drm/i915: CABC support for backlight control
diff mbox

Message ID 1442224394-6297-1-git-send-email-m.deepak@intel.com
State New
Headers show

Commit Message

Deepak M Sept. 14, 2015, 9:53 a.m. UTC
In CABC (Content Adaptive Brightness Control) content grey level
scale can be increased while simultaneously decreasing
brightness of the backlight to achieve same perceived brightness.

The CABC is not standardized and panel vendors are free to follow
their implementation. The CABC implementaion here assumes that the
panels use standard SW register for control.

In this design there will be no PWM signal from the SoC and DCS
commands are sent to enable and control the backlight brightness.

v2:
- Created a new backlight driver for cabc, which will be registered
  only when it cabc is supported by panel. (Daniel Vetter)
v3:
- Use for_each_dsi_port macro for handling port C also (Gaurav)
- Rebase

Signed-off-by: Deepak M <m.deepak@intel.com>
---
 drivers/gpu/drm/i915/Makefile         |    1 +
 drivers/gpu/drm/i915/intel_dsi.c      |   18 +-
 drivers/gpu/drm/i915/intel_dsi_cabc.c |  310 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_dsi_cabc.h |   46 +++++
 drivers/gpu/drm/i915/intel_panel.c    |   23 ++-
 include/video/mipi_display.h          |    8 +
 6 files changed, 399 insertions(+), 7 deletions(-)
 create mode 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c
 create mode 100644 drivers/gpu/drm/i915/intel_dsi_cabc.h

Comments

Jani Nikula Sept. 14, 2015, 12:20 p.m. UTC | #1
On Mon, 14 Sep 2015, Deepak M <m.deepak@intel.com> wrote:
> In CABC (Content Adaptive Brightness Control) content grey level
> scale can be increased while simultaneously decreasing
> brightness of the backlight to achieve same perceived brightness.
>
> The CABC is not standardized and panel vendors are free to follow
> their implementation. The CABC implementaion here assumes that the
> panels use standard SW register for control.
>
> In this design there will be no PWM signal from the SoC and DCS
> commands are sent to enable and control the backlight brightness.

I think CABC is a confusing name for this. At the high level, this
should be called, say, DCS backlight control. I think CABC is a special
case of backlight control in the DSI panel; there are panels with
brightness control via DCS *without* CABC.

See further comments inline.

>
> v2:
> - Created a new backlight driver for cabc, which will be registered
>   only when it cabc is supported by panel. (Daniel Vetter)
> v3:
> - Use for_each_dsi_port macro for handling port C also (Gaurav)
> - Rebase
>
> Signed-off-by: Deepak M <m.deepak@intel.com>
> ---
>  drivers/gpu/drm/i915/Makefile         |    1 +
>  drivers/gpu/drm/i915/intel_dsi.c      |   18 +-
>  drivers/gpu/drm/i915/intel_dsi_cabc.c |  310 +++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_dsi_cabc.h |   46 +++++
>  drivers/gpu/drm/i915/intel_panel.c    |   23 ++-
>  include/video/mipi_display.h          |    8 +
>  6 files changed, 399 insertions(+), 7 deletions(-)
>  create mode 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c
>  create mode 100644 drivers/gpu/drm/i915/intel_dsi_cabc.h
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 44d290a..d87c690 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -82,6 +82,7 @@ i915-y += dvo_ch7017.o \
>  	  intel_dsi.o \
>  	  intel_dsi_panel_vbt.o \
>  	  intel_dsi_pll.o \
> +	  intel_dsi_cabc.o \
>  	  intel_dvo.o \
>  	  intel_hdmi.o \
>  	  intel_i2c.o \
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 781c267..1d98ed8 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -35,6 +35,7 @@
>  #include "i915_drv.h"
>  #include "intel_drv.h"
>  #include "intel_dsi.h"
> +#include "intel_dsi_cabc.h"
>  
>  static const struct {
>  	u16 panel_id;
> @@ -398,7 +399,10 @@ static void intel_dsi_enable(struct intel_encoder *encoder)
>  		intel_dsi_port_enable(encoder);
>  	}
>  
> -	intel_panel_enable_backlight(intel_dsi->attached_connector);
> +	if (dev_priv->vbt.dsi.config->cabc_supported)
> +		cabc_enable_backlight(intel_dsi->attached_connector);
> +	else
> +		intel_panel_enable_backlight(intel_dsi->attached_connector);

See my patch at [1] for how I think all of this should be handled.

[1] http://mid.gmane.org/cover.1442227790.git.jani.nikula@intel.com

>  }
>  
>  static void intel_dsi_pre_enable(struct intel_encoder *encoder)
> @@ -458,12 +462,17 @@ static void intel_dsi_enable_nop(struct intel_encoder *encoder)
>  
>  static void intel_dsi_pre_disable(struct intel_encoder *encoder)
>  {
> +	struct drm_device *dev = encoder->base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
>  	enum port port;
>  
>  	DRM_DEBUG_KMS("\n");
>  
> -	intel_panel_disable_backlight(intel_dsi->attached_connector);
> +	if (dev_priv->vbt.dsi.config->cabc_supported)
> +		cabc_disable_backlight(intel_dsi->attached_connector);
> +	else
> +		intel_panel_disable_backlight(intel_dsi->attached_connector);
>  
>  	if (is_vid_mode(intel_dsi)) {
>  		/* Send Shutdown command to the panel in LP mode */
> @@ -1133,7 +1142,10 @@ void intel_dsi_init(struct drm_device *dev)
>  	}
>  
>  	intel_panel_init(&intel_connector->panel, fixed_mode, NULL);
> -	intel_panel_setup_backlight(connector, INVALID_PIPE);
> +	if (dev_priv->vbt.dsi.config->cabc_supported)
> +		cabc_setup_backlight(connector, INVALID_PIPE);
> +	else
> +		intel_panel_setup_backlight(connector, INVALID_PIPE);
>  
>  	return;
>  
> diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.c b/drivers/gpu/drm/i915/intel_dsi_cabc.c
> new file mode 100644
> index 0000000..c2fcd95
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_dsi_cabc.c
> @@ -0,0 +1,310 @@
> +/*
> + * Copyright © 2006-2010 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + *
> + * Author: Deepak M <m.deepak@intel.com>
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/moduleparam.h>
> +#include "intel_drv.h"
> +#include "intel_dsi.h"
> +#include "i915_drv.h"
> +#include "intel_dsi_cabc.h"
> +#include <video/mipi_display.h>
> +#include <drm/drm_mipi_dsi.h>
> +
> +static inline enum port get_cabc_port(struct intel_dsi *intel_dsi)
> +{
> +	if (intel_dsi->dl_cabc_port == CABC_PORT_C)
> +		return PORT_C;
> +	else
> +		return PORT_A;
> +}
> +
> +int cabc_setup_backlight(struct drm_connector *connector,
> +		enum pipe unused)
> +{
> +	struct drm_device *dev = connector->dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct intel_connector *intel_connector = to_intel_connector(connector);
> +	struct intel_panel *panel = &intel_connector->panel;
> +
> +	if (dev_priv->vbt.backlight.present)
> +		panel->backlight.present = true;
> +	else {
> +		DRM_ERROR("no backlight present per VBT\n");
> +		return 0;
> +	}
> +
> +	panel->backlight.max = CABC_MAX_VALUE;
> +	panel->backlight.level = CABC_MAX_VALUE;
> +
> +	return 0;
> +}
> +
> +u32 cabc_get_backlight(struct intel_connector *connector)
> +{
> +	struct drm_device *dev = connector->base.dev;
> +	struct intel_dsi *intel_dsi = NULL;
> +	struct drm_crtc *crtc = NULL;
> +	struct intel_encoder *encoder = NULL;
> +	struct mipi_dsi_device *dsi_device;
> +	u8 data[2] = {0};
> +	enum port port;
> +	u32 ret;
> +
> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
> +		for_each_encoder_on_crtc(dev, crtc, encoder) {
> +			if (encoder->type == INTEL_OUTPUT_DSI) {
> +				intel_dsi = enc_to_intel_dsi(&encoder->base);
> +				break;
> +			}
> +		}
> +		if (intel_dsi != NULL)
> +			break;
> +	}

You can get at intel_dsi via connector->encoder. No need for this kind
of loops.

