drivers/gpu/drm/vc4/vc4_dpi.c - linux/kernel/git/torvalds/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2016 Broadcom Limited
  */

 /**
  * DOC: VC4 DPI module
  *
  * The VC4 DPI hardware supports MIPI DPI type 4 and Nokia ViSSI
  * signals.  On BCM2835, these can be routed out to GPIO0-27 with the
  * ALT2 function.
  */

 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_edid.h>
 #include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_simple_kms_helper.h>
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/media-bus-format.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 vc4_encoder encoder;

 	struct platform_device *pdev;

 	void __iomem *regs;

 	struct clk *pixel_clock;
 	struct clk *core_clock;

 	struct debugfs_regset32 regset;
 };

 static inline struct vc4_dpi *
 to_vc4_dpi(struct drm_encoder *encoder)
 {
 	return container_of(encoder, struct vc4_dpi, encoder.base);
 }

 #define DPI_READ(offset) readl(dpi->regs + (offset))
 #define DPI_WRITE(offset, val) writel(val, dpi->regs + (offset))

 static const struct debugfs_reg32 dpi_regs[] = {
 	VC4_REG32(DPI_C),
 	VC4_REG32(DPI_ID),
 };

 static void vc4_dpi_encoder_disable(struct drm_encoder *encoder)
 {
 	struct drm_device *dev = encoder->dev;
 	struct vc4_dpi *dpi = to_vc4_dpi(encoder);
 	int idx;

 	if (!drm_dev_enter(dev, &idx))
 		return;

 	clk_disable_unprepare(dpi->pixel_clock);

 	drm_dev_exit(idx);
 }

 static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
 {
 	struct drm_device *dev = encoder->dev;
 	struct drm_display_mode *mode = &encoder->crtc->mode;
 	struct vc4_dpi *dpi = to_vc4_dpi(encoder);
 	struct drm_connector_list_iter conn_iter;
 	struct drm_connector *connector = NULL, *connector_scan;
 	u32 dpi_c = DPI_ENABLE;
 	int idx;
 	int ret;

 	/* Look up the connector attached to DPI so we can get the
 	 * bus_format.  Ideally the bridge would tell us the
 	 * bus_format we want, but it doesn't yet, so assume that it's
 	 * uniform throughout the bridge chain.
 	 */
 	drm_connector_list_iter_begin(dev, &conn_iter);
 	drm_for_each_connector_iter(connector_scan, &conn_iter) {
 		if (connector_scan->encoder == encoder) {
 			connector = connector_scan;
 			break;
 		}
 	}
 	drm_connector_list_iter_end(&conn_iter);

 	/* Default to 24bit if no connector or format found. */
 	dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB, DPI_FORMAT);

 	if (connector) {
 		if (connector->display_info.num_bus_formats) {
 			u32 bus_format = connector->display_info.bus_formats[0];

 			dpi_c &= ~DPI_FORMAT_MASK;

 			switch (bus_format) {
 			case MEDIA_BUS_FMT_RGB888_1X24:
 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
 						       DPI_FORMAT);
 				break;
 			case MEDIA_BUS_FMT_BGR888_1X24:
 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
 						       DPI_FORMAT);
 				dpi_c |= VC4_SET_FIELD(DPI_ORDER_BGR,
 						       DPI_ORDER);
 				break;
 			case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_2,
 						       DPI_FORMAT);
 				break;
 			case MEDIA_BUS_FMT_RGB666_1X18:
 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_1,
 						       DPI_FORMAT);
 				break;
 			case MEDIA_BUS_FMT_RGB565_1X16:
 				dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_3,
 						       DPI_FORMAT);
 				break;
 			default:
 				DRM_ERROR("Unknown media bus format %d\n",
 					  bus_format);
 				break;
 			}
 		}

 		if (connector->display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
 			dpi_c |= DPI_PIXEL_CLK_INVERT;

