drivers/gpu/drm/vc4/vc4_dpi.c - kernel/quantenna - Git at Google

 /*
  * 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;
 };

 #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_ENABLE | DPI_OUTPUT_ENABLE_MODE;
 	int ret;

 	ret = drm_panel_prepare(dpi->panel);
 	if (ret) {
 		DRM_ERROR("Panel failed to prepare\n");
 		return;
 	}

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

 		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 (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;

 	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);

 	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;
 	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->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);

 	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);
 	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,
 	},
 };
	/*
	* 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;
	};

	#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_ENABLE \| DPI_OUTPUT_ENABLE_MODE;
	int ret;

	ret = drm_panel_prepare(dpi->panel);
	if (ret) {
	DRM_ERROR("Panel failed to prepare\n");
	return;
	}

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

	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 (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;

	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);

	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;
	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->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);

	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);
	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,
	},
	};