Same for similar loops below.

> +
> +	for_each_dsi_port(port, intel_dsi->ports) {
> +		if (intel_dsi->dual_link)
> +			port = get_cabc_port(intel_dsi);
> +
> +		dsi_device = intel_dsi->dsi_hosts[port]->device;
> +		mipi_dsi_dcs_read(dsi_device, MIPI_DCS_CABC_LEVEL_RD, data, 2);
> +
> +		if (intel_dsi->dual_link &&
> +				!(intel_dsi->dl_cabc_port == CABC_PORT_A_AND_C))
> +			break;
> +	}

That is a really confusing way to do the dcs command on one or more
ports. How about making dl_cabc_port (hopefully renamed to something
referring to dcs rather than cabc) a bitmap of ports similar to
intel_dsi->ports, so you can make this loop simply:

	for_each_dsi_port(port, dcs_backlight_ports)
        	...

There'd be no need for special casing and conditional breaks out of the
loop or anything.

Same for similar loops below.

> +
> +	ret = data[1];
> +
> +	return ret;
> +}
> +
> +void cabc_set_backlight(struct intel_connector *connector, u32 level)
> +{
> +	struct drm_device *dev = connector->base.dev;
> +	struct intel_dsi *intel_dsi = NULL;
> +	struct drm_crtc *crtc = NULL;
> +	struct intel_encoder *encoder = NULL;
> +	struct mipi_dsi_device *dsi_device;
> +	u8 data[2] = {0};
> +	enum port port;
> +
> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
> +		for_each_encoder_on_crtc(dev, crtc, encoder) {
> +			if (encoder->type == INTEL_OUTPUT_DSI) {
> +				intel_dsi = enc_to_intel_dsi(&encoder->base);
> +				break;
> +			}
> +		}
> +		if (intel_dsi != NULL)
> +			break;
> +	}
> +
> +	for_each_dsi_port(port, intel_dsi->ports) {
> +		if (intel_dsi->dual_link)
> +			port = get_cabc_port(intel_dsi);
> +
> +		dsi_device = intel_dsi->dsi_hosts[port]->device;
> +		data[1] = level;
> +		data[0] = MIPI_DCS_CABC_LEVEL_WR;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
> +
> +		if (intel_dsi->dual_link &&
> +			!(intel_dsi->dl_cabc_port == CABC_PORT_A_AND_C))
> +			break;
> +	}
> +}
> +
> +void cabc_enable_backlight(struct intel_connector *connector)
> +{
> +	struct drm_device *dev = connector->base.dev;
> +	struct intel_dsi *intel_dsi = NULL;
> +	struct drm_crtc *crtc = NULL;
> +	struct intel_encoder *encoder = NULL;
> +	struct intel_panel *panel = &connector->panel;
> +	struct mipi_dsi_device *dsi_device;
> +	enum port port;
> +	u8 data[2] = {0};
> +
> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
> +		for_each_encoder_on_crtc(dev, crtc, encoder) {
> +			if (encoder->type == INTEL_OUTPUT_DSI) {
> +				intel_dsi = enc_to_intel_dsi(&encoder->base);
> +				break;
> +			}
> +		}
> +		if (intel_dsi != NULL)
> +			break;
> +	}
> +
> +	for_each_dsi_port(port, intel_dsi->ports) {
> +		if (intel_dsi->dual_link)
> +			port = get_cabc_port(intel_dsi);
> +
> +		dsi_device = intel_dsi->dsi_hosts[port]->device;
> +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
> +		data[1] = CABC_BACKLIGHT | CABC_DIMMING_DISPLAY | CABC_BCTRL;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
> +		data[0] = MIPI_DCS_CABC_CONTROL_WR;
> +		data[1] = CABC_STILL_PICTURE;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
> +
> +		if (intel_dsi->dual_link &&
> +				!(intel_dsi->dl_cabc_port == CABC_PORT_A_AND_C))
> +			break;
> +	}
> +
> +	cabc_set_backlight(connector, panel->backlight.level);
> +}
> +
> +void cabc_disable_backlight(struct intel_connector *connector)
> +{
> +	struct drm_device *dev = connector->base.dev;
> +	struct intel_dsi *intel_dsi = NULL;
> +	struct drm_crtc *crtc = NULL;
> +	struct intel_encoder *encoder = NULL;
> +	struct mipi_dsi_device *dsi_device;
> +	enum port port;
> +	u8 data[2] = {0};
> +
> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
> +		for_each_encoder_on_crtc(dev, crtc, encoder) {
> +			if (encoder->type == INTEL_OUTPUT_DSI) {
> +				intel_dsi = enc_to_intel_dsi(&encoder->base);
> +				break;
> +			}
> +		}
> +		if (intel_dsi != NULL)
> +			break;
> +	}
> +
> +	cabc_set_backlight(connector, 0);
> +
> +	for_each_dsi_port(port, intel_dsi->ports) {
> +		if (intel_dsi->dual_link)
> +			port = get_cabc_port(intel_dsi);
> +		dsi_device = intel_dsi->dsi_hosts[port]->device;
> +
> +		data[1] = CABC_OFF;
> +		data[0] = MIPI_DCS_CABC_CONTROL_WR;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
> +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
> +
> +		if (intel_dsi->dual_link &&
> +				!(intel_dsi->dl_cabc_port == CABC_PORT_A_AND_C))
> +			break;
> +	}
> +}
> +static int cabc_backlight_device_update_status(struct backlight_device *bd)
> +{
> +	struct intel_connector *connector = bl_get_data(bd);
> +	struct drm_device *dev = connector->base.dev;
> +
> +	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> +	DRM_DEBUG_KMS("updating intel_backlight, brightness=%d/%d\n",
> +			bd->props.brightness, bd->props.max_brightness);
> +
> +	cabc_set_backlight(connector, bd->props.brightness);
> +
> +	drm_modeset_unlock(&dev->mode_config.connection_mutex);
> +
> +	return 0;
> +}
> +
> +static int cabc_backlight_device_get_brightness(struct backlight_device *bd)
> +{
> +	struct intel_connector *connector = bl_get_data(bd);
> +	struct drm_device *dev = connector->base.dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	int ret;
> +
> +	intel_runtime_pm_get(dev_priv);
> +	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
> +
> +	ret = cabc_get_backlight(connector);
> +
> +	drm_modeset_unlock(&dev->mode_config.connection_mutex);
> +	intel_runtime_pm_put(dev_priv);
> +
> +	return ret;
> +}
> +
> +static const struct backlight_ops cabc_backlight_device_ops = {
> +	.update_status = cabc_backlight_device_update_status,
> +	.get_brightness = cabc_backlight_device_get_brightness,
> +};
> +
> +int cabc_backlight_device_register(struct intel_connector *connector)
> +{
> +	struct intel_panel *panel = &connector->panel;
> +	struct backlight_properties props;
> +
> +	if (WARN_ON(panel->backlight.device))
> +		return -ENODEV;
> +
> +	if (!panel->backlight.present) {
> +		DRM_ERROR("No backlight present\n");
> +		return 0;
> +	}
> +
> +	WARN_ON(panel->backlight.max == 0);
> +
> +	memset(&props, 0, sizeof(props));
> +	props.type = BACKLIGHT_FIRMWARE;
> +	props.max_brightness = panel->backlight.max;
> +	props.brightness = props.max_brightness;
> +
> +	/*
> +	 * Note: using the same name independent of the connector prevents
> +	 * registration of multiple backlight devices in the driver.
> +	 */
> +	panel->backlight.device =
> +		backlight_device_register("intel_backlight",
> +				connector->base.kdev,
> +				connector,
> +				&cabc_backlight_device_ops, &props);
> +
> +	if (IS_ERR(panel->backlight.device)) {
> +		DRM_ERROR("Failed to register backlight: %ld\n",
> +				PTR_ERR(panel->backlight.device));
> +		panel->backlight.device = NULL;
> +		return -ENODEV;
> +	}
> +
> +	DRM_DEBUG_KMS("Connector %s backlight sysfs interface registered\n",
> +			connector->base.name);
> +
> +	return 0;
> +}
> +
> +void cabc_backlight_device_unregister(struct intel_connector *connector)
> +{
> +	struct intel_panel *panel = &connector->panel;
> +
> +	if (panel->backlight.device) {
> +		backlight_device_unregister(panel->backlight.device);
> +		panel->backlight.device = NULL;
> +	}
> +}
> diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.h b/drivers/gpu/drm/i915/intel_dsi_cabc.h
> new file mode 100644
> index 0000000..b1a79d9
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/intel_dsi_cabc.h
> @@ -0,0 +1,46 @@
> +/*
> + * Copyright © 2013 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + *
> + * Author: Deepak M <m.deepak@intel.com>
> + */
> +
> +extern int cabc_backlight_device_register(struct intel_connector *connector);
> +extern void cabc_backlight_device_unregister(struct intel_connector *connector);
> +void cabc_set_backlight(struct intel_connector *connector, u32 level);
> +u32 cabc_get_backlight(struct intel_connector *connector);
> +void cabc_enable_backlight(struct intel_connector *connector);
> +void cabc_disable_backlight(struct intel_connector *connector);
> +int cabc_setup_backlight(struct drm_connector *connector, enum pipe unused);
> +
> +#define CABC_OFF			(0 << 0)
> +#define CABC_USER_INTERFACE_IMAGE	(1 << 0)
> +#define CABC_STILL_PICTURE		(2 << 0)
> +#define CABC_VIDEO_MODE			(3 << 0)
> +
> +#define CABC_BACKLIGHT			(1 << 2)
> +#define CABC_DIMMING_DISPLAY		(1 << 3)
> +#define CABC_BCTRL			(1 << 5)
> +
> +#define CABC_PORT_A			0x00
> +#define CABC_PORT_C			0x01
> +#define CABC_PORT_A_AND_C		0x02
> +#define CABC_MAX_VALUE			0xff
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index e2ab3f6..ff2e586 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -34,6 +34,7 @@
>  #include <linux/moduleparam.h>
>  #include <linux/pwm.h>
>  #include "intel_drv.h"
> +#include "intel_dsi_cabc.h"
>  
>  #define CRC_PMIC_PWM_PERIOD_NS	21333
>  
> @@ -1586,15 +1587,29 @@ void intel_panel_fini(struct intel_panel *panel)
>  void intel_backlight_register(struct drm_device *dev)
>  {
>  	struct intel_connector *connector;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	list_for_each_entry(connector, &dev->mode_config.connector_list, base.head)
> -		intel_backlight_device_register(connector);
> +	list_for_each_entry(connector, &dev->mode_config.connector_list,
> +					base.head) {
> +		if (connector->encoder->type == INTEL_OUTPUT_DSI &&
> +			dev_priv->vbt.dsi.config->cabc_supported)
> +			cabc_backlight_device_register(connector);
> +		else
> +			intel_backlight_device_register(connector);
> +	}
>  }
>  
>  void intel_backlight_unregister(struct drm_device *dev)
>  {
>  	struct intel_connector *connector;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	list_for_each_entry(connector, &dev->mode_config.connector_list, base.head)
> -		intel_backlight_device_unregister(connector);
> +	list_for_each_entry(connector, &dev->mode_config.connector_list,
> +					base.head) {
> +		if (connector->encoder->type == INTEL_OUTPUT_DSI &&
> +			dev_priv->vbt.dsi.config->cabc_supported)
> +			cabc_backlight_device_unregister(connector);
> +		else
> +			intel_backlight_device_unregister(connector);
> +	}
>  }
> diff --git a/include/video/mipi_display.h b/include/video/mipi_display.h
> index ddcc8ca..5b8eeec 100644
> --- a/include/video/mipi_display.h
> +++ b/include/video/mipi_display.h
> @@ -117,6 +117,14 @@ enum {
>  	MIPI_DCS_GET_SCANLINE		= 0x45,
>  	MIPI_DCS_READ_DDB_START		= 0xA1,
>  	MIPI_DCS_READ_DDB_CONTINUE	= 0xA8,
> +	MIPI_DCS_CABC_LEVEL_RD          = 0x52,
> +	MIPI_DCS_CABC_MIN_BRIGHTNESS_RD = 0x5F,
> +	MIPI_DCS_CABC_CONTROL_RD        = 0x56,
> +	MIPI_DCS_CABC_CONTROL_BRIGHT_RD = 0x54,
> +	MIPI_DCS_CABC_LEVEL_WR          = 0x51,
> +	MIPI_DCS_CABC_MIN_BRIGHTNESS_WR = 0x5E,
> +	MIPI_DCS_CABC_CONTROL_WR        = 0x55,
> +	MIPI_DCS_CABC_CONTROL_BRIGHT_WR = 0x53,

