drivers/media/platform/cadence/cdns-csi2tx.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Driver for Cadence MIPI-CSI2 TX Controller
  *
  * Copyright (C) 2017-2018 Cadence Design Systems Inc.
  */

 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_graph.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>

 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-fwnode.h>
 #include <media/v4l2-subdev.h>

 #define CSI2TX_DEVICE_CONFIG_REG	0x00
 #define CSI2TX_DEVICE_CONFIG_STREAMS_MASK	GENMASK(6, 4)
 #define CSI2TX_DEVICE_CONFIG_HAS_DPHY		BIT(3)
 #define CSI2TX_DEVICE_CONFIG_LANES_MASK		GENMASK(2, 0)

 #define CSI2TX_CONFIG_REG		0x20
 #define CSI2TX_CONFIG_CFG_REQ			BIT(2)
 #define CSI2TX_CONFIG_SRST_REQ			BIT(1)

 #define CSI2TX_DPHY_CFG_REG		0x28
 #define CSI2TX_DPHY_CFG_CLK_RESET		BIT(16)
 #define CSI2TX_DPHY_CFG_LANE_RESET(n)		BIT((n) + 12)
 #define CSI2TX_DPHY_CFG_MODE_MASK		GENMASK(9, 8)
 #define CSI2TX_DPHY_CFG_MODE_LPDT		(2 << 8)
 #define CSI2TX_DPHY_CFG_MODE_HS			(1 << 8)
 #define CSI2TX_DPHY_CFG_MODE_ULPS		(0 << 8)
 #define CSI2TX_DPHY_CFG_CLK_ENABLE		BIT(4)
 #define CSI2TX_DPHY_CFG_LANE_ENABLE(n)		BIT(n)

 #define CSI2TX_DPHY_CLK_WAKEUP_REG	0x2c
 #define CSI2TX_DPHY_CLK_WAKEUP_ULPS_CYCLES(n)	((n) & 0xffff)

 #define CSI2TX_DT_CFG_REG(n)		(0x80 + (n) * 8)
 #define CSI2TX_DT_CFG_DT(n)			(((n) & 0x3f) << 2)

 #define CSI2TX_DT_FORMAT_REG(n)		(0x84 + (n) * 8)
 #define CSI2TX_DT_FORMAT_BYTES_PER_LINE(n)	(((n) & 0xffff) << 16)
 #define CSI2TX_DT_FORMAT_MAX_LINE_NUM(n)	((n) & 0xffff)

 #define CSI2TX_STREAM_IF_CFG_REG(n)	(0x100 + (n) * 4)
 #define CSI2TX_STREAM_IF_CFG_FILL_LEVEL(n)	((n) & 0x1f)

 #define CSI2TX_LANES_MAX	4
 #define CSI2TX_STREAMS_MAX	4

 enum csi2tx_pads {
 	CSI2TX_PAD_SOURCE,
 	CSI2TX_PAD_SINK_STREAM0,
 	CSI2TX_PAD_SINK_STREAM1,
 	CSI2TX_PAD_SINK_STREAM2,
 	CSI2TX_PAD_SINK_STREAM3,
 	CSI2TX_PAD_MAX,
 };

 struct csi2tx_fmt {
 	u32	mbus;
 	u32	dt;
 	u32	bpp;
 };

 struct csi2tx_priv {
 	struct device			*dev;
 	unsigned int			count;

 	/*
 	 * Used to prevent race conditions between multiple,
 	 * concurrent calls to start and stop.
 	 */
 	struct mutex			lock;

 	void __iomem			*base;

 	struct clk			*esc_clk;
 	struct clk			*p_clk;
 	struct clk			*pixel_clk[CSI2TX_STREAMS_MAX];

 	struct v4l2_subdev		subdev;
 	struct media_pad		pads[CSI2TX_PAD_MAX];
 	struct v4l2_mbus_framefmt	pad_fmts[CSI2TX_PAD_MAX];

 	bool				has_internal_dphy;
 	u8				lanes[CSI2TX_LANES_MAX];
 	unsigned int			num_lanes;
 	unsigned int			max_lanes;
 	unsigned int			max_streams;
 };

 static const struct csi2tx_fmt csi2tx_formats[] = {
 	{
 		.mbus	= MEDIA_BUS_FMT_UYVY8_1X16,
 		.bpp	= 2,
 		.dt	= 0x1e,
 	},
 	{
 		.mbus	= MEDIA_BUS_FMT_RGB888_1X24,
 		.bpp	= 3,
 		.dt	= 0x24,
 	},
 };

 static const struct v4l2_mbus_framefmt fmt_default = {
 	.width		= 1280,
 	.height		= 720,
 	.code		= MEDIA_BUS_FMT_RGB888_1X24,
 	.field		= V4L2_FIELD_NONE,
 	.colorspace	= V4L2_COLORSPACE_DEFAULT,
 };

 static inline
 struct csi2tx_priv *v4l2_subdev_to_csi2tx(struct v4l2_subdev *subdev)
 {
 	return container_of(subdev, struct csi2tx_priv, subdev);
 }

 static const struct csi2tx_fmt *csi2tx_get_fmt_from_mbus(u32 mbus)
 {
 	unsigned int i;

