drivers/media/platform/video-mux.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * video stream multiplexer controlled via mux control
  *
  * Copyright (C) 2013 Pengutronix, Sascha Hauer <kernel@pengutronix.de>
  * Copyright (C) 2016-2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
  */

 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/mux/consumer.h>
 #include <linux/of.h>
 #include <linux/of_graph.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <media/v4l2-async.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-fwnode.h>
 #include <media/v4l2-mc.h>
 #include <media/v4l2-subdev.h>

 struct video_mux {
 	struct v4l2_subdev subdev;
 	struct v4l2_async_notifier notifier;
 	struct media_pad *pads;
 	struct v4l2_mbus_framefmt *format_mbus;
 	struct mux_control *mux;
 	struct mutex lock;
 	int active;
 };

 static const struct v4l2_mbus_framefmt video_mux_format_mbus_default = {
 	.width = 1,
 	.height = 1,
 	.code = MEDIA_BUS_FMT_Y8_1X8,
 	.field = V4L2_FIELD_NONE,
 };

 static inline struct video_mux *
 notifier_to_video_mux(struct v4l2_async_notifier *n)
 {
 	return container_of(n, struct video_mux, notifier);
 }

 static inline struct video_mux *v4l2_subdev_to_video_mux(struct v4l2_subdev *sd)
 {
 	return container_of(sd, struct video_mux, subdev);
 }

 static int video_mux_link_setup(struct media_entity *entity,
 				const struct media_pad *local,
 				const struct media_pad *remote, u32 flags)
 {
 	struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
 	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
 	u16 source_pad = entity->num_pads - 1;
 	int ret = 0;

 	/*
 	 * The mux state is determined by the enabled sink pad link.
 	 * Enabling or disabling the source pad link has no effect.
 	 */
 	if (local->flags & MEDIA_PAD_FL_SOURCE)
 		return 0;

 	dev_dbg(sd->dev, "link setup '%s':%d->'%s':%d[%d]",
 		remote->entity->name, remote->index, local->entity->name,
 		local->index, flags & MEDIA_LNK_FL_ENABLED);

 	mutex_lock(&vmux->lock);

 	if (flags & MEDIA_LNK_FL_ENABLED) {
 		if (vmux->active == local->index)
 			goto out;

 		if (vmux->active >= 0) {
 			ret = -EBUSY;
 			goto out;
 		}

 		dev_dbg(sd->dev, "setting %d active\n", local->index);
 		ret = mux_control_try_select(vmux->mux, local->index);
 		if (ret < 0)
 			goto out;
 		vmux->active = local->index;

 		/* Propagate the active format to the source */
 		vmux->format_mbus[source_pad] = vmux->format_mbus[vmux->active];
 	} else {
 		if (vmux->active != local->index)
 			goto out;

 		dev_dbg(sd->dev, "going inactive\n");
 		mux_control_deselect(vmux->mux);
 		vmux->active = -1;
 	}

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

 static const struct media_entity_operations video_mux_ops = {
 	.link_setup = video_mux_link_setup,
 	.link_validate = v4l2_subdev_link_validate,
 	.get_fwnode_pad = v4l2_subdev_get_fwnode_pad_1_to_1,
 };

 static int video_mux_s_stream(struct v4l2_subdev *sd, int enable)
 {
 	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
 	struct v4l2_subdev *upstream_sd;
 	struct media_pad *pad;

 	if (vmux->active == -1) {
 		dev_err(sd->dev, "Can not start streaming on inactive mux\n");
 		return -EINVAL;
 	}

 	pad = media_pad_remote_pad_first(&sd->entity.pads[vmux->active]);
 	if (!pad) {
 		dev_err(sd->dev, "Failed to find remote source pad\n");
 		return -ENOLINK;
 	}

 	if (!is_media_entity_v4l2_subdev(pad->entity)) {
 		dev_err(sd->dev, "Upstream entity is not a v4l2 subdev\n");
 		return -ENODEV;
 	}

 	upstream_sd = media_entity_to_v4l2_subdev(pad->entity);

 	return v4l2_subdev_call(upstream_sd, video, s_stream, enable);
 }

 static const struct v4l2_subdev_video_ops video_mux_subdev_video_ops = {
 	.s_stream = video_mux_s_stream,
 };

 static struct v4l2_mbus_framefmt *
 __video_mux_get_pad_format(struct v4l2_subdev *sd,
 			   struct v4l2_subdev_state *sd_state,
 			   unsigned int pad, u32 which)
 {
 	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);

 	switch (which) {
 	case V4L2_SUBDEV_FORMAT_TRY:
 		return v4l2_subdev_get_try_format(sd, sd_state, pad);
 	case V4L2_SUBDEV_FORMAT_ACTIVE:
 		return &vmux->format_mbus[pad];
 	default:
 		return NULL;
 	}
 }

 static int video_mux_get_format(struct v4l2_subdev *sd,
 			    struct v4l2_subdev_state *sd_state,
 			    struct v4l2_subdev_format *sdformat)
 {
 	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);

