drivers/media/test-drivers/vimc/vimc-common.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * vimc-common.c Virtual Media Controller Driver
  *
  * Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
  */

 #include <linux/init.h>
 #include <linux/module.h>

 #include <media/v4l2-ctrls.h>

 #include "vimc-common.h"

 /*
  * NOTE: non-bayer formats need to come first (necessary for enum_mbus_code
  * in the scaler)
  */
 static const struct vimc_pix_map vimc_pix_map_list[] = {
 	/* TODO: add all missing formats */

 	/* RGB formats */
 	{
 		.code = {
 			MEDIA_BUS_FMT_BGR888_1X24,
 			MEDIA_BUS_FMT_BGR888_3X8
 		},
 		.pixelformat = V4L2_PIX_FMT_BGR24,
 		.bpp = 3,
 		.bayer = false,
 	},
 	{
 		.code = {
 			MEDIA_BUS_FMT_RGB888_1X24,
 			MEDIA_BUS_FMT_RGB888_2X12_BE,
 			MEDIA_BUS_FMT_RGB888_2X12_LE,
 			MEDIA_BUS_FMT_RGB888_3X8,
 			MEDIA_BUS_FMT_RGB888_1X7X4_SPWG,
 			MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA,
 			MEDIA_BUS_FMT_RGB888_1X32_PADHI,
 			MEDIA_BUS_FMT_GBR888_1X24
 		},
 		.pixelformat = V4L2_PIX_FMT_RGB24,
 		.bpp = 3,
 		.bayer = false,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_ARGB8888_1X32 },
 		.pixelformat = V4L2_PIX_FMT_ARGB32,
 		.bpp = 4,
 		.bayer = false,
 	},

 	/* Bayer formats */
 	{
 		.code = { MEDIA_BUS_FMT_SBGGR8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SBGGR8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGBRG8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SGBRG8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGRBG8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SGRBG8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SRGGB8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SRGGB8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SBGGR10_1X10 },
 		.pixelformat = V4L2_PIX_FMT_SBGGR10,
 		.bpp = 2,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGBRG10_1X10 },
 		.pixelformat = V4L2_PIX_FMT_SGBRG10,
 		.bpp = 2,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGRBG10_1X10 },
 		.pixelformat = V4L2_PIX_FMT_SGRBG10,
 		.bpp = 2,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SRGGB10_1X10 },
 		.pixelformat = V4L2_PIX_FMT_SRGGB10,
 		.bpp = 2,
 		.bayer = true,
 	},

 	/* 10bit raw bayer a-law compressed to 8 bits */
 	{
 		.code = { MEDIA_BUS_FMT_SBGGR10_ALAW8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SBGGR10ALAW8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGBRG10_ALAW8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SGBRG10ALAW8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGRBG10_ALAW8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SGRBG10ALAW8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SRGGB10_ALAW8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SRGGB10ALAW8,
 		.bpp = 1,
 		.bayer = true,
 	},

 	/* 10bit raw bayer DPCM compressed to 8 bits */
 	{
 		.code = { MEDIA_BUS_FMT_SBGGR10_DPCM8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SBGGR10DPCM8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGBRG10_DPCM8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SGBRG10DPCM8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SGRBG10DPCM8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SRGGB10_DPCM8_1X8 },
 		.pixelformat = V4L2_PIX_FMT_SRGGB10DPCM8,
 		.bpp = 1,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SBGGR12_1X12 },
 		.pixelformat = V4L2_PIX_FMT_SBGGR12,
 		.bpp = 2,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGBRG12_1X12 },
 		.pixelformat = V4L2_PIX_FMT_SGBRG12,
 		.bpp = 2,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SGRBG12_1X12 },
 		.pixelformat = V4L2_PIX_FMT_SGRBG12,
 		.bpp = 2,
 		.bayer = true,
 	},
 	{
 		.code = { MEDIA_BUS_FMT_SRGGB12_1X12 },
 		.pixelformat = V4L2_PIX_FMT_SRGGB12,
 		.bpp = 2,
 		.bayer = true,
 	},
 };

 bool vimc_is_source(struct media_entity *ent)
 {
 	unsigned int i;