 	for (i = 0; i < ARRAY_SIZE(csi2tx_formats); i++)
 		if (csi2tx_formats[i].mbus == mbus)
 			return &csi2tx_formats[i];

 	return NULL;
 }

 static int csi2tx_enum_mbus_code(struct v4l2_subdev *subdev,
 				 struct v4l2_subdev_pad_config *cfg,
 				 struct v4l2_subdev_mbus_code_enum *code)
 {
 	if (code->pad || code->index >= ARRAY_SIZE(csi2tx_formats))
 		return -EINVAL;

 	code->code = csi2tx_formats[code->index].mbus;

 	return 0;
 }

 static struct v4l2_mbus_framefmt *
 __csi2tx_get_pad_format(struct v4l2_subdev *subdev,
 			struct v4l2_subdev_pad_config *cfg,
 			struct v4l2_subdev_format *fmt)
 {
 	struct csi2tx_priv *csi2tx = v4l2_subdev_to_csi2tx(subdev);

 	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY)
 		return v4l2_subdev_get_try_format(subdev, cfg,
 						  fmt->pad);

 	return &csi2tx->pad_fmts[fmt->pad];
 }

 static int csi2tx_get_pad_format(struct v4l2_subdev *subdev,
 				 struct v4l2_subdev_pad_config *cfg,
 				 struct v4l2_subdev_format *fmt)
 {
 	const struct v4l2_mbus_framefmt *format;

 	/* Multiplexed pad? */
 	if (fmt->pad == CSI2TX_PAD_SOURCE)
 		return -EINVAL;

 	format = __csi2tx_get_pad_format(subdev, cfg, fmt);
 	if (!format)
 		return -EINVAL;

 	fmt->format = *format;

 	return 0;
 }

 static int csi2tx_set_pad_format(struct v4l2_subdev *subdev,
 				 struct v4l2_subdev_pad_config *cfg,
 				 struct v4l2_subdev_format *fmt)
 {
 	const struct v4l2_mbus_framefmt *src_format = &fmt->format;
 	struct v4l2_mbus_framefmt *dst_format;

 	/* Multiplexed pad? */
 	if (fmt->pad == CSI2TX_PAD_SOURCE)
 		return -EINVAL;

 	if (!csi2tx_get_fmt_from_mbus(fmt->format.code))
 		src_format = &fmt_default;

 	dst_format = __csi2tx_get_pad_format(subdev, cfg, fmt);
 	if (!dst_format)
 		return -EINVAL;

 	*dst_format = *src_format;

 	return 0;
 }

 static const struct v4l2_subdev_pad_ops csi2tx_pad_ops = {
 	.enum_mbus_code	= csi2tx_enum_mbus_code,
 	.get_fmt	= csi2tx_get_pad_format,
 	.set_fmt	= csi2tx_set_pad_format,
 };

 static void csi2tx_reset(struct csi2tx_priv *csi2tx)
 {
 	writel(CSI2TX_CONFIG_SRST_REQ, csi2tx->base + CSI2TX_CONFIG_REG);

 	udelay(10);
 }

 static int csi2tx_start(struct csi2tx_priv *csi2tx)
 {
 	struct media_entity *entity = &csi2tx->subdev.entity;
 	struct media_link *link;
 	unsigned int i;
 	u32 reg;

 	csi2tx_reset(csi2tx);

 	writel(CSI2TX_CONFIG_CFG_REQ, csi2tx->base + CSI2TX_CONFIG_REG);

 	udelay(10);

 	/* Configure our PPI interface with the D-PHY */
 	writel(CSI2TX_DPHY_CLK_WAKEUP_ULPS_CYCLES(32),
 	       csi2tx->base + CSI2TX_DPHY_CLK_WAKEUP_REG);

 	/* Put our lanes (clock and data) out of reset */
 	reg = CSI2TX_DPHY_CFG_CLK_RESET | CSI2TX_DPHY_CFG_MODE_LPDT;
 	for (i = 0; i < csi2tx->num_lanes; i++)
 		reg |= CSI2TX_DPHY_CFG_LANE_RESET(csi2tx->lanes[i]);
 	writel(reg, csi2tx->base + CSI2TX_DPHY_CFG_REG);

 	udelay(10);

 	/* Enable our (clock and data) lanes */
 	reg |= CSI2TX_DPHY_CFG_CLK_ENABLE;
 	for (i = 0; i < csi2tx->num_lanes; i++)
 		reg |= CSI2TX_DPHY_CFG_LANE_ENABLE(csi2tx->lanes[i]);
 	writel(reg, csi2tx->base + CSI2TX_DPHY_CFG_REG);

 	udelay(10);

 	/* Switch to HS mode */
 	reg &= ~CSI2TX_DPHY_CFG_MODE_MASK;
 	writel(reg | CSI2TX_DPHY_CFG_MODE_HS,
 	       csi2tx->base + CSI2TX_DPHY_CFG_REG);

 	udelay(10);

 	/*
 	 * Create a static mapping between the CSI virtual channels
 	 * and the input streams.
 	 *
 	 * This should be enhanced, but v4l2 lacks the support for
 	 * changing that mapping dynamically at the moment.
 	 *
 	 * We're protected from the userspace setting up links at the
 	 * same time by the upper layer having called
 	 * media_pipeline_start().
 	 */
 	list_for_each_entry(link, &entity->links, list) {
 		struct v4l2_mbus_framefmt *mfmt;
 		const struct csi2tx_fmt *fmt;
 		unsigned int stream;
 		int pad_idx = -1;

