    int (*init)(void *priv_data);
>>> +    int (*get_lane_mbps)(void *priv_data, struct drm_display_mode *mode,
>>> +                 unsigned long mode_flags, u32 lanes, u32 format,
>>> +                 unsigned int *lane_mbps);
>>> +};
>>> +
>>> +struct dw_mipi_dsi_plat_data {
>>> +    void __iomem *base;
>>> +    unsigned int max_data_lanes;
>>> +
>>> +    enum drm_mode_status (*mode_valid)(void *priv_data,
>>> +                       const struct drm_display_mode *mode);
>>> +
>>> +    const struct dw_mipi_dsi_phy_ops *phy_ops;
>>> +
>>> +    void *priv_data;
>>> +};
>>> +
>>> +int dw_mipi_dsi_probe(struct platform_device *pdev,
>>> +              const struct dw_mipi_dsi_plat_data *plat_data);
>>> +void dw_mipi_dsi_remove(struct platform_device *pdev);
>>> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder
>>> *encoder,
>>> +             const struct dw_mipi_dsi_plat_data *plat_data);
>>> +void dw_mipi_dsi_unbind(struct device *dev);
>>> +
>>> +#endif /* __DW_MIPI_DSI__ */
>>>
>>
> _______________________________________________
> linux-arm-kernel mailing list
> [e-mail]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

Philippe CORNU July 3, 2017, 9:03 a.m. UTC | #6

On 07/03/2017 08:31 AM, Archit Taneja wrote:
> 
> 
> On 06/29/2017 08:13 PM, Philippe CORNU wrote:
>>
>>
>> On 06/28/2017 08:44 AM, Archit Taneja wrote:
>>>
>>>
>>> On 06/19/2017 09:58 PM, Philippe CORNU wrote:
>>>> Add a Synopsys Designware MIPI DSI host DRM bridge driver, based on the
>>>> Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
>>>>
>>>> Signed-off-by: Philippe CORNU <[e-mail]>
>>>> ---
>>>>    drivers/gpu/drm/bridge/synopsys/Kconfig       |   6 +
>>>>    drivers/gpu/drm/bridge/synopsys/Makefile      |   2 +
>>>>    drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 976
>>>> ++++++++++++++++++++++++++
>>>>    include/drm/bridge/dw_mipi_dsi.h              |  39 +
>>>>    4 files changed, 1023 insertions(+)
>>>>    create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>>>    create mode 100644 include/drm/bridge/dw_mipi_dsi.h
>>>>
>>>> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig
>>>> b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>>> index 40d2827..f00ee26 100644
>>>> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
>>>> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
>>>> @@ -21,3 +21,9 @@ config DRM_DW_HDMI_I2S_AUDIO
>>>>        help
>>>>          Support the I2S Audio interface which is part of the Synopsys
>>>>          Designware HDMI block.
>>>> +
>>>> +config DRM_DW_MIPI_DSI
>>>> +    tristate
>>>> +    select DRM_KMS_HELPER
>>>> +    select DRM_MIPI_DSI
>>>> +    select DRM_PANEL_BRIDGE
>>>> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile
>>>> b/drivers/gpu/drm/bridge/synopsys/Makefile
>>>> index 17aa7a6..5f57d36 100644
>>>> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
>>>> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
>>>> @@ -3,3 +3,5 @@
>>>>    obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
>>>>    obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
>>>>    obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
>>>> +
>>>> +obj-$(CONFIG_DRM_DW_MIPI_DSI) += dw-mipi-dsi.o
>>>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>>> b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>>> new file mode 100644
>>>> index 0000000..416ed7f
>>>> --- /dev/null
>>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>>>> @@ -0,0 +1,976 @@
>>>> +/*
>>>> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
>>>> + * Copyright (C) STMicroelectronics SA 2017
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or 
>>>> modify
>>>> + * it under the terms of the GNU General Public License as 
>>>> published by
>>>> + * the Free Software Foundation; either version 2 of the License, or
>>>> + * (at your option) any later version.
>>>> + *
>>>> + * Modified by Philippe Cornu <[e-mail]>
>>>> + * This generic Synopsys DesignWare MIPI DSI host driver is based 
>>>> on the
>>>> + * Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge 
>>>> APIs.
>>>> + */
>>>> +
>>>> +#include <linux/clk.h>
>>>> +#include <linux/component.h>
>>>> +#include <linux/iopoll.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/of_device.h>
>>>> +#include <linux/pm_runtime.h>
>>>> +#include <linux/reset.h>
>>>> +#include <drm/drmP.h>
>>>> +#include <drm/drm_atomic_helper.h>
>>>> +#include <drm/drm_bridge.h>
>>>> +#include <drm/drm_crtc.h>
>>>> +#include <drm/drm_crtc_helper.h>
>>>> +#include <drm/drm_mipi_dsi.h>
>>>> +#include <drm/drm_of.h>
>>>> +#include <drm/bridge/dw_mipi_dsi.h>
>>>> +#include <video/mipi_display.h>
>>>> +
>>>> +#define DSI_VERSION            0x00
>>>> +#define DSI_PWR_UP            0x04
>>>> +#define RESET                0
>>>> +#define POWERUP                BIT(0)
>>>> +
>>>> +#define DSI_CLKMGR_CFG            0x08
>>>> +#define TO_CLK_DIVIDSION(div)        (((div) & 0xff) << 8)
>>>> +#define TX_ESC_CLK_DIVIDSION(div)    (((div) & 0xff) << 0)
>>>> +
>>>> +#define DSI_DPI_VCID            0x0c
>>>> +#define DPI_VID(vid)            (((vid) & 0x3) << 0)
>>>> +
>>>> +#define DSI_DPI_COLOR_CODING        0x10
>>>> +#define EN18_LOOSELY            BIT(8)
>>>> +#define DPI_COLOR_CODING_16BIT_1    0x0
>>>> +#define DPI_COLOR_CODING_16BIT_2    0x1
>>>> +#define DPI_COLOR_CODING_16BIT_3    0x2
>>>> +#define DPI_COLOR_CODING_18BIT_1    0x3
>>>> +#define DPI_COLOR_CODING_18BIT_2    0x4
>>>> +#define DPI_COLOR_CODING_24BIT        0x5
>>>> +
>>>> +#define DSI_DPI_CFG_POL            0x14
>>>> +#define COLORM_ACTIVE_LOW        BIT(4)
>>>> +#define SHUTD_ACTIVE_LOW        BIT(3)
>>>> +#define HSYNC_ACTIVE_LOW        BIT(2)
>>>> +#define VSYNC_ACTIVE_LOW        BIT(1)
>>>> +#define DATAEN_ACTIVE_LOW        BIT(0)
>>>> +
>>>> +#define DSI_DPI_LP_CMD_TIM        0x18
>>>> +#define OUTVACT_LPCMD_TIME(p)        (((p) & 0xff) << 16)
>>>> +#define INVACT_LPCMD_TIME(p)        ((p) & 0xff)
>>>> +
>>>> +#define DSI_DBI_CFG            0x20
>>>> +#define DSI_DBI_CMDSIZE            0x28
>>>> +
>>>> +#define DSI_PCKHDL_CFG            0x2c
>>>> +#define EN_CRC_RX            BIT(4)
>>>> +#define EN_ECC_RX            BIT(3)
>>>> +#define EN_BTA                BIT(2)
>>>> +#define EN_EOTP_RX            BIT(1)
>>>> +#define EN_EOTP_TX            BIT(0)
>>>> +
>>>> +#define DSI_MODE_CFG            0x34
>>>> +#define ENABLE_VIDEO_MODE        0
>>>> +#define ENABLE_CMD_MODE            BIT(0)
>>>> +
>>>> +#define DSI_VID_MODE_CFG        0x38
>>>> +#define FRAME_BTA_ACK            BIT(14)
>>>> +#define ENABLE_LOW_POWER        (0x3f << 8)
>>>> +#define ENABLE_LOW_POWER_MASK        (0x3f << 8)
>>>> +#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES    0x0
>>>> +#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS    0x1
>>>> +#define VID_MODE_TYPE_BURST            0x2
>>>> +#define VID_MODE_TYPE_MASK            0x3
>>>> +
>>>> +#define DSI_VID_PKT_SIZE        0x3c
>>>> +#define VID_PKT_SIZE(p)            (((p) & 0x3fff) << 0)
>>>> +#define VID_PKT_MAX_SIZE        0x3fff
>>>> +
>>>> +#define DSI_VID_HSA_TIME        0x48
>>>> +#define DSI_VID_HBP_TIME        0x4c
>>>> +#define DSI_VID_HLINE_TIME        0x50
>>>> +#define DSI_VID_VSA_LINES        0x54
>>>> +#define DSI_VID_VBP_LINES        0x58
>>>> +#define DSI_VID_VFP_LINES        0x5c
>>>> +#define DSI_VID_VACTIVE_LINES        0x60
>>>> +#define DSI_CMD_MODE_CFG        0x68
>>>> +#define MAX_RD_PKT_SIZE_LP        BIT(24)
>>>> +#define DCS_LW_TX_LP            BIT(19)
>>>> +#define DCS_SR_0P_TX_LP            BIT(18)
>>>> +#define DCS_SW_1P_TX_LP            BIT(17)
>>>> +#define DCS_SW_0P_TX_LP            BIT(16)
>>>> +#define GEN_LW_TX_LP            BIT(14)
>>>> +#define GEN_SR_2P_TX_LP            BIT(13)
>>>> +#define GEN_SR_1P_TX_LP            BIT(12)
>>>> +#define GEN_SR_0P_TX_LP            BIT(11)
>>>> +#define GEN_SW_2P_TX_LP            BIT(10)
>>>> +#define GEN_SW_1P_TX_LP            BIT(9)
>>>> +#define GEN_SW_0P_TX_LP            BIT(8)
>>>> +#define EN_ACK_RQST            BIT(1)
>>>> +#define EN_TEAR_FX            BIT(0)
>>>> +
>>>> +#define CMD_MODE_ALL_LP            (MAX_RD_PKT_SIZE_LP | \
>>>> +                     DCS_LW_TX_LP | \
>>>> +                     DCS_SR_0P_TX_LP | \
>>>> +                     DCS_SW_1P_TX_LP | \
>>>> +                     DCS_SW_0P_TX_LP | \
>>>> +                     GEN_LW_TX_LP | \
>>>> +                     GEN_SR_2P_TX_LP | \
>>>> +                     GEN_SR_1P_TX_LP | \
>>>> +                     GEN_SR_0P_TX_LP | \
>>>> +                     GEN_SW_2P_TX_LP | \
>>>> +                     GEN_SW_1P_TX_LP | \
>>>> +                     GEN_SW_0P_TX_LP)
>>>> +
>>>> +#define DSI_GEN_HDR            0x6c
>>>> +#define GEN_HDATA(data)            (((data) & 0xffff) << 8)
>>>> +#define GEN_HDATA_MASK            (0xffff << 8)
>>>> +#define GEN_HTYPE(type)            (((type) & 0xff) << 0)
>>>> +#define GEN_HTYPE_MASK            0xff
>>>> +
>>>> +#define DSI_GEN_PLD_DATA        0x70
>>>> +
>>>> +#define DSI_CMD_PKT_STATUS        0x74
>>>> +#define GEN_CMD_EMPTY            BIT(0)
>>>> +#define GEN_CMD_FULL            BIT(1)
>>>> +#define GEN_PLD_W_EMPTY            BIT(2)
>>>> +#define GEN_PLD_W_FULL            BIT(3)
>>>> +#define GEN_PLD_R_EMPTY            BIT(4)
>>>> +#define GEN_PLD_R_FULL            BIT(5)
>>>> +#define GEN_RD_CMD_BUSY            BIT(6)
>>>> +
>>>> +#define DSI_TO_CNT_CFG            0x78
