[4/5] drm/vc4: Add DPI driver
diff mbox

Message ID 1458355366-7073-5-git-send-email-eric@anholt.net
State New
Headers show

Commit Message

Eric Anholt March 19, 2016, 2:42 a.m. UTC
The DPI interface involves taking a ton of our GPIOs to be used as
outputs, and routing display signals over them in parallel.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 .../devicetree/bindings/display/brcm,bcm-vc4.txt   |  67 +++
 drivers/gpu/drm/vc4/Kconfig                        |   1 +
 drivers/gpu/drm/vc4/Makefile                       |   1 +
 drivers/gpu/drm/vc4/vc4_debugfs.c                  |   1 +
 drivers/gpu/drm/vc4/vc4_dpi.c                      | 518 +++++++++++++++++++++
 drivers/gpu/drm/vc4/vc4_drv.c                      |   1 +
 drivers/gpu/drm/vc4/vc4_drv.h                      |   5 +
 7 files changed, 594 insertions(+)
 create mode 100644 drivers/gpu/drm/vc4/vc4_dpi.c

Comments

Rob Herring March 21, 2016, 12:57 p.m. UTC | #1
On Fri, Mar 18, 2016 at 07:42:45PM -0700, Eric Anholt wrote:
> The DPI interface involves taking a ton of our GPIOs to be used as
> outputs, and routing display signals over them in parallel.
> 
> Signed-off-by: Eric Anholt <eric@anholt.net>
> ---
>  .../devicetree/bindings/display/brcm,bcm-vc4.txt   |  67 +++
>  drivers/gpu/drm/vc4/Kconfig                        |   1 +
>  drivers/gpu/drm/vc4/Makefile                       |   1 +
>  drivers/gpu/drm/vc4/vc4_debugfs.c                  |   1 +
>  drivers/gpu/drm/vc4/vc4_dpi.c                      | 518 +++++++++++++++++++++
>  drivers/gpu/drm/vc4/vc4_drv.c                      |   1 +
>  drivers/gpu/drm/vc4/vc4_drv.h                      |   5 +
>  7 files changed, 594 insertions(+)
>  create mode 100644 drivers/gpu/drm/vc4/vc4_dpi.c
> 
> diff --git a/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt b/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
> index 56a961a..1782c3f 100644
> --- a/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
> +++ b/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
> @@ -35,6 +35,44 @@ Optional properties for HDMI:
>  		  as an interrupt/status bit in the HDMI controller
>  		  itself).  See bindings/pinctrl/brcm,bcm2835-gpio.txt
>  
> +Required properties for DPI:
> +- compatible:		Should be "brcm,bcm2835-dpi"
> +- reg:			Physical base address and length of the registers
> +- clocks:		a) core: The core clock the unit runs on
> +			b) pixel: The pixel clock that feeds the pixelvalve
> +- port:			Port node with a single endpoint connecting to the
> +			  panel device, as defined in [1]
> +- brcm,output-format:	Output data format, must be one of:
> +			0) disabled
> +			1) 00000000rrrrrggggggbbbbb
> +			2) 000rrrrr00gggggg000bbbbb
> +			3) 00rrrrr000gggggg00bbbbb0
> +			4) 000000rrrrrrggggggbbbbbb
> +			5) 00rrrrrr00gggggg00bbbbbb
> +			6) rrrrrrrrggggggggbbbbbbbb
> +
> +Optional properties for DPI:
> +- brcm,rgb-order:		RGB reordering, must be one of:
> +				0) RGB
> +				1) BGR
> +				2) GRB
> +				3) BRG

> +- brcm,hsync-disable:		Disables the hsync signal
> +- brcm,vsync-disable:		Disables the vsync signal
> +- brcm,output-enable-disable:	Disables the output enable signal
> +- brcm,hsync-falling:		Outputs the hsync signal on the falling clk edge
> +- brcm,vsync-falling:		Outputs the vsync signal on the falling clk edge
> +- brcm,output-enable-falling:	Outputs the output enable signal on the
> +				  falling clk edge
> +- brcm,output-enable-invert:	Inverts the polarity of the output enable
> +				  signal
> +- brcm,pixel-clk-invert:	Inverts the polarity of the pixel clk signal
> +- brcm,output-enable-mode:	Sets output enable when (vsync | hsync)
> +				  instead of (hactive & vactive)

These are all really properties of what the panel requires and we 
already have video timings binding that would cover some of these.