These changes need to be a separate patch. And what's the spec
reference, I can't find these.

BR,
Jani.


>  };
>  
>  /* MIPI DCS pixel formats */
> -- 
> 1.7.9.5
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
Deepak M Sept. 14, 2015, 3:31 p.m. UTC | #2
>-----Original Message-----

>From: Jani Nikula [mailto:jani.nikula@linux.intel.com]

>Sent: Monday, September 14, 2015 5:51 PM

>To: Deepak, M; intel-gfx@lists.freedesktop.org

>Cc: Deepak, M

>Subject: Re: [Intel-gfx] [PATCH] drm/i915: CABC support for backlight control

>

>On Mon, 14 Sep 2015, Deepak M <m.deepak@intel.com> wrote:

>> In CABC (Content Adaptive Brightness Control) content grey level scale

>> can be increased while simultaneously decreasing brightness of the

>> backlight to achieve same perceived brightness.

>>

>> The CABC is not standardized and panel vendors are free to follow

>> their implementation. The CABC implementaion here assumes that the

>> panels use standard SW register for control.

>>

>> In this design there will be no PWM signal from the SoC and DCS

>> commands are sent to enable and control the backlight brightness.

>

>I think CABC is a confusing name for this. At the high level, this should be

>called, say, DCS backlight control. I think CABC is a special case of backlight

>control in the DSI panel; there are panels with brightness control via DCS

>*without* CABC.

>

>See further comments inline.

>

>>

>> v2:

>> - Created a new backlight driver for cabc, which will be registered

>>   only when it cabc is supported by panel. (Daniel Vetter)

>> v3:

>> - Use for_each_dsi_port macro for handling port C also (Gaurav)

>> - Rebase

>>

>> Signed-off-by: Deepak M <m.deepak@intel.com>

>> ---

>>  drivers/gpu/drm/i915/Makefile         |    1 +

>>  drivers/gpu/drm/i915/intel_dsi.c      |   18 +-

>>  drivers/gpu/drm/i915/intel_dsi_cabc.c |  310

>+++++++++++++++++++++++++++++++++

>>  drivers/gpu/drm/i915/intel_dsi_cabc.h |   46 +++++

>>  drivers/gpu/drm/i915/intel_panel.c    |   23 ++-

>>  include/video/mipi_display.h          |    8 +

>>  6 files changed, 399 insertions(+), 7 deletions(-)  create mode

>> 100644 drivers/gpu/drm/i915/intel_dsi_cabc.c

>>  create mode 100644 drivers/gpu/drm/i915/intel_dsi_cabc.h

>>

>> diff --git a/drivers/gpu/drm/i915/Makefile

>> b/drivers/gpu/drm/i915/Makefile index 44d290a..d87c690 100644

>> --- a/drivers/gpu/drm/i915/Makefile

>> +++ b/drivers/gpu/drm/i915/Makefile

>> @@ -82,6 +82,7 @@ i915-y += dvo_ch7017.o \

>>  	  intel_dsi.o \

>>  	  intel_dsi_panel_vbt.o \

>>  	  intel_dsi_pll.o \

>> +	  intel_dsi_cabc.o \

>>  	  intel_dvo.o \

>>  	  intel_hdmi.o \

>>  	  intel_i2c.o \

>> diff --git a/drivers/gpu/drm/i915/intel_dsi.c

>> b/drivers/gpu/drm/i915/intel_dsi.c

>> index 781c267..1d98ed8 100644

>> --- a/drivers/gpu/drm/i915/intel_dsi.c

>> +++ b/drivers/gpu/drm/i915/intel_dsi.c

>> @@ -35,6 +35,7 @@

>>  #include "i915_drv.h"

>>  #include "intel_drv.h"

>>  #include "intel_dsi.h"

>> +#include "intel_dsi_cabc.h"

>>

>>  static const struct {

>>  	u16 panel_id;

>> @@ -398,7 +399,10 @@ static void intel_dsi_enable(struct intel_encoder

>*encoder)

>>  		intel_dsi_port_enable(encoder);

>>  	}

>>

>> -	intel_panel_enable_backlight(intel_dsi->attached_connector);

>> +	if (dev_priv->vbt.dsi.config->cabc_supported)

>> +		cabc_enable_backlight(intel_dsi->attached_connector);

>> +	else

>> +		intel_panel_enable_backlight(intel_dsi-

>>attached_connector);

>

>See my patch at [1] for how I think all of this should be handled.