>>>> +#define HSTX_TO_CNT(p)            (((p) & 0xffff) << 16)
>>>> +#define LPRX_TO_CNT(p)            ((p) & 0xffff)
>>>> +
>>>> +#define DSI_BTA_TO_CNT            0x8c
>>>> +#define DSI_LPCLK_CTRL            0x94
>>>> +#define AUTO_CLKLANE_CTRL        BIT(1)
>>>> +#define PHY_TXREQUESTCLKHS        BIT(0)
>>>> +
>>>> +#define DSI_PHY_TMR_LPCLK_CFG        0x98
>>>> +#define PHY_CLKHS2LP_TIME(lbcc)        (((lbcc) & 0x3ff) << 16)
>>>> +#define PHY_CLKLP2HS_TIME(lbcc)        ((lbcc) & 0x3ff)
>>>> +
>>>> +#define DSI_PHY_TMR_CFG            0x9c
>>>> +#define PHY_HS2LP_TIME(lbcc)        (((lbcc) & 0xff) << 24)
>>>> +#define PHY_LP2HS_TIME(lbcc)        (((lbcc) & 0xff) << 16)
>>>> +#define MAX_RD_TIME(lbcc)        ((lbcc) & 0x7fff)
>>>> +
>>>> +#define DSI_PHY_RSTZ            0xa0
>>>> +#define PHY_DISFORCEPLL            0
>>>> +#define PHY_ENFORCEPLL            BIT(3)
>>>> +#define PHY_DISABLECLK            0
>>>> +#define PHY_ENABLECLK            BIT(2)
>>>> +#define PHY_RSTZ            0
>>>> +#define PHY_UNRSTZ            BIT(1)
>>>> +#define PHY_SHUTDOWNZ            0
>>>> +#define PHY_UNSHUTDOWNZ            BIT(0)
>>>> +
>>>> +#define DSI_PHY_IF_CFG            0xa4
>>>> +#define N_LANES(n)            ((((n) - 1) & 0x3) << 0)
>>>> +#define PHY_STOP_WAIT_TIME(cycle)    (((cycle) & 0xff) << 8)
>>>> +
>>>> +#define DSI_PHY_STATUS            0xb0
>>>> +#define LOCK                BIT(0)
>>>> +#define STOP_STATE_CLK_LANE        BIT(2)
>>>> +
>>>> +#define DSI_PHY_TST_CTRL0        0xb4
>>>> +#define PHY_TESTCLK            BIT(1)
>>>> +#define PHY_UNTESTCLK            0
>>>> +#define PHY_TESTCLR            BIT(0)
>>>> +#define PHY_UNTESTCLR            0
>>>> +
>>>> +#define DSI_PHY_TST_CTRL1        0xb8
>>>> +#define PHY_TESTEN            BIT(16)
>>>> +#define PHY_UNTESTEN            0
>>>> +#define PHY_TESTDOUT(n)            (((n) & 0xff) << 8)
>>>> +#define PHY_TESTDIN(n)            (((n) & 0xff) << 0)
>>>> +
>>>> +#define DSI_INT_ST0            0xbc
>>>> +#define DSI_INT_ST1            0xc0
>>>> +#define DSI_INT_MSK0            0xc4
>>>> +#define DSI_INT_MSK1            0xc8
>>>> +
>>>> +#define PHY_STATUS_TIMEOUT_US        10000
>>>> +#define CMD_PKT_STATUS_TIMEOUT_US    20000
>>>> +
>>>> +struct dw_mipi_dsi {
>>>> +    struct drm_bridge bridge;
>>>> +    struct mipi_dsi_host dsi_host;
>>>> +    struct drm_bridge *panel_bridge;
>>>> +    bool is_panel_bridge;
>>>> +    struct device *dev;
>>>> +    void __iomem *base;
>>>> +
>>>> +    struct clk *pclk;
>>>> +
>>>> +    unsigned int lane_mbps; /* per lane */
>>>> +    u32 channel;
>>>> +    u32 lanes;
>>>> +    u32 format;
>>>> +    unsigned long mode_flags;
>>>> +
>>>> +    const struct dw_mipi_dsi_plat_data *plat_data;
>>>> +};
>>>> +
>>>> +/*
>>>> + * The controller should generate 2 frames before
>>>> + * preparing the peripheral.
>>>> + */
>>>> +static void dw_mipi_dsi_wait_for_two_frames(struct drm_display_mode
>>>> *mode)
>>>> +{
>>>> +    int refresh, two_frames;
>>>> +
>>>> +    refresh = drm_mode_vrefresh(mode);
>>>> +    two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
>>>> +    msleep(two_frames);
>>>> +}
>>>> +
>>>> +static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host
>>>> *host)
>>>> +{
>>>> +    return container_of(host, struct dw_mipi_dsi, dsi_host);
>>>> +}
>>>> +
>>>> +static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge
>>>> *bridge)
>>>> +{
>>>> +    return container_of(bridge, struct dw_mipi_dsi, bridge);
>>>> +}
>>>> +
>>>> +static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 
>>>> val)
>>>> +{
>>>> +    writel(val, dsi->base + reg);
>>>> +}
>>>> +
>>>> +static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
>>>> +{
>>>> +    return readl(dsi->base + reg);
>>>> +}
>>>> +
>>>> +static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
>>>> +                   struct mipi_dsi_device *device)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>>> +    struct drm_bridge *bridge;
>>>> +    struct drm_panel *panel;
>>>> +    int ret;
>>>> +
>>>> +    if (device->lanes > dsi->plat_data->max_data_lanes) {
>>>> +        dev_err(dsi->dev, "the number of data lanes(%u) is too 
>>>> many\n",
>>>> +            device->lanes);
>>>> +        return -EINVAL;
>>>> +    }
>>>> +
>>>> +    dsi->lanes = device->lanes;
>>>> +    dsi->channel = device->channel;
>>>> +    dsi->format = device->format;
>>>> +    dsi->mode_flags = device->mode_flags;
>>>> +
>>>> +    ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
>>>> +                      &panel, &bridge);
>>>> +    if (ret)
>>>> +        return ret;
>>>> +
>>>> +    if (panel) {
>>>> +        bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DSI);
>>>> +        if (IS_ERR(bridge))
>>>> +            return PTR_ERR(bridge);
>>>> +        dsi->is_panel_bridge = true;
>>>> +    }
>>>> +
>>>> +    dsi->panel_bridge = bridge;
>>>> +
>>>> +    return drm_bridge_add(&dsi->bridge);
>>>> +}
>>>> +
>>>> +static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
>>>> +                   struct mipi_dsi_device *device)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>>> +
>>>> +    if (dsi->is_panel_bridge)
>>>> +        drm_panel_bridge_remove(dsi->panel_bridge);
>>>> +
>>>> +    drm_bridge_remove(&dsi->bridge);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
>>>> +                   const struct mipi_dsi_msg *msg)
>>>> +{
>>>> +    bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
>>>> +    u32 val = 0;
>>>> +
>>>> +    if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
>>>> +        val |= EN_ACK_RQST;
>>>> +    if (lpm)
>>>> +        val |= CMD_MODE_ALL_LP;
>>>> +
>>>> +    dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
>>>> +    dsi_write(dsi, DSI_CMD_MODE_CFG, val);
>>>> +}
>>>> +
>>>> +static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32
>>>> hdr_val)
>>>> +{
>>>> +    int ret;
>>>> +    u32 val, mask;
>>>> +
>>>> +    ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>>>> +                 val, !(val & GEN_CMD_FULL), 1000,
>>>> +                 CMD_PKT_STATUS_TIMEOUT_US);
>>>> +    if (ret < 0) {
>>>> +        dev_err(dsi->dev, "failed to get available command FIFO\n");
>>>> +        return ret;
>>>> +    }
>>>> +
>>>> +    dsi_write(dsi, DSI_GEN_HDR, hdr_val);
>>>> +
>>>> +    mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
>>>> +    ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>>>> +                 val, (val & mask) == mask,
>>>> +                 1000, CMD_PKT_STATUS_TIMEOUT_US);
>>>> +    if (ret < 0) {
>>>> +        dev_err(dsi->dev, "failed to write command FIFO\n");
>>>> +        return ret;
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
>>>> +                       const struct mipi_dsi_msg *msg)
>>>> +{
>>>> +    const u8 *tx_buf = msg->tx_buf;
>>>> +    u16 data = 0;
>>>> +    u32 val;
>>>> +
>>>> +    if (msg->tx_len > 0)
>>>> +        data |= tx_buf[0];
>>>> +    if (msg->tx_len > 1)
>>>> +        data |= tx_buf[1] << 8;
>>>> +
>>>> +    if (msg->tx_len > 2) {
>>>> +        dev_err(dsi->dev, "too long tx buf length %zu for short
>>>> write\n",
>>>> +            msg->tx_len);
>>>> +        return -EINVAL;
>>>> +    }
>>>> +
>>>> +    val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
>>>> +    return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
>>>> +}
>>>> +
>>>> +static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
>>>> +                      const struct mipi_dsi_msg *msg)
>>>> +{
>>>> +    const u8 *tx_buf = msg->tx_buf;
>>>> +    int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
>>>> +    u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
>>>> +    u32 remainder;
>>>> +    u32 val;
>>>> +
>>>> +    if (msg->tx_len < 3) {
>>>> +        dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
>>>> +            msg->tx_len);
>>>> +        return -EINVAL;
>>>> +    }
>>>> +
>>>> +    while (DIV_ROUND_UP(len, pld_data_bytes)) {
>>>> +        if (len < pld_data_bytes) {
>>>> +            remainder = 0;
>>>> +            memcpy(&remainder, tx_buf, len);
>>>> +            dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>>>> +            len = 0;
>>>> +        } else {
>>>> +            memcpy(&remainder, tx_buf, pld_data_bytes);
>>>> +            dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
>>>> +            tx_buf += pld_data_bytes;
>>>> +            len -= pld_data_bytes;
>>>> +        }
>>>> +
>>>> +        ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>>>> +                     val, !(val & GEN_PLD_W_FULL), 1000,
>>>> +                     CMD_PKT_STATUS_TIMEOUT_US);
>>>> +        if (ret < 0) {
>>>> +            dev_err(dsi->dev,
>>>> +                "failed to get available write payload FIFO\n");
>>>> +            return ret;
>>>> +        }
>>>> +    }
>>>> +
>>>> +    return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
>>>> +}
>>>> +
>>>> +static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>>>> +                     const struct mipi_dsi_msg *msg)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = host_to_dsi(host);
>>>> +    int ret;
>>>> +
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * use mipi_dsi_create_packet() instead of all following
>>>> +     * functions and code (no switch cases, no
>>>> +     * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
>>>> +     * and use packet.header...