Also, do you have actual users? Some of these seem like they would be 
rare or never. I've not seen panels caring about which clock edge the 
sync signals are on.

Rob
Eric Anholt March 25, 2016, 12:02 a.m. UTC | #2
Rob Herring <robh@kernel.org> writes:

> On Fri, Mar 18, 2016 at 07:42:45PM -0700, Eric Anholt wrote:
>> The DPI interface involves taking a ton of our GPIOs to be used as
>> outputs, and routing display signals over them in parallel.
>> 
>> Signed-off-by: Eric Anholt <eric@anholt.net>
>> ---
>>  .../devicetree/bindings/display/brcm,bcm-vc4.txt   |  67 +++
>>  drivers/gpu/drm/vc4/Kconfig                        |   1 +
>>  drivers/gpu/drm/vc4/Makefile                       |   1 +
>>  drivers/gpu/drm/vc4/vc4_debugfs.c                  |   1 +
>>  drivers/gpu/drm/vc4/vc4_dpi.c                      | 518 +++++++++++++++++++++
>>  drivers/gpu/drm/vc4/vc4_drv.c                      |   1 +
>>  drivers/gpu/drm/vc4/vc4_drv.h                      |   5 +
>>  7 files changed, 594 insertions(+)
>>  create mode 100644 drivers/gpu/drm/vc4/vc4_dpi.c
>> 
>> diff --git a/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt b/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
>> index 56a961a..1782c3f 100644
>> --- a/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
>> +++ b/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
>> @@ -35,6 +35,44 @@ Optional properties for HDMI:
>>  		  as an interrupt/status bit in the HDMI controller
>>  		  itself).  See bindings/pinctrl/brcm,bcm2835-gpio.txt
>>  
>> +Required properties for DPI:
>> +- compatible:		Should be "brcm,bcm2835-dpi"
>> +- reg:			Physical base address and length of the registers
>> +- clocks:		a) core: The core clock the unit runs on
>> +			b) pixel: The pixel clock that feeds the pixelvalve
>> +- port:			Port node with a single endpoint connecting to the
>> +			  panel device, as defined in [1]
>> +- brcm,output-format:	Output data format, must be one of:
>> +			0) disabled
>> +			1) 00000000rrrrrggggggbbbbb
>> +			2) 000rrrrr00gggggg000bbbbb
>> +			3) 00rrrrr000gggggg00bbbbb0
>> +			4) 000000rrrrrrggggggbbbbbb
>> +			5) 00rrrrrr00gggggg00bbbbbb
>> +			6) rrrrrrrrggggggggbbbbbbbb
>> +
>> +Optional properties for DPI:
>> +- brcm,rgb-order:		RGB reordering, must be one of:
>> +				0) RGB
>> +				1) BGR
>> +				2) GRB
>> +				3) BRG
>
>> +- brcm,hsync-disable:		Disables the hsync signal
>> +- brcm,vsync-disable:		Disables the vsync signal
>> +- brcm,output-enable-disable:	Disables the output enable signal
>> +- brcm,hsync-falling:		Outputs the hsync signal on the falling clk edge
>> +- brcm,vsync-falling:		Outputs the vsync signal on the falling clk edge
>> +- brcm,output-enable-falling:	Outputs the output enable signal on the
>> +				  falling clk edge
>> +- brcm,output-enable-invert:	Inverts the polarity of the output enable
>> +				  signal
>> +- brcm,pixel-clk-invert:	Inverts the polarity of the pixel clk signal
>> +- brcm,output-enable-mode:	Sets output enable when (vsync | hsync)
>> +				  instead of (hactive & vactive)
>
> These are all really properties of what the panel requires and we 
> already have video timings binding that would cover some of these.
>
> Also, do you have actual users? Some of these seem like they would be 
> rare or never. I've not seen panels caring about which clock edge the 
> sync signals are on.

I was using output-format, rgb_order, output-enable-mode to get my panel
to work.  I'm suspicious that the !output_enable_mode is not useful,
though (Note: I had documented it backwards: false is hsync|vsync, true
is hactive&vactive).  That just left me with output-format.  I think
.bus_format in the panel_desc can cover that, so I've now dropped all of
these brcm properties.