 	for (i = 0; i < ent->num_pads; i++)
 		if (ent->pads[i].flags & MEDIA_PAD_FL_SINK)
 			return false;
 	return true;
 }

 const struct vimc_pix_map *vimc_pix_map_by_index(unsigned int i)
 {
 	if (i >= ARRAY_SIZE(vimc_pix_map_list))
 		return NULL;

 	return &vimc_pix_map_list[i];
 }

 u32 vimc_mbus_code_by_index(unsigned int index)
 {
 	unsigned int i, j;

 	for (i = 0; i < ARRAY_SIZE(vimc_pix_map_list); i++) {
 		for (j = 0; j < ARRAY_SIZE(vimc_pix_map_list[i].code); j++) {
 			if (!vimc_pix_map_list[i].code[j])
 				break;

 			if (!index)
 				return vimc_pix_map_list[i].code[j];
 			index--;
 		}
 	}
 	return 0;
 }

 const struct vimc_pix_map *vimc_pix_map_by_code(u32 code)
 {
 	unsigned int i, j;

 	for (i = 0; i < ARRAY_SIZE(vimc_pix_map_list); i++) {
 		for (j = 0; j < ARRAY_SIZE(vimc_pix_map_list[i].code); j++) {
 			if (vimc_pix_map_list[i].code[j] == code)
 				return &vimc_pix_map_list[i];
 		}
 	}
 	return NULL;
 }

 const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat)
 {
 	unsigned int i;

 	for (i = 0; i < ARRAY_SIZE(vimc_pix_map_list); i++) {
 		if (vimc_pix_map_list[i].pixelformat == pixelformat)
 			return &vimc_pix_map_list[i];
 	}
 	return NULL;
 }

 static int vimc_get_pix_format(struct media_pad *pad,
 			       struct v4l2_pix_format *fmt)
 {
 	if (is_media_entity_v4l2_subdev(pad->entity)) {
 		struct v4l2_subdev *sd =
 			media_entity_to_v4l2_subdev(pad->entity);
 		struct v4l2_subdev_format sd_fmt = {
 			.which = V4L2_SUBDEV_FORMAT_ACTIVE,
 			.pad = pad->index,
 		};
 		const struct vimc_pix_map *pix_map;
 		int ret;

 		ret = v4l2_subdev_call(sd, pad, get_fmt, NULL, &sd_fmt);
 		if (ret)
 			return ret;

 		v4l2_fill_pix_format(fmt, &sd_fmt.format);
 		pix_map = vimc_pix_map_by_code(sd_fmt.format.code);
 		fmt->pixelformat = pix_map->pixelformat;
 	} else if (is_media_entity_v4l2_video_device(pad->entity)) {
 		struct video_device *vdev = container_of(pad->entity,
 							 struct video_device,
 							 entity);
 		struct vimc_ent_device *ved = video_get_drvdata(vdev);

 		if (!ved->vdev_get_format)
 			return -ENOIOCTLCMD;

 		ved->vdev_get_format(ved, fmt);
 	} else {
 		return -EINVAL;
 	}

 	return 0;
 }

 int vimc_vdev_link_validate(struct media_link *link)
 {
 	struct v4l2_pix_format source_fmt, sink_fmt;
 	int ret;

 	ret = vimc_get_pix_format(link->source, &source_fmt);
 	if (ret)
 		return ret;

 	ret = vimc_get_pix_format(link->sink, &sink_fmt);
 	if (ret)
 		return ret;

 	pr_info("vimc link validate: "
 		"%s:src:%dx%d (0x%x, %d, %d, %d, %d) "
 		"%s:snk:%dx%d (0x%x, %d, %d, %d, %d)\n",
 		/* src */
 		link->source->entity->name,
 		source_fmt.width, source_fmt.height,
 		source_fmt.pixelformat, source_fmt.colorspace,
 		source_fmt.quantization, source_fmt.xfer_func,
 		source_fmt.ycbcr_enc,
 		/* sink */
 		link->sink->entity->name,
 		sink_fmt.width, sink_fmt.height,
 		sink_fmt.pixelformat, sink_fmt.colorspace,
 		sink_fmt.quantization, sink_fmt.xfer_func,
 		sink_fmt.ycbcr_enc);