>>>> +     */
>>>> +    dw_mipi_message_config(dsi, msg);
>>>> +
>>>> +    switch (msg->type) {
>>>> +    case MIPI_DSI_DCS_SHORT_WRITE:
>>>> +    case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
>>>> +    case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
>>>> +        ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
>>>> +        break;
>>>> +    case MIPI_DSI_DCS_LONG_WRITE:
>>>> +        ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
>>>> +        break;
>>>> +    default:
>>>> +        dev_err(dsi->dev, "unsupported message type 0x%02x\n",
>>>> +            msg->type);
>>>> +        ret = -EINVAL;
>>>> +    }
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +
>>>> +static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
>>>> +    .attach = dw_mipi_dsi_host_attach,
>>>> +    .detach = dw_mipi_dsi_host_detach,
>>>> +    .transfer = dw_mipi_dsi_host_transfer,
>>>> +};
>>>> +
>>>> +static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    u32 val;
>>>> +
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * enabling low power is panel-dependent, we should use the
>>>> +     * panel configuration here...
>>>> +     */
>>>> +    val = ENABLE_LOW_POWER;
>>>> +
>>>> +    if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
>>>> +        val |= VID_MODE_TYPE_BURST;
>>>> +    else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
>>>> +        val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
>>>> +    else
>>>> +        val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
>>>> +
>>>> +    dsi_write(dsi, DSI_VID_MODE_CFG, val);
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
>>>> +                 unsigned long mode_flags)
>>>> +{
>>>> +    dsi_write(dsi, DSI_PWR_UP, RESET);
>>>> +
>>>> +    if (mode_flags & MIPI_DSI_MODE_VIDEO) {
>>>> +        dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
>>>> +        dw_mipi_dsi_video_mode_config(dsi);
>>>> +        dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
>>>> +    } else {
>>>> +        dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>>>> +    }
>>>> +
>>>> +    dsi_write(dsi, DSI_PWR_UP, POWERUP);
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    dsi_write(dsi, DSI_PWR_UP, RESET);
>>>> +    dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    /*
>>>> +     * The maximum permitted escape clock is 20MHz and it is derived
>>>> from
>>>> +     * lanebyteclk, which is running at "lane_mbps / 8".  Thus we 
>>>> want:
>>>> +     *
>>>> +     *     (lane_mbps >> 3) / esc_clk_division < 20
>>>> +     * which is:
>>>> +     *     (lane_mbps >> 3) / 20 > esc_clk_division
>>>> +     */
>>>> +    u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
>>>> +
>>>> +    dsi_write(dsi, DSI_PWR_UP, RESET);
>>>> +
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * timeout clock division should be computed with the
>>>> +     * high speed transmission counter timeout and byte lane...
>>>> +     */
>>>> +    dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
>>>> +          TX_ESC_CLK_DIVIDSION(esc_clk_division));
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
>>>> +                   struct drm_display_mode *mode)
>>>> +{
>>>> +    u32 val = 0, color = 0;
>>>> +
>>>> +    switch (dsi->format) {
>>>> +    case MIPI_DSI_FMT_RGB888:
>>>> +        color = DPI_COLOR_CODING_24BIT;
>>>> +        break;
>>>> +    case MIPI_DSI_FMT_RGB666:
>>>> +        color = DPI_COLOR_CODING_18BIT_2 | EN18_LOOSELY;
>>>> +        break;
>>>> +    case MIPI_DSI_FMT_RGB666_PACKED:
>>>> +        color = DPI_COLOR_CODING_18BIT_1;
>>>> +        break;
>>>> +    case MIPI_DSI_FMT_RGB565:
>>>> +        color = DPI_COLOR_CODING_16BIT_1;
>>>> +        break;
>>>> +    }
>>>> +
>>>> +    if (mode->flags & DRM_MODE_FLAG_NVSYNC)
>>>> +        val |= VSYNC_ACTIVE_LOW;
>>>> +    if (mode->flags & DRM_MODE_FLAG_NHSYNC)
>>>> +        val |= HSYNC_ACTIVE_LOW;
>>>> +
>>>> +    dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));
>>>> +    dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
>>>> +    dsi_write(dsi, DSI_DPI_CFG_POL, val);
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * largest packet sizes during hfp or during vsa/vpb/vfp
>>>> +     * should be computed according to byte lane, lane number and only
>>>> +     * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
>>>> +     */
>>>> +    dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
>>>> +          | INVACT_LPCMD_TIME(4));
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
>>>> +                        struct drm_display_mode *mode)
>>>> +{
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * only burst mode is supported here. For non-burst video modes,
>>>> +     * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
>>>> +     * DSI_VNPCR.NPSIZE... especially because this driver supports
>>>> +     * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
>>>> +     */
>>>> +    dsi_write(dsi, DSI_VID_PKT_SIZE, VID_PKT_SIZE(mode->hdisplay));
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * compute high speed transmission counter timeout according
>>>> +     * to the timeout clock division (TO_CLK_DIVIDSION) and byte 
>>>> lane...
>>>> +     */
>>>> +    dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) |
>>>> LPRX_TO_CNT(1000));
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * the Bus-Turn-Around Timeout Counter should be computed
>>>> +     * according to byte lane...
>>>> +     */
>>>> +    dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
>>>> +    dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
>>>> +}
>>>> +
>>>> +/* Get lane byte clock cycles. */
>>>> +static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
>>>> +                       struct drm_display_mode *mode,
>>>> +                       u32 hcomponent)
>>>> +{
>>>> +    u32 frac, lbcc;
>>>> +
>>>> +    lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
>>>> +
>>>> +    frac = lbcc % mode->clock;
>>>> +    lbcc = lbcc / mode->clock;
>>>> +    if (frac)
>>>> +        lbcc++;
>>>> +
>>>> +    return lbcc;
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
>>>> +                      struct drm_display_mode *mode)
>>>> +{
>>>> +    u32 htotal, hsa, hbp, lbcc;
>>>> +
>>>> +    htotal = mode->htotal;
>>>> +    hsa = mode->hsync_end - mode->hsync_start;
>>>> +    hbp = mode->htotal - mode->hsync_end;
>>>> +
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * computations below may be improved...
>>>> +     */
>>>> +    lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
>>>> +    dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);
>>>> +
>>>> +    lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
>>>> +    dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);
>>>> +
>>>> +    lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
>>>> +    dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi 
>>>> *dsi,
>>>> +                           struct drm_display_mode *mode)
>>>> +{
>>>> +    u32 vactive, vsa, vfp, vbp;
>>>> +
>>>> +    vactive = mode->vdisplay;
>>>> +    vsa = mode->vsync_end - mode->vsync_start;
>>>> +    vfp = mode->vsync_start - mode->vdisplay;
>>>> +    vbp = mode->vtotal - mode->vsync_end;
>>>> +
>>>> +    dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
>>>> +    dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
>>>> +    dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
>>>> +    dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * data & clock lane timers should be computed according to panel
>>>> +     * blankings and to the automatic clock lane control mode...
>>>> +     * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
>>>> +     * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
>>>> +     */
>>>> +    dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
>>>> +          | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
>>>> +
>>>> +    dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
>>>> +          | PHY_CLKLP2HS_TIME(0x40));
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    /*
>>>> +     * TODO dw drv improvements
>>>> +     * stop wait time should be the maximum between host dsi
>>>> +     * and panel stop wait times
>>>> +     */
>>>> +    dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
>>>> +          N_LANES(dsi->lanes));
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_dphy_init(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    /* Clear PHY state */
>>>> +    dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
>>>> +          | PHY_RSTZ | PHY_SHUTDOWNZ);
>>>> +    dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>>>> +    dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLR);
>>>> +    dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_dphy_enable(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    u32 val;
>>>> +    int ret;
>>>> +
>>>> +    dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
>>>> +          PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
>>>> +
>>>> +    ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>>>> +                 val, val & LOCK, 1000, PHY_STATUS_TIMEOUT_US);
>>>> +    if (ret < 0)
>>>> +        DRM_DEBUG_DRIVER("failed to wait phy lock state\n");
>>>> +
>>>> +    ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
>>>> +                 val, val & STOP_STATE_CLK_LANE, 1000,
>>>> +                 PHY_STATUS_TIMEOUT_US);
>>>> +    if (ret < 0)
>>>> +        DRM_DEBUG_DRIVER("failed to wait phy clk lane stop state\n");
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    dsi_read(dsi, DSI_INT_ST0);
>>>> +    dsi_read(dsi, DSI_INT_ST1);
>>>> +    dsi_write(dsi, DSI_INT_MSK0, 0);
>>>> +    dsi_write(dsi, DSI_INT_MSK1, 0);
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_bridge_post_disable(struct drm_bridge *bridge)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>>> +
>>>> +    /*
>>>> +     * Switch to cmd mode before panel-bridge disable & panel 
>>>> unprepare.
>>>> +     * Note: panel-bridge disable & panel disable has been called
>>>> +     * before by the drm framework.
>>>
>>> I don't think that's exactly the case. I think the sequence should be as
>>> in the
>>> call chain below.
>>>
>>
>> Hi Archit,
>> And many thanks for your comments :-)
>> the word "post_" is missing in the above comment, sorry for that. I
>> should have written "Switch to cmd mode before panel-bridge post_disable
>> & ..." that is much more correct I think, I will update this comment for
>> v5 : )
>>
>>
>>>> +     */
>>>> +    dw_mipi_dsi_set_mode(dsi, 0);
>>>> +
>>>> +    /*
>>>> +     * TODO Only way found to call panel-bridge disable & panel
>>>> unprepare
>>>> +     * before the dsi "final" disable... can we do better?
>>>
>>> I agree, this is a problem. More below.
>>
>> Same remark here, I forgot "post_" in the above comment.
>>
>>>
>>>> +     */
>>>> +    drm_bridge_post_disable(dsi->panel_bridge);
>>>> +
>>>
>>> I'm guessing our display chain is something like:
>>>
>>> KMS_encoder -> DW_DSI_bridge -> Panel_bridge -> Panel
>>>
>>> The order in which the disable ops are called:
>>>
>>> drm_bridge_disable(Panel_bridge)
>>>     - drm_panel_disable(Panel)
>>> drm_bridge_disable(DW_DSI_bridge)
>>> encoder_funcs->prepare(KMS_encoder)
>>> drm_bridge_post_disable(DW_DSI_bridge)
>>> drm_bridge_post_disable(Panel_bridge)
>>>     - drm_panel_unprepare(Panel)
>>>
>>
>> 100%-perfect sequence, I do agree with you : )
>>
>>> Assuming that only drm_panel_unprepare() requires sending DSI commands,
>>
>> Well, it really depends on DSI panels. For instance, panel drivers can
>> send DCS/Generic DSI commands:
>> * in drm_panel_disable(): then these commands are sent during blankings,
>> many lcds allow that. This is the proper place for backlight through DSI
>> (dimming or off), for sleep mode DCS commands...
>>
>> or/and
>>
>> * in drm_panel_unprepare(): then these commands are sent during a
>> "command mode" phase. This is the proper place for many things, from
>> backlight off through DSI, sleep mode DCS commands... to a full power
>> off (voltage regulators are switched off).