 	mutex_lock(&vmux->lock);

 	sdformat->format = *__video_mux_get_pad_format(sd, sd_state,
 						       sdformat->pad,
 						       sdformat->which);

 	mutex_unlock(&vmux->lock);

 	return 0;
 }

 static int video_mux_set_format(struct v4l2_subdev *sd,
 			    struct v4l2_subdev_state *sd_state,
 			    struct v4l2_subdev_format *sdformat)
 {
 	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
 	struct v4l2_mbus_framefmt *mbusformat, *source_mbusformat;
 	struct media_pad *pad = &vmux->pads[sdformat->pad];
 	u16 source_pad = sd->entity.num_pads - 1;

 	mbusformat = __video_mux_get_pad_format(sd, sd_state, sdformat->pad,
 						sdformat->which);
 	if (!mbusformat)
 		return -EINVAL;

 	source_mbusformat = __video_mux_get_pad_format(sd, sd_state,
 						       source_pad,
 						       sdformat->which);
 	if (!source_mbusformat)
 		return -EINVAL;

 	/* No size limitations except V4L2 compliance requirements */
 	v4l_bound_align_image(&sdformat->format.width, 1, 65536, 0,
 			      &sdformat->format.height, 1, 65536, 0, 0);

 	/* All formats except LVDS and vendor specific formats are acceptable */
 	switch (sdformat->format.code) {
 	case MEDIA_BUS_FMT_RGB444_1X12:
 	case MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE:
 	case MEDIA_BUS_FMT_RGB444_2X8_PADHI_LE:
 	case MEDIA_BUS_FMT_RGB555_2X8_PADHI_BE:
 	case MEDIA_BUS_FMT_RGB555_2X8_PADHI_LE:
 	case MEDIA_BUS_FMT_RGB565_1X16:
 	case MEDIA_BUS_FMT_BGR565_2X8_BE:
 	case MEDIA_BUS_FMT_BGR565_2X8_LE:
 	case MEDIA_BUS_FMT_RGB565_2X8_BE:
 	case MEDIA_BUS_FMT_RGB565_2X8_LE:
 	case MEDIA_BUS_FMT_RGB666_1X18:
 	case MEDIA_BUS_FMT_RBG888_1X24:
 	case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
 	case MEDIA_BUS_FMT_BGR888_1X24:
 	case MEDIA_BUS_FMT_GBR888_1X24:
 	case MEDIA_BUS_FMT_RGB888_1X24:
 	case MEDIA_BUS_FMT_RGB888_2X12_BE:
 	case MEDIA_BUS_FMT_RGB888_2X12_LE:
 	case MEDIA_BUS_FMT_ARGB8888_1X32:
 	case MEDIA_BUS_FMT_RGB888_1X32_PADHI:
 	case MEDIA_BUS_FMT_RGB101010_1X30:
 	case MEDIA_BUS_FMT_RGB121212_1X36:
 	case MEDIA_BUS_FMT_RGB161616_1X48:
 	case MEDIA_BUS_FMT_Y8_1X8:
 	case MEDIA_BUS_FMT_UV8_1X8:
 	case MEDIA_BUS_FMT_UYVY8_1_5X8:
 	case MEDIA_BUS_FMT_VYUY8_1_5X8:
 	case MEDIA_BUS_FMT_YUYV8_1_5X8:
 	case MEDIA_BUS_FMT_YVYU8_1_5X8:
 	case MEDIA_BUS_FMT_UYVY8_2X8:
 	case MEDIA_BUS_FMT_VYUY8_2X8:
 	case MEDIA_BUS_FMT_YUYV8_2X8:
 	case MEDIA_BUS_FMT_YVYU8_2X8:
 	case MEDIA_BUS_FMT_Y10_1X10:
 	case MEDIA_BUS_FMT_UYVY10_2X10:
 	case MEDIA_BUS_FMT_VYUY10_2X10:
 	case MEDIA_BUS_FMT_YUYV10_2X10:
 	case MEDIA_BUS_FMT_YVYU10_2X10:
 	case MEDIA_BUS_FMT_Y12_1X12:
 	case MEDIA_BUS_FMT_UYVY12_2X12:
 	case MEDIA_BUS_FMT_VYUY12_2X12:
 	case MEDIA_BUS_FMT_YUYV12_2X12:
 	case MEDIA_BUS_FMT_YVYU12_2X12:
 	case MEDIA_BUS_FMT_UYVY8_1X16:
 	case MEDIA_BUS_FMT_VYUY8_1X16:
 	case MEDIA_BUS_FMT_YUYV8_1X16:
 	case MEDIA_BUS_FMT_YVYU8_1X16:
 	case MEDIA_BUS_FMT_YDYUYDYV8_1X16:
 	case MEDIA_BUS_FMT_UYVY10_1X20:
 	case MEDIA_BUS_FMT_VYUY10_1X20:
 	case MEDIA_BUS_FMT_YUYV10_1X20:
 	case MEDIA_BUS_FMT_YVYU10_1X20:
 	case MEDIA_BUS_FMT_VUY8_1X24:
 	case MEDIA_BUS_FMT_YUV8_1X24:
 	case MEDIA_BUS_FMT_UYYVYY8_0_5X24:
 	case MEDIA_BUS_FMT_UYVY12_1X24:
 	case MEDIA_BUS_FMT_VYUY12_1X24:
 	case MEDIA_BUS_FMT_YUYV12_1X24:
 	case MEDIA_BUS_FMT_YVYU12_1X24:
 	case MEDIA_BUS_FMT_YUV10_1X30:
 	case MEDIA_BUS_FMT_UYYVYY10_0_5X30:
 	case MEDIA_BUS_FMT_AYUV8_1X32:
 	case MEDIA_BUS_FMT_UYYVYY12_0_5X36:
 	case MEDIA_BUS_FMT_YUV12_1X36:
 	case MEDIA_BUS_FMT_YUV16_1X48:
 	case MEDIA_BUS_FMT_UYYVYY16_0_5X48:
 	case MEDIA_BUS_FMT_JPEG_1X8:
 	case MEDIA_BUS_FMT_AHSV8888_1X32:
 	case MEDIA_BUS_FMT_SBGGR8_1X8:
 	case MEDIA_BUS_FMT_SGBRG8_1X8:
 	case MEDIA_BUS_FMT_SGRBG8_1X8:
 	case MEDIA_BUS_FMT_SRGGB8_1X8:
 	case MEDIA_BUS_FMT_SBGGR10_1X10:
 	case MEDIA_BUS_FMT_SGBRG10_1X10:
 	case MEDIA_BUS_FMT_SGRBG10_1X10:
 	case MEDIA_BUS_FMT_SRGGB10_1X10:
 	case MEDIA_BUS_FMT_SBGGR12_1X12:
 	case MEDIA_BUS_FMT_SGBRG12_1X12:
 	case MEDIA_BUS_FMT_SGRBG12_1X12:
 	case MEDIA_BUS_FMT_SRGGB12_1X12:
 	case MEDIA_BUS_FMT_SBGGR14_1X14:
 	case MEDIA_BUS_FMT_SGBRG14_1X14:
 	case MEDIA_BUS_FMT_SGRBG14_1X14:
 	case MEDIA_BUS_FMT_SRGGB14_1X14:
 	case MEDIA_BUS_FMT_SBGGR16_1X16:
 	case MEDIA_BUS_FMT_SGBRG16_1X16:
 	case MEDIA_BUS_FMT_SGRBG16_1X16:
 	case MEDIA_BUS_FMT_SRGGB16_1X16:
 		break;
 	default:
 		sdformat->format.code = MEDIA_BUS_FMT_Y8_1X8;
 		break;
 	}
 	if (sdformat->format.field == V4L2_FIELD_ANY)
 		sdformat->format.field = V4L2_FIELD_NONE;