Patch
diff mbox

diff --git a/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt b/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
index 56a961a..1782c3f 100644
--- a/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
+++ b/Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt
@@ -35,6 +35,44 @@  Optional properties for HDMI:
 		  as an interrupt/status bit in the HDMI controller
 		  itself).  See bindings/pinctrl/brcm,bcm2835-gpio.txt
 
+Required properties for DPI:
+- compatible:		Should be "brcm,bcm2835-dpi"
+- reg:			Physical base address and length of the registers
+- clocks:		a) core: The core clock the unit runs on
+			b) pixel: The pixel clock that feeds the pixelvalve
+- port:			Port node with a single endpoint connecting to the
+			  panel device, as defined in [1]
+- brcm,output-format:	Output data format, must be one of:
+			0) disabled
+			1) 00000000rrrrrggggggbbbbb
+			2) 000rrrrr00gggggg000bbbbb
+			3) 00rrrrr000gggggg00bbbbb0
+			4) 000000rrrrrrggggggbbbbbb
+			5) 00rrrrrr00gggggg00bbbbbb
+			6) rrrrrrrrggggggggbbbbbbbb
+
+Optional properties for DPI:
+- brcm,rgb-order:		RGB reordering, must be one of:
+				0) RGB
+				1) BGR
+				2) GRB
+				3) BRG
+- brcm,hsync-disable:		Disables the hsync signal
+- brcm,vsync-disable:		Disables the vsync signal
+- brcm,output-enable-disable:	Disables the output enable signal
+- brcm,hsync-falling:		Outputs the hsync signal on the falling clk edge
+- brcm,vsync-falling:		Outputs the vsync signal on the falling clk edge
+- brcm,output-enable-falling:	Outputs the output enable signal on the
+				  falling clk edge
+- brcm,output-enable-invert:	Inverts the polarity of the output enable
+				  signal
+- brcm,pixel-clk-invert:	Inverts the polarity of the pixel clk signal
+- brcm,output-enable-mode:	Sets output enable when (vsync | hsync)
+				  instead of (hactive & vactive)
+
+
+[1] Documentation/devicetree/bindings/media/video-interfaces.txt
+
 Example:
 pixelvalve@7e807000 {
 	compatible = "brcm,bcm2835-pixelvalve2";
@@ -60,6 +98,35 @@  hdmi: hdmi@7e902000 {
 	clock-names = "pixel", "hdmi";
 };
 
+dpi: dpi@7e208000 {
+	compatible = "brcm,bcm2835-dpi";
+	reg = <0x7e208000 0x8c>;
+	clocks = <&clocks BCM2835_CLOCK_VPU>,
+	         <&clocks BCM2835_CLOCK_DPI>;
+	clock-names = "core", "pixel";
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	brcm,rgb-order = <0>;
+	brcm,output-format = <4>;
+
+	port {
+		dpi_out: endpoint@0 {
+			remote-endpoint = <&panel_in>;
+		};
+	};
+};
+
 vc4: gpu {
 	compatible = "brcm,bcm2835-vc4";
 };
+
+panel: panel {
+	compatible = "ontat,yx700wv03", "simple-panel";
+
+	port {
+		panel_in: endpoint {
+			remote-endpoint = <&dpi_out>;
+		};
+	};
+};
diff --git a/drivers/gpu/drm/vc4/Kconfig b/drivers/gpu/drm/vc4/Kconfig
index 5848104..e53df59 100644
--- a/drivers/gpu/drm/vc4/Kconfig
+++ b/drivers/gpu/drm/vc4/Kconfig
@@ -5,6 +5,7 @@  config DRM_VC4
 	select DRM_KMS_HELPER
 	select DRM_KMS_CMA_HELPER
 	select DRM_GEM_CMA_HELPER
+	select DRM_PANEL
 	help
 	  Choose this option if you have a system that has a Broadcom
 	  VC4 GPU, such as the Raspberry Pi or other BCM2708/BCM2835.
diff --git a/drivers/gpu/drm/vc4/Makefile b/drivers/gpu/drm/vc4/Makefile
index 4c6a99f..fb77db7 100644
--- a/drivers/gpu/drm/vc4/Makefile
+++ b/drivers/gpu/drm/vc4/Makefile
@@ -7,6 +7,7 @@  vc4-y := \
 	vc4_bo.o \
 	vc4_crtc.o \
 	vc4_drv.o \
+	vc4_dpi.o \
 	vc4_kms.o \
 	vc4_gem.o \
 	vc4_hdmi.o \
diff --git a/drivers/gpu/drm/vc4/vc4_debugfs.c b/drivers/gpu/drm/vc4/vc4_debugfs.c
index d76ad10..245115d 100644
--- a/drivers/gpu/drm/vc4/vc4_debugfs.c
+++ b/drivers/gpu/drm/vc4/vc4_debugfs.c
@@ -17,6 +17,7 @@ 
 
