drivers/media/v4l2-core/v4l2-device.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
     V4L2 device support.

     Copyright (C) 2008  Hans Verkuil <hverkuil@xs4all.nl>

  */

 #include <linux/types.h>
 #include <linux/ioctl.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/videodev2.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-ctrls.h>

 int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
 {
 	if (v4l2_dev == NULL)
 		return -EINVAL;

 	INIT_LIST_HEAD(&v4l2_dev->subdevs);
 	spin_lock_init(&v4l2_dev->lock);
 	v4l2_prio_init(&v4l2_dev->prio);
 	kref_init(&v4l2_dev->ref);
 	get_device(dev);
 	v4l2_dev->dev = dev;
 	if (dev == NULL) {
 		/* If dev == NULL, then name must be filled in by the caller */
 		if (WARN_ON(!v4l2_dev->name[0]))
 			return -EINVAL;
 		return 0;
 	}

 	/* Set name to driver name + device name if it is empty. */
 	if (!v4l2_dev->name[0])
 		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
 			dev->driver->name, dev_name(dev));
 	if (!dev_get_drvdata(dev))
 		dev_set_drvdata(dev, v4l2_dev);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_register);

 static void v4l2_device_release(struct kref *ref)
 {
 	struct v4l2_device *v4l2_dev =
 		container_of(ref, struct v4l2_device, ref);

 	if (v4l2_dev->release)
 		v4l2_dev->release(v4l2_dev);
 }

 int v4l2_device_put(struct v4l2_device *v4l2_dev)
 {
 	return kref_put(&v4l2_dev->ref, v4l2_device_release);
 }
 EXPORT_SYMBOL_GPL(v4l2_device_put);

 int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
 						atomic_t *instance)
 {
 	int num = atomic_inc_return(instance) - 1;
 	int len = strlen(basename);

 	if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
 		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
 				"%s-%d", basename, num);
 	else
 		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
 				"%s%d", basename, num);
 	return num;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_set_name);

 void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
 {
 	if (v4l2_dev->dev == NULL)
 		return;

 	if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
 		dev_set_drvdata(v4l2_dev->dev, NULL);
 	put_device(v4l2_dev->dev);
 	v4l2_dev->dev = NULL;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_disconnect);

 void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
 {
 	struct v4l2_subdev *sd, *next;

 	/* Just return if v4l2_dev is NULL or if it was already
 	 * unregistered before. */
 	if (v4l2_dev == NULL || !v4l2_dev->name[0])
 		return;
 	v4l2_device_disconnect(v4l2_dev);

 	/* Unregister subdevs */
 	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
 		v4l2_device_unregister_subdev(sd);
 		if (sd->flags & V4L2_SUBDEV_FL_IS_I2C)
 			v4l2_i2c_subdev_unregister(sd);
 		else if (sd->flags & V4L2_SUBDEV_FL_IS_SPI)
 			v4l2_spi_subdev_unregister(sd);
 	}
 	/* Mark as unregistered, thus preventing duplicate unregistrations */
 	v4l2_dev->name[0] = '\0';
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister);

 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
 				struct v4l2_subdev *sd)
 {
 	int err;

 	/* Check for valid input */
 	if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])
 		return -EINVAL;

 	/*
 	 * The reason to acquire the module here is to avoid unloading
 	 * a module of sub-device which is registered to a media
 	 * device. To make it possible to unload modules for media
 	 * devices that also register sub-devices, do not
 	 * try_module_get() such sub-device owners.
 	 */
 	sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
 		sd->owner == v4l2_dev->dev->driver->owner;

 	if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
 		return -ENODEV;

 	sd->v4l2_dev = v4l2_dev;
 	/* This just returns 0 if either of the two args is NULL */
 	err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler,
 				    NULL, true);
 	if (err)
 		goto error_module;