>

>[1] http://mid.gmane.org/cover.1442227790.git.jani.nikula@intel.com

>

[Deepak M] Will go through that patch. 
>>  }

>>

>>  static void intel_dsi_pre_enable(struct intel_encoder *encoder) @@

>> -458,12 +462,17 @@ static void intel_dsi_enable_nop(struct

>> intel_encoder *encoder)

>>

>>  static void intel_dsi_pre_disable(struct intel_encoder *encoder)  {

>> +	struct drm_device *dev = encoder->base.dev;

>> +	struct drm_i915_private *dev_priv = dev->dev_private;

>>  	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);

>>  	enum port port;

>>

>>  	DRM_DEBUG_KMS("\n");

>>

>> -	intel_panel_disable_backlight(intel_dsi->attached_connector);

>> +	if (dev_priv->vbt.dsi.config->cabc_supported)

>> +		cabc_disable_backlight(intel_dsi->attached_connector);

>> +	else

>> +		intel_panel_disable_backlight(intel_dsi-

>>attached_connector);

>>

>>  	if (is_vid_mode(intel_dsi)) {

>>  		/* Send Shutdown command to the panel in LP mode */ @@ -

>1133,7

>> +1142,10 @@ void intel_dsi_init(struct drm_device *dev)

>>  	}

>>

>>  	intel_panel_init(&intel_connector->panel, fixed_mode, NULL);

>> -	intel_panel_setup_backlight(connector, INVALID_PIPE);

>> +	if (dev_priv->vbt.dsi.config->cabc_supported)

>> +		cabc_setup_backlight(connector, INVALID_PIPE);

>> +	else

>> +		intel_panel_setup_backlight(connector, INVALID_PIPE);

>>

>>  	return;

>>

>> diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.c

>> b/drivers/gpu/drm/i915/intel_dsi_cabc.c

>> new file mode 100644

>> index 0000000..c2fcd95

>> --- /dev/null

>> +++ b/drivers/gpu/drm/i915/intel_dsi_cabc.c

>> @@ -0,0 +1,310 @@

>> +/*

>> + * Copyright © 2006-2010 Intel Corporation

>> + *

>> + * Permission is hereby granted, free of charge, to any person

>> +obtaining a

>> + * copy of this software and associated documentation files (the

>> +"Software"),

>> + * to deal in the Software without restriction, including without

>> +limitation

>> + * the rights to use, copy, modify, merge, publish, distribute,

>> +sublicense,

>> + * and/or sell copies of the Software, and to permit persons to whom

>> +the

>> + * Software is furnished to do so, subject to the following conditions:

>> + *

>> + * The above copyright notice and this permission notice (including

>> +the next

>> + * paragraph) shall be included in all copies or substantial portions

>> +of the

>> + * Software.

>> + *

>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY

>KIND,

>> +EXPRESS OR

>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

>> +MERCHANTABILITY,

>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO

>EVENT

>> +SHALL

>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

>DAMAGES

>> +OR OTHER

>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,

>> +ARISING

>> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE

>OR

>> +OTHER

>> + * DEALINGS IN THE SOFTWARE.

>> + *

>> + * Author: Deepak M <m.deepak@intel.com>  */

>> +

>> +#include <linux/kernel.h>

>> +#include <linux/moduleparam.h>

>> +#include "intel_drv.h"

>> +#include "intel_dsi.h"

>> +#include "i915_drv.h"

>> +#include "intel_dsi_cabc.h"

>> +#include <video/mipi_display.h>

>> +#include <drm/drm_mipi_dsi.h>

>> +

>> +static inline enum port get_cabc_port(struct intel_dsi *intel_dsi) {

>> +	if (intel_dsi->dl_cabc_port == CABC_PORT_C)

>> +		return PORT_C;

>> +	else

>> +		return PORT_A;

>> +}

>> +

>> +int cabc_setup_backlight(struct drm_connector *connector,

>> +		enum pipe unused)

>> +{

>> +	struct drm_device *dev = connector->dev;

>> +	struct drm_i915_private *dev_priv = dev->dev_private;

>> +	struct intel_connector *intel_connector =

>to_intel_connector(connector);

>> +	struct intel_panel *panel = &intel_connector->panel;

>> +

>> +	if (dev_priv->vbt.backlight.present)

>> +		panel->backlight.present = true;

>> +	else {

>> +		DRM_ERROR("no backlight present per VBT\n");

>> +		return 0;

>> +	}

>> +

>> +	panel->backlight.max = CABC_MAX_VALUE;

>> +	panel->backlight.level = CABC_MAX_VALUE;

>> +

>> +	return 0;

>> +}

>> +

>> +u32 cabc_get_backlight(struct intel_connector *connector) {

>> +	struct drm_device *dev = connector->base.dev;

>> +	struct intel_dsi *intel_dsi = NULL;

>> +	struct drm_crtc *crtc = NULL;

>> +	struct intel_encoder *encoder = NULL;

>> +	struct mipi_dsi_device *dsi_device;

>> +	u8 data[2] = {0};

>> +	enum port port;

>> +	u32 ret;

>> +

>> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {

>> +		for_each_encoder_on_crtc(dev, crtc, encoder) {

>> +			if (encoder->type == INTEL_OUTPUT_DSI) {

>> +				intel_dsi = enc_to_intel_dsi(&encoder-

>>base);

>> +				break;

>> +			}

>> +		}

>> +		if (intel_dsi != NULL)

>> +			break;

>> +	}

>

>You can get at intel_dsi via connector->encoder. No need for this kind of

>loops.

>

[Deepak M] Okay
>Same for similar loops below.

>

>> +

>> +	for_each_dsi_port(port, intel_dsi->ports) {

>> +		if (intel_dsi->dual_link)

>> +			port = get_cabc_port(intel_dsi);

>> +

>> +		dsi_device = intel_dsi->dsi_hosts[port]->device;

>> +		mipi_dsi_dcs_read(dsi_device, MIPI_DCS_CABC_LEVEL_RD,

>data, 2);

>> +

>> +		if (intel_dsi->dual_link &&

>> +				!(intel_dsi->dl_cabc_port ==

>CABC_PORT_A_AND_C))

>> +			break;

>> +	}

>

>That is a really confusing way to do the dcs command on one or more ports.

>How about making dl_cabc_port (hopefully renamed to something referring

>to dcs rather than cabc) a bitmap of ports similar to intel_dsi->ports, so you

>can make this loop simply:

>

>	for_each_dsi_port(port, dcs_backlight_ports)

>        	...

>

>There'd be no need for special casing and conditional breaks out of the loop or

>anything.

>

>Same for similar loops below.