 static const struct drm_info_list vc4_debugfs_list[] = {
 	{"bo_stats", vc4_bo_stats_debugfs, 0},
+	{"dpi_regs", vc4_dpi_debugfs_regs, 0},
 	{"hdmi_regs", vc4_hdmi_debugfs_regs, 0},
 	{"hvs_regs", vc4_hvs_debugfs_regs, 0},
 	{"crtc0_regs", vc4_crtc_debugfs_regs, 0, (void *)(uintptr_t)0},
diff --git a/drivers/gpu/drm/vc4/vc4_dpi.c b/drivers/gpu/drm/vc4/vc4_dpi.c
new file mode 100644
index 0000000..4edb70c
--- /dev/null
+++ b/drivers/gpu/drm/vc4/vc4_dpi.c
@@ -0,0 +1,518 @@ 
+/*
+ * Copyright (C) 2016 Broadcom Limited
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * DOC: VC4 DPI module
+ *
+ * The VC4 DPI hardware supports MIPI DPI type 4 and Nokia ViSSI
+ * signals, which are routed out to GPIO0-27 with the ALT2 function.
+ */
+
+#include "drm_atomic_helper.h"
+#include "drm_crtc_helper.h"
+#include "drm_edid.h"
+#include "drm_panel.h"
+#include "linux/clk.h"
+#include "linux/component.h"
+#include "linux/of_graph.h"
+#include "linux/of_platform.h"
+#include "vc4_drv.h"
+#include "vc4_regs.h"
+
+#define DPI_C			0x00
+# define DPI_OUTPUT_ENABLE_MODE		BIT(16)
+
+/* The order field takes the incoming 24 bit RGB from the pixel valve
+ * and shuffles the 3 channels.
+ */
+# define DPI_ORDER_MASK			VC4_MASK(15, 14)
+# define DPI_ORDER_SHIFT		14
+# define DPI_ORDER_RGB			0
+# define DPI_ORDER_BGR			1
+# define DPI_ORDER_GRB			2
+# define DPI_ORDER_BRG			3
+
+/* The format field takes the ORDER-shuffled pixel valve data and
+ * formats it onto the output lines.
+ */
+# define DPI_FORMAT_MASK		VC4_MASK(13, 11)
+# define DPI_FORMAT_SHIFT		11
+/* This define is named in the hardware, but actually just outputs 0. */
+# define DPI_FORMAT_9BIT_666_RGB	0
+/* Outputs 00000000rrrrrggggggbbbbb */
+# define DPI_FORMAT_16BIT_565_RGB_1	1
+/* Outputs 000rrrrr00gggggg000bbbbb */
+# define DPI_FORMAT_16BIT_565_RGB_2	2
+/* Outputs 00rrrrr000gggggg00bbbbb0 */
+# define DPI_FORMAT_16BIT_565_RGB_3	3
+/* Outputs 000000rrrrrrggggggbbbbbb */
+# define DPI_FORMAT_18BIT_666_RGB_1	4
+/* Outputs 00rrrrrr00gggggg00bbbbbb */
+# define DPI_FORMAT_18BIT_666_RGB_2	5
+/* Outputs rrrrrrrrggggggggbbbbbbbb */
+# define DPI_FORMAT_24BIT_888_RGB	6
+
+/* Reverses the polarity of the corresponding signal */
+# define DPI_PIXEL_CLK_INVERT		BIT(10)
+# define DPI_HSYNC_INVERT		BIT(9)
+# define DPI_VSYNC_INVERT		BIT(8)
+# define DPI_OUTPUT_ENABLE_INVERT	BIT(7)
+
+/* Outputs the signal the falling clock edge instead of rising. */
+# define DPI_HSYNC_NEGATE		BIT(6)
+# define DPI_VSYNC_NEGATE		BIT(5)
+# define DPI_OUTPUT_ENABLE_NEGATE	BIT(4)
+
+/* Disables the signal */
+# define DPI_HSYNC_DISABLE		BIT(3)
+# define DPI_VSYNC_DISABLE		BIT(2)
+# define DPI_OUTPUT_ENABLE_DISABLE	BIT(1)
+
+/* Power gate to the device, full reset at 0 -> 1 transition */
+# define DPI_ENABLE			BIT(0)
+
+/* All other registers besides DPI_C return the ID */
+#define DPI_ID			0x04
+# define DPI_ID_VALUE		0x00647069
+
+/* General DPI hardware state. */
+struct vc4_dpi {
+	struct platform_device *pdev;
+
+	struct drm_encoder *encoder;
+	struct drm_connector *connector;