 		/* Only consider our enabled input pads */
 		for (i = CSI2TX_PAD_SINK_STREAM0; i < CSI2TX_PAD_MAX; i++) {
 			struct media_pad *pad = &csi2tx->pads[i];

 			if ((pad == link->sink) &&
 			    (link->flags & MEDIA_LNK_FL_ENABLED)) {
 				pad_idx = i;
 				break;
 			}
 		}

 		if (pad_idx < 0)
 			continue;

 		mfmt = &csi2tx->pad_fmts[pad_idx];
 		fmt = csi2tx_get_fmt_from_mbus(mfmt->code);
 		if (!fmt)
 			continue;

 		stream = pad_idx - CSI2TX_PAD_SINK_STREAM0;

 		/*
 		 * We use the stream ID there, but it's wrong.
 		 *
 		 * A stream could very well send a data type that is
 		 * not equal to its stream ID. We need to find a
 		 * proper way to address it.
 		 */
 		writel(CSI2TX_DT_CFG_DT(fmt->dt),
 		       csi2tx->base + CSI2TX_DT_CFG_REG(stream));

 		writel(CSI2TX_DT_FORMAT_BYTES_PER_LINE(mfmt->width * fmt->bpp) |
 		       CSI2TX_DT_FORMAT_MAX_LINE_NUM(mfmt->height + 1),
 		       csi2tx->base + CSI2TX_DT_FORMAT_REG(stream));

 		/*
 		 * TODO: This needs to be calculated based on the
 		 * output CSI2 clock rate.
 		 */
 		writel(CSI2TX_STREAM_IF_CFG_FILL_LEVEL(4),
 		       csi2tx->base + CSI2TX_STREAM_IF_CFG_REG(stream));
 	}

 	/* Disable the configuration mode */
 	writel(0, csi2tx->base + CSI2TX_CONFIG_REG);

 	return 0;
 }

 static void csi2tx_stop(struct csi2tx_priv *csi2tx)
 {
 	writel(CSI2TX_CONFIG_CFG_REQ | CSI2TX_CONFIG_SRST_REQ,
 	       csi2tx->base + CSI2TX_CONFIG_REG);
 }

 static int csi2tx_s_stream(struct v4l2_subdev *subdev, int enable)
 {
 	struct csi2tx_priv *csi2tx = v4l2_subdev_to_csi2tx(subdev);
 	int ret = 0;

 	mutex_lock(&csi2tx->lock);

 	if (enable) {
 		/*
 		 * If we're not the first users, there's no need to
 		 * enable the whole controller.
 		 */
 		if (!csi2tx->count) {
 			ret = csi2tx_start(csi2tx);
 			if (ret)
 				goto out;
 		}

 		csi2tx->count++;
 	} else {
 		csi2tx->count--;

 		/*
 		 * Let the last user turn off the lights.
 		 */
 		if (!csi2tx->count)
 			csi2tx_stop(csi2tx);
 	}

 out:
 	mutex_unlock(&csi2tx->lock);
 	return ret;
 }

 static const struct v4l2_subdev_video_ops csi2tx_video_ops = {
 	.s_stream	= csi2tx_s_stream,
 };

 static const struct v4l2_subdev_ops csi2tx_subdev_ops = {
 	.pad		= &csi2tx_pad_ops,
 	.video		= &csi2tx_video_ops,
 };

 static int csi2tx_get_resources(struct csi2tx_priv *csi2tx,
 				struct platform_device *pdev)
 {
 	struct resource *res;
 	unsigned int i;
 	u32 dev_cfg;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	csi2tx->base = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(csi2tx->base))
 		return PTR_ERR(csi2tx->base);

 	csi2tx->p_clk = devm_clk_get(&pdev->dev, "p_clk");
 	if (IS_ERR(csi2tx->p_clk)) {
 		dev_err(&pdev->dev, "Couldn't get p_clk\n");
 		return PTR_ERR(csi2tx->p_clk);
 	}

 	csi2tx->esc_clk = devm_clk_get(&pdev->dev, "esc_clk");
 	if (IS_ERR(csi2tx->esc_clk)) {
 		dev_err(&pdev->dev, "Couldn't get the esc_clk\n");
 		return PTR_ERR(csi2tx->esc_clk);
 	}

 	clk_prepare_enable(csi2tx->p_clk);
 	dev_cfg = readl(csi2tx->base + CSI2TX_DEVICE_CONFIG_REG);
 	clk_disable_unprepare(csi2tx->p_clk);

 	csi2tx->max_lanes = dev_cfg & CSI2TX_DEVICE_CONFIG_LANES_MASK;
 	if (csi2tx->max_lanes > CSI2TX_LANES_MAX) {
 		dev_err(&pdev->dev, "Invalid number of lanes: %u\n",
 			csi2tx->max_lanes);
 		return -EINVAL;
 	}

 	csi2tx->max_streams = (dev_cfg & CSI2TX_DEVICE_CONFIG_STREAMS_MASK) >> 4;
 	if (csi2tx->max_streams > CSI2TX_STREAMS_MAX) {
 		dev_err(&pdev->dev, "Invalid number of streams: %u\n",
 			csi2tx->max_streams);
 		return -EINVAL;
 	}