>>
>>   From my pov, both drm_panel_disable() & drm_panel_unprepare() may send
>> DSI commands... but it is not a real problem in fact as DSI commands can
>> be sent through blankings in video mode or can be sent in "command 
>> mode"...
>>
>>> you could have
>>> switched to command mode in DW_DSI_bridge's disable() op, and do the
>>> "final" DSI disable
>>> in DW_DSI_bridge's post_disable(), but that would still result in
>>> drm_panel_unprepare()
>>> being called with the DSI host dead.
>>>
>>> The existing call chain of consecutive bridges is the most symmetric
>>> one, and the one
>>> expected to work in most cases, but it clearly doesn't work in your use
>>> case.
>>>
>>> We have a few options:
>>>
>>> - Undo the drm-panel-bridge stuff, and have the freedom of calling
>>> drm_panel ops in
>>> whatever order we want.
>>>
>>> - Put a big TODO/HACK comment here, saying that this needs to be fixed
>>> in the drm_bridge
>>> framework and the API needs to be updated to manage our own call chains.
>>> Also,
>>> instead of calling "drm_bridge_post_disable(dsi->panel_bridge);"
>>> explicitly, we
>>> can manually call panel_bridge->post_disable() op directly. This avoids
>>> us doing
>>> things recursively.
>>>
>>> We would implement the TODO task in drm_bridges only when there are more
>>> people
>>> desperately in the need to have customizable call chains of bridge ops
>>> for long
>>> display chains, so I don't see it being implemented in the near future,
>>> but I don't
>>> think there should be any problem keeping this hack in the dw dsi driver
>>> for now.
>>>
>>> What choice do you prefer?
>>
>> Well, not so easy to decide what could be the best solution...
>>
>> For the time being, I think I prefer keeping the panel bridge proposal
>> (the v4 one), for several reasons in fact:
>>
>> * It saves "many" lines of code, and supporting *both* panels & bridges
>> (homogeneous approach).
>>
>> * It helps reducing explicit calls like drm_panel_() or drm_bridge_()
>> letting the drm framework doing its job :-)
>>
>> * It is not an issue to have a TODO/HACK for the only remaining function
>> call (drm_bridge_post_disable() here). I mean many others drivers calls
>> directly these panel & bridge functions and this forces panel drivers to
>> have in many places in their code "if (enabled) return;" or "if
>> (prepared) return;" and we should work in the future to improve that
>> (ie. Let's drm framework doing its job).
>>
>> * It covers/offers the 3 important "hw disable" phases:
>>     - panel sends DCS/Generic DSI commands during its blankings in a 
>> video
>> mode phase (most of the times, these commands are short, for backlight
>> updates or sleep for instance...), it's correspond to panel_disable().
>>     - panel sends DCS/Generic DSI commands in a command mode phase 
>> (sleep,
>> power off...), it's correspond to panel_unprepare().
>>     - the dsi IP is stopped after the 2 previous phases.
>>
>> So, for all these reasons, I prefer the "Put a big TODO/HACK" option :)
> 
> Sure. For v5, could you consider calling
> panel_bridge->funcs->post_disable() op directly instead of calling
> "drm_bridge_post_disable(dsi->panel_bridge);"? The hack would be more 
> legible,
> and we'd avoid unnecessary recursive chains.
> 
> Thanks,
> Archit
> 

Hi Archit,
I sent the v5 taking into account your comments.
Many thanks : )
Philippe

>>
>> Thank you,
>> Philippe
>>
>>>
>>> Eric, Daniel,
>>>
>>> Fyi, this is another case where the panel-bridge stuff doesn't work so
>>> well. Not
>>> criticizing or anything, just pointing out :)
>>>
>>> Archit
>>>
>>>
>>>> +    dw_mipi_dsi_disable(dsi);
>>>> +    clk_disable_unprepare(dsi->pclk);
>>>> +    pm_runtime_put(dsi->dev);
>>>> +}
>>>> +
>>>> +void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
>>>> +                 struct drm_display_mode *mode,
>>>> +                 struct drm_display_mode *adjusted_mode)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>>> +    const struct dw_mipi_dsi_phy_ops *phy_ops = 
>>>> dsi->plat_data->phy_ops;
>>>> +    void *priv_data = dsi->plat_data->priv_data;
>>>> +    int ret;
>>>> +
>>>> +    clk_prepare_enable(dsi->pclk);
>>>> +
>>>> +    ret = phy_ops->get_lane_mbps(priv_data, mode, dsi->mode_flags,
>>>> +                     dsi->lanes, dsi->format, &dsi->lane_mbps);
>>>> +    if (ret)
>>>> +        DRM_DEBUG_DRIVER("Phy get_lane_mbps() failed\n");
>>>> +
>>>> +    pm_runtime_get_sync(dsi->dev);
>>>> +    dw_mipi_dsi_init(dsi);
>>>> +    dw_mipi_dsi_dpi_config(dsi, mode);
>>>> +    dw_mipi_dsi_packet_handler_config(dsi);
>>>> +    dw_mipi_dsi_video_mode_config(dsi);
>>>> +    dw_mipi_dsi_video_packet_config(dsi, mode);
>>>> +    dw_mipi_dsi_command_mode_config(dsi);
>>>> +    dw_mipi_dsi_line_timer_config(dsi, mode);
>>>> +    dw_mipi_dsi_vertical_timing_config(dsi, mode);
>>>> +
>>>> +    dw_mipi_dsi_dphy_init(dsi);
>>>> +    dw_mipi_dsi_dphy_timing_config(dsi);
>>>> +    dw_mipi_dsi_dphy_interface_config(dsi);
>>>> +
>>>> +    dw_mipi_dsi_clear_err(dsi);
>>>> +
>>>> +    ret = phy_ops->init(priv_data);
>>>> +    if (ret)
>>>> +        DRM_DEBUG_DRIVER("Phy init() failed\n");
>>>> +
>>>> +    dw_mipi_dsi_dphy_enable(dsi);
>>>> +
>>>> +    dw_mipi_dsi_wait_for_two_frames(mode);
>>>> +
>>>> +    /* Switch to cmd mode for panel-bridge pre_enable & panel 
>>>> prepare */
>>>> +    dw_mipi_dsi_set_mode(dsi, 0);
>>>> +}
>>>> +
>>>> +static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>>> +
>>>> +    /* Switch to video mode for panel-bridge enable & panel enable */
>>>> +    dw_mipi_dsi_set_mode(dsi, MIPI_DSI_MODE_VIDEO);
>>>> +}
>>>> +
>>>> +static enum drm_mode_status
>>>> +dw_mipi_dsi_bridge_mode_valid(struct drm_bridge *bridge,
>>>> +                  const struct drm_display_mode *mode)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>>> +    const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
>>>> +    enum drm_mode_status mode_status = MODE_OK;
>>>> +
>>>> +    if (pdata->mode_valid)
>>>> +        mode_status = pdata->mode_valid(pdata->priv_data, mode);
>>>> +
>>>> +    return mode_status;
>>>> +}
>>>> +
>>>> +static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
>>>> +
>>>> +    if (!bridge->encoder) {
>>>> +        DRM_ERROR("Parent encoder object not found\n");
>>>> +        return -ENODEV;
>>>> +    }
>>>> +
>>>> +    /* Set the encoder type as caller does not know it */
>>>> +    bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
>>>> +
>>>> +    /* Attach the panel-bridge to the dsi bridge */
>>>> +    return drm_bridge_attach(bridge->encoder, dsi->panel_bridge,
>>>> bridge);
>>>> +}
>>>> +
>>>> +static struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
>>>> +    .mode_set     = dw_mipi_dsi_bridge_mode_set,
>>>> +    .enable          = dw_mipi_dsi_bridge_enable,
>>>> +    .post_disable = dw_mipi_dsi_bridge_post_disable,
>>>> +    .mode_valid   = dw_mipi_dsi_bridge_mode_valid,
>>>> +    .attach          = dw_mipi_dsi_bridge_attach,
>>>> +};
>>>> +
>>>> +static struct dw_mipi_dsi *
>>>> +__dw_mipi_dsi_probe(struct platform_device *pdev,
>>>> +            const struct dw_mipi_dsi_plat_data *plat_data)
>>>> +{
>>>> +    struct device *dev = &pdev->dev;
>>>> +    struct reset_control *apb_rst;
>>>> +    struct dw_mipi_dsi *dsi;
>>>> +    struct resource *res;
>>>> +    int ret;
>>>> +
>>>> +    dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
>>>> +    if (!dsi)
>>>> +        return ERR_PTR(-ENOMEM);
>>>> +
>>>> +    dsi->dev = dev;
>>>> +    dsi->plat_data = plat_data;
>>>> +
>>>> +    if (!plat_data->phy_ops->init ||
>>>> !plat_data->phy_ops->get_lane_mbps) {
>>>> +        DRM_ERROR("Phy not properly configured\n");
>>>> +        return ERR_PTR(-ENODEV);
>>>> +    }
>>>> +
>>>> +    if (!plat_data->base) {
>>>> +        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>>> +        if (!res)
>>>> +            return ERR_PTR(-ENODEV);
>>>> +
>>>> +        dsi->base = devm_ioremap_resource(dev, res);
>>>> +        if (IS_ERR(dsi->base))
>>>> +            return ERR_PTR(-ENODEV);
>>>> +
>>>> +    } else {
>>>> +        dsi->base = plat_data->base;
>>>> +    }
>>>> +
>>>> +    dsi->pclk = devm_clk_get(dev, "pclk");
>>>> +    if (IS_ERR(dsi->pclk)) {
>>>> +        ret = PTR_ERR(dsi->pclk);
>>>> +        dev_err(dev, "Unable to get pclk: %d\n", ret);
>>>> +        return ERR_PTR(ret);
>>>> +    }
>>>> +
>>>> +    /*
>>>> +     * Note that the reset was not defined in the initial device
>>>> tree, so
>>>> +     * we have to be prepared for it not being found.
>>>> +     */
>>>> +    apb_rst = devm_reset_control_get(dev, "apb");
>>>> +    if (IS_ERR(apb_rst)) {
>>>> +        ret = PTR_ERR(apb_rst);
>>>> +        if (ret == -ENOENT) {
>>>> +            apb_rst = NULL;
>>>> +        } else {
>>>> +            dev_err(dev, "Unable to get reset control: %d\n", ret);
>>>> +            return ERR_PTR(ret);
>>>> +        }
>>>> +    }
>>>> +
>>>> +    if (apb_rst) {
>>>> +        ret = clk_prepare_enable(dsi->pclk);
>>>> +        if (ret) {
>>>> +            dev_err(dev, "%s: Failed to enable pclk\n", __func__);
>>>> +            return ERR_PTR(ret);
>>>> +        }
>>>> +
>>>> +        reset_control_assert(apb_rst);
>>>> +        usleep_range(10, 20);
>>>> +        reset_control_deassert(apb_rst);
>>>> +
>>>> +        clk_disable_unprepare(dsi->pclk);
>>>> +    }
>>>> +
>>>> +    pm_runtime_enable(dev);
>>>> +
>>>> +    dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
>>>> +    dsi->dsi_host.dev = dev;
>>>> +    ret = mipi_dsi_host_register(&dsi->dsi_host);
>>>> +    if (ret) {
>>>> +        dev_err(dev, "Failed to register MIPI host: %d\n", ret);
>>>> +        return ERR_PTR(ret);
>>>> +    }
>>>> +
>>>> +    dsi->bridge.driver_private = dsi;
>>>> +    dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
>>>> +#ifdef CONFIG_OF
>>>> +    dsi->bridge.of_node = pdev->dev.of_node;
>>>> +#endif
>>>> +
>>>> +    dev_set_drvdata(dev, dsi);
>>>> +
>>>> +    return dsi;
>>>> +}
>>>> +
>>>> +static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
>>>> +{
>>>> +    pm_runtime_disable(dsi->dev);
>>>> +}
>>>> +
>>>> +/*
>>>> + * Probe/remove API, used from platforms based on the DRM bridge API.