 	mutex_lock(&vmux->lock);

 	/* Source pad mirrors active sink pad, no limitations on sink pads */
 	if ((pad->flags & MEDIA_PAD_FL_SOURCE) && vmux->active >= 0)
 		sdformat->format = vmux->format_mbus[vmux->active];

 	*mbusformat = sdformat->format;

 	/* Propagate the format from an active sink to source */
 	if ((pad->flags & MEDIA_PAD_FL_SINK) && (pad->index == vmux->active))
 		*source_mbusformat = sdformat->format;

 	mutex_unlock(&vmux->lock);

 	return 0;
 }

 static int video_mux_init_cfg(struct v4l2_subdev *sd,
 			      struct v4l2_subdev_state *sd_state)
 {
 	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
 	struct v4l2_mbus_framefmt *mbusformat;
 	unsigned int i;

 	mutex_lock(&vmux->lock);

 	for (i = 0; i < sd->entity.num_pads; i++) {
 		mbusformat = v4l2_subdev_get_try_format(sd, sd_state, i);
 		*mbusformat = video_mux_format_mbus_default;
 	}

 	mutex_unlock(&vmux->lock);

 	return 0;
 }

 static const struct v4l2_subdev_pad_ops video_mux_pad_ops = {
 	.init_cfg = video_mux_init_cfg,
 	.get_fmt = video_mux_get_format,
 	.set_fmt = video_mux_set_format,
 };

 static const struct v4l2_subdev_ops video_mux_subdev_ops = {
 	.pad = &video_mux_pad_ops,
 	.video = &video_mux_subdev_video_ops,
 };

 static int video_mux_notify_bound(struct v4l2_async_notifier *notifier,
 				  struct v4l2_subdev *sd,
 				  struct v4l2_async_subdev *asd)
 {
 	struct video_mux *vmux = notifier_to_video_mux(notifier);

 	return v4l2_create_fwnode_links(sd, &vmux->subdev);
 }

 static const struct v4l2_async_notifier_operations video_mux_notify_ops = {
 	.bound = video_mux_notify_bound,
 };

 static int video_mux_async_register(struct video_mux *vmux,
 				    unsigned int num_input_pads)
 {
 	unsigned int i;
 	int ret;

 	v4l2_async_nf_init(&vmux->notifier);

 	for (i = 0; i < num_input_pads; i++) {
 		struct v4l2_async_subdev *asd;
 		struct fwnode_handle *ep, *remote_ep;

 		ep = fwnode_graph_get_endpoint_by_id(
 			dev_fwnode(vmux->subdev.dev), i, 0,
 			FWNODE_GRAPH_ENDPOINT_NEXT);
 		if (!ep)
 			continue;