 	csi2tx->has_internal_dphy = !!(dev_cfg & CSI2TX_DEVICE_CONFIG_HAS_DPHY);

 	for (i = 0; i < csi2tx->max_streams; i++) {
 		char clk_name[16];

 		snprintf(clk_name, sizeof(clk_name), "pixel_if%u_clk", i);
 		csi2tx->pixel_clk[i] = devm_clk_get(&pdev->dev, clk_name);
 		if (IS_ERR(csi2tx->pixel_clk[i])) {
 			dev_err(&pdev->dev, "Couldn't get clock %s\n",
 				clk_name);
 			return PTR_ERR(csi2tx->pixel_clk[i]);
 		}
 	}

 	return 0;
 }

 static int csi2tx_check_lanes(struct csi2tx_priv *csi2tx)
 {
 	struct v4l2_fwnode_endpoint v4l2_ep;
 	struct device_node *ep;
 	int ret;

 	ep = of_graph_get_endpoint_by_regs(csi2tx->dev->of_node, 0, 0);
 	if (!ep)
 		return -EINVAL;

 	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &v4l2_ep);
 	if (ret) {
 		dev_err(csi2tx->dev, "Could not parse v4l2 endpoint\n");
 		goto out;
 	}

 	if (v4l2_ep.bus_type != V4L2_MBUS_CSI2) {
 		dev_err(csi2tx->dev, "Unsupported media bus type: 0x%x\n",
 			v4l2_ep.bus_type);
 		ret = -EINVAL;
 		goto out;
 	}

 	csi2tx->num_lanes = v4l2_ep.bus.mipi_csi2.num_data_lanes;
 	if (csi2tx->num_lanes > csi2tx->max_lanes) {
 		dev_err(csi2tx->dev,
 			"Current configuration uses more lanes than supported\n");
 		ret = -EINVAL;
 		goto out;
 	}

 	memcpy(csi2tx->lanes, v4l2_ep.bus.mipi_csi2.data_lanes,
 	       sizeof(csi2tx->lanes));

 out:
 	of_node_put(ep);
 	return ret;
 }

 static int csi2tx_probe(struct platform_device *pdev)
 {
 	struct csi2tx_priv *csi2tx;
 	unsigned int i;
 	int ret;

 	csi2tx = kzalloc(sizeof(*csi2tx), GFP_KERNEL);
 	if (!csi2tx)
 		return -ENOMEM;
 	platform_set_drvdata(pdev, csi2tx);
 	mutex_init(&csi2tx->lock);
 	csi2tx->dev = &pdev->dev;

 	ret = csi2tx_get_resources(csi2tx, pdev);
 	if (ret)
 		goto err_free_priv;

 	v4l2_subdev_init(&csi2tx->subdev, &csi2tx_subdev_ops);
 	csi2tx->subdev.owner = THIS_MODULE;
 	csi2tx->subdev.dev = &pdev->dev;
 	csi2tx->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
 	snprintf(csi2tx->subdev.name, V4L2_SUBDEV_NAME_SIZE, "%s.%s",
 		 KBUILD_MODNAME, dev_name(&pdev->dev));

 	ret = csi2tx_check_lanes(csi2tx);
 	if (ret)
 		goto err_free_priv;

 	/* Create our media pads */
 	csi2tx->subdev.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
 	csi2tx->pads[CSI2TX_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
 	for (i = CSI2TX_PAD_SINK_STREAM0; i < CSI2TX_PAD_MAX; i++)
 		csi2tx->pads[i].flags = MEDIA_PAD_FL_SINK;

 	/*
 	 * Only the input pads are considered to have a format at the
 	 * moment. The CSI link can multiplex various streams with
 	 * different formats, and we can't expose this in v4l2 right
 	 * now.
 	 */
 	for (i = CSI2TX_PAD_SINK_STREAM0; i < CSI2TX_PAD_MAX; i++)
 		csi2tx->pad_fmts[i] = fmt_default;

 	ret = media_entity_pads_init(&csi2tx->subdev.entity, CSI2TX_PAD_MAX,
 				     csi2tx->pads);
 	if (ret)
 		goto err_free_priv;

 	ret = v4l2_async_register_subdev(&csi2tx->subdev);
 	if (ret < 0)
 		goto err_free_priv;

 	dev_info(&pdev->dev,
 		 "Probed CSI2TX with %u/%u lanes, %u streams, %s D-PHY\n",
 		 csi2tx->num_lanes, csi2tx->max_lanes, csi2tx->max_streams,
 		 csi2tx->has_internal_dphy ? "internal" : "no");

 	return 0;

 err_free_priv:
 	kfree(csi2tx);
 	return ret;
 }

 static int csi2tx_remove(struct platform_device *pdev)
 {
 	struct csi2tx_priv *csi2tx = platform_get_drvdata(pdev);

 	v4l2_async_unregister_subdev(&csi2tx->subdev);
 	kfree(csi2tx);

 	return 0;
 }

 static const struct of_device_id csi2tx_of_table[] = {
 	{ .compatible = "cdns,csi2tx" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, csi2tx_of_table);

 static struct platform_driver csi2tx_driver = {
 	.probe	= csi2tx_probe,
 	.remove	= csi2tx_remove,