 	/* The width, height and pixelformat must match. */
 	if (source_fmt.width != sink_fmt.width ||
 	    source_fmt.height != sink_fmt.height ||
 	    source_fmt.pixelformat != sink_fmt.pixelformat)
 		return -EPIPE;

 	/*
 	 * The field order must match, or the sink field order must be NONE
 	 * to support interlaced hardware connected to bridges that support
 	 * progressive formats only.
 	 */
 	if (source_fmt.field != sink_fmt.field &&
 	    sink_fmt.field != V4L2_FIELD_NONE)
 		return -EPIPE;

 	/*
 	 * If colorspace is DEFAULT, then assume all the colorimetry is also
 	 * DEFAULT, return 0 to skip comparing the other colorimetry parameters
 	 */
 	if (source_fmt.colorspace == V4L2_COLORSPACE_DEFAULT ||
 	    sink_fmt.colorspace == V4L2_COLORSPACE_DEFAULT)
 		return 0;

 	/* Colorspace must match. */
 	if (source_fmt.colorspace != sink_fmt.colorspace)
 		return -EPIPE;

 	/* Colorimetry must match if they are not set to DEFAULT */
 	if (source_fmt.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT &&
 	    sink_fmt.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT &&
 	    source_fmt.ycbcr_enc != sink_fmt.ycbcr_enc)
 		return -EPIPE;

 	if (source_fmt.quantization != V4L2_QUANTIZATION_DEFAULT &&
 	    sink_fmt.quantization != V4L2_QUANTIZATION_DEFAULT &&
 	    source_fmt.quantization != sink_fmt.quantization)
 		return -EPIPE;

 	if (source_fmt.xfer_func != V4L2_XFER_FUNC_DEFAULT &&
 	    sink_fmt.xfer_func != V4L2_XFER_FUNC_DEFAULT &&
 	    source_fmt.xfer_func != sink_fmt.xfer_func)
 		return -EPIPE;

 	return 0;
 }

 static const struct media_entity_operations vimc_ent_sd_mops = {
 	.link_validate = v4l2_subdev_link_validate,
 };

 int vimc_ent_sd_register(struct vimc_ent_device *ved,
 			 struct v4l2_subdev *sd,
 			 struct v4l2_device *v4l2_dev,
 			 const char *const name,
 			 u32 function,
 			 u16 num_pads,
 			 struct media_pad *pads,
 			 const struct v4l2_subdev_internal_ops *int_ops,
 			 const struct v4l2_subdev_ops *sd_ops)
 {
 	int ret;

 	/* Fill the vimc_ent_device struct */
 	ved->ent = &sd->entity;

 	/* Initialize the subdev */
 	v4l2_subdev_init(sd, sd_ops);
 	sd->internal_ops = int_ops;
 	sd->entity.function = function;
 	sd->entity.ops = &vimc_ent_sd_mops;
 	sd->owner = THIS_MODULE;
 	strscpy(sd->name, name, sizeof(sd->name));
 	v4l2_set_subdevdata(sd, ved);

 	/* Expose this subdev to user space */
 	sd->flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
 	if (sd->ctrl_handler)
 		sd->flags |= V4L2_SUBDEV_FL_HAS_EVENTS;

 	/* Initialize the media entity */
 	ret = media_entity_pads_init(&sd->entity, num_pads, pads);
 	if (ret)
 		return ret;

 	/*
 	 * Finalize the subdev initialization if it supports active states. Use
 	 * the control handler lock as the state lock if available.
 	 */
 	if (int_ops && int_ops->init_state) {
 		if (sd->ctrl_handler)
 			sd->state_lock = sd->ctrl_handler->lock;

 		ret = v4l2_subdev_init_finalize(sd);
 		if (ret) {
 			dev_err(v4l2_dev->dev,
 				"%s: subdev initialization failed (err=%d)\n",
 				name, ret);
 			goto err_clean_m_ent;
 		}
 	}