>

[Deepak M] Nice, will try to implement this way
>> +

>> +	ret = data[1];

>> +

>> +	return ret;

>> +}

>> +

>> +void cabc_set_backlight(struct intel_connector *connector, u32 level)

>> +{

>> +	struct drm_device *dev = connector->base.dev;

>> +	struct intel_dsi *intel_dsi = NULL;

>> +	struct drm_crtc *crtc = NULL;

>> +	struct intel_encoder *encoder = NULL;

>> +	struct mipi_dsi_device *dsi_device;

>> +	u8 data[2] = {0};

>> +	enum port port;

>> +

>> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {

>> +		for_each_encoder_on_crtc(dev, crtc, encoder) {

>> +			if (encoder->type == INTEL_OUTPUT_DSI) {

>> +				intel_dsi = enc_to_intel_dsi(&encoder-

>>base);

>> +				break;

>> +			}

>> +		}

>> +		if (intel_dsi != NULL)

>> +			break;

>> +	}

>> +

>> +	for_each_dsi_port(port, intel_dsi->ports) {

>> +		if (intel_dsi->dual_link)

>> +			port = get_cabc_port(intel_dsi);

>> +

>> +		dsi_device = intel_dsi->dsi_hosts[port]->device;

>> +		data[1] = level;

>> +		data[0] = MIPI_DCS_CABC_LEVEL_WR;

>> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

>> +

>> +		if (intel_dsi->dual_link &&

>> +			!(intel_dsi->dl_cabc_port == CABC_PORT_A_AND_C))

>> +			break;

>> +	}

>> +}

>> +

>> +void cabc_enable_backlight(struct intel_connector *connector) {

>> +	struct drm_device *dev = connector->base.dev;

>> +	struct intel_dsi *intel_dsi = NULL;

>> +	struct drm_crtc *crtc = NULL;

>> +	struct intel_encoder *encoder = NULL;

>> +	struct intel_panel *panel = &connector->panel;

>> +	struct mipi_dsi_device *dsi_device;

>> +	enum port port;

>> +	u8 data[2] = {0};

>> +

>> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {

>> +		for_each_encoder_on_crtc(dev, crtc, encoder) {

>> +			if (encoder->type == INTEL_OUTPUT_DSI) {

>> +				intel_dsi = enc_to_intel_dsi(&encoder-

>>base);

>> +				break;

>> +			}

>> +		}

>> +		if (intel_dsi != NULL)

>> +			break;

>> +	}

>> +

>> +	for_each_dsi_port(port, intel_dsi->ports) {

>> +		if (intel_dsi->dual_link)

>> +			port = get_cabc_port(intel_dsi);

>> +

>> +		dsi_device = intel_dsi->dsi_hosts[port]->device;

>> +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;

>> +		data[1] = CABC_BACKLIGHT | CABC_DIMMING_DISPLAY |

>CABC_BCTRL;

>> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

>> +		data[0] = MIPI_DCS_CABC_CONTROL_WR;

>> +		data[1] = CABC_STILL_PICTURE;

>> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

>> +

>> +		if (intel_dsi->dual_link &&

>> +				!(intel_dsi->dl_cabc_port ==

>CABC_PORT_A_AND_C))

>> +			break;

>> +	}

>> +

>> +	cabc_set_backlight(connector, panel->backlight.level); }

>> +

>> +void cabc_disable_backlight(struct intel_connector *connector) {

>> +	struct drm_device *dev = connector->base.dev;

>> +	struct intel_dsi *intel_dsi = NULL;

>> +	struct drm_crtc *crtc = NULL;

>> +	struct intel_encoder *encoder = NULL;

>> +	struct mipi_dsi_device *dsi_device;

>> +	enum port port;

>> +	u8 data[2] = {0};

>> +

>> +	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {

>> +		for_each_encoder_on_crtc(dev, crtc, encoder) {

>> +			if (encoder->type == INTEL_OUTPUT_DSI) {

>> +				intel_dsi = enc_to_intel_dsi(&encoder-

>>base);

>> +				break;

>> +			}

>> +		}

>> +		if (intel_dsi != NULL)

>> +			break;

>> +	}

>> +

>> +	cabc_set_backlight(connector, 0);

>> +

>> +	for_each_dsi_port(port, intel_dsi->ports) {

>> +		if (intel_dsi->dual_link)

>> +			port = get_cabc_port(intel_dsi);

>> +		dsi_device = intel_dsi->dsi_hosts[port]->device;

>> +

>> +		data[1] = CABC_OFF;

>> +		data[0] = MIPI_DCS_CABC_CONTROL_WR;

>> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

>> +		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;

>> +		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);

>> +

>> +		if (intel_dsi->dual_link &&

>> +				!(intel_dsi->dl_cabc_port ==

>CABC_PORT_A_AND_C))

>> +			break;

>> +	}

>> +}

>> +static int cabc_backlight_device_update_status(struct

>> +backlight_device *bd) {

>> +	struct intel_connector *connector = bl_get_data(bd);

>> +	struct drm_device *dev = connector->base.dev;

>> +

>> +	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);

>> +	DRM_DEBUG_KMS("updating intel_backlight, brightness=%d/%d\n",

>> +			bd->props.brightness, bd->props.max_brightness);

>> +

>> +	cabc_set_backlight(connector, bd->props.brightness);

>> +

>> +	drm_modeset_unlock(&dev->mode_config.connection_mutex);

>> +

>> +	return 0;

>> +}

>> +

>> +static int cabc_backlight_device_get_brightness(struct

>> +backlight_device *bd) {

>> +	struct intel_connector *connector = bl_get_data(bd);

>> +	struct drm_device *dev = connector->base.dev;

>> +	struct drm_i915_private *dev_priv = dev->dev_private;

>> +	int ret;

>> +

>> +	intel_runtime_pm_get(dev_priv);

>> +	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);

>> +

>> +	ret = cabc_get_backlight(connector);

>> +

>> +	drm_modeset_unlock(&dev->mode_config.connection_mutex);

>> +	intel_runtime_pm_put(dev_priv);

>> +

>> +	return ret;

>> +}

>> +

>> +static const struct backlight_ops cabc_backlight_device_ops = {

>> +	.update_status = cabc_backlight_device_update_status,

>> +	.get_brightness = cabc_backlight_device_get_brightness,

>> +};

>> +

>> +int cabc_backlight_device_register(struct intel_connector *connector)

>> +{

>> +	struct intel_panel *panel = &connector->panel;

>> +	struct backlight_properties props;

>> +

>> +	if (WARN_ON(panel->backlight.device))

>> +		return -ENODEV;

>> +

>> +	if (!panel->backlight.present) {

>> +		DRM_ERROR("No backlight present\n");

>> +		return 0;

>> +	}

>> +

>> +	WARN_ON(panel->backlight.max == 0);

>> +

>> +	memset(&props, 0, sizeof(props));

>> +	props.type = BACKLIGHT_FIRMWARE;

>> +	props.max_brightness = panel->backlight.max;

>> +	props.brightness = props.max_brightness;

>> +

>> +	/*

>> +	 * Note: using the same name independent of the connector prevents

>> +	 * registration of multiple backlight devices in the driver.

>> +	 */

>> +	panel->backlight.device =

>> +		backlight_device_register("intel_backlight",

>> +				connector->base.kdev,

>> +				connector,

>> +				&cabc_backlight_device_ops, &props);

>> +

>> +	if (IS_ERR(panel->backlight.device)) {

>> +		DRM_ERROR("Failed to register backlight: %ld\n",

>> +				PTR_ERR(panel->backlight.device));

>> +		panel->backlight.device = NULL;

>> +		return -ENODEV;

>> +	}

>> +

>> +	DRM_DEBUG_KMS("Connector %s backlight sysfs interface

>registered\n",

>> +			connector->base.name);

>> +

>> +	return 0;

>> +}

>> +

>> +void cabc_backlight_device_unregister(struct intel_connector

>> +*connector) {

>> +	struct intel_panel *panel = &connector->panel;

>> +

>> +	if (panel->backlight.device) {

>> +		backlight_device_unregister(panel->backlight.device);

>> +		panel->backlight.device = NULL;

>> +	}

>> +}

>> diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.h

>> b/drivers/gpu/drm/i915/intel_dsi_cabc.h

>> new file mode 100644

>> index 0000000..b1a79d9

>> --- /dev/null

>> +++ b/drivers/gpu/drm/i915/intel_dsi_cabc.h

>> @@ -0,0 +1,46 @@

>> +/*

>> + * Copyright © 2013 Intel Corporation

>> + *

>> + * Permission is hereby granted, free of charge, to any person

>> +obtaining a

>> + * copy of this software and associated documentation files (the

>> +"Software"),

>> + * to deal in the Software without restriction, including without

>> +limitation

>> + * the rights to use, copy, modify, merge, publish, distribute,

>> +sublicense,

>> + * and/or sell copies of the Software, and to permit persons to whom

>> +the

>> + * Software is furnished to do so, subject to the following conditions:

>> + *

>> + * The above copyright notice and this permission notice (including

>> +the next

>> + * paragraph) shall be included in all copies or substantial portions

>> +of the

>> + * Software.