+	struct drm_panel *panel;
+
+	void __iomem *regs;
+
+	struct clk *pixel_clock;
+	struct clk *core_clock;
+
+	u32 dpi_c;
+};
+
+#define DPI_READ(offset) readl(dpi->regs + (offset))
+#define DPI_WRITE(offset, val) writel(val, dpi->regs + (offset))
+
+/* VC4 DPI encoder KMS struct */
+struct vc4_dpi_encoder {
+	struct vc4_encoder base;
+	struct vc4_dpi *dpi;
+};
+
+static inline struct vc4_dpi_encoder *
+to_vc4_dpi_encoder(struct drm_encoder *encoder)
+{
+	return container_of(encoder, struct vc4_dpi_encoder, base.base);
+}
+
+/* VC4 DPI connector KMS struct */
+struct vc4_dpi_connector {
+	struct drm_connector base;
+	struct vc4_dpi *dpi;
+
+	/* Since the connector is attached to just the one encoder,
+	 * this is the reference to it so we can do the best_encoder()
+	 * hook.
+	 */
+	struct drm_encoder *encoder;
+};
+
+static inline struct vc4_dpi_connector *
+to_vc4_dpi_connector(struct drm_connector *connector)
+{
+	return container_of(connector, struct vc4_dpi_connector, base);
+}
+
+#define DPI_REG(reg) { reg, #reg }
+static const struct {
+	u32 reg;
+	const char *name;
+} dpi_regs[] = {
+	DPI_REG(DPI_C),
+	DPI_REG(DPI_ID),
+};
+
+static void vc4_dpi_dump_regs(struct vc4_dpi *dpi)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(dpi_regs); i++) {
+		DRM_INFO("0x%04x (%s): 0x%08x\n",
+			 dpi_regs[i].reg, dpi_regs[i].name,
+			 DPI_READ(dpi_regs[i].reg));
+	}
+}
+
+#ifdef CONFIG_DEBUG_FS
+int vc4_dpi_debugfs_regs(struct seq_file *m, void *unused)
+{
+	struct drm_info_node *node = (struct drm_info_node *)m->private;
+	struct drm_device *dev = node->minor->dev;
+	struct vc4_dev *vc4 = to_vc4_dev(dev);
+	struct vc4_dpi *dpi = vc4->dpi;
+	int i;
+
+	if (!dpi)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(dpi_regs); i++) {
+		seq_printf(m, "%s (0x%04x): 0x%08x\n",
+			   dpi_regs[i].name, dpi_regs[i].reg,
+			   DPI_READ(dpi_regs[i].reg));
+	}
+
+	return 0;
+}
+#endif
+
+static enum drm_connector_status
+vc4_dpi_connector_detect(struct drm_connector *connector, bool force)
+{
+	struct vc4_dpi_connector *vc4_connector =
+		to_vc4_dpi_connector(connector);
+	struct vc4_dpi *dpi = vc4_connector->dpi;
+
+	if (dpi->panel)
+		return connector_status_connected;
+	else
+		return connector_status_disconnected;
+}
+
+static void vc4_dpi_connector_destroy(struct drm_connector *connector)
+{
+	drm_connector_unregister(connector);
+	drm_connector_cleanup(connector);
+}
+
+static int vc4_dpi_connector_get_modes(struct drm_connector *connector)
+{
+	struct vc4_dpi_connector *vc4_connector =
+		to_vc4_dpi_connector(connector);
+	struct vc4_dpi *dpi = vc4_connector->dpi;
+
+	if (dpi->panel)
+		return drm_panel_get_modes(dpi->panel);
+
+	return 0;
+}
+
+static struct drm_encoder *
+vc4_dpi_connector_best_encoder(struct drm_connector *connector)
+{
+	struct vc4_dpi_connector *dpi_connector =
+		to_vc4_dpi_connector(connector);
+	return dpi_connector->encoder;
+}
+
+static const struct drm_connector_funcs vc4_dpi_connector_funcs = {
+	.dpms = drm_atomic_helper_connector_dpms,