 	/* Register the subdev with the v4l2 and the media framework */
 	ret = v4l2_device_register_subdev(v4l2_dev, sd);
 	if (ret) {
 		dev_err(v4l2_dev->dev,
 			"%s: subdev register failed (err=%d)\n",
 			name, ret);
 		goto err_clean_sd;
 	}

 	return 0;

 err_clean_sd:
 	v4l2_subdev_cleanup(sd);
 err_clean_m_ent:
 	media_entity_cleanup(&sd->entity);
 	return ret;
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* vimc-common.c Virtual Media Controller Driver
	*
	* Copyright (C) 2015-2017 Helen Koike <helen.fornazier@gmail.com>
	*/

	#include <linux/init.h>
	#include <linux/module.h>

	#include <media/v4l2-ctrls.h>

	#include "vimc-common.h"

	/*
	* NOTE: non-bayer formats need to come first (necessary for enum_mbus_code
	* in the scaler)
	*/
	static const struct vimc_pix_map vimc_pix_map_list[] = {
	/* TODO: add all missing formats */

	/* RGB formats */
	{
	.code = {
	MEDIA_BUS_FMT_BGR888_1X24,
	MEDIA_BUS_FMT_BGR888_3X8
	},
	.pixelformat = V4L2_PIX_FMT_BGR24,
	.bpp = 3,
	.bayer = false,
	},
	{
	.code = {
	MEDIA_BUS_FMT_RGB888_1X24,
	MEDIA_BUS_FMT_RGB888_2X12_BE,
	MEDIA_BUS_FMT_RGB888_2X12_LE,
	MEDIA_BUS_FMT_RGB888_3X8,
	MEDIA_BUS_FMT_RGB888_1X7X4_SPWG,
	MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA,
	MEDIA_BUS_FMT_RGB888_1X32_PADHI,
	MEDIA_BUS_FMT_GBR888_1X24
	},
	.pixelformat = V4L2_PIX_FMT_RGB24,
	.bpp = 3,
	.bayer = false,
	},
	{
	.code = { MEDIA_BUS_FMT_ARGB8888_1X32 },
	.pixelformat = V4L2_PIX_FMT_ARGB32,
	.bpp = 4,
	.bayer = false,
	},

	/* Bayer formats */
	{
	.code = { MEDIA_BUS_FMT_SBGGR8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SBGGR8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGBRG8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SGBRG8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGRBG8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SGRBG8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SRGGB8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SRGGB8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SBGGR10_1X10 },
	.pixelformat = V4L2_PIX_FMT_SBGGR10,
	.bpp = 2,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGBRG10_1X10 },
	.pixelformat = V4L2_PIX_FMT_SGBRG10,
	.bpp = 2,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGRBG10_1X10 },
	.pixelformat = V4L2_PIX_FMT_SGRBG10,
	.bpp = 2,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SRGGB10_1X10 },
	.pixelformat = V4L2_PIX_FMT_SRGGB10,
	.bpp = 2,
	.bayer = true,
	},

	/* 10bit raw bayer a-law compressed to 8 bits */
	{
	.code = { MEDIA_BUS_FMT_SBGGR10_ALAW8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SBGGR10ALAW8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGBRG10_ALAW8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SGBRG10ALAW8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGRBG10_ALAW8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SGRBG10ALAW8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SRGGB10_ALAW8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SRGGB10ALAW8,
	.bpp = 1,
	.bayer = true,
	},

	/* 10bit raw bayer DPCM compressed to 8 bits */
	{
	.code = { MEDIA_BUS_FMT_SBGGR10_DPCM8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SBGGR10DPCM8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGBRG10_DPCM8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SGBRG10DPCM8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGRBG10_DPCM8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SGRBG10DPCM8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SRGGB10_DPCM8_1X8 },
	.pixelformat = V4L2_PIX_FMT_SRGGB10DPCM8,
	.bpp = 1,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SBGGR12_1X12 },
	.pixelformat = V4L2_PIX_FMT_SBGGR12,
	.bpp = 2,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGBRG12_1X12 },
	.pixelformat = V4L2_PIX_FMT_SGBRG12,
	.bpp = 2,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SGRBG12_1X12 },
	.pixelformat = V4L2_PIX_FMT_SGRBG12,
	.bpp = 2,
	.bayer = true,
	},
	{
	.code = { MEDIA_BUS_FMT_SRGGB12_1X12 },
	.pixelformat = V4L2_PIX_FMT_SRGGB12,
	.bpp = 2,
	.bayer = true,
	},
	};