 		/* Skip dangling endpoints for backwards compatibility */
 		remote_ep = fwnode_graph_get_remote_endpoint(ep);
 		if (!remote_ep) {
 			fwnode_handle_put(ep);
 			continue;
 		}
 		fwnode_handle_put(remote_ep);

 		asd = v4l2_async_nf_add_fwnode_remote(&vmux->notifier, ep,
 						      struct v4l2_async_subdev);

 		fwnode_handle_put(ep);

 		if (IS_ERR(asd)) {
 			ret = PTR_ERR(asd);
 			/* OK if asd already exists */
 			if (ret != -EEXIST)
 				return ret;
 		}
 	}

 	vmux->notifier.ops = &video_mux_notify_ops;

 	ret = v4l2_async_subdev_nf_register(&vmux->subdev, &vmux->notifier);
 	if (ret)
 		return ret;

 	return v4l2_async_register_subdev(&vmux->subdev);
 }

 static int video_mux_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct device *dev = &pdev->dev;
 	struct device_node *ep;
 	struct video_mux *vmux;
 	unsigned int num_pads = 0;
 	unsigned int i;
 	int ret;

 	vmux = devm_kzalloc(dev, sizeof(*vmux), GFP_KERNEL);
 	if (!vmux)
 		return -ENOMEM;

 	platform_set_drvdata(pdev, vmux);

 	v4l2_subdev_init(&vmux->subdev, &video_mux_subdev_ops);
 	snprintf(vmux->subdev.name, sizeof(vmux->subdev.name), "%pOFn", np);
 	vmux->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
 	vmux->subdev.dev = dev;

 	/*
 	 * The largest numbered port is the output port. It determines
 	 * total number of pads.
 	 */
 	for_each_endpoint_of_node(np, ep) {
 		struct of_endpoint endpoint;

 		of_graph_parse_endpoint(ep, &endpoint);
 		num_pads = max(num_pads, endpoint.port + 1);
 	}

 	if (num_pads < 2) {
 		dev_err(dev, "Not enough ports %d\n", num_pads);
 		return -EINVAL;
 	}

 	vmux->mux = devm_mux_control_get(dev, NULL);
 	if (IS_ERR(vmux->mux)) {
 		ret = PTR_ERR(vmux->mux);
 		return dev_err_probe(dev, ret, "Failed to get mux\n");
 	}

 	mutex_init(&vmux->lock);
 	vmux->active = -1;
 	vmux->pads = devm_kcalloc(dev, num_pads, sizeof(*vmux->pads),
 				  GFP_KERNEL);
 	if (!vmux->pads)
 		return -ENOMEM;

 	vmux->format_mbus = devm_kcalloc(dev, num_pads,
 					 sizeof(*vmux->format_mbus),
 					 GFP_KERNEL);
 	if (!vmux->format_mbus)
 		return -ENOMEM;

 	for (i = 0; i < num_pads; i++) {
 		vmux->pads[i].flags = (i < num_pads - 1) ? MEDIA_PAD_FL_SINK
 							 : MEDIA_PAD_FL_SOURCE;
 		vmux->format_mbus[i] = video_mux_format_mbus_default;
 	}

 	vmux->subdev.entity.function = MEDIA_ENT_F_VID_MUX;
 	ret = media_entity_pads_init(&vmux->subdev.entity, num_pads,
 				     vmux->pads);
 	if (ret < 0)
 		return ret;

 	vmux->subdev.entity.ops = &video_mux_ops;

 	ret = video_mux_async_register(vmux, num_pads - 1);
 	if (ret) {
 		v4l2_async_nf_unregister(&vmux->notifier);
 		v4l2_async_nf_cleanup(&vmux->notifier);
 	}

 	return ret;
 }

 static int video_mux_remove(struct platform_device *pdev)
 {
 	struct video_mux *vmux = platform_get_drvdata(pdev);
 	struct v4l2_subdev *sd = &vmux->subdev;

 	v4l2_async_nf_unregister(&vmux->notifier);
 	v4l2_async_nf_cleanup(&vmux->notifier);
 	v4l2_async_unregister_subdev(sd);
 	media_entity_cleanup(&sd->entity);

 	return 0;
 }

 static const struct of_device_id video_mux_dt_ids[] = {
 	{ .compatible = "video-mux", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, video_mux_dt_ids);

 static struct platform_driver video_mux_driver = {
 	.probe		= video_mux_probe,
 	.remove		= video_mux_remove,
 	.driver		= {
 		.of_match_table = video_mux_dt_ids,
 		.name = "video-mux",
 	},
 };

 module_platform_driver(video_mux_driver);