>>>> + */
>>>> +int dw_mipi_dsi_probe(struct platform_device *pdev,
>>>> +              const struct dw_mipi_dsi_plat_data *plat_data)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi;
>>>> +
>>>> +    dsi = __dw_mipi_dsi_probe(pdev, plat_data);
>>>> +    if (IS_ERR(dsi))
>>>> +        return PTR_ERR(dsi);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_probe);
>>>> +
>>>> +void dw_mipi_dsi_remove(struct platform_device *pdev)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = platform_get_drvdata(pdev);
>>>> +
>>>> +    mipi_dsi_host_unregister(&dsi->dsi_host);
>>>> +
>>>> +    __dw_mipi_dsi_remove(dsi);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_remove);
>>>> +
>>>> +/*
>>>> + * Bind/unbind API, used from platforms based on the component
>>>> framework.
>>>> + */
>>>> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder
>>>> *encoder,
>>>> +             const struct dw_mipi_dsi_plat_data *plat_data)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi;
>>>> +    int ret;
>>>> +
>>>> +    dsi = __dw_mipi_dsi_probe(pdev, plat_data);
>>>> +    if (IS_ERR(dsi))
>>>> +        return PTR_ERR(dsi);
>>>> +
>>>> +    ret = drm_bridge_attach(encoder, &dsi->bridge, NULL);
>>>> +    if (ret) {
>>>> +        dw_mipi_dsi_remove(pdev);
>>>> +        DRM_ERROR("Failed to initialize bridge with drm\n");
>>>> +        return ret;
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_bind);
>>>> +
>>>> +void dw_mipi_dsi_unbind(struct device *dev)
>>>> +{
>>>> +    struct dw_mipi_dsi *dsi = dev_get_drvdata(dev);
>>>> +
>>>> +    __dw_mipi_dsi_remove(dsi);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(dw_mipi_dsi_unbind);
>>>> +
>>>> +MODULE_AUTHOR("Chris Zhong <[e-mail]>");
>>>> +MODULE_AUTHOR("Philippe Cornu <[e-mail]>");
>>>> +MODULE_DESCRIPTION("DW MIPI DSI host controller driver");
>>>> +MODULE_LICENSE("GPL");
>>>> +MODULE_ALIAS("platform:dw-mipi-dsi");
>>>> diff --git a/include/drm/bridge/dw_mipi_dsi.h
>>>> b/include/drm/bridge/dw_mipi_dsi.h
>>>> new file mode 100644
>>>> index 0000000..9b30fec
>>>> --- /dev/null
>>>> +++ b/include/drm/bridge/dw_mipi_dsi.h
>>>> @@ -0,0 +1,39 @@
>>>> +/*
>>>> + * Copyright (C) STMicroelectronics SA 2017
>>>> + *
>>>> + * Authors: Philippe Cornu <[e-mail]>
>>>> + *          Yannick Fertre <[e-mail]>
>>>> + *
>>>> + * License terms:  GNU General Public License (GPL), version 2
>>>> + */
>>>> +
>>>> +#ifndef __DW_MIPI_DSI__
>>>> +#define __DW_MIPI_DSI__
>>>> +
>>>> +struct dw_mipi_dsi_phy_ops {
>>>> +    int (*init)(void *priv_data);
>>>> +    int (*get_lane_mbps)(void *priv_data, struct drm_display_mode 
>>>> *mode,
>>>> +                 unsigned long mode_flags, u32 lanes, u32 format,
>>>> +                 unsigned int *lane_mbps);
>>>> +};
>>>> +
>>>> +struct dw_mipi_dsi_plat_data {
>>>> +    void __iomem *base;
>>>> +    unsigned int max_data_lanes;
>>>> +
>>>> +    enum drm_mode_status (*mode_valid)(void *priv_data,
>>>> +                       const struct drm_display_mode *mode);
>>>> +
>>>> +    const struct dw_mipi_dsi_phy_ops *phy_ops;
>>>> +
>>>> +    void *priv_data;
>>>> +};
>>>> +
>>>> +int dw_mipi_dsi_probe(struct platform_device *pdev,
>>>> +              const struct dw_mipi_dsi_plat_data *plat_data);
>>>> +void dw_mipi_dsi_remove(struct platform_device *pdev);
>>>> +int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder
>>>> *encoder,
>>>> +             const struct dw_mipi_dsi_plat_data *plat_data);
>>>> +void dw_mipi_dsi_unbind(struct device *dev);
>>>> +
>>>> +#endif /* __DW_MIPI_DSI__ */
>>>>
>>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> [e-mail]
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
>

Patch

diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig b/drivers/gpu/drm/bridge/synopsys/Kconfig
index 40d2827..f00ee26 100644
--- a/drivers/gpu/drm/bridge/synopsys/Kconfig
+++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
@@ -21,3 +21,9 @@  config DRM_DW_HDMI_I2S_AUDIO
 	help
 	  Support the I2S Audio interface which is part of the Synopsys
 	  Designware HDMI block.
+
+config DRM_DW_MIPI_DSI
+	tristate
+	select DRM_KMS_HELPER
+	select DRM_MIPI_DSI
+	select DRM_PANEL_BRIDGE
diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile b/drivers/gpu/drm/bridge/synopsys/Makefile
index 17aa7a6..5f57d36 100644
--- a/drivers/gpu/drm/bridge/synopsys/Makefile
+++ b/drivers/gpu/drm/bridge/synopsys/Makefile
@@ -3,3 +3,5 @@ 
 obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
 obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
 obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
+
+obj-$(CONFIG_DRM_DW_MIPI_DSI) += dw-mipi-dsi.o
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
new file mode 100644
index 0000000..416ed7f
--- /dev/null
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -0,0 +1,976 @@ 
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
+ * Copyright (C) STMicroelectronics SA 2017
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Modified by Philippe Cornu <[e-mail]>
+ * This generic Synopsys DesignWare MIPI DSI host driver is based on the
+ * Rockchip version from rockchip/dw-mipi-dsi.c with phy & bridge APIs.
+ */
+
+#include <linux/clk.h>
+#include <linux/component.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <drm/drmP.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_of.h>
+#include <drm/bridge/dw_mipi_dsi.h>
+#include <video/mipi_display.h>
+
+#define DSI_VERSION			0x00
+#define DSI_PWR_UP			0x04
+#define RESET				0
+#define POWERUP				BIT(0)
+
+#define DSI_CLKMGR_CFG			0x08
+#define TO_CLK_DIVIDSION(div)		(((div) & 0xff) << 8)
+#define TX_ESC_CLK_DIVIDSION(div)	(((div) & 0xff) << 0)
+
+#define DSI_DPI_VCID			0x0c
+#define DPI_VID(vid)			(((vid) & 0x3) << 0)
+
+#define DSI_DPI_COLOR_CODING		0x10
+#define EN18_LOOSELY			BIT(8)
+#define DPI_COLOR_CODING_16BIT_1	0x0
+#define DPI_COLOR_CODING_16BIT_2	0x1
+#define DPI_COLOR_CODING_16BIT_3	0x2
+#define DPI_COLOR_CODING_18BIT_1	0x3
+#define DPI_COLOR_CODING_18BIT_2	0x4
+#define DPI_COLOR_CODING_24BIT		0x5
+
+#define DSI_DPI_CFG_POL			0x14
+#define COLORM_ACTIVE_LOW		BIT(4)
+#define SHUTD_ACTIVE_LOW		BIT(3)
+#define HSYNC_ACTIVE_LOW		BIT(2)
+#define VSYNC_ACTIVE_LOW		BIT(1)
+#define DATAEN_ACTIVE_LOW		BIT(0)
+
+#define DSI_DPI_LP_CMD_TIM		0x18
+#define OUTVACT_LPCMD_TIME(p)		(((p) & 0xff) << 16)
+#define INVACT_LPCMD_TIME(p)		((p) & 0xff)
+
+#define DSI_DBI_CFG			0x20
+#define DSI_DBI_CMDSIZE			0x28
+
+#define DSI_PCKHDL_CFG			0x2c
+#define EN_CRC_RX			BIT(4)
+#define EN_ECC_RX			BIT(3)
+#define EN_BTA				BIT(2)
+#define EN_EOTP_RX			BIT(1)
+#define EN_EOTP_TX			BIT(0)
+
+#define DSI_MODE_CFG			0x34
+#define ENABLE_VIDEO_MODE		0
+#define ENABLE_CMD_MODE			BIT(0)
+
+#define DSI_VID_MODE_CFG		0x38
+#define FRAME_BTA_ACK			BIT(14)
+#define ENABLE_LOW_POWER		(0x3f << 8)
+#define ENABLE_LOW_POWER_MASK		(0x3f << 8)
+#define VID_MODE_TYPE_NON_BURST_SYNC_PULSES	0x0
+#define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS	0x1
+#define VID_MODE_TYPE_BURST			0x2
+#define VID_MODE_TYPE_MASK			0x3
+
+#define DSI_VID_PKT_SIZE		0x3c
+#define VID_PKT_SIZE(p)			(((p) & 0x3fff) << 0)
+#define VID_PKT_MAX_SIZE		0x3fff
+
+#define DSI_VID_HSA_TIME		0x48
+#define DSI_VID_HBP_TIME		0x4c
+#define DSI_VID_HLINE_TIME		0x50
+#define DSI_VID_VSA_LINES		0x54
+#define DSI_VID_VBP_LINES		0x58
+#define DSI_VID_VFP_LINES		0x5c
+#define DSI_VID_VACTIVE_LINES		0x60
+#define DSI_CMD_MODE_CFG		0x68
+#define MAX_RD_PKT_SIZE_LP		BIT(24)
+#define DCS_LW_TX_LP			BIT(19)
+#define DCS_SR_0P_TX_LP			BIT(18)
+#define DCS_SW_1P_TX_LP			BIT(17)
+#define DCS_SW_0P_TX_LP			BIT(16)
+#define GEN_LW_TX_LP			BIT(14)
+#define GEN_SR_2P_TX_LP			BIT(13)
+#define GEN_SR_1P_TX_LP			BIT(12)
+#define GEN_SR_0P_TX_LP			BIT(11)
+#define GEN_SW_2P_TX_LP			BIT(10)
+#define GEN_SW_1P_TX_LP			BIT(9)
+#define GEN_SW_0P_TX_LP			BIT(8)
+#define EN_ACK_RQST			BIT(1)
+#define EN_TEAR_FX			BIT(0)
+