 		if (connector->display_info.bus_flags & DRM_BUS_FLAG_DE_LOW)
 			dpi_c |= DPI_OUTPUT_ENABLE_INVERT;
 	}

 	if (mode->flags & DRM_MODE_FLAG_CSYNC) {
 		if (mode->flags & DRM_MODE_FLAG_NCSYNC)
 			dpi_c |= DPI_OUTPUT_ENABLE_INVERT;
 	} else {
 		dpi_c |= DPI_OUTPUT_ENABLE_MODE;

 		if (mode->flags & DRM_MODE_FLAG_NHSYNC)
 			dpi_c |= DPI_HSYNC_INVERT;
 		else if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
 			dpi_c |= DPI_HSYNC_DISABLE;

 		if (mode->flags & DRM_MODE_FLAG_NVSYNC)
 			dpi_c |= DPI_VSYNC_INVERT;
 		else if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
 			dpi_c |= DPI_VSYNC_DISABLE;
 	}

 	if (!drm_dev_enter(dev, &idx))
 		return;

 	DPI_WRITE(DPI_C, dpi_c);

 	ret = clk_set_rate(dpi->pixel_clock, mode->clock * 1000);
 	if (ret)
 		DRM_ERROR("Failed to set clock rate: %d\n", ret);

 	ret = clk_prepare_enable(dpi->pixel_clock);
 	if (ret)
 		DRM_ERROR("Failed to set clock rate: %d\n", ret);

 	drm_dev_exit(idx);
 }

 static enum drm_mode_status vc4_dpi_encoder_mode_valid(struct drm_encoder *encoder,
 						       const struct drm_display_mode *mode)
 {
 	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
 		return MODE_NO_INTERLACE;

 	return MODE_OK;
 }

 static const struct drm_encoder_helper_funcs vc4_dpi_encoder_helper_funcs = {
 	.disable = vc4_dpi_encoder_disable,
 	.enable = vc4_dpi_encoder_enable,
 	.mode_valid = vc4_dpi_encoder_mode_valid,
 };

 static int vc4_dpi_late_register(struct drm_encoder *encoder)
 {
 	struct drm_device *drm = encoder->dev;
 	struct vc4_dpi *dpi = to_vc4_dpi(encoder);
 	int ret;

 	ret = vc4_debugfs_add_regset32(drm->primary, "dpi_regs", &dpi->regset);
 	if (ret)
 		return ret;

 	return 0;
 }

 static const struct drm_encoder_funcs vc4_dpi_encoder_funcs = {
 	.late_register = vc4_dpi_late_register,
 };

 static const struct of_device_id vc4_dpi_dt_match[] = {
 	{ .compatible = "brcm,bcm2835-dpi", .data = NULL },
 	{}
 };

 /* Sets up the next link in the display chain, whether it's a panel or
  * a bridge.
  */
 static int vc4_dpi_init_bridge(struct vc4_dpi *dpi)
 {
 	struct drm_device *drm = dpi->encoder.base.dev;
 	struct device *dev = &dpi->pdev->dev;
 	struct drm_bridge *bridge;

 	bridge = drmm_of_get_bridge(drm, dev->of_node, 0, 0);
 	if (IS_ERR(bridge)) {
 		/* If nothing was connected in the DT, that's not an
 		 * error.
 		 */
 		if (PTR_ERR(bridge) == -ENODEV)
 			return 0;
 		else
 			return PTR_ERR(bridge);
 	}

 	return drm_bridge_attach(&dpi->encoder.base, bridge, NULL, 0);
 }

 static void vc4_dpi_disable_clock(void *ptr)
 {
 	struct vc4_dpi *dpi = ptr;

 	clk_disable_unprepare(dpi->core_clock);
 }

 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_dpi *dpi;
 	int ret;

 	dpi = drmm_kzalloc(drm, sizeof(*dpi), GFP_KERNEL);
 	if (!dpi)
 		return -ENOMEM;

 	dpi->encoder.type = VC4_ENCODER_TYPE_DPI;
 	dpi->pdev = pdev;
 	dpi->regs = vc4_ioremap_regs(pdev, 0);
 	if (IS_ERR(dpi->regs))
 		return PTR_ERR(dpi->regs);
 	dpi->regset.base = dpi->regs;
 	dpi->regset.regs = dpi_regs;
 	dpi->regset.nregs = ARRAY_SIZE(dpi_regs);