 MODULE_DESCRIPTION("video stream multiplexer");
 MODULE_AUTHOR("Sascha Hauer, Pengutronix");
 MODULE_AUTHOR("Philipp Zabel, Pengutronix");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* video stream multiplexer controlled via mux control
	*
	* Copyright (C) 2013 Pengutronix, Sascha Hauer <kernel@pengutronix.de>
	* Copyright (C) 2016-2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
	*/

	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/mux/consumer.h>
	#include <linux/of.h>
	#include <linux/of_graph.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <media/v4l2-async.h>
	#include <media/v4l2-device.h>
	#include <media/v4l2-fwnode.h>
	#include <media/v4l2-mc.h>
	#include <media/v4l2-subdev.h>

	struct video_mux {
	struct v4l2_subdev subdev;
	struct v4l2_async_notifier notifier;
	struct media_pad *pads;
	struct v4l2_mbus_framefmt *format_mbus;
	struct mux_control *mux;
	struct mutex lock;
	int active;
	};

	static const struct v4l2_mbus_framefmt video_mux_format_mbus_default = {
	.width = 1,
	.height = 1,
	.code = MEDIA_BUS_FMT_Y8_1X8,
	.field = V4L2_FIELD_NONE,
	};

	static inline struct video_mux *
	notifier_to_video_mux(struct v4l2_async_notifier *n)
	{
	return container_of(n, struct video_mux, notifier);
	}

	static inline struct video_mux v4l2_subdev_to_video_mux(struct v4l2_subdev sd)
	{
	return container_of(sd, struct video_mux, subdev);
	}

	static int video_mux_link_setup(struct media_entity *entity,
	const struct media_pad *local,
	const struct media_pad *remote, u32 flags)
	{
	struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
	u16 source_pad = entity->num_pads - 1;
	int ret = 0;

	/*
	* The mux state is determined by the enabled sink pad link.
	* Enabling or disabling the source pad link has no effect.
	*/
	if (local->flags & MEDIA_PAD_FL_SOURCE)
	return 0;

	dev_dbg(sd->dev, "link setup '%s':%d->'%s':%d[%d]",
	remote->entity->name, remote->index, local->entity->name,
	local->index, flags & MEDIA_LNK_FL_ENABLED);

	mutex_lock(&vmux->lock);

	if (flags & MEDIA_LNK_FL_ENABLED) {
	if (vmux->active == local->index)
	goto out;

	if (vmux->active >= 0) {
	ret = -EBUSY;
	goto out;
	}

	dev_dbg(sd->dev, "setting %d active\n", local->index);
	ret = mux_control_try_select(vmux->mux, local->index);
	if (ret < 0)
	goto out;
	vmux->active = local->index;

	/* Propagate the active format to the source */
	vmux->format_mbus[source_pad] = vmux->format_mbus[vmux->active];
	} else {
	if (vmux->active != local->index)
	goto out;

	dev_dbg(sd->dev, "going inactive\n");
	mux_control_deselect(vmux->mux);
	vmux->active = -1;
	}

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

	static const struct media_entity_operations video_mux_ops = {
	.link_setup = video_mux_link_setup,
	.link_validate = v4l2_subdev_link_validate,
	.get_fwnode_pad = v4l2_subdev_get_fwnode_pad_1_to_1,
	};

	static int video_mux_s_stream(struct v4l2_subdev *sd, int enable)
	{
	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
	struct v4l2_subdev *upstream_sd;
	struct media_pad *pad;

	if (vmux->active == -1) {
	dev_err(sd->dev, "Can not start streaming on inactive mux\n");
	return -EINVAL;
	}

	pad = media_pad_remote_pad_first(&sd->entity.pads[vmux->active]);
	if (!pad) {
	dev_err(sd->dev, "Failed to find remote source pad\n");
	return -ENOLINK;
	}

	if (!is_media_entity_v4l2_subdev(pad->entity)) {
	dev_err(sd->dev, "Upstream entity is not a v4l2 subdev\n");
	return -ENODEV;
	}

	upstream_sd = media_entity_to_v4l2_subdev(pad->entity);

	return v4l2_subdev_call(upstream_sd, video, s_stream, enable);
	}

	static const struct v4l2_subdev_video_ops video_mux_subdev_video_ops = {
	.s_stream = video_mux_s_stream,
	};

	static struct v4l2_mbus_framefmt *
	__video_mux_get_pad_format(struct v4l2_subdev *sd,
	struct v4l2_subdev_state *sd_state,
	unsigned int pad, u32 which)
	{
	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);

	switch (which) {
	case V4L2_SUBDEV_FORMAT_TRY:
	return v4l2_subdev_get_try_format(sd, sd_state, pad);
	case V4L2_SUBDEV_FORMAT_ACTIVE:
	return &vmux->format_mbus[pad];
	default:
	return NULL;
	}
	}

	static int video_mux_get_format(struct v4l2_subdev *sd,
	struct v4l2_subdev_state *sd_state,
	struct v4l2_subdev_format *sdformat)
	{
	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);