>> + *

>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY

>KIND,

>> +EXPRESS OR

>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

>> +MERCHANTABILITY,

>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO

>EVENT

>> +SHALL

>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,

>DAMAGES

>> +OR OTHER

>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,

>> +ARISING

>> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE

>OR

>> +OTHER

>> + * DEALINGS IN THE SOFTWARE.

>> + *

>> + * Author: Deepak M <m.deepak@intel.com>  */

>> +

>> +extern int cabc_backlight_device_register(struct intel_connector

>> +*connector); extern void cabc_backlight_device_unregister(struct

>> +intel_connector *connector); void cabc_set_backlight(struct

>> +intel_connector *connector, u32 level);

>> +u32 cabc_get_backlight(struct intel_connector *connector); void

>> +cabc_enable_backlight(struct intel_connector *connector); void

>> +cabc_disable_backlight(struct intel_connector *connector); int

>> +cabc_setup_backlight(struct drm_connector *connector, enum pipe

>> +unused);

>> +

>> +#define CABC_OFF			(0 << 0)

>> +#define CABC_USER_INTERFACE_IMAGE	(1 << 0)

>> +#define CABC_STILL_PICTURE		(2 << 0)

>> +#define CABC_VIDEO_MODE			(3 << 0)

>> +

>> +#define CABC_BACKLIGHT			(1 << 2)

>> +#define CABC_DIMMING_DISPLAY		(1 << 3)

>> +#define CABC_BCTRL			(1 << 5)

>> +

>> +#define CABC_PORT_A			0x00

>> +#define CABC_PORT_C			0x01

>> +#define CABC_PORT_A_AND_C		0x02

>> +#define CABC_MAX_VALUE			0xff

>> diff --git a/drivers/gpu/drm/i915/intel_panel.c

>> b/drivers/gpu/drm/i915/intel_panel.c

>> index e2ab3f6..ff2e586 100644

>> --- a/drivers/gpu/drm/i915/intel_panel.c

>> +++ b/drivers/gpu/drm/i915/intel_panel.c

>> @@ -34,6 +34,7 @@

>>  #include <linux/moduleparam.h>

>>  #include <linux/pwm.h>

>>  #include "intel_drv.h"

>> +#include "intel_dsi_cabc.h"

>>

>>  #define CRC_PMIC_PWM_PERIOD_NS	21333

>>

>> @@ -1586,15 +1587,29 @@ void intel_panel_fini(struct intel_panel

>> *panel)  void intel_backlight_register(struct drm_device *dev)  {

>>  	struct intel_connector *connector;

>> +	struct drm_i915_private *dev_priv = dev->dev_private;

>>

>> -	list_for_each_entry(connector, &dev->mode_config.connector_list,

>base.head)

>> -		intel_backlight_device_register(connector);

>> +	list_for_each_entry(connector, &dev->mode_config.connector_list,

>> +					base.head) {

>> +		if (connector->encoder->type == INTEL_OUTPUT_DSI &&

>> +			dev_priv->vbt.dsi.config->cabc_supported)

>> +			cabc_backlight_device_register(connector);

>> +		else

>> +			intel_backlight_device_register(connector);

>> +	}

>>  }

>>

>>  void intel_backlight_unregister(struct drm_device *dev)  {

>>  	struct intel_connector *connector;

>> +	struct drm_i915_private *dev_priv = dev->dev_private;

>>

>> -	list_for_each_entry(connector, &dev->mode_config.connector_list,

>base.head)

>> -		intel_backlight_device_unregister(connector);

>> +	list_for_each_entry(connector, &dev->mode_config.connector_list,

>> +					base.head) {

>> +		if (connector->encoder->type == INTEL_OUTPUT_DSI &&

>> +			dev_priv->vbt.dsi.config->cabc_supported)

>> +			cabc_backlight_device_unregister(connector);

>> +		else

>> +			intel_backlight_device_unregister(connector);

>> +	}

>>  }

>> diff --git a/include/video/mipi_display.h

>> b/include/video/mipi_display.h index ddcc8ca..5b8eeec 100644

>> --- a/include/video/mipi_display.h

>> +++ b/include/video/mipi_display.h

>> @@ -117,6 +117,14 @@ enum {

>>  	MIPI_DCS_GET_SCANLINE		= 0x45,

>>  	MIPI_DCS_READ_DDB_START		= 0xA1,

>>  	MIPI_DCS_READ_DDB_CONTINUE	= 0xA8,

>> +	MIPI_DCS_CABC_LEVEL_RD          = 0x52,

>> +	MIPI_DCS_CABC_MIN_BRIGHTNESS_RD = 0x5F,

>> +	MIPI_DCS_CABC_CONTROL_RD        = 0x56,

>> +	MIPI_DCS_CABC_CONTROL_BRIGHT_RD = 0x54,

>> +	MIPI_DCS_CABC_LEVEL_WR          = 0x51,

>> +	MIPI_DCS_CABC_MIN_BRIGHTNESS_WR = 0x5E,

>> +	MIPI_DCS_CABC_CONTROL_WR        = 0x55,

>> +	MIPI_DCS_CABC_CONTROL_BRIGHT_WR = 0x53,

>

>These changes need to be a separate patch. And what's the spec reference, I

>can't find these.

>

[Deepak M] The HLD can be found in the link https://securewiki.ith.intel.com/display/GfxDisplay/MIPI+Display (it is under Intel firewall)
>BR,

>Jani.

>

>

>>  };

>>

>>  /* MIPI DCS pixel formats */

>> --

>> 1.7.9.5

>>

>> _______________________________________________

>> Intel-gfx mailing list

>> Intel-gfx@lists.freedesktop.org

>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

>

>--

>Jani Nikula, Intel Open Source Technology Center
Jani Nikula Sept. 15, 2015, 7:03 a.m. UTC | #3
On Mon, 14 Sep 2015, "Deepak, M" <m.deepak@intel.com> wrote:
>>-----Original Message-----
>>From: Jani Nikula [mailto:jani.nikula@linux.intel.com]
>>Sent: Monday, September 14, 2015 5:51 PM
>>To: Deepak, M; intel-gfx@lists.freedesktop.org
>>Cc: Deepak, M
>>Subject: Re: [Intel-gfx] [PATCH] drm/i915: CABC support for backlight control
>>
>>On Mon, 14 Sep 2015, Deepak M <m.deepak@intel.com> wrote:
>>> diff --git a/include/video/mipi_display.h
>>> b/include/video/mipi_display.h index ddcc8ca..5b8eeec 100644
>>> --- a/include/video/mipi_display.h
>>> +++ b/include/video/mipi_display.h
>>> @@ -117,6 +117,14 @@ enum {
>>>  	MIPI_DCS_GET_SCANLINE		= 0x45,
>>>  	MIPI_DCS_READ_DDB_START		= 0xA1,
>>>  	MIPI_DCS_READ_DDB_CONTINUE	= 0xA8,
>>> +	MIPI_DCS_CABC_LEVEL_RD          = 0x52,
>>> +	MIPI_DCS_CABC_MIN_BRIGHTNESS_RD = 0x5F,
>>> +	MIPI_DCS_CABC_CONTROL_RD        = 0x56,
>>> +	MIPI_DCS_CABC_CONTROL_BRIGHT_RD = 0x54,
>>> +	MIPI_DCS_CABC_LEVEL_WR          = 0x51,
>>> +	MIPI_DCS_CABC_MIN_BRIGHTNESS_WR = 0x5E,
>>> +	MIPI_DCS_CABC_CONTROL_WR        = 0x55,
>>> +	MIPI_DCS_CABC_CONTROL_BRIGHT_WR = 0x53,
>>
>>These changes need to be a separate patch. And what's the spec reference, I
>>can't find these.
>>
> [Deepak M] The HLD can be found in the link https://securewiki.ith.intel.com/display/GfxDisplay/MIPI+Display (it is under Intel firewall)

If you want to add stuff to include/video/mipi_display.h it has to be
standard DCS commands, in actual MIPI issued specs, not something
internal to us.