 	.driver	= {
 		.name		= "cdns-csi2tx",
 		.of_match_table	= csi2tx_of_table,
 	},
 };
 module_platform_driver(csi2tx_driver);
 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@bootlin.com>");
 MODULE_DESCRIPTION("Cadence CSI2-TX controller");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Driver for Cadence MIPI-CSI2 TX Controller
	*
	* Copyright (C) 2017-2018 Cadence Design Systems Inc.
	*/

	#include <linux/clk.h>
	#include <linux/delay.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>
	#include <linux/of_graph.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>

	#include <media/v4l2-ctrls.h>
	#include <media/v4l2-device.h>
	#include <media/v4l2-fwnode.h>
	#include <media/v4l2-subdev.h>

	#define CSI2TX_DEVICE_CONFIG_REG 0x00
	#define CSI2TX_DEVICE_CONFIG_STREAMS_MASK GENMASK(6, 4)
	#define CSI2TX_DEVICE_CONFIG_HAS_DPHY BIT(3)
	#define CSI2TX_DEVICE_CONFIG_LANES_MASK GENMASK(2, 0)

	#define CSI2TX_CONFIG_REG 0x20
	#define CSI2TX_CONFIG_CFG_REQ BIT(2)
	#define CSI2TX_CONFIG_SRST_REQ BIT(1)

	#define CSI2TX_DPHY_CFG_REG 0x28
	#define CSI2TX_DPHY_CFG_CLK_RESET BIT(16)
	#define CSI2TX_DPHY_CFG_LANE_RESET(n) BIT((n) + 12)
	#define CSI2TX_DPHY_CFG_MODE_MASK GENMASK(9, 8)
	#define CSI2TX_DPHY_CFG_MODE_LPDT (2 << 8)
	#define CSI2TX_DPHY_CFG_MODE_HS (1 << 8)
	#define CSI2TX_DPHY_CFG_MODE_ULPS (0 << 8)
	#define CSI2TX_DPHY_CFG_CLK_ENABLE BIT(4)
	#define CSI2TX_DPHY_CFG_LANE_ENABLE(n) BIT(n)

	#define CSI2TX_DPHY_CLK_WAKEUP_REG 0x2c
	#define CSI2TX_DPHY_CLK_WAKEUP_ULPS_CYCLES(n) ((n) & 0xffff)

	#define CSI2TX_DT_CFG_REG(n) (0x80 + (n) * 8)
	#define CSI2TX_DT_CFG_DT(n) (((n) & 0x3f) << 2)

	#define CSI2TX_DT_FORMAT_REG(n) (0x84 + (n) * 8)
	#define CSI2TX_DT_FORMAT_BYTES_PER_LINE(n) (((n) & 0xffff) << 16)
	#define CSI2TX_DT_FORMAT_MAX_LINE_NUM(n) ((n) & 0xffff)

	#define CSI2TX_STREAM_IF_CFG_REG(n) (0x100 + (n) * 4)
	#define CSI2TX_STREAM_IF_CFG_FILL_LEVEL(n) ((n) & 0x1f)

	#define CSI2TX_LANES_MAX 4
	#define CSI2TX_STREAMS_MAX 4

	enum csi2tx_pads {
	CSI2TX_PAD_SOURCE,
	CSI2TX_PAD_SINK_STREAM0,
	CSI2TX_PAD_SINK_STREAM1,
	CSI2TX_PAD_SINK_STREAM2,
	CSI2TX_PAD_SINK_STREAM3,
	CSI2TX_PAD_MAX,
	};

	struct csi2tx_fmt {
	u32 mbus;
	u32 dt;
	u32 bpp;
	};

	struct csi2tx_priv {
	struct device *dev;
	unsigned int count;

	/*
	* Used to prevent race conditions between multiple,
	* concurrent calls to start and stop.
	*/
	struct mutex lock;

	void __iomem *base;

	struct clk *esc_clk;
	struct clk *p_clk;
	struct clk *pixel_clk[CSI2TX_STREAMS_MAX];

	struct v4l2_subdev subdev;
	struct media_pad pads[CSI2TX_PAD_MAX];
	struct v4l2_mbus_framefmt pad_fmts[CSI2TX_PAD_MAX];

	bool has_internal_dphy;
	u8 lanes[CSI2TX_LANES_MAX];
	unsigned int num_lanes;
	unsigned int max_lanes;
	unsigned int max_streams;
	};

	static const struct csi2tx_fmt csi2tx_formats[] = {
	{
	.mbus = MEDIA_BUS_FMT_UYVY8_1X16,
	.bpp = 2,
	.dt = 0x1e,
	},
	{
	.mbus = MEDIA_BUS_FMT_RGB888_1X24,
	.bpp = 3,
	.dt = 0x24,
	},
	};

	static const struct v4l2_mbus_framefmt fmt_default = {
	.width = 1280,
	.height = 720,
	.code = MEDIA_BUS_FMT_RGB888_1X24,
	.field = V4L2_FIELD_NONE,
	.colorspace = V4L2_COLORSPACE_DEFAULT,
	};