+	.detect = vc4_dpi_connector_detect,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = vc4_dpi_connector_destroy,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static const struct drm_connector_helper_funcs vc4_dpi_connector_helper_funcs = {
+	.get_modes = vc4_dpi_connector_get_modes,
+	.best_encoder = vc4_dpi_connector_best_encoder,
+};
+
+static struct drm_connector *vc4_dpi_connector_init(struct drm_device *dev,
+						    struct vc4_dpi *dpi)
+{
+	struct drm_connector *connector = NULL;
+	struct vc4_dpi_connector *dpi_connector;
+	int ret = 0;
+
+	dpi_connector = devm_kzalloc(dev->dev, sizeof(*dpi_connector),
+				     GFP_KERNEL);
+	if (!dpi_connector) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+	connector = &dpi_connector->base;
+
+	dpi_connector->encoder = dpi->encoder;
+	dpi_connector->dpi = dpi;
+
+	drm_connector_init(dev, connector, &vc4_dpi_connector_funcs,
+			   DRM_MODE_CONNECTOR_DPI);
+	drm_connector_helper_add(connector, &vc4_dpi_connector_helper_funcs);
+
+	connector->polled = 0;
+	connector->interlace_allowed = 0;
+	connector->doublescan_allowed = 0;
+
+	drm_mode_connector_attach_encoder(connector, dpi->encoder);
+
+	return connector;
+
+ fail:
+	if (connector)
+		vc4_dpi_connector_destroy(connector);
+
+	return ERR_PTR(ret);
+}
+
+static const struct drm_encoder_funcs vc4_dpi_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
+static void vc4_dpi_encoder_disable(struct drm_encoder *encoder)
+{
+	struct vc4_dpi_encoder *vc4_encoder = to_vc4_dpi_encoder(encoder);
+	struct vc4_dpi *dpi = vc4_encoder->dpi;
+
+	drm_panel_disable(dpi->panel);
+
+	clk_disable_unprepare(dpi->pixel_clock);
+
+	drm_panel_unprepare(dpi->panel);
+}
+
+static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
+{
+	struct drm_display_mode *mode = &encoder->crtc->mode;
+	struct vc4_dpi_encoder *vc4_encoder = to_vc4_dpi_encoder(encoder);
+	struct vc4_dpi *dpi = vc4_encoder->dpi;
+	u32 dpi_c = dpi->dpi_c;
+	int ret;
+
+	ret = drm_panel_prepare(dpi->panel);
+	if (ret) {
+		DRM_ERROR("Panel failed to prepare\n");
+		return;
+	}
+
+	ret = clk_set_rate(dpi->pixel_clock, mode->clock * 1000);
+	if (ret)
+		DRM_ERROR("Failed to set clock rate: %d\n", ret);
+
+	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+		dpi_c |= DPI_HSYNC_INVERT;
+	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+		dpi_c |= DPI_VSYNC_INVERT;
+
+	DPI_WRITE(DPI_C, dpi_c);
+
+	ret = clk_prepare_enable(dpi->pixel_clock);
+	if (ret)
+		DRM_ERROR("Failed to set clock rate: %d\n", ret);
+
+	ret = drm_panel_enable(dpi->panel);
+	if (ret) {
+		DRM_ERROR("Panel failed to enable\n");
+		drm_panel_unprepare(dpi->panel);
+		return;
+	}
+}
+
+static const struct drm_encoder_helper_funcs vc4_dpi_encoder_helper_funcs = {
+	.disable = vc4_dpi_encoder_disable,
+	.enable = vc4_dpi_encoder_enable,
+};
+
+static const struct of_device_id vc4_dpi_dt_match[] = {
+	{ .compatible = "brcm,bcm2835-dpi", .data = NULL },
+	{}
+};
+
+/* Walks the OF graph to find the panel node and then asks DRM to look
+ * up the panel.
+ */