+#define CMD_MODE_ALL_LP			(MAX_RD_PKT_SIZE_LP | \
+					 DCS_LW_TX_LP | \
+					 DCS_SR_0P_TX_LP | \
+					 DCS_SW_1P_TX_LP | \
+					 DCS_SW_0P_TX_LP | \
+					 GEN_LW_TX_LP | \
+					 GEN_SR_2P_TX_LP | \
+					 GEN_SR_1P_TX_LP | \
+					 GEN_SR_0P_TX_LP | \
+					 GEN_SW_2P_TX_LP | \
+					 GEN_SW_1P_TX_LP | \
+					 GEN_SW_0P_TX_LP)
+
+#define DSI_GEN_HDR			0x6c
+#define GEN_HDATA(data)			(((data) & 0xffff) << 8)
+#define GEN_HDATA_MASK			(0xffff << 8)
+#define GEN_HTYPE(type)			(((type) & 0xff) << 0)
+#define GEN_HTYPE_MASK			0xff
+
+#define DSI_GEN_PLD_DATA		0x70
+
+#define DSI_CMD_PKT_STATUS		0x74
+#define GEN_CMD_EMPTY			BIT(0)
+#define GEN_CMD_FULL			BIT(1)
+#define GEN_PLD_W_EMPTY			BIT(2)
+#define GEN_PLD_W_FULL			BIT(3)
+#define GEN_PLD_R_EMPTY			BIT(4)
+#define GEN_PLD_R_FULL			BIT(5)
+#define GEN_RD_CMD_BUSY			BIT(6)
+
+#define DSI_TO_CNT_CFG			0x78
+#define HSTX_TO_CNT(p)			(((p) & 0xffff) << 16)
+#define LPRX_TO_CNT(p)			((p) & 0xffff)
+
+#define DSI_BTA_TO_CNT			0x8c
+#define DSI_LPCLK_CTRL			0x94
+#define AUTO_CLKLANE_CTRL		BIT(1)
+#define PHY_TXREQUESTCLKHS		BIT(0)
+
+#define DSI_PHY_TMR_LPCLK_CFG		0x98
+#define PHY_CLKHS2LP_TIME(lbcc)		(((lbcc) & 0x3ff) << 16)
+#define PHY_CLKLP2HS_TIME(lbcc)		((lbcc) & 0x3ff)
+
+#define DSI_PHY_TMR_CFG			0x9c
+#define PHY_HS2LP_TIME(lbcc)		(((lbcc) & 0xff) << 24)
+#define PHY_LP2HS_TIME(lbcc)		(((lbcc) & 0xff) << 16)
+#define MAX_RD_TIME(lbcc)		((lbcc) & 0x7fff)
+
+#define DSI_PHY_RSTZ			0xa0
+#define PHY_DISFORCEPLL			0
+#define PHY_ENFORCEPLL			BIT(3)
+#define PHY_DISABLECLK			0
+#define PHY_ENABLECLK			BIT(2)
+#define PHY_RSTZ			0
+#define PHY_UNRSTZ			BIT(1)
+#define PHY_SHUTDOWNZ			0
+#define PHY_UNSHUTDOWNZ			BIT(0)
+
+#define DSI_PHY_IF_CFG			0xa4
+#define N_LANES(n)			((((n) - 1) & 0x3) << 0)
+#define PHY_STOP_WAIT_TIME(cycle)	(((cycle) & 0xff) << 8)
+
+#define DSI_PHY_STATUS			0xb0
+#define LOCK				BIT(0)
+#define STOP_STATE_CLK_LANE		BIT(2)
+
+#define DSI_PHY_TST_CTRL0		0xb4
+#define PHY_TESTCLK			BIT(1)
+#define PHY_UNTESTCLK			0
+#define PHY_TESTCLR			BIT(0)
+#define PHY_UNTESTCLR			0
+
+#define DSI_PHY_TST_CTRL1		0xb8
+#define PHY_TESTEN			BIT(16)
+#define PHY_UNTESTEN			0
+#define PHY_TESTDOUT(n)			(((n) & 0xff) << 8)
+#define PHY_TESTDIN(n)			(((n) & 0xff) << 0)
+
+#define DSI_INT_ST0			0xbc
+#define DSI_INT_ST1			0xc0
+#define DSI_INT_MSK0			0xc4
+#define DSI_INT_MSK1			0xc8
+
+#define PHY_STATUS_TIMEOUT_US		10000
+#define CMD_PKT_STATUS_TIMEOUT_US	20000
+
+struct dw_mipi_dsi {
+	struct drm_bridge bridge;
+	struct mipi_dsi_host dsi_host;
+	struct drm_bridge *panel_bridge;
+	bool is_panel_bridge;
+	struct device *dev;
+	void __iomem *base;
+
+	struct clk *pclk;
+
+	unsigned int lane_mbps; /* per lane */
+	u32 channel;
+	u32 lanes;
+	u32 format;
+	unsigned long mode_flags;
+
+	const struct dw_mipi_dsi_plat_data *plat_data;
+};
+
+/*
+ * The controller should generate 2 frames before
+ * preparing the peripheral.
+ */
+static void dw_mipi_dsi_wait_for_two_frames(struct drm_display_mode *mode)
+{
+	int refresh, two_frames;
+
+	refresh = drm_mode_vrefresh(mode);
+	two_frames = DIV_ROUND_UP(MSEC_PER_SEC, refresh) * 2;
+	msleep(two_frames);
+}
+
+static inline struct dw_mipi_dsi *host_to_dsi(struct mipi_dsi_host *host)
+{
+	return container_of(host, struct dw_mipi_dsi, dsi_host);
+}
+
+static inline struct dw_mipi_dsi *bridge_to_dsi(struct drm_bridge *bridge)
+{
+	return container_of(bridge, struct dw_mipi_dsi, bridge);
+}
+
+static inline void dsi_write(struct dw_mipi_dsi *dsi, u32 reg, u32 val)
+{
+	writel(val, dsi->base + reg);
+}
+
+static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
+{
+	return readl(dsi->base + reg);
+}
+
+static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
+				   struct mipi_dsi_device *device)
+{
+	struct dw_mipi_dsi *dsi = host_to_dsi(host);
+	struct drm_bridge *bridge;
+	struct drm_panel *panel;
+	int ret;
+
+	if (device->lanes > dsi->plat_data->max_data_lanes) {
+		dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
+			device->lanes);
+		return -EINVAL;
+	}
+
+	dsi->lanes = device->lanes;
+	dsi->channel = device->channel;
+	dsi->format = device->format;
+	dsi->mode_flags = device->mode_flags;
+
+	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
+					  &panel, &bridge);
+	if (ret)
+		return ret;
+
+	if (panel) {
+		bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DSI);
+		if (IS_ERR(bridge))
+			return PTR_ERR(bridge);
+		dsi->is_panel_bridge = true;
+	}
+
+	dsi->panel_bridge = bridge;
+
+	return drm_bridge_add(&dsi->bridge);
+}
+
+static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
+				   struct mipi_dsi_device *device)
+{
+	struct dw_mipi_dsi *dsi = host_to_dsi(host);
+
+	if (dsi->is_panel_bridge)
+		drm_panel_bridge_remove(dsi->panel_bridge);
+
+	drm_bridge_remove(&dsi->bridge);
+
+	return 0;
+}
+
+static void dw_mipi_message_config(struct dw_mipi_dsi *dsi,
+				   const struct mipi_dsi_msg *msg)
+{
+	bool lpm = msg->flags & MIPI_DSI_MSG_USE_LPM;
+	u32 val = 0;
+
+	if (msg->flags & MIPI_DSI_MSG_REQ_ACK)
+		val |= EN_ACK_RQST;
+	if (lpm)
+		val |= CMD_MODE_ALL_LP;
+
+	dsi_write(dsi, DSI_LPCLK_CTRL, lpm ? 0 : PHY_TXREQUESTCLKHS);
+	dsi_write(dsi, DSI_CMD_MODE_CFG, val);
+}
+
+static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
+{
+	int ret;
+	u32 val, mask;
+
+	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+				 val, !(val & GEN_CMD_FULL), 1000,
+				 CMD_PKT_STATUS_TIMEOUT_US);
+	if (ret < 0) {
+		dev_err(dsi->dev, "failed to get available command FIFO\n");
+		return ret;
+	}
+
+	dsi_write(dsi, DSI_GEN_HDR, hdr_val);
+
+	mask = GEN_CMD_EMPTY | GEN_PLD_W_EMPTY;
+	ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+				 val, (val & mask) == mask,
+				 1000, CMD_PKT_STATUS_TIMEOUT_US);
+	if (ret < 0) {
+		dev_err(dsi->dev, "failed to write command FIFO\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int dw_mipi_dsi_dcs_short_write(struct dw_mipi_dsi *dsi,
+				       const struct mipi_dsi_msg *msg)
+{
+	const u8 *tx_buf = msg->tx_buf;
+	u16 data = 0;
+	u32 val;
+
+	if (msg->tx_len > 0)
+		data |= tx_buf[0];
+	if (msg->tx_len > 1)
+		data |= tx_buf[1] << 8;
+
+	if (msg->tx_len > 2) {
+		dev_err(dsi->dev, "too long tx buf length %zu for short write\n",
+			msg->tx_len);
+		return -EINVAL;
+	}
+
+	val = GEN_HDATA(data) | GEN_HTYPE(msg->type);
+	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
+}
+
+static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
+				      const struct mipi_dsi_msg *msg)
+{
+	const u8 *tx_buf = msg->tx_buf;
+	int len = msg->tx_len, pld_data_bytes = sizeof(u32), ret;
+	u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
+	u32 remainder;
+	u32 val;
+
+	if (msg->tx_len < 3) {
+		dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
+			msg->tx_len);
+		return -EINVAL;
+	}
+
+	while (DIV_ROUND_UP(len, pld_data_bytes)) {
+		if (len < pld_data_bytes) {
+			remainder = 0;
+			memcpy(&remainder, tx_buf, len);
+			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
+			len = 0;
+		} else {
+			memcpy(&remainder, tx_buf, pld_data_bytes);
+			dsi_write(dsi, DSI_GEN_PLD_DATA, remainder);
+			tx_buf += pld_data_bytes;
+			len -= pld_data_bytes;
+		}
+
+		ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
+					 val, !(val & GEN_PLD_W_FULL), 1000,
+					 CMD_PKT_STATUS_TIMEOUT_US);
+		if (ret < 0) {
+			dev_err(dsi->dev,
+				"failed to get available write payload FIFO\n");
+			return ret;
+		}
+	}
+
+	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
+}
+
+static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
+					 const struct mipi_dsi_msg *msg)
+{
+	struct dw_mipi_dsi *dsi = host_to_dsi(host);
+	int ret;
+
+	/*
+	 * TODO dw drv improvements
+	 * use mipi_dsi_create_packet() instead of all following
+	 * functions and code (no switch cases, no
+	 * dw_mipi_dsi_dcs_short_write(), only the loop in long_write...)
+	 * and use packet.header...