	mutex_lock(&vmux->lock);

	sdformat->format = *__video_mux_get_pad_format(sd, sd_state,
	sdformat->pad,
	sdformat->which);

	mutex_unlock(&vmux->lock);

	return 0;
	}

	static int video_mux_set_format(struct v4l2_subdev *sd,
	struct v4l2_subdev_state *sd_state,
	struct v4l2_subdev_format *sdformat)
	{
	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
	struct v4l2_mbus_framefmt mbusformat, source_mbusformat;
	struct media_pad *pad = &vmux->pads[sdformat->pad];
	u16 source_pad = sd->entity.num_pads - 1;

	mbusformat = __video_mux_get_pad_format(sd, sd_state, sdformat->pad,
	sdformat->which);
	if (!mbusformat)
	return -EINVAL;

	source_mbusformat = __video_mux_get_pad_format(sd, sd_state,
	source_pad,
	sdformat->which);
	if (!source_mbusformat)
	return -EINVAL;

	/* No size limitations except V4L2 compliance requirements */
	v4l_bound_align_image(&sdformat->format.width, 1, 65536, 0,
	&sdformat->format.height, 1, 65536, 0, 0);

	/* All formats except LVDS and vendor specific formats are acceptable */
	switch (sdformat->format.code) {
	case MEDIA_BUS_FMT_RGB444_1X12:
	case MEDIA_BUS_FMT_RGB444_2X8_PADHI_BE:
	case MEDIA_BUS_FMT_RGB444_2X8_PADHI_LE:
	case MEDIA_BUS_FMT_RGB555_2X8_PADHI_BE:
	case MEDIA_BUS_FMT_RGB555_2X8_PADHI_LE:
	case MEDIA_BUS_FMT_RGB565_1X16:
	case MEDIA_BUS_FMT_BGR565_2X8_BE:
	case MEDIA_BUS_FMT_BGR565_2X8_LE:
	case MEDIA_BUS_FMT_RGB565_2X8_BE:
	case MEDIA_BUS_FMT_RGB565_2X8_LE:
	case MEDIA_BUS_FMT_RGB666_1X18:
	case MEDIA_BUS_FMT_RBG888_1X24:
	case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
	case MEDIA_BUS_FMT_BGR888_1X24:
	case MEDIA_BUS_FMT_GBR888_1X24:
	case MEDIA_BUS_FMT_RGB888_1X24:
	case MEDIA_BUS_FMT_RGB888_2X12_BE:
	case MEDIA_BUS_FMT_RGB888_2X12_LE:
	case MEDIA_BUS_FMT_ARGB8888_1X32:
	case MEDIA_BUS_FMT_RGB888_1X32_PADHI:
	case MEDIA_BUS_FMT_RGB101010_1X30:
	case MEDIA_BUS_FMT_RGB121212_1X36:
	case MEDIA_BUS_FMT_RGB161616_1X48:
	case MEDIA_BUS_FMT_Y8_1X8:
	case MEDIA_BUS_FMT_UV8_1X8:
	case MEDIA_BUS_FMT_UYVY8_1_5X8:
	case MEDIA_BUS_FMT_VYUY8_1_5X8:
	case MEDIA_BUS_FMT_YUYV8_1_5X8:
	case MEDIA_BUS_FMT_YVYU8_1_5X8:
	case MEDIA_BUS_FMT_UYVY8_2X8:
	case MEDIA_BUS_FMT_VYUY8_2X8:
	case MEDIA_BUS_FMT_YUYV8_2X8:
	case MEDIA_BUS_FMT_YVYU8_2X8:
	case MEDIA_BUS_FMT_Y10_1X10:
	case MEDIA_BUS_FMT_UYVY10_2X10:
	case MEDIA_BUS_FMT_VYUY10_2X10:
	case MEDIA_BUS_FMT_YUYV10_2X10:
	case MEDIA_BUS_FMT_YVYU10_2X10:
	case MEDIA_BUS_FMT_Y12_1X12:
	case MEDIA_BUS_FMT_UYVY12_2X12:
	case MEDIA_BUS_FMT_VYUY12_2X12:
	case MEDIA_BUS_FMT_YUYV12_2X12:
	case MEDIA_BUS_FMT_YVYU12_2X12:
	case MEDIA_BUS_FMT_UYVY8_1X16:
	case MEDIA_BUS_FMT_VYUY8_1X16:
	case MEDIA_BUS_FMT_YUYV8_1X16:
	case MEDIA_BUS_FMT_YVYU8_1X16:
	case MEDIA_BUS_FMT_YDYUYDYV8_1X16:
	case MEDIA_BUS_FMT_UYVY10_1X20:
	case MEDIA_BUS_FMT_VYUY10_1X20:
	case MEDIA_BUS_FMT_YUYV10_1X20:
	case MEDIA_BUS_FMT_YVYU10_1X20:
	case MEDIA_BUS_FMT_VUY8_1X24:
	case MEDIA_BUS_FMT_YUV8_1X24:
	case MEDIA_BUS_FMT_UYYVYY8_0_5X24:
	case MEDIA_BUS_FMT_UYVY12_1X24:
	case MEDIA_BUS_FMT_VYUY12_1X24:
	case MEDIA_BUS_FMT_YUYV12_1X24:
	case MEDIA_BUS_FMT_YVYU12_1X24:
	case MEDIA_BUS_FMT_YUV10_1X30:
	case MEDIA_BUS_FMT_UYYVYY10_0_5X30:
	case MEDIA_BUS_FMT_AYUV8_1X32:
	case MEDIA_BUS_FMT_UYYVYY12_0_5X36:
	case MEDIA_BUS_FMT_YUV12_1X36:
	case MEDIA_BUS_FMT_YUV16_1X48:
	case MEDIA_BUS_FMT_UYYVYY16_0_5X48:
	case MEDIA_BUS_FMT_JPEG_1X8:
	case MEDIA_BUS_FMT_AHSV8888_1X32:
	case MEDIA_BUS_FMT_SBGGR8_1X8:
	case MEDIA_BUS_FMT_SGBRG8_1X8:
	case MEDIA_BUS_FMT_SGRBG8_1X8:
	case MEDIA_BUS_FMT_SRGGB8_1X8:
	case MEDIA_BUS_FMT_SBGGR10_1X10:
	case MEDIA_BUS_FMT_SGBRG10_1X10:
	case MEDIA_BUS_FMT_SGRBG10_1X10:
	case MEDIA_BUS_FMT_SRGGB10_1X10:
	case MEDIA_BUS_FMT_SBGGR12_1X12:
	case MEDIA_BUS_FMT_SGBRG12_1X12:
	case MEDIA_BUS_FMT_SGRBG12_1X12:
	case MEDIA_BUS_FMT_SRGGB12_1X12:
	case MEDIA_BUS_FMT_SBGGR14_1X14:
	case MEDIA_BUS_FMT_SGBRG14_1X14:
	case MEDIA_BUS_FMT_SGRBG14_1X14:
	case MEDIA_BUS_FMT_SRGGB14_1X14:
	case MEDIA_BUS_FMT_SBGGR16_1X16:
	case MEDIA_BUS_FMT_SGBRG16_1X16:
	case MEDIA_BUS_FMT_SGRBG16_1X16:
	case MEDIA_BUS_FMT_SRGGB16_1X16:
	break;
	default:
	sdformat->format.code = MEDIA_BUS_FMT_Y8_1X8;
	break;
	}
	if (sdformat->format.field == V4L2_FIELD_ANY)
	sdformat->format.field = V4L2_FIELD_NONE;