	static inline
	struct csi2tx_priv v4l2_subdev_to_csi2tx(struct v4l2_subdev subdev)
	{
	return container_of(subdev, struct csi2tx_priv, subdev);
	}

	static const struct csi2tx_fmt *csi2tx_get_fmt_from_mbus(u32 mbus)
	{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(csi2tx_formats); i++)
	if (csi2tx_formats[i].mbus == mbus)
	return &csi2tx_formats[i];

	return NULL;
	}

	static int csi2tx_enum_mbus_code(struct v4l2_subdev *subdev,
	struct v4l2_subdev_pad_config *cfg,
	struct v4l2_subdev_mbus_code_enum *code)
	{
	if (code->pad \|\| code->index >= ARRAY_SIZE(csi2tx_formats))
	return -EINVAL;

	code->code = csi2tx_formats[code->index].mbus;

	return 0;
	}

	static struct v4l2_mbus_framefmt *
	__csi2tx_get_pad_format(struct v4l2_subdev *subdev,
	struct v4l2_subdev_pad_config *cfg,
	struct v4l2_subdev_format *fmt)
	{
	struct csi2tx_priv *csi2tx = v4l2_subdev_to_csi2tx(subdev);

	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY)
	return v4l2_subdev_get_try_format(subdev, cfg,
	fmt->pad);

	return &csi2tx->pad_fmts[fmt->pad];
	}

	static int csi2tx_get_pad_format(struct v4l2_subdev *subdev,
	struct v4l2_subdev_pad_config *cfg,
	struct v4l2_subdev_format *fmt)
	{
	const struct v4l2_mbus_framefmt *format;

	/* Multiplexed pad? */
	if (fmt->pad == CSI2TX_PAD_SOURCE)
	return -EINVAL;

	format = __csi2tx_get_pad_format(subdev, cfg, fmt);
	if (!format)
	return -EINVAL;

	fmt->format = *format;

	return 0;
	}

	static int csi2tx_set_pad_format(struct v4l2_subdev *subdev,
	struct v4l2_subdev_pad_config *cfg,
	struct v4l2_subdev_format *fmt)
	{
	const struct v4l2_mbus_framefmt *src_format = &fmt->format;
	struct v4l2_mbus_framefmt *dst_format;

	/* Multiplexed pad? */
	if (fmt->pad == CSI2TX_PAD_SOURCE)
	return -EINVAL;

	if (!csi2tx_get_fmt_from_mbus(fmt->format.code))
	src_format = &fmt_default;

	dst_format = __csi2tx_get_pad_format(subdev, cfg, fmt);
	if (!dst_format)
	return -EINVAL;

	dst_format = src_format;

	return 0;
	}

	static const struct v4l2_subdev_pad_ops csi2tx_pad_ops = {
	.enum_mbus_code = csi2tx_enum_mbus_code,
	.get_fmt = csi2tx_get_pad_format,
	.set_fmt = csi2tx_set_pad_format,
	};

	static void csi2tx_reset(struct csi2tx_priv *csi2tx)
	{
	writel(CSI2TX_CONFIG_SRST_REQ, csi2tx->base + CSI2TX_CONFIG_REG);

	udelay(10);
	}

	static int csi2tx_start(struct csi2tx_priv *csi2tx)
	{
	struct media_entity *entity = &csi2tx->subdev.entity;
	struct media_link *link;
	unsigned int i;
	u32 reg;

	csi2tx_reset(csi2tx);

	writel(CSI2TX_CONFIG_CFG_REQ, csi2tx->base + CSI2TX_CONFIG_REG);

	udelay(10);

	/* Configure our PPI interface with the D-PHY */
	writel(CSI2TX_DPHY_CLK_WAKEUP_ULPS_CYCLES(32),
	csi2tx->base + CSI2TX_DPHY_CLK_WAKEUP_REG);

	/* Put our lanes (clock and data) out of reset */
	reg = CSI2TX_DPHY_CFG_CLK_RESET \| CSI2TX_DPHY_CFG_MODE_LPDT;
	for (i = 0; i < csi2tx->num_lanes; i++)
	reg \|= CSI2TX_DPHY_CFG_LANE_RESET(csi2tx->lanes[i]);
	writel(reg, csi2tx->base + CSI2TX_DPHY_CFG_REG);

	udelay(10);

	/* Enable our (clock and data) lanes */
	reg \|= CSI2TX_DPHY_CFG_CLK_ENABLE;
	for (i = 0; i < csi2tx->num_lanes; i++)
	reg \|= CSI2TX_DPHY_CFG_LANE_ENABLE(csi2tx->lanes[i]);
	writel(reg, csi2tx->base + CSI2TX_DPHY_CFG_REG);

	udelay(10);

	/* Switch to HS mode */
	reg &= ~CSI2TX_DPHY_CFG_MODE_MASK;
	writel(reg \| CSI2TX_DPHY_CFG_MODE_HS,
	csi2tx->base + CSI2TX_DPHY_CFG_REG);

	udelay(10);

	/*
	* Create a static mapping between the CSI virtual channels
	* and the input streams.
	*
	* This should be enhanced, but v4l2 lacks the support for
	* changing that mapping dynamically at the moment.
	*
	* We're protected from the userspace setting up links at the
	* same time by the upper layer having called
	* media_pipeline_start().
	*/
	list_for_each_entry(link, &entity->links, list) {
	struct v4l2_mbus_framefmt *mfmt;
	const struct csi2tx_fmt *fmt;
	unsigned int stream;
	int pad_idx = -1;