	bool vimc_is_source(struct media_entity *ent)
	{
	unsigned int i;

	for (i = 0; i < ent->num_pads; i++)
	if (ent->pads[i].flags & MEDIA_PAD_FL_SINK)
	return false;
	return true;
	}

	const struct vimc_pix_map *vimc_pix_map_by_index(unsigned int i)
	{
	if (i >= ARRAY_SIZE(vimc_pix_map_list))
	return NULL;

	return &vimc_pix_map_list[i];
	}

	u32 vimc_mbus_code_by_index(unsigned int index)
	{
	unsigned int i, j;

	for (i = 0; i < ARRAY_SIZE(vimc_pix_map_list); i++) {
	for (j = 0; j < ARRAY_SIZE(vimc_pix_map_list[i].code); j++) {
	if (!vimc_pix_map_list[i].code[j])
	break;

	if (!index)
	return vimc_pix_map_list[i].code[j];
	index--;
	}
	}
	return 0;
	}

	const struct vimc_pix_map *vimc_pix_map_by_code(u32 code)
	{
	unsigned int i, j;

	for (i = 0; i < ARRAY_SIZE(vimc_pix_map_list); i++) {
	for (j = 0; j < ARRAY_SIZE(vimc_pix_map_list[i].code); j++) {
	if (vimc_pix_map_list[i].code[j] == code)
	return &vimc_pix_map_list[i];
	}
	}
	return NULL;
	}

	const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat)
	{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(vimc_pix_map_list); i++) {
	if (vimc_pix_map_list[i].pixelformat == pixelformat)
	return &vimc_pix_map_list[i];
	}
	return NULL;
	}

	static int vimc_get_pix_format(struct media_pad *pad,
	struct v4l2_pix_format *fmt)
	{
	if (is_media_entity_v4l2_subdev(pad->entity)) {
	struct v4l2_subdev *sd =
	media_entity_to_v4l2_subdev(pad->entity);
	struct v4l2_subdev_format sd_fmt = {
	.which = V4L2_SUBDEV_FORMAT_ACTIVE,
	.pad = pad->index,
	};
	const struct vimc_pix_map *pix_map;
	int ret;

	ret = v4l2_subdev_call(sd, pad, get_fmt, NULL, &sd_fmt);
	if (ret)
	return ret;

	v4l2_fill_pix_format(fmt, &sd_fmt.format);
	pix_map = vimc_pix_map_by_code(sd_fmt.format.code);
	fmt->pixelformat = pix_map->pixelformat;
	} else if (is_media_entity_v4l2_video_device(pad->entity)) {
	struct video_device *vdev = container_of(pad->entity,
	struct video_device,
	entity);
	struct vimc_ent_device *ved = video_get_drvdata(vdev);

	if (!ved->vdev_get_format)
	return -ENOIOCTLCMD;

	ved->vdev_get_format(ved, fmt);
	} else {
	return -EINVAL;
	}

	return 0;
	}

	int vimc_vdev_link_validate(struct media_link *link)
	{
	struct v4l2_pix_format source_fmt, sink_fmt;
	int ret;

	ret = vimc_get_pix_format(link->source, &source_fmt);
	if (ret)
	return ret;

	ret = vimc_get_pix_format(link->sink, &sink_fmt);
	if (ret)
	return ret;

	pr_info("vimc link validate: "
	"%s:src:%dx%d (0x%x, %d, %d, %d, %d) "
	"%s:snk:%dx%d (0x%x, %d, %d, %d, %d)\n",
	/* src */
	link->source->entity->name,
	source_fmt.width, source_fmt.height,
	source_fmt.pixelformat, source_fmt.colorspace,
	source_fmt.quantization, source_fmt.xfer_func,
	source_fmt.ycbcr_enc,
	/* sink */
	link->sink->entity->name,
	sink_fmt.width, sink_fmt.height,
	sink_fmt.pixelformat, sink_fmt.colorspace,
	sink_fmt.quantization, sink_fmt.xfer_func,
	sink_fmt.ycbcr_enc);