	mutex_lock(&vmux->lock);

	/* Source pad mirrors active sink pad, no limitations on sink pads */
	if ((pad->flags & MEDIA_PAD_FL_SOURCE) && vmux->active >= 0)
	sdformat->format = vmux->format_mbus[vmux->active];

	*mbusformat = sdformat->format;

	/* Propagate the format from an active sink to source */
	if ((pad->flags & MEDIA_PAD_FL_SINK) && (pad->index == vmux->active))
	*source_mbusformat = sdformat->format;

	mutex_unlock(&vmux->lock);

	return 0;
	}

	static int video_mux_init_cfg(struct v4l2_subdev *sd,
	struct v4l2_subdev_state *sd_state)
	{
	struct video_mux *vmux = v4l2_subdev_to_video_mux(sd);
	struct v4l2_mbus_framefmt *mbusformat;
	unsigned int i;

	mutex_lock(&vmux->lock);

	for (i = 0; i < sd->entity.num_pads; i++) {
	mbusformat = v4l2_subdev_get_try_format(sd, sd_state, i);
	*mbusformat = video_mux_format_mbus_default;
	}

	mutex_unlock(&vmux->lock);

	return 0;
	}

	static const struct v4l2_subdev_pad_ops video_mux_pad_ops = {
	.init_cfg = video_mux_init_cfg,
	.get_fmt = video_mux_get_format,
	.set_fmt = video_mux_set_format,
	};

	static const struct v4l2_subdev_ops video_mux_subdev_ops = {
	.pad = &video_mux_pad_ops,
	.video = &video_mux_subdev_video_ops,
	};

	static int video_mux_notify_bound(struct v4l2_async_notifier *notifier,
	struct v4l2_subdev *sd,
	struct v4l2_async_subdev *asd)
	{
	struct video_mux *vmux = notifier_to_video_mux(notifier);

	return v4l2_create_fwnode_links(sd, &vmux->subdev);
	}

	static const struct v4l2_async_notifier_operations video_mux_notify_ops = {
	.bound = video_mux_notify_bound,
	};

	static int video_mux_async_register(struct video_mux *vmux,
	unsigned int num_input_pads)
	{
	unsigned int i;
	int ret;

	v4l2_async_nf_init(&vmux->notifier);

	for (i = 0; i < num_input_pads; i++) {
	struct v4l2_async_subdev *asd;
	struct fwnode_handle ep, remote_ep;

	ep = fwnode_graph_get_endpoint_by_id(
	dev_fwnode(vmux->subdev.dev), i, 0,
	FWNODE_GRAPH_ENDPOINT_NEXT);
	if (!ep)
	continue;