+static struct drm_panel *vc4_dpi_get_panel(struct device *dev)
+{
+	struct device_node *endpoint, *panel_node;
+	struct device_node *np = dev->of_node;
+	struct drm_panel *panel;
+
+	endpoint = of_graph_get_next_endpoint(np, NULL);
+	if (!endpoint) {
+		dev_err(dev, "no endpoint to fetch DPI panel\n");
+		return NULL;
+	}
+
+	/* don't proceed if we have an endpoint but no panel_node tied to it */
+	panel_node = of_graph_get_remote_port_parent(endpoint);
+	of_node_put(endpoint);
+	if (!panel_node) {
+		dev_err(dev, "no valid panel node\n");
+		return NULL;
+	}
+
+	panel = of_drm_find_panel(panel_node);
+	of_node_put(panel_node);
+
+	return panel;
+}
+
+static int vc4_dpi_bind(struct device *dev, struct device *master, void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct drm_device *drm = dev_get_drvdata(master);
+	struct vc4_dev *vc4 = to_vc4_dev(drm);
+	struct vc4_dpi *dpi;
+	struct vc4_dpi_encoder *vc4_dpi_encoder;
+	u32 prop;
+	int ret;
+
+	dpi = devm_kzalloc(dev, sizeof(*dpi), GFP_KERNEL);
+	if (!dpi)
+		return -ENOMEM;
+
+	vc4_dpi_encoder = devm_kzalloc(dev, sizeof(*vc4_dpi_encoder),
+				       GFP_KERNEL);
+	if (!vc4_dpi_encoder)
+		return -ENOMEM;
+	vc4_dpi_encoder->base.type = VC4_ENCODER_TYPE_DPI;
+	vc4_dpi_encoder->dpi = dpi;
+	dpi->encoder = &vc4_dpi_encoder->base.base;
+
+	dpi->pdev = pdev;
+	dpi->regs = vc4_ioremap_regs(pdev, 0);
+	if (IS_ERR(dpi->regs))
+		return PTR_ERR(dpi->regs);
+
+	vc4_dpi_dump_regs(dpi);
+
+	if (DPI_READ(DPI_ID) != DPI_ID_VALUE) {
+		dev_err(dev, "Port returned 0x%08x for ID instead of 0x%08x\n",
+			DPI_READ(DPI_ID), DPI_ID_VALUE);
+		return -ENODEV;
+	}
+
+	dpi->dpi_c = DPI_ENABLE;
+
+	ret = of_property_read_u32(dev->of_node, "brcm,rgb-order", &prop);
+	if (ret == 0)
+		dpi->dpi_c |= VC4_SET_FIELD(prop, DPI_ORDER);
+
+	ret = of_property_read_u32(dev->of_node, "brcm,output-format", &prop);
+	if (ret == 0)
+		dpi->dpi_c |= VC4_SET_FIELD(prop, DPI_FORMAT);
+	else
+		goto err;
+
+	if (of_property_read_bool(dev->of_node, "brcm,hsync-falling"))
+		dpi->dpi_c |= DPI_HSYNC_NEGATE;
+	if (of_property_read_bool(dev->of_node, "brcm,vsync-falling"))
+		dpi->dpi_c |= DPI_VSYNC_NEGATE;
+	if (of_property_read_bool(dev->of_node, "brcm,output-enable-falling"))
+		dpi->dpi_c |= DPI_OUTPUT_ENABLE_NEGATE;
+
+	if (of_property_read_bool(dev->of_node, "brcm,hsync-disable"))
+		dpi->dpi_c |= DPI_HSYNC_DISABLE;
+	if (of_property_read_bool(dev->of_node, "brcm,vsync-disable"))
+		dpi->dpi_c |= DPI_VSYNC_DISABLE;
+	if (of_property_read_bool(dev->of_node, "brcm,output-enable-disable"))
+		dpi->dpi_c |= DPI_OUTPUT_ENABLE_DISABLE;
+
+	if (of_property_read_bool(dev->of_node, "brcm,output-enable-invert"))
+		dpi->dpi_c |= DPI_OUTPUT_ENABLE_INVERT;
+	if (of_property_read_bool(dev->of_node, "brcm,pixel-clock-invert"))
+		dpi->dpi_c |= DPI_PIXEL_CLK_INVERT;
+
+	if (of_property_read_bool(dev->of_node, "brcm,output-enable-mode"))
+		dpi->dpi_c |= DPI_OUTPUT_ENABLE_MODE;
+
+	dpi->core_clock = devm_clk_get(dev, "core");
+	if (IS_ERR(dpi->core_clock)) {
+		DRM_ERROR("Failed to get core clock\n");