+	 */
+	dw_mipi_message_config(dsi, msg);
+
+	switch (msg->type) {
+	case MIPI_DSI_DCS_SHORT_WRITE:
+	case MIPI_DSI_DCS_SHORT_WRITE_PARAM:
+	case MIPI_DSI_SET_MAXIMUM_RETURN_PACKET_SIZE:
+		ret = dw_mipi_dsi_dcs_short_write(dsi, msg);
+		break;
+	case MIPI_DSI_DCS_LONG_WRITE:
+		ret = dw_mipi_dsi_dcs_long_write(dsi, msg);
+		break;
+	default:
+		dev_err(dsi->dev, "unsupported message type 0x%02x\n",
+			msg->type);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
+	.attach = dw_mipi_dsi_host_attach,
+	.detach = dw_mipi_dsi_host_detach,
+	.transfer = dw_mipi_dsi_host_transfer,
+};
+
+static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
+{
+	u32 val;
+
+	/*
+	 * TODO dw drv improvements
+	 * enabling low power is panel-dependent, we should use the
+	 * panel configuration here...
+	 */
+	val = ENABLE_LOW_POWER;
+
+	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
+		val |= VID_MODE_TYPE_BURST;
+	else if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
+		val |= VID_MODE_TYPE_NON_BURST_SYNC_PULSES;
+	else
+		val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
+
+	dsi_write(dsi, DSI_VID_MODE_CFG, val);
+}
+
+static void dw_mipi_dsi_set_mode(struct dw_mipi_dsi *dsi,
+				 unsigned long mode_flags)
+{
+	dsi_write(dsi, DSI_PWR_UP, RESET);
+
+	if (mode_flags & MIPI_DSI_MODE_VIDEO) {
+		dsi_write(dsi, DSI_MODE_CFG, ENABLE_VIDEO_MODE);
+		dw_mipi_dsi_video_mode_config(dsi);
+		dsi_write(dsi, DSI_LPCLK_CTRL, PHY_TXREQUESTCLKHS);
+	} else {
+		dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
+	}
+
+	dsi_write(dsi, DSI_PWR_UP, POWERUP);
+}
+
+static void dw_mipi_dsi_disable(struct dw_mipi_dsi *dsi)
+{
+	dsi_write(dsi, DSI_PWR_UP, RESET);
+	dsi_write(dsi, DSI_PHY_RSTZ, PHY_RSTZ);
+}
+
+static void dw_mipi_dsi_init(struct dw_mipi_dsi *dsi)
+{
+	/*
+	 * The maximum permitted escape clock is 20MHz and it is derived from
+	 * lanebyteclk, which is running at "lane_mbps / 8".  Thus we want:
+	 *
+	 *     (lane_mbps >> 3) / esc_clk_division < 20
+	 * which is:
+	 *     (lane_mbps >> 3) / 20 > esc_clk_division
+	 */
+	u32 esc_clk_division = (dsi->lane_mbps >> 3) / 20 + 1;
+
+	dsi_write(dsi, DSI_PWR_UP, RESET);
+
+	/*
+	 * TODO dw drv improvements
+	 * timeout clock division should be computed with the
+	 * high speed transmission counter timeout and byte lane...
+	 */
+	dsi_write(dsi, DSI_CLKMGR_CFG, TO_CLK_DIVIDSION(10) |
+		  TX_ESC_CLK_DIVIDSION(esc_clk_division));
+}
+
+static void dw_mipi_dsi_dpi_config(struct dw_mipi_dsi *dsi,
+				   struct drm_display_mode *mode)
+{
+	u32 val = 0, color = 0;
+
+	switch (dsi->format) {
+	case MIPI_DSI_FMT_RGB888:
+		color = DPI_COLOR_CODING_24BIT;
+		break;
+	case MIPI_DSI_FMT_RGB666:
+		color = DPI_COLOR_CODING_18BIT_2 | EN18_LOOSELY;
+		break;
+	case MIPI_DSI_FMT_RGB666_PACKED:
+		color = DPI_COLOR_CODING_18BIT_1;
+		break;
+	case MIPI_DSI_FMT_RGB565:
+		color = DPI_COLOR_CODING_16BIT_1;
+		break;
+	}
+
+	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+		val |= VSYNC_ACTIVE_LOW;
+	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+		val |= HSYNC_ACTIVE_LOW;
+
+	dsi_write(dsi, DSI_DPI_VCID, DPI_VID(dsi->channel));
+	dsi_write(dsi, DSI_DPI_COLOR_CODING, color);
+	dsi_write(dsi, DSI_DPI_CFG_POL, val);
+	/*
+	 * TODO dw drv improvements
+	 * largest packet sizes during hfp or during vsa/vpb/vfp
+	 * should be computed according to byte lane, lane number and only
+	 * if sending lp cmds in high speed is enable (PHY_TXREQUESTCLKHS)
+	 */
+	dsi_write(dsi, DSI_DPI_LP_CMD_TIM, OUTVACT_LPCMD_TIME(4)
+		  | INVACT_LPCMD_TIME(4));
+}
+
+static void dw_mipi_dsi_packet_handler_config(struct dw_mipi_dsi *dsi)
+{
+	dsi_write(dsi, DSI_PCKHDL_CFG, EN_CRC_RX | EN_ECC_RX | EN_BTA);
+}
+
+static void dw_mipi_dsi_video_packet_config(struct dw_mipi_dsi *dsi,
+					    struct drm_display_mode *mode)
+{
+	/*
+	 * TODO dw drv improvements
+	 * only burst mode is supported here. For non-burst video modes,
+	 * we should compute DSI_VID_PKT_SIZE, DSI_VCCR.NUMC &
+	 * DSI_VNPCR.NPSIZE... especially because this driver supports
+	 * non-burst video modes, see dw_mipi_dsi_video_mode_config()...
+	 */
+	dsi_write(dsi, DSI_VID_PKT_SIZE, VID_PKT_SIZE(mode->hdisplay));
+}
+
+static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi)
+{
+	/*
+	 * TODO dw drv improvements
+	 * compute high speed transmission counter timeout according
+	 * to the timeout clock division (TO_CLK_DIVIDSION) and byte lane...
+	 */
+	dsi_write(dsi, DSI_TO_CNT_CFG, HSTX_TO_CNT(1000) | LPRX_TO_CNT(1000));
+	/*
+	 * TODO dw drv improvements
+	 * the Bus-Turn-Around Timeout Counter should be computed
+	 * according to byte lane...
+	 */
+	dsi_write(dsi, DSI_BTA_TO_CNT, 0xd00);
+	dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE);
+}
+
+/* Get lane byte clock cycles. */
+static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi,
+					   struct drm_display_mode *mode,
+					   u32 hcomponent)
+{
+	u32 frac, lbcc;
+
+	lbcc = hcomponent * dsi->lane_mbps * MSEC_PER_SEC / 8;
+
+	frac = lbcc % mode->clock;
+	lbcc = lbcc / mode->clock;
+	if (frac)
+		lbcc++;
+
+	return lbcc;
+}
+
+static void dw_mipi_dsi_line_timer_config(struct dw_mipi_dsi *dsi,
+					  struct drm_display_mode *mode)
+{
+	u32 htotal, hsa, hbp, lbcc;
+
+	htotal = mode->htotal;
+	hsa = mode->hsync_end - mode->hsync_start;
+	hbp = mode->htotal - mode->hsync_end;
+
+	/*
+	 * TODO dw drv improvements
+	 * computations below may be improved...
+	 */
+	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, htotal);
+	dsi_write(dsi, DSI_VID_HLINE_TIME, lbcc);
+
+	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hsa);
+	dsi_write(dsi, DSI_VID_HSA_TIME, lbcc);
+
+	lbcc = dw_mipi_dsi_get_hcomponent_lbcc(dsi, mode, hbp);
+	dsi_write(dsi, DSI_VID_HBP_TIME, lbcc);
+}
+
+static void dw_mipi_dsi_vertical_timing_config(struct dw_mipi_dsi *dsi,
+					       struct drm_display_mode *mode)
+{
+	u32 vactive, vsa, vfp, vbp;
+
+	vactive = mode->vdisplay;
+	vsa = mode->vsync_end - mode->vsync_start;
+	vfp = mode->vsync_start - mode->vdisplay;
+	vbp = mode->vtotal - mode->vsync_end;
+
+	dsi_write(dsi, DSI_VID_VACTIVE_LINES, vactive);
+	dsi_write(dsi, DSI_VID_VSA_LINES, vsa);
+	dsi_write(dsi, DSI_VID_VFP_LINES, vfp);
+	dsi_write(dsi, DSI_VID_VBP_LINES, vbp);
+}
+
+static void dw_mipi_dsi_dphy_timing_config(struct dw_mipi_dsi *dsi)
+{
+	/*
+	 * TODO dw drv improvements
+	 * data & clock lane timers should be computed according to panel
+	 * blankings and to the automatic clock lane control mode...
+	 * note: DSI_PHY_TMR_CFG.MAX_RD_TIME should be in line with
+	 * DSI_CMD_MODE_CFG.MAX_RD_PKT_SIZE_LP (see CMD_MODE_ALL_LP)
+	 */
+	dsi_write(dsi, DSI_PHY_TMR_CFG, PHY_HS2LP_TIME(0x40)
+		  | PHY_LP2HS_TIME(0x40) | MAX_RD_TIME(10000));
+
+	dsi_write(dsi, DSI_PHY_TMR_LPCLK_CFG, PHY_CLKHS2LP_TIME(0x40)
+		  | PHY_CLKLP2HS_TIME(0x40));
+}
+
+static void dw_mipi_dsi_dphy_interface_config(struct dw_mipi_dsi *dsi)
+{
+	/*
+	 * TODO dw drv improvements
+	 * stop wait time should be the maximum between host dsi
+	 * and panel stop wait times
+	 */
+	dsi_write(dsi, DSI_PHY_IF_CFG, PHY_STOP_WAIT_TIME(0x20) |
+		  N_LANES(dsi->lanes));
+}
+
+static void dw_mipi_dsi_dphy_init(struct dw_mipi_dsi *dsi)
+{
+	/* Clear PHY state */
+	dsi_write(dsi, DSI_PHY_RSTZ, PHY_DISFORCEPLL | PHY_DISABLECLK
+		  | PHY_RSTZ | PHY_SHUTDOWNZ);
+	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
+	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_TESTCLR);
+	dsi_write(dsi, DSI_PHY_TST_CTRL0, PHY_UNTESTCLR);
+}
+
+static void dw_mipi_dsi_dphy_enable(struct dw_mipi_dsi *dsi)
+{
+	u32 val;
+	int ret;
+
+	dsi_write(dsi, DSI_PHY_RSTZ, PHY_ENFORCEPLL | PHY_ENABLECLK |
+		  PHY_UNRSTZ | PHY_UNSHUTDOWNZ);
+
+	ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
+				 val, val & LOCK, 1000, PHY_STATUS_TIMEOUT_US);
+	if (ret < 0)
+		DRM_DEBUG_DRIVER("failed to wait phy lock state\n");
+
+	ret = readl_poll_timeout(dsi->base + DSI_PHY_STATUS,
+				 val, val & STOP_STATE_CLK_LANE, 1000,
+				 PHY_STATUS_TIMEOUT_US);
+	if (ret < 0)
+		DRM_DEBUG_DRIVER("failed to wait phy clk lane stop state\n");
+}
+
+static void dw_mipi_dsi_clear_err(struct dw_mipi_dsi *dsi)
+{
+	dsi_read(dsi, DSI_INT_ST0);
+	dsi_read(dsi, DSI_INT_ST1);
+	dsi_write(dsi, DSI_INT_MSK0, 0);
+	dsi_write(dsi, DSI_INT_MSK1, 0);
+}
+
+static void dw_mipi_dsi_bridge_post_disable(struct drm_bridge *bridge)
+{
+	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+
+	/*
+	 * Switch to cmd mode before panel-bridge disable & panel unprepare.