 	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->core_clock = devm_clk_get(dev, "core");
 	if (IS_ERR(dpi->core_clock)) {
 		ret = PTR_ERR(dpi->core_clock);
 		if (ret != -EPROBE_DEFER)
 			DRM_ERROR("Failed to get core clock: %d\n", ret);
 		return ret;
 	}

 	dpi->pixel_clock = devm_clk_get(dev, "pixel");
 	if (IS_ERR(dpi->pixel_clock)) {
 		ret = PTR_ERR(dpi->pixel_clock);
 		if (ret != -EPROBE_DEFER)
 			DRM_ERROR("Failed to get pixel clock: %d\n", ret);
 		return ret;
 	}

 	ret = clk_prepare_enable(dpi->core_clock);
 	if (ret) {
 		DRM_ERROR("Failed to turn on core clock: %d\n", ret);
 		return ret;
 	}

 	ret = devm_add_action_or_reset(dev, vc4_dpi_disable_clock, dpi);
 	if (ret)
 		return ret;

 	ret = drmm_encoder_init(drm, &dpi->encoder.base,
 				&vc4_dpi_encoder_funcs,
 				DRM_MODE_ENCODER_DPI,
 				NULL);
 	if (ret)
 		return ret;

 	drm_encoder_helper_add(&dpi->encoder.base, &vc4_dpi_encoder_helper_funcs);

 	ret = vc4_dpi_init_bridge(dpi);
 	if (ret)
 		return ret;

 	dev_set_drvdata(dev, dpi);

 	return 0;
 }

 static const struct component_ops vc4_dpi_ops = {
 	.bind   = vc4_dpi_bind,
 };

 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,
 	},
 };
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2016 Broadcom Limited
	*/

	/**
	* DOC: VC4 DPI module
	*
	* The VC4 DPI hardware supports MIPI DPI type 4 and Nokia ViSSI
	* signals. On BCM2835, these can be routed out to GPIO0-27 with the
	* ALT2 function.
	*/

	#include <drm/drm_atomic_helper.h>
	#include <drm/drm_bridge.h>
	#include <drm/drm_drv.h>
	#include <drm/drm_edid.h>
	#include <drm/drm_of.h>
	#include <drm/drm_panel.h>
	#include <drm/drm_probe_helper.h>
	#include <drm/drm_simple_kms_helper.h>
	#include <linux/clk.h>
	#include <linux/component.h>
	#include <linux/media-bus-format.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 vc4_encoder encoder;

	struct platform_device *pdev;

	void __iomem *regs;

	struct clk *pixel_clock;
	struct clk *core_clock;

	struct debugfs_regset32 regset;
	};

	static inline struct vc4_dpi *
	to_vc4_dpi(struct drm_encoder *encoder)
	{
	return container_of(encoder, struct vc4_dpi, encoder.base);
	}

	#define DPI_READ(offset) readl(dpi->regs + (offset))
	#define DPI_WRITE(offset, val) writel(val, dpi->regs + (offset))

	static const struct debugfs_reg32 dpi_regs[] = {
	VC4_REG32(DPI_C),
	VC4_REG32(DPI_ID),
	};

	static void vc4_dpi_encoder_disable(struct drm_encoder *encoder)
	{
	struct drm_device *dev = encoder->dev;
	struct vc4_dpi *dpi = to_vc4_dpi(encoder);
	int idx;

	if (!drm_dev_enter(dev, &idx))
	return;

	clk_disable_unprepare(dpi->pixel_clock);

	drm_dev_exit(idx);
	}

	static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
	{
	struct drm_device *dev = encoder->dev;
	struct drm_display_mode *mode = &encoder->crtc->mode;
	struct vc4_dpi *dpi = to_vc4_dpi(encoder);
	struct drm_connector_list_iter conn_iter;
	struct drm_connector connector = NULL, connector_scan;
	u32 dpi_c = DPI_ENABLE;
	int idx;
	int ret;