	/* Only consider our enabled input pads */
	for (i = CSI2TX_PAD_SINK_STREAM0; i < CSI2TX_PAD_MAX; i++) {
	struct media_pad *pad = &csi2tx->pads[i];

	if ((pad == link->sink) &&
	(link->flags & MEDIA_LNK_FL_ENABLED)) {
	pad_idx = i;
	break;
	}
	}

	if (pad_idx < 0)
	continue;

	mfmt = &csi2tx->pad_fmts[pad_idx];
	fmt = csi2tx_get_fmt_from_mbus(mfmt->code);
	if (!fmt)
	continue;

	stream = pad_idx - CSI2TX_PAD_SINK_STREAM0;

	/*
	* We use the stream ID there, but it's wrong.
	*
	* A stream could very well send a data type that is
	* not equal to its stream ID. We need to find a
	* proper way to address it.
	*/
	writel(CSI2TX_DT_CFG_DT(fmt->dt),
	csi2tx->base + CSI2TX_DT_CFG_REG(stream));

	writel(CSI2TX_DT_FORMAT_BYTES_PER_LINE(mfmt->width * fmt->bpp) \|
	CSI2TX_DT_FORMAT_MAX_LINE_NUM(mfmt->height + 1),
	csi2tx->base + CSI2TX_DT_FORMAT_REG(stream));

	/*
	* TODO: This needs to be calculated based on the
	* output CSI2 clock rate.
	*/
	writel(CSI2TX_STREAM_IF_CFG_FILL_LEVEL(4),
	csi2tx->base + CSI2TX_STREAM_IF_CFG_REG(stream));
	}

	/* Disable the configuration mode */
	writel(0, csi2tx->base + CSI2TX_CONFIG_REG);

	return 0;
	}

	static void csi2tx_stop(struct csi2tx_priv *csi2tx)
	{
	writel(CSI2TX_CONFIG_CFG_REQ \| CSI2TX_CONFIG_SRST_REQ,
	csi2tx->base + CSI2TX_CONFIG_REG);
	}

	static int csi2tx_s_stream(struct v4l2_subdev *subdev, int enable)
	{
	struct csi2tx_priv *csi2tx = v4l2_subdev_to_csi2tx(subdev);
	int ret = 0;

	mutex_lock(&csi2tx->lock);

	if (enable) {
	/*
	* If we're not the first users, there's no need to
	* enable the whole controller.
	*/
	if (!csi2tx->count) {
	ret = csi2tx_start(csi2tx);
	if (ret)
	goto out;
	}

	csi2tx->count++;
	} else {
	csi2tx->count--;

	/*
	* Let the last user turn off the lights.
	*/
	if (!csi2tx->count)
	csi2tx_stop(csi2tx);
	}

	out:
	mutex_unlock(&csi2tx->lock);
	return ret;
	}

	static const struct v4l2_subdev_video_ops csi2tx_video_ops = {
	.s_stream = csi2tx_s_stream,
	};

	static const struct v4l2_subdev_ops csi2tx_subdev_ops = {
	.pad = &csi2tx_pad_ops,
	.video = &csi2tx_video_ops,
	};

	static int csi2tx_get_resources(struct csi2tx_priv *csi2tx,
	struct platform_device *pdev)
	{
	struct resource *res;
	unsigned int i;
	u32 dev_cfg;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	csi2tx->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(csi2tx->base))
	return PTR_ERR(csi2tx->base);

	csi2tx->p_clk = devm_clk_get(&pdev->dev, "p_clk");
	if (IS_ERR(csi2tx->p_clk)) {
	dev_err(&pdev->dev, "Couldn't get p_clk\n");
	return PTR_ERR(csi2tx->p_clk);
	}

	csi2tx->esc_clk = devm_clk_get(&pdev->dev, "esc_clk");
	if (IS_ERR(csi2tx->esc_clk)) {
	dev_err(&pdev->dev, "Couldn't get the esc_clk\n");
	return PTR_ERR(csi2tx->esc_clk);
	}

	clk_prepare_enable(csi2tx->p_clk);
	dev_cfg = readl(csi2tx->base + CSI2TX_DEVICE_CONFIG_REG);
	clk_disable_unprepare(csi2tx->p_clk);

	csi2tx->max_lanes = dev_cfg & CSI2TX_DEVICE_CONFIG_LANES_MASK;
	if (csi2tx->max_lanes > CSI2TX_LANES_MAX) {
	dev_err(&pdev->dev, "Invalid number of lanes: %u\n",
	csi2tx->max_lanes);
	return -EINVAL;
	}

	csi2tx->max_streams = (dev_cfg & CSI2TX_DEVICE_CONFIG_STREAMS_MASK) >> 4;
	if (csi2tx->max_streams > CSI2TX_STREAMS_MAX) {
	dev_err(&pdev->dev, "Invalid number of streams: %u\n",
	csi2tx->max_streams);
	return -EINVAL;
	}

	csi2tx->has_internal_dphy = !!(dev_cfg & CSI2TX_DEVICE_CONFIG_HAS_DPHY);