	/* Skip dangling endpoints for backwards compatibility */
	remote_ep = fwnode_graph_get_remote_endpoint(ep);
	if (!remote_ep) {
	fwnode_handle_put(ep);
	continue;
	}
	fwnode_handle_put(remote_ep);

	asd = v4l2_async_nf_add_fwnode_remote(&vmux->notifier, ep,
	struct v4l2_async_subdev);

	fwnode_handle_put(ep);

	if (IS_ERR(asd)) {
	ret = PTR_ERR(asd);
	/* OK if asd already exists */
	if (ret != -EEXIST)
	return ret;
	}
	}

	vmux->notifier.ops = &video_mux_notify_ops;

	ret = v4l2_async_subdev_nf_register(&vmux->subdev, &vmux->notifier);
	if (ret)
	return ret;

	return v4l2_async_register_subdev(&vmux->subdev);
	}

	static int video_mux_probe(struct platform_device *pdev)
	{
	struct device_node *np = pdev->dev.of_node;
	struct device *dev = &pdev->dev;
	struct device_node *ep;
	struct video_mux *vmux;
	unsigned int num_pads = 0;
	unsigned int i;
	int ret;

	vmux = devm_kzalloc(dev, sizeof(*vmux), GFP_KERNEL);
	if (!vmux)
	return -ENOMEM;

	platform_set_drvdata(pdev, vmux);

	v4l2_subdev_init(&vmux->subdev, &video_mux_subdev_ops);
	snprintf(vmux->subdev.name, sizeof(vmux->subdev.name), "%pOFn", np);
	vmux->subdev.flags \|= V4L2_SUBDEV_FL_HAS_DEVNODE;
	vmux->subdev.dev = dev;

	/*
	* The largest numbered port is the output port. It determines
	* total number of pads.
	*/
	for_each_endpoint_of_node(np, ep) {
	struct of_endpoint endpoint;

	of_graph_parse_endpoint(ep, &endpoint);
	num_pads = max(num_pads, endpoint.port + 1);
	}

	if (num_pads < 2) {
	dev_err(dev, "Not enough ports %d\n", num_pads);
	return -EINVAL;
	}

	vmux->mux = devm_mux_control_get(dev, NULL);
	if (IS_ERR(vmux->mux)) {
	ret = PTR_ERR(vmux->mux);
	return dev_err_probe(dev, ret, "Failed to get mux\n");
	}

	mutex_init(&vmux->lock);
	vmux->active = -1;
	vmux->pads = devm_kcalloc(dev, num_pads, sizeof(*vmux->pads),
	GFP_KERNEL);
	if (!vmux->pads)
	return -ENOMEM;

	vmux->format_mbus = devm_kcalloc(dev, num_pads,
	sizeof(*vmux->format_mbus),
	GFP_KERNEL);
	if (!vmux->format_mbus)
	return -ENOMEM;

	for (i = 0; i < num_pads; i++) {
	vmux->pads[i].flags = (i < num_pads - 1) ? MEDIA_PAD_FL_SINK
	: MEDIA_PAD_FL_SOURCE;
	vmux->format_mbus[i] = video_mux_format_mbus_default;
	}

	vmux->subdev.entity.function = MEDIA_ENT_F_VID_MUX;
	ret = media_entity_pads_init(&vmux->subdev.entity, num_pads,
	vmux->pads);
	if (ret < 0)
	return ret;

	vmux->subdev.entity.ops = &video_mux_ops;

	ret = video_mux_async_register(vmux, num_pads - 1);
	if (ret) {
	v4l2_async_nf_unregister(&vmux->notifier);
	v4l2_async_nf_cleanup(&vmux->notifier);
	}

	return ret;
	}

	static int video_mux_remove(struct platform_device *pdev)
	{
	struct video_mux *vmux = platform_get_drvdata(pdev);
	struct v4l2_subdev *sd = &vmux->subdev;

	v4l2_async_nf_unregister(&vmux->notifier);
	v4l2_async_nf_cleanup(&vmux->notifier);
	v4l2_async_unregister_subdev(sd);
	media_entity_cleanup(&sd->entity);

	return 0;
	}

	static const struct of_device_id video_mux_dt_ids[] = {
	{ .compatible = "video-mux", },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, video_mux_dt_ids);

	static struct platform_driver video_mux_driver = {
	.probe = video_mux_probe,
	.remove = video_mux_remove,
	.driver = {
	.of_match_table = video_mux_dt_ids,
	.name = "video-mux",
	},
	};

	module_platform_driver(video_mux_driver);

	MODULE_DESCRIPTION("video stream multiplexer");
	MODULE_AUTHOR("Sascha Hauer, Pengutronix");
	MODULE_AUTHOR("Philipp Zabel, Pengutronix");
	MODULE_LICENSE("GPL");