	/* Look up the connector attached to DPI so we can get the
	* bus_format. Ideally the bridge would tell us the
	* bus_format we want, but it doesn't yet, so assume that it's
	* uniform throughout the bridge chain.
	*/
	drm_connector_list_iter_begin(dev, &conn_iter);
	drm_for_each_connector_iter(connector_scan, &conn_iter) {
	if (connector_scan->encoder == encoder) {
	connector = connector_scan;
	break;
	}
	}
	drm_connector_list_iter_end(&conn_iter);

	/* Default to 24bit if no connector or format found. */
	dpi_c \|= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB, DPI_FORMAT);

	if (connector) {
	if (connector->display_info.num_bus_formats) {
	u32 bus_format = connector->display_info.bus_formats[0];

	dpi_c &= ~DPI_FORMAT_MASK;

	switch (bus_format) {
	case MEDIA_BUS_FMT_RGB888_1X24:
	dpi_c \|= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
	DPI_FORMAT);
	break;
	case MEDIA_BUS_FMT_BGR888_1X24:
	dpi_c \|= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
	DPI_FORMAT);
	dpi_c \|= VC4_SET_FIELD(DPI_ORDER_BGR,
	DPI_ORDER);
	break;
	case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
	dpi_c \|= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_2,
	DPI_FORMAT);
	break;
	case MEDIA_BUS_FMT_RGB666_1X18:
	dpi_c \|= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_1,
	DPI_FORMAT);
	break;
	case MEDIA_BUS_FMT_RGB565_1X16:
	dpi_c \|= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_3,
	DPI_FORMAT);
	break;
	default:
	DRM_ERROR("Unknown media bus format %d\n",
	bus_format);
	break;
	}
	}

	if (connector->display_info.bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)
	dpi_c \|= DPI_PIXEL_CLK_INVERT;

	if (connector->display_info.bus_flags & DRM_BUS_FLAG_DE_LOW)
	dpi_c \|= DPI_OUTPUT_ENABLE_INVERT;
	}

	if (mode->flags & DRM_MODE_FLAG_CSYNC) {
	if (mode->flags & DRM_MODE_FLAG_NCSYNC)
	dpi_c \|= DPI_OUTPUT_ENABLE_INVERT;
	} else {
	dpi_c \|= DPI_OUTPUT_ENABLE_MODE;

	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
	dpi_c \|= DPI_HSYNC_INVERT;
	else if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
	dpi_c \|= DPI_HSYNC_DISABLE;

	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
	dpi_c \|= DPI_VSYNC_INVERT;
	else if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
	dpi_c \|= DPI_VSYNC_DISABLE;
	}

	if (!drm_dev_enter(dev, &idx))
	return;

	DPI_WRITE(DPI_C, dpi_c);

	ret = clk_set_rate(dpi->pixel_clock, mode->clock * 1000);
	if (ret)
	DRM_ERROR("Failed to set clock rate: %d\n", ret);

	ret = clk_prepare_enable(dpi->pixel_clock);
	if (ret)
	DRM_ERROR("Failed to set clock rate: %d\n", ret);

	drm_dev_exit(idx);
	}

	static enum drm_mode_status vc4_dpi_encoder_mode_valid(struct drm_encoder *encoder,
	const struct drm_display_mode *mode)
	{
	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
	return MODE_NO_INTERLACE;

	return MODE_OK;
	}

	static const struct drm_encoder_helper_funcs vc4_dpi_encoder_helper_funcs = {
	.disable = vc4_dpi_encoder_disable,
	.enable = vc4_dpi_encoder_enable,
	.mode_valid = vc4_dpi_encoder_mode_valid,
	};