Manufacturer specific commands (usually referred to as MCS) need to be
hidden in manufacturer specific files in the driver.

BR,
Jani.

Patch
diff mbox

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 44d290a..d87c690 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -82,6 +82,7 @@  i915-y += dvo_ch7017.o \
 	  intel_dsi.o \
 	  intel_dsi_panel_vbt.o \
 	  intel_dsi_pll.o \
+	  intel_dsi_cabc.o \
 	  intel_dvo.o \
 	  intel_hdmi.o \
 	  intel_i2c.o \
diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
index 781c267..1d98ed8 100644
--- a/drivers/gpu/drm/i915/intel_dsi.c
+++ b/drivers/gpu/drm/i915/intel_dsi.c
@@ -35,6 +35,7 @@ 
 #include "i915_drv.h"
 #include "intel_drv.h"
 #include "intel_dsi.h"
+#include "intel_dsi_cabc.h"
 
 static const struct {
 	u16 panel_id;
@@ -398,7 +399,10 @@  static void intel_dsi_enable(struct intel_encoder *encoder)
 		intel_dsi_port_enable(encoder);
 	}
 
-	intel_panel_enable_backlight(intel_dsi->attached_connector);
+	if (dev_priv->vbt.dsi.config->cabc_supported)
+		cabc_enable_backlight(intel_dsi->attached_connector);
+	else
+		intel_panel_enable_backlight(intel_dsi->attached_connector);
 }
 
 static void intel_dsi_pre_enable(struct intel_encoder *encoder)
@@ -458,12 +462,17 @@  static void intel_dsi_enable_nop(struct intel_encoder *encoder)
 
 static void intel_dsi_pre_disable(struct intel_encoder *encoder)
 {
+	struct drm_device *dev = encoder->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
 	enum port port;
 
 	DRM_DEBUG_KMS("\n");
 
-	intel_panel_disable_backlight(intel_dsi->attached_connector);
+	if (dev_priv->vbt.dsi.config->cabc_supported)
+		cabc_disable_backlight(intel_dsi->attached_connector);
+	else
+		intel_panel_disable_backlight(intel_dsi->attached_connector);
 
 	if (is_vid_mode(intel_dsi)) {
 		/* Send Shutdown command to the panel in LP mode */
@@ -1133,7 +1142,10 @@  void intel_dsi_init(struct drm_device *dev)
 	}
 
 	intel_panel_init(&intel_connector->panel, fixed_mode, NULL);
-	intel_panel_setup_backlight(connector, INVALID_PIPE);
+	if (dev_priv->vbt.dsi.config->cabc_supported)
+		cabc_setup_backlight(connector, INVALID_PIPE);
+	else
+		intel_panel_setup_backlight(connector, INVALID_PIPE);
 
 	return;
 
diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.c b/drivers/gpu/drm/i915/intel_dsi_cabc.c
new file mode 100644
index 0000000..c2fcd95
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_dsi_cabc.c
@@ -0,0 +1,310 @@ 
+/*
+ * Copyright © 2006-2010 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Author: Deepak M <m.deepak@intel.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include "intel_drv.h"
+#include "intel_dsi.h"
+#include "i915_drv.h"
+#include "intel_dsi_cabc.h"
+#include <video/mipi_display.h>
+#include <drm/drm_mipi_dsi.h>
+
+static inline enum port get_cabc_port(struct intel_dsi *intel_dsi)
+{
+	if (intel_dsi->dl_cabc_port == CABC_PORT_C)
+		return PORT_C;
+	else
+		return PORT_A;
+}
+
+int cabc_setup_backlight(struct drm_connector *connector,
+		enum pipe unused)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct intel_panel *panel = &intel_connector->panel;
+
+	if (dev_priv->vbt.backlight.present)
+		panel->backlight.present = true;
+	else {
+		DRM_ERROR("no backlight present per VBT\n");
+		return 0;
+	}
+
+	panel->backlight.max = CABC_MAX_VALUE;
+	panel->backlight.level = CABC_MAX_VALUE;
+
+	return 0;
+}
+
+u32 cabc_get_backlight(struct intel_connector *connector)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct intel_dsi *intel_dsi = NULL;
+	struct drm_crtc *crtc = NULL;
+	struct intel_encoder *encoder = NULL;
+	struct mipi_dsi_device *dsi_device;
+	u8 data[2] = {0};
+	enum port port;
+	u32 ret;
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		for_each_encoder_on_crtc(dev, crtc, encoder) {
+			if (encoder->type == INTEL_OUTPUT_DSI) {
+				intel_dsi = enc_to_intel_dsi(&encoder->base);
+				break;
+			}
+		}
+		if (intel_dsi != NULL)
+			break;
+	}
+
+	for_each_dsi_port(port, intel_dsi->ports) {
+		if (intel_dsi->dual_link)
+			port = get_cabc_port(intel_dsi);
+
+		dsi_device = intel_dsi->dsi_hosts[port]->device;
+		mipi_dsi_dcs_read(dsi_device, MIPI_DCS_CABC_LEVEL_RD, data, 2);
+
+		if (intel_dsi->dual_link &&
+				!(intel_dsi->dl_cabc_port == CABC_PORT_A_AND_C))
+			break;
+	}
+
+	ret = data[1];
+
+	return ret;
+}
+
+void cabc_set_backlight(struct intel_connector *connector, u32 level)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct intel_dsi *intel_dsi = NULL;
+	struct drm_crtc *crtc = NULL;
+	struct intel_encoder *encoder = NULL;
+	struct mipi_dsi_device *dsi_device;
+	u8 data[2] = {0};
+	enum port port;
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		for_each_encoder_on_crtc(dev, crtc, encoder) {
+			if (encoder->type == INTEL_OUTPUT_DSI) {
+				intel_dsi = enc_to_intel_dsi(&encoder->base);
+				break;
+			}
+		}
+		if (intel_dsi != NULL)
+			break;
+	}
+
+	for_each_dsi_port(port, intel_dsi->ports) {
+		if (intel_dsi->dual_link)
+			port = get_cabc_port(intel_dsi);
+
+		dsi_device = intel_dsi->dsi_hosts[port]->device;
+		data[1] = level;
+		data[0] = MIPI_DCS_CABC_LEVEL_WR;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+
+		if (intel_dsi->dual_link &&
+			!(intel_dsi->dl_cabc_port == CABC_PORT_A_AND_C))
+			break;
+	}
+}
+
+void cabc_enable_backlight(struct intel_connector *connector)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct intel_dsi *intel_dsi = NULL;
+	struct drm_crtc *crtc = NULL;
+	struct intel_encoder *encoder = NULL;
+	struct intel_panel *panel = &connector->panel;
+	struct mipi_dsi_device *dsi_device;
+	enum port port;
+	u8 data[2] = {0};
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		for_each_encoder_on_crtc(dev, crtc, encoder) {
+			if (encoder->type == INTEL_OUTPUT_DSI) {
+				intel_dsi = enc_to_intel_dsi(&encoder->base);
+				break;
+			}
+		}
+		if (intel_dsi != NULL)
+			break;
+	}
+
+	for_each_dsi_port(port, intel_dsi->ports) {
+		if (intel_dsi->dual_link)
+			port = get_cabc_port(intel_dsi);
+
+		dsi_device = intel_dsi->dsi_hosts[port]->device;
+		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
+		data[1] = CABC_BACKLIGHT | CABC_DIMMING_DISPLAY | CABC_BCTRL;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+		data[0] = MIPI_DCS_CABC_CONTROL_WR;
+		data[1] = CABC_STILL_PICTURE;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+
+		if (intel_dsi->dual_link &&
+				!(intel_dsi->dl_cabc_port == CABC_PORT_A_AND_C))
+			break;
+	}
+
+	cabc_set_backlight(connector, panel->backlight.level);
+}
+
+void cabc_disable_backlight(struct intel_connector *connector)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct intel_dsi *intel_dsi = NULL;
+	struct drm_crtc *crtc = NULL;
+	struct intel_encoder *encoder = NULL;
+	struct mipi_dsi_device *dsi_device;
+	enum port port;
+	u8 data[2] = {0};
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		for_each_encoder_on_crtc(dev, crtc, encoder) {
+			if (encoder->type == INTEL_OUTPUT_DSI) {
+				intel_dsi = enc_to_intel_dsi(&encoder->base);
+				break;
+			}
+		}
+		if (intel_dsi != NULL)
+			break;
+	}
+
+	cabc_set_backlight(connector, 0);
+
+	for_each_dsi_port(port, intel_dsi->ports) {
+		if (intel_dsi->dual_link)
+			port = get_cabc_port(intel_dsi);
+		dsi_device = intel_dsi->dsi_hosts[port]->device;
+
+		data[1] = CABC_OFF;
+		data[0] = MIPI_DCS_CABC_CONTROL_WR;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+		data[0] = MIPI_DCS_CABC_CONTROL_BRIGHT_WR;
+		mipi_dsi_dcs_write_buffer(dsi_device, data, 2);
+
+		if (intel_dsi->dual_link &&
+				!(intel_dsi->dl_cabc_port == CABC_PORT_A_AND_C))
+			break;
+	}
+}
+static int cabc_backlight_device_update_status(struct backlight_device *bd)
+{
+	struct intel_connector *connector = bl_get_data(bd);
+	struct drm_device *dev = connector->base.dev;
+
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+	DRM_DEBUG_KMS("updating intel_backlight, brightness=%d/%d\n",
+			bd->props.brightness, bd->props.max_brightness);
+
+	cabc_set_backlight(connector, bd->props.brightness);
+
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+	return 0;
+}
+
+static int cabc_backlight_device_get_brightness(struct backlight_device *bd)
+{
+	struct intel_connector *connector = bl_get_data(bd);
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int ret;
+
+	intel_runtime_pm_get(dev_priv);
+	drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+
+	ret = cabc_get_backlight(connector);
+
+	drm_modeset_unlock(&dev->mode_config.connection_mutex);
+	intel_runtime_pm_put(dev_priv);
+
+	return ret;
+}
+
+static const struct backlight_ops cabc_backlight_device_ops = {
+	.update_status = cabc_backlight_device_update_status,
+	.get_brightness = cabc_backlight_device_get_brightness,
+};
+
+int cabc_backlight_device_register(struct intel_connector *connector)
+{
+	struct intel_panel *panel = &connector->panel;
+	struct backlight_properties props;
+
+	if (WARN_ON(panel->backlight.device))
+		return -ENODEV;
+
+	if (!panel->backlight.present) {
+		DRM_ERROR("No backlight present\n");
+		return 0;
+	}
+
+	WARN_ON(panel->backlight.max == 0);
+
+	memset(&props, 0, sizeof(props));
+	props.type = BACKLIGHT_FIRMWARE;
+	props.max_brightness = panel->backlight.max;
+	props.brightness = props.max_brightness;
+
+	/*
+	 * Note: using the same name independent of the connector prevents
+	 * registration of multiple backlight devices in the driver.
+	 */
+	panel->backlight.device =
+		backlight_device_register("intel_backlight",
+				connector->base.kdev,
+				connector,
+				&cabc_backlight_device_ops, &props);
+
+	if (IS_ERR(panel->backlight.device)) {
+		DRM_ERROR("Failed to register backlight: %ld\n",
+				PTR_ERR(panel->backlight.device));
+		panel->backlight.device = NULL;
+		return -ENODEV;
+	}
+
+	DRM_DEBUG_KMS("Connector %s backlight sysfs interface registered\n",
+			connector->base.name);
+
+	return 0;
+}
+
+void cabc_backlight_device_unregister(struct intel_connector *connector)
+{
+	struct intel_panel *panel = &connector->panel;
+
+	if (panel->backlight.device) {
+		backlight_device_unregister(panel->backlight.device);
+		panel->backlight.device = NULL;
+	}
+}
diff --git a/drivers/gpu/drm/i915/intel_dsi_cabc.h b/drivers/gpu/drm/i915/intel_dsi_cabc.h
new file mode 100644
index 0000000..b1a79d9
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_dsi_cabc.h
@@ -0,0 +1,46 @@ 
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Author: Deepak M <m.deepak@intel.com>
+ */
+
+extern int cabc_backlight_device_register(struct intel_connector *connector);
+extern void cabc_backlight_device_unregister(struct intel_connector *connector);
+void cabc_set_backlight(struct intel_connector *connector, u32 level);
+u32 cabc_get_backlight(struct intel_connector *connector);
+void cabc_enable_backlight(struct intel_connector *connector);
+void cabc_disable_backlight(struct intel_connector *connector);
+int cabc_setup_backlight(struct drm_connector *connector, enum pipe unused);
+
+#define CABC_OFF			(0 << 0)
+#define CABC_USER_INTERFACE_IMAGE	(1 << 0)
+#define CABC_STILL_PICTURE		(2 << 0)
+#define CABC_VIDEO_MODE			(3 << 0)
+
+#define CABC_BACKLIGHT			(1 << 2)
+#define CABC_DIMMING_DISPLAY		(1 << 3)
+#define CABC_BCTRL			(1 << 5)
+
+#define CABC_PORT_A			0x00
+#define CABC_PORT_C			0x01
+#define CABC_PORT_A_AND_C		0x02
+#define CABC_MAX_VALUE			0xff
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index e2ab3f6..ff2e586 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -34,6 +34,7 @@ 
 #include <linux/moduleparam.h>
 #include <linux/pwm.h>
 #include "intel_drv.h"
+#include "intel_dsi_cabc.h"
 
 #define CRC_PMIC_PWM_PERIOD_NS	21333
 
@@ -1586,15 +1587,29 @@  void intel_panel_fini(struct intel_panel *panel)
 void intel_backlight_register(struct drm_device *dev)
 {
 	struct intel_connector *connector;
+	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	list_for_each_entry(connector, &dev->mode_config.connector_list, base.head)
-		intel_backlight_device_register(connector);
+	list_for_each_entry(connector, &dev->mode_config.connector_list,
+					base.head) {
+		if (connector->encoder->type == INTEL_OUTPUT_DSI &&
+			dev_priv->vbt.dsi.config->cabc_supported)
+			cabc_backlight_device_register(connector);
+		else
+			intel_backlight_device_register(connector);
+	}
 }
 
 void intel_backlight_unregister(struct drm_device *dev)
 {
 	struct intel_connector *connector;
+	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	list_for_each_entry(connector, &dev->mode_config.connector_list, base.head)
-		intel_backlight_device_unregister(connector);
+	list_for_each_entry(connector, &dev->mode_config.connector_list,
+					base.head) {
+		if (connector->encoder->type == INTEL_OUTPUT_DSI &&
+			dev_priv->vbt.dsi.config->cabc_supported)
+			cabc_backlight_device_unregister(connector);
+		else
+			intel_backlight_device_unregister(connector);
+	}
 }
diff --git a/include/video/mipi_display.h b/include/video/mipi_display.h
index ddcc8ca..5b8eeec 100644
--- a/include/video/mipi_display.h
+++ b/include/video/mipi_display.h
@@ -117,6 +117,14 @@  enum {
 	MIPI_DCS_GET_SCANLINE		= 0x45,
 	MIPI_DCS_READ_DDB_START		= 0xA1,
 	MIPI_DCS_READ_DDB_CONTINUE	= 0xA8,
+	MIPI_DCS_CABC_LEVEL_RD          = 0x52,
+	MIPI_DCS_CABC_MIN_BRIGHTNESS_RD = 0x5F,
+	MIPI_DCS_CABC_CONTROL_RD        = 0x56,
+	MIPI_DCS_CABC_CONTROL_BRIGHT_RD = 0x54,
+	MIPI_DCS_CABC_LEVEL_WR          = 0x51,
+	MIPI_DCS_CABC_MIN_BRIGHTNESS_WR = 0x5E,
+	MIPI_DCS_CABC_CONTROL_WR        = 0x55,
+	MIPI_DCS_CABC_CONTROL_BRIGHT_WR = 0x53,
 };
 
 /* MIPI DCS pixel formats */