+		return PTR_ERR(dpi->core_clock);
+	}
+	dpi->pixel_clock = devm_clk_get(dev, "pixel");
+	if (IS_ERR(dpi->pixel_clock)) {
+		DRM_ERROR("Failed to get pixel clock\n");
+		return PTR_ERR(dpi->pixel_clock);
+	}
+
+	ret = clk_prepare_enable(dpi->core_clock);
+	if (ret)
+		DRM_ERROR("Failed to turn on core clock: %d\n", ret);
+
+	dpi->panel = vc4_dpi_get_panel(dev);
+
+	drm_encoder_init(drm, dpi->encoder, &vc4_dpi_encoder_funcs,
+			 DRM_MODE_ENCODER_DPI, NULL);
+	drm_encoder_helper_add(dpi->encoder, &vc4_dpi_encoder_helper_funcs);
+
+	dpi->connector = vc4_dpi_connector_init(drm, dpi);
+	if (IS_ERR(dpi->connector)) {
+		ret = PTR_ERR(dpi->connector);
+		goto err_destroy_encoder;
+	}
+
+	if (dpi->panel)
+		drm_panel_attach(dpi->panel, dpi->connector);
+
+	dev_set_drvdata(dev, dpi);
+
+	vc4->dpi = dpi;
+
+	return 0;
+
+err_destroy_encoder:
+	drm_encoder_cleanup(dpi->encoder);
+	clk_disable_unprepare(dpi->core_clock);
+err:
+	return ret;
+}
+
+static void vc4_dpi_unbind(struct device *dev, struct device *master,
+			   void *data)
+{
+	struct drm_device *drm = dev_get_drvdata(master);
+	struct vc4_dev *vc4 = to_vc4_dev(drm);
+	struct vc4_dpi *dpi = dev_get_drvdata(dev);
+
+	if (dpi->panel)
+		drm_panel_detach(dpi->panel);
+
+	vc4_dpi_connector_destroy(dpi->connector);
+	drm_encoder_cleanup(dpi->encoder);
+
+	clk_disable_unprepare(dpi->core_clock);
+
+	vc4->dpi = NULL;
+}
+
+static const struct component_ops vc4_dpi_ops = {
+	.bind   = vc4_dpi_bind,
+	.unbind = vc4_dpi_unbind,
+};
+
+static int vc4_dpi_dev_probe(struct platform_device *pdev)
+{
+	return component_add(&pdev->dev, &vc4_dpi_ops);
+}
+
+static int vc4_dpi_dev_remove(struct platform_device *pdev)
+{
+	component_del(&pdev->dev, &vc4_dpi_ops);
+	return 0;
+}
+
+struct platform_driver vc4_dpi_driver = {
+	.probe = vc4_dpi_dev_probe,
+	.remove = vc4_dpi_dev_remove,
+	.driver = {
+		.name = "vc4_dpi",
+		.of_match_table = vc4_dpi_dt_match,
+	},
+};
diff --git a/drivers/gpu/drm/vc4/vc4_drv.c b/drivers/gpu/drm/vc4/vc4_drv.c
index f1655ff..0474777 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.c
+++ b/drivers/gpu/drm/vc4/vc4_drv.c
@@ -247,6 +247,7 @@  static const struct component_master_ops vc4_drm_ops = {
 
 static struct platform_driver *const component_drivers[] = {
 	&vc4_hdmi_driver,
+	&vc4_dpi_driver,
 	&vc4_crtc_driver,
 	&vc4_hvs_driver,
 	&vc4_v3d_driver,
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 83db0b7..8f22dd2 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -16,6 +16,7 @@  struct vc4_dev {
 	struct vc4_hvs *hvs;
 	struct vc4_crtc *crtc[3];
 	struct vc4_v3d *v3d;
+	struct vc4_dpi *dpi;
 
 	struct drm_fbdev_cma *fbdev;
 
@@ -406,6 +407,10 @@  void vc4_debugfs_cleanup(struct drm_minor *minor);
 /* vc4_drv.c */
 void __iomem *vc4_ioremap_regs(struct platform_device *dev, int index);
 
+/* vc4_dpi.c */
+extern struct platform_driver vc4_dpi_driver;
+int vc4_dpi_debugfs_regs(struct seq_file *m, void *unused);
+
 /* vc4_gem.c */
 void vc4_gem_init(struct drm_device *dev);
 void vc4_gem_destroy(struct drm_device *dev);