	static int vc4_dpi_late_register(struct drm_encoder *encoder)
	{
	struct drm_device *drm = encoder->dev;
	struct vc4_dpi *dpi = to_vc4_dpi(encoder);
	int ret;

	ret = vc4_debugfs_add_regset32(drm->primary, "dpi_regs", &dpi->regset);
	if (ret)
	return ret;

	return 0;
	}

	static const struct drm_encoder_funcs vc4_dpi_encoder_funcs = {
	.late_register = vc4_dpi_late_register,
	};

	static const struct of_device_id vc4_dpi_dt_match[] = {
	{ .compatible = "brcm,bcm2835-dpi", .data = NULL },
	{}
	};

	/* Sets up the next link in the display chain, whether it's a panel or
	* a bridge.
	*/
	static int vc4_dpi_init_bridge(struct vc4_dpi *dpi)
	{
	struct drm_device *drm = dpi->encoder.base.dev;
	struct device *dev = &dpi->pdev->dev;
	struct drm_bridge *bridge;

	bridge = drmm_of_get_bridge(drm, dev->of_node, 0, 0);
	if (IS_ERR(bridge)) {
	/* If nothing was connected in the DT, that's not an
	* error.
	*/
	if (PTR_ERR(bridge) == -ENODEV)
	return 0;
	else
	return PTR_ERR(bridge);
	}

	return drm_bridge_attach(&dpi->encoder.base, bridge, NULL, 0);
	}

	static void vc4_dpi_disable_clock(void *ptr)
	{
	struct vc4_dpi *dpi = ptr;

	clk_disable_unprepare(dpi->core_clock);
	}

	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_dpi *dpi;
	int ret;

	dpi = drmm_kzalloc(drm, sizeof(*dpi), GFP_KERNEL);
	if (!dpi)
	return -ENOMEM;

	dpi->encoder.type = VC4_ENCODER_TYPE_DPI;
	dpi->pdev = pdev;
	dpi->regs = vc4_ioremap_regs(pdev, 0);
	if (IS_ERR(dpi->regs))
	return PTR_ERR(dpi->regs);
	dpi->regset.base = dpi->regs;
	dpi->regset.regs = dpi_regs;
	dpi->regset.nregs = ARRAY_SIZE(dpi_regs);

	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->core_clock = devm_clk_get(dev, "core");
	if (IS_ERR(dpi->core_clock)) {
	ret = PTR_ERR(dpi->core_clock);
	if (ret != -EPROBE_DEFER)
	DRM_ERROR("Failed to get core clock: %d\n", ret);
	return ret;
	}

	dpi->pixel_clock = devm_clk_get(dev, "pixel");
	if (IS_ERR(dpi->pixel_clock)) {
	ret = PTR_ERR(dpi->pixel_clock);
	if (ret != -EPROBE_DEFER)
	DRM_ERROR("Failed to get pixel clock: %d\n", ret);
	return ret;
	}

	ret = clk_prepare_enable(dpi->core_clock);
	if (ret) {
	DRM_ERROR("Failed to turn on core clock: %d\n", ret);
	return ret;
	}

	ret = devm_add_action_or_reset(dev, vc4_dpi_disable_clock, dpi);
	if (ret)
	return ret;

	ret = drmm_encoder_init(drm, &dpi->encoder.base,
	&vc4_dpi_encoder_funcs,
	DRM_MODE_ENCODER_DPI,
	NULL);
	if (ret)
	return ret;

	drm_encoder_helper_add(&dpi->encoder.base, &vc4_dpi_encoder_helper_funcs);

	ret = vc4_dpi_init_bridge(dpi);
	if (ret)
	return ret;

	dev_set_drvdata(dev, dpi);

	return 0;
	}

	static const struct component_ops vc4_dpi_ops = {
	.bind = vc4_dpi_bind,
	};

	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,
	},
	};