	/* The width, height and pixelformat must match. */
	if (source_fmt.width != sink_fmt.width \|\|
	source_fmt.height != sink_fmt.height \|\|
	source_fmt.pixelformat != sink_fmt.pixelformat)
	return -EPIPE;

	/*
	* The field order must match, or the sink field order must be NONE
	* to support interlaced hardware connected to bridges that support
	* progressive formats only.
	*/
	if (source_fmt.field != sink_fmt.field &&
	sink_fmt.field != V4L2_FIELD_NONE)
	return -EPIPE;

	/*
	* If colorspace is DEFAULT, then assume all the colorimetry is also
	* DEFAULT, return 0 to skip comparing the other colorimetry parameters
	*/
	if (source_fmt.colorspace == V4L2_COLORSPACE_DEFAULT \|\|
	sink_fmt.colorspace == V4L2_COLORSPACE_DEFAULT)
	return 0;

	/* Colorspace must match. */
	if (source_fmt.colorspace != sink_fmt.colorspace)
	return -EPIPE;

	/* Colorimetry must match if they are not set to DEFAULT */
	if (source_fmt.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT &&
	sink_fmt.ycbcr_enc != V4L2_YCBCR_ENC_DEFAULT &&
	source_fmt.ycbcr_enc != sink_fmt.ycbcr_enc)
	return -EPIPE;

	if (source_fmt.quantization != V4L2_QUANTIZATION_DEFAULT &&
	sink_fmt.quantization != V4L2_QUANTIZATION_DEFAULT &&
	source_fmt.quantization != sink_fmt.quantization)
	return -EPIPE;

	if (source_fmt.xfer_func != V4L2_XFER_FUNC_DEFAULT &&
	sink_fmt.xfer_func != V4L2_XFER_FUNC_DEFAULT &&
	source_fmt.xfer_func != sink_fmt.xfer_func)
	return -EPIPE;

	return 0;
	}

	static const struct media_entity_operations vimc_ent_sd_mops = {
	.link_validate = v4l2_subdev_link_validate,
	};

	int vimc_ent_sd_register(struct vimc_ent_device *ved,
	struct v4l2_subdev *sd,
	struct v4l2_device *v4l2_dev,
	const char *const name,
	u32 function,
	u16 num_pads,
	struct media_pad *pads,
	const struct v4l2_subdev_internal_ops *int_ops,
	const struct v4l2_subdev_ops *sd_ops)
	{
	int ret;

	/* Fill the vimc_ent_device struct */
	ved->ent = &sd->entity;

	/* Initialize the subdev */
	v4l2_subdev_init(sd, sd_ops);
	sd->internal_ops = int_ops;
	sd->entity.function = function;
	sd->entity.ops = &vimc_ent_sd_mops;
	sd->owner = THIS_MODULE;
	strscpy(sd->name, name, sizeof(sd->name));
	v4l2_set_subdevdata(sd, ved);

	/* Expose this subdev to user space */
	sd->flags \|= V4L2_SUBDEV_FL_HAS_DEVNODE;
	if (sd->ctrl_handler)
	sd->flags \|= V4L2_SUBDEV_FL_HAS_EVENTS;

	/* Initialize the media entity */
	ret = media_entity_pads_init(&sd->entity, num_pads, pads);
	if (ret)
	return ret;

	/*
	* Finalize the subdev initialization if it supports active states. Use
	* the control handler lock as the state lock if available.
	*/
	if (int_ops && int_ops->init_state) {
	if (sd->ctrl_handler)
	sd->state_lock = sd->ctrl_handler->lock;

	ret = v4l2_subdev_init_finalize(sd);
	if (ret) {
	dev_err(v4l2_dev->dev,
	"%s: subdev initialization failed (err=%d)\n",
	name, ret);
	goto err_clean_m_ent;
	}
	}

	/* Register the subdev with the v4l2 and the media framework */
	ret = v4l2_device_register_subdev(v4l2_dev, sd);
	if (ret) {
	dev_err(v4l2_dev->dev,
	"%s: subdev register failed (err=%d)\n",
	name, ret);
	goto err_clean_sd;
	}

	return 0;

	err_clean_sd:
	v4l2_subdev_cleanup(sd);
	err_clean_m_ent:
	media_entity_cleanup(&sd->entity);
	return ret;
	}