+	 * Note: panel-bridge disable & panel disable has been called
+	 * before by the drm framework.
+	 */
+	dw_mipi_dsi_set_mode(dsi, 0);
+
+	/*
+	 * TODO Only way found to call panel-bridge disable & panel unprepare
+	 * before the dsi "final" disable... can we do better?
+	 */
+	drm_bridge_post_disable(dsi->panel_bridge);
+
+	dw_mipi_dsi_disable(dsi);
+	clk_disable_unprepare(dsi->pclk);
+	pm_runtime_put(dsi->dev);
+}
+
+void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
+				 struct drm_display_mode *mode,
+				 struct drm_display_mode *adjusted_mode)
+{
+	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+	const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
+	void *priv_data = dsi->plat_data->priv_data;
+	int ret;
+
+	clk_prepare_enable(dsi->pclk);
+
+	ret = phy_ops->get_lane_mbps(priv_data, mode, dsi->mode_flags,
+				     dsi->lanes, dsi->format, &dsi->lane_mbps);
+	if (ret)
+		DRM_DEBUG_DRIVER("Phy get_lane_mbps() failed\n");
+
+	pm_runtime_get_sync(dsi->dev);
+	dw_mipi_dsi_init(dsi);
+	dw_mipi_dsi_dpi_config(dsi, mode);
+	dw_mipi_dsi_packet_handler_config(dsi);
+	dw_mipi_dsi_video_mode_config(dsi);
+	dw_mipi_dsi_video_packet_config(dsi, mode);
+	dw_mipi_dsi_command_mode_config(dsi);
+	dw_mipi_dsi_line_timer_config(dsi, mode);
+	dw_mipi_dsi_vertical_timing_config(dsi, mode);
+
+	dw_mipi_dsi_dphy_init(dsi);
+	dw_mipi_dsi_dphy_timing_config(dsi);
+	dw_mipi_dsi_dphy_interface_config(dsi);
+
+	dw_mipi_dsi_clear_err(dsi);
+
+	ret = phy_ops->init(priv_data);
+	if (ret)
+		DRM_DEBUG_DRIVER("Phy init() failed\n");
+
+	dw_mipi_dsi_dphy_enable(dsi);
+
+	dw_mipi_dsi_wait_for_two_frames(mode);
+
+	/* Switch to cmd mode for panel-bridge pre_enable & panel prepare */
+	dw_mipi_dsi_set_mode(dsi, 0);
+}
+
+static void dw_mipi_dsi_bridge_enable(struct drm_bridge *bridge)
+{
+	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+
+	/* Switch to video mode for panel-bridge enable & panel enable */
+	dw_mipi_dsi_set_mode(dsi, MIPI_DSI_MODE_VIDEO);
+}
+
+static enum drm_mode_status
+dw_mipi_dsi_bridge_mode_valid(struct drm_bridge *bridge,
+			      const struct drm_display_mode *mode)
+{
+	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+	const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
+	enum drm_mode_status mode_status = MODE_OK;
+
+	if (pdata->mode_valid)
+		mode_status = pdata->mode_valid(pdata->priv_data, mode);
+
+	return mode_status;
+}
+
+static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge)
+{
+	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
+
+	if (!bridge->encoder) {
+		DRM_ERROR("Parent encoder object not found\n");
+		return -ENODEV;
+	}
+
+	/* Set the encoder type as caller does not know it */
+	bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
+
+	/* Attach the panel-bridge to the dsi bridge */
+	return drm_bridge_attach(bridge->encoder, dsi->panel_bridge, bridge);
+}
+
+static struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
+	.mode_set     = dw_mipi_dsi_bridge_mode_set,
+	.enable	      = dw_mipi_dsi_bridge_enable,
+	.post_disable = dw_mipi_dsi_bridge_post_disable,
+	.mode_valid   = dw_mipi_dsi_bridge_mode_valid,
+	.attach	      = dw_mipi_dsi_bridge_attach,
+};
+
+static struct dw_mipi_dsi *
+__dw_mipi_dsi_probe(struct platform_device *pdev,
+		    const struct dw_mipi_dsi_plat_data *plat_data)
+{
+	struct device *dev = &pdev->dev;
+	struct reset_control *apb_rst;
+	struct dw_mipi_dsi *dsi;
+	struct resource *res;
+	int ret;
+
+	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
+	if (!dsi)
+		return ERR_PTR(-ENOMEM);
+
+	dsi->dev = dev;
+	dsi->plat_data = plat_data;
+
+	if (!plat_data->phy_ops->init || !plat_data->phy_ops->get_lane_mbps) {
+		DRM_ERROR("Phy not properly configured\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	if (!plat_data->base) {
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		if (!res)
+			return ERR_PTR(-ENODEV);
+
+		dsi->base = devm_ioremap_resource(dev, res);
+		if (IS_ERR(dsi->base))
+			return ERR_PTR(-ENODEV);
+
+	} else {
+		dsi->base = plat_data->base;
+	}
+
+	dsi->pclk = devm_clk_get(dev, "pclk");
+	if (IS_ERR(dsi->pclk)) {
+		ret = PTR_ERR(dsi->pclk);
+		dev_err(dev, "Unable to get pclk: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	/*
+	 * Note that the reset was not defined in the initial device tree, so
+	 * we have to be prepared for it not being found.
+	 */
+	apb_rst = devm_reset_control_get(dev, "apb");
+	if (IS_ERR(apb_rst)) {
+		ret = PTR_ERR(apb_rst);
+		if (ret == -ENOENT) {
+			apb_rst = NULL;
+		} else {
+			dev_err(dev, "Unable to get reset control: %d\n", ret);
+			return ERR_PTR(ret);
+		}
+	}
+
+	if (apb_rst) {
+		ret = clk_prepare_enable(dsi->pclk);
+		if (ret) {
+			dev_err(dev, "%s: Failed to enable pclk\n", __func__);
+			return ERR_PTR(ret);
+		}
+
+		reset_control_assert(apb_rst);
+		usleep_range(10, 20);
+		reset_control_deassert(apb_rst);
+
+		clk_disable_unprepare(dsi->pclk);
+	}
+
+	pm_runtime_enable(dev);
+
+	dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
+	dsi->dsi_host.dev = dev;
+	ret = mipi_dsi_host_register(&dsi->dsi_host);
+	if (ret) {
+		dev_err(dev, "Failed to register MIPI host: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	dsi->bridge.driver_private = dsi;
+	dsi->bridge.funcs = &dw_mipi_dsi_bridge_funcs;
+#ifdef CONFIG_OF
+	dsi->bridge.of_node = pdev->dev.of_node;
+#endif
+
+	dev_set_drvdata(dev, dsi);
+
+	return dsi;
+}
+
+static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
+{
+	pm_runtime_disable(dsi->dev);
+}
+
+/*
+ * Probe/remove API, used from platforms based on the DRM bridge API.
+ */
+int dw_mipi_dsi_probe(struct platform_device *pdev,
+		      const struct dw_mipi_dsi_plat_data *plat_data)
+{
+	struct dw_mipi_dsi *dsi;
+
+	dsi = __dw_mipi_dsi_probe(pdev, plat_data);
+	if (IS_ERR(dsi))
+		return PTR_ERR(dsi);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_mipi_dsi_probe);
+
+void dw_mipi_dsi_remove(struct platform_device *pdev)
+{
+	struct dw_mipi_dsi *dsi = platform_get_drvdata(pdev);
+
+	mipi_dsi_host_unregister(&dsi->dsi_host);
+
+	__dw_mipi_dsi_remove(dsi);
+}
+EXPORT_SYMBOL_GPL(dw_mipi_dsi_remove);
+
+/*
+ * Bind/unbind API, used from platforms based on the component framework.
+ */
+int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder *encoder,
+		     const struct dw_mipi_dsi_plat_data *plat_data)
+{
+	struct dw_mipi_dsi *dsi;
+	int ret;
+
+	dsi = __dw_mipi_dsi_probe(pdev, plat_data);
+	if (IS_ERR(dsi))
+		return PTR_ERR(dsi);
+
+	ret = drm_bridge_attach(encoder, &dsi->bridge, NULL);
+	if (ret) {
+		dw_mipi_dsi_remove(pdev);
+		DRM_ERROR("Failed to initialize bridge with drm\n");
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_mipi_dsi_bind);
+
+void dw_mipi_dsi_unbind(struct device *dev)
+{
+	struct dw_mipi_dsi *dsi = dev_get_drvdata(dev);
+
+	__dw_mipi_dsi_remove(dsi);
+}
+EXPORT_SYMBOL_GPL(dw_mipi_dsi_unbind);
+
+MODULE_AUTHOR("Chris Zhong <[e-mail]>");
+MODULE_AUTHOR("Philippe Cornu <[e-mail]>");
+MODULE_DESCRIPTION("DW MIPI DSI host controller driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:dw-mipi-dsi");
diff --git a/include/drm/bridge/dw_mipi_dsi.h b/include/drm/bridge/dw_mipi_dsi.h
new file mode 100644
index 0000000..9b30fec
--- /dev/null
+++ b/include/drm/bridge/dw_mipi_dsi.h
@@ -0,0 +1,39 @@ 
+/*
+ * Copyright (C) STMicroelectronics SA 2017
+ *
+ * Authors: Philippe Cornu <[e-mail]>
+ *          Yannick Fertre <[e-mail]>
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#ifndef __DW_MIPI_DSI__
+#define __DW_MIPI_DSI__
+
+struct dw_mipi_dsi_phy_ops {
+	int (*init)(void *priv_data);
+	int (*get_lane_mbps)(void *priv_data, struct drm_display_mode *mode,
+			     unsigned long mode_flags, u32 lanes, u32 format,
+			     unsigned int *lane_mbps);
+};
+
+struct dw_mipi_dsi_plat_data {
+	void __iomem *base;
+	unsigned int max_data_lanes;
+
+	enum drm_mode_status (*mode_valid)(void *priv_data,
+					   const struct drm_display_mode *mode);
+
+	const struct dw_mipi_dsi_phy_ops *phy_ops;
+
+	void *priv_data;
+};
+
+int dw_mipi_dsi_probe(struct platform_device *pdev,
+		      const struct dw_mipi_dsi_plat_data *plat_data);
+void dw_mipi_dsi_remove(struct platform_device *pdev);
+int dw_mipi_dsi_bind(struct platform_device *pdev, struct drm_encoder *encoder,
+		     const struct dw_mipi_dsi_plat_data *plat_data);
+void dw_mipi_dsi_unbind(struct device *dev);
+
+#endif /* __DW_MIPI_DSI__ */