	for (i = 0; i < csi2tx->max_streams; i++) {
	char clk_name[16];

	snprintf(clk_name, sizeof(clk_name), "pixel_if%u_clk", i);
	csi2tx->pixel_clk[i] = devm_clk_get(&pdev->dev, clk_name);
	if (IS_ERR(csi2tx->pixel_clk[i])) {
	dev_err(&pdev->dev, "Couldn't get clock %s\n",
	clk_name);
	return PTR_ERR(csi2tx->pixel_clk[i]);
	}
	}

	return 0;
	}

	static int csi2tx_check_lanes(struct csi2tx_priv *csi2tx)
	{
	struct v4l2_fwnode_endpoint v4l2_ep;
	struct device_node *ep;
	int ret;

	ep = of_graph_get_endpoint_by_regs(csi2tx->dev->of_node, 0, 0);
	if (!ep)
	return -EINVAL;

	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &v4l2_ep);
	if (ret) {
	dev_err(csi2tx->dev, "Could not parse v4l2 endpoint\n");
	goto out;
	}

	if (v4l2_ep.bus_type != V4L2_MBUS_CSI2) {
	dev_err(csi2tx->dev, "Unsupported media bus type: 0x%x\n",
	v4l2_ep.bus_type);
	ret = -EINVAL;
	goto out;
	}

	csi2tx->num_lanes = v4l2_ep.bus.mipi_csi2.num_data_lanes;
	if (csi2tx->num_lanes > csi2tx->max_lanes) {
	dev_err(csi2tx->dev,
	"Current configuration uses more lanes than supported\n");
	ret = -EINVAL;
	goto out;
	}

	memcpy(csi2tx->lanes, v4l2_ep.bus.mipi_csi2.data_lanes,
	sizeof(csi2tx->lanes));

	out:
	of_node_put(ep);
	return ret;
	}

	static int csi2tx_probe(struct platform_device *pdev)
	{
	struct csi2tx_priv *csi2tx;
	unsigned int i;
	int ret;

	csi2tx = kzalloc(sizeof(*csi2tx), GFP_KERNEL);
	if (!csi2tx)
	return -ENOMEM;
	platform_set_drvdata(pdev, csi2tx);
	mutex_init(&csi2tx->lock);
	csi2tx->dev = &pdev->dev;

	ret = csi2tx_get_resources(csi2tx, pdev);
	if (ret)
	goto err_free_priv;

	v4l2_subdev_init(&csi2tx->subdev, &csi2tx_subdev_ops);
	csi2tx->subdev.owner = THIS_MODULE;
	csi2tx->subdev.dev = &pdev->dev;
	csi2tx->subdev.flags \|= V4L2_SUBDEV_FL_HAS_DEVNODE;
	snprintf(csi2tx->subdev.name, V4L2_SUBDEV_NAME_SIZE, "%s.%s",
	KBUILD_MODNAME, dev_name(&pdev->dev));

	ret = csi2tx_check_lanes(csi2tx);
	if (ret)
	goto err_free_priv;

	/* Create our media pads */
	csi2tx->subdev.entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
	csi2tx->pads[CSI2TX_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
	for (i = CSI2TX_PAD_SINK_STREAM0; i < CSI2TX_PAD_MAX; i++)
	csi2tx->pads[i].flags = MEDIA_PAD_FL_SINK;

	/*
	* Only the input pads are considered to have a format at the
	* moment. The CSI link can multiplex various streams with
	* different formats, and we can't expose this in v4l2 right
	* now.
	*/
	for (i = CSI2TX_PAD_SINK_STREAM0; i < CSI2TX_PAD_MAX; i++)
	csi2tx->pad_fmts[i] = fmt_default;

	ret = media_entity_pads_init(&csi2tx->subdev.entity, CSI2TX_PAD_MAX,
	csi2tx->pads);
	if (ret)
	goto err_free_priv;

	ret = v4l2_async_register_subdev(&csi2tx->subdev);
	if (ret < 0)
	goto err_free_priv;

	dev_info(&pdev->dev,
	"Probed CSI2TX with %u/%u lanes, %u streams, %s D-PHY\n",
	csi2tx->num_lanes, csi2tx->max_lanes, csi2tx->max_streams,
	csi2tx->has_internal_dphy ? "internal" : "no");

	return 0;

	err_free_priv:
	kfree(csi2tx);
	return ret;
	}

	static int csi2tx_remove(struct platform_device *pdev)
	{
	struct csi2tx_priv *csi2tx = platform_get_drvdata(pdev);

	v4l2_async_unregister_subdev(&csi2tx->subdev);
	kfree(csi2tx);

	return 0;
	}

	static const struct of_device_id csi2tx_of_table[] = {
	{ .compatible = "cdns,csi2tx" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, csi2tx_of_table);

	static struct platform_driver csi2tx_driver = {
	.probe = csi2tx_probe,
	.remove = csi2tx_remove,

	.driver = {
	.name = "cdns-csi2tx",
	.of_match_table = csi2tx_of_table,
	},
	};
	module_platform_driver(csi2tx_driver);
	MODULE_AUTHOR("Maxime Ripard <maxime.ripard@bootlin.com>");
	MODULE_DESCRIPTION("Cadence CSI2-TX controller");
	MODULE_LICENSE("GPL");