 #if defined(CONFIG_MEDIA_CONTROLLER)
 	/* Register the entity. */
 	if (v4l2_dev->mdev) {
 		err = media_device_register_entity(v4l2_dev->mdev, &sd->entity);
 		if (err < 0)
 			goto error_module;
 	}
 #endif

 	if (sd->internal_ops && sd->internal_ops->registered) {
 		err = sd->internal_ops->registered(sd);
 		if (err)
 			goto error_unregister;
 	}

 	spin_lock(&v4l2_dev->lock);
 	list_add_tail(&sd->list, &v4l2_dev->subdevs);
 	spin_unlock(&v4l2_dev->lock);

 	return 0;

 error_unregister:
 #if defined(CONFIG_MEDIA_CONTROLLER)
 	media_device_unregister_entity(&sd->entity);
 #endif
 error_module:
 	if (!sd->owner_v4l2_dev)
 		module_put(sd->owner);
 	sd->v4l2_dev = NULL;
 	return err;
 }
 EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);

 static void v4l2_subdev_release(struct v4l2_subdev *sd)
 {
 	struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;

 	if (sd->internal_ops && sd->internal_ops->release)
 		sd->internal_ops->release(sd);
 	sd->devnode = NULL;
 	module_put(owner);
 }

 static void v4l2_device_release_subdev_node(struct video_device *vdev)
 {
 	v4l2_subdev_release(video_get_drvdata(vdev));
 	kfree(vdev);
 }

 int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
 					bool read_only)
 {
 	struct video_device *vdev;
 	struct v4l2_subdev *sd;
 	int err;

 	/* Register a device node for every subdev marked with the
 	 * V4L2_SUBDEV_FL_HAS_DEVNODE flag.
 	 */
 	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
 			continue;

 		if (sd->devnode)
 			continue;

 		vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 		if (!vdev) {
 			err = -ENOMEM;
 			goto clean_up;
 		}

 		video_set_drvdata(vdev, sd);
 		strscpy(vdev->name, sd->name, sizeof(vdev->name));
 		vdev->dev_parent = sd->dev;
 		vdev->v4l2_dev = v4l2_dev;
 		vdev->fops = &v4l2_subdev_fops;
 		vdev->release = v4l2_device_release_subdev_node;
 		vdev->ctrl_handler = sd->ctrl_handler;
 		if (read_only)
 			set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
 		sd->devnode = vdev;
 		err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
 					      sd->owner);
 		if (err < 0) {
 			sd->devnode = NULL;
 			kfree(vdev);
 			goto clean_up;
 		}
 #if defined(CONFIG_MEDIA_CONTROLLER)
 		sd->entity.info.dev.major = VIDEO_MAJOR;
 		sd->entity.info.dev.minor = vdev->minor;

 		/* Interface is created by __video_register_device() */
 		if (vdev->v4l2_dev->mdev) {
 			struct media_link *link;

 			link = media_create_intf_link(&sd->entity,
 						      &vdev->intf_devnode->intf,
 						      MEDIA_LNK_FL_ENABLED |
 						      MEDIA_LNK_FL_IMMUTABLE);
 			if (!link) {
 				err = -ENOMEM;
 				goto clean_up;
 			}
 		}
 #endif
 	}
 	return 0;

 clean_up:
 	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
 		if (!sd->devnode)
 			break;
 		video_unregister_device(sd->devnode);
 	}

 	return err;
 }
 EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);

 void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
 {
 	struct v4l2_device *v4l2_dev;

 	/* return if it isn't registered */
 	if (sd == NULL || sd->v4l2_dev == NULL)
 		return;

 	v4l2_dev = sd->v4l2_dev;

 	spin_lock(&v4l2_dev->lock);
 	list_del(&sd->list);
 	spin_unlock(&v4l2_dev->lock);

 	if (sd->internal_ops && sd->internal_ops->unregistered)
 		sd->internal_ops->unregistered(sd);
 	sd->v4l2_dev = NULL;

 #if defined(CONFIG_MEDIA_CONTROLLER)
 	if (v4l2_dev->mdev) {
 		/*
 		 * No need to explicitly remove links, as both pads and
 		 * links are removed by the function below, in the right order
 		 */
 		media_device_unregister_entity(&sd->entity);
 	}
 #endif
 	if (sd->devnode)
 		video_unregister_device(sd->devnode);
 	else
 		v4l2_subdev_release(sd);
 }
 EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	V4L2 device support.

	Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>

	*/

	#include <linux/types.h>
	#include <linux/ioctl.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/videodev2.h>
	#include <media/v4l2-device.h>
	#include <media/v4l2-ctrls.h>

	int v4l2_device_register(struct device dev, struct v4l2_device v4l2_dev)
	{
	if (v4l2_dev == NULL)
	return -EINVAL;

	INIT_LIST_HEAD(&v4l2_dev->subdevs);
	spin_lock_init(&v4l2_dev->lock);
	v4l2_prio_init(&v4l2_dev->prio);
	kref_init(&v4l2_dev->ref);
	get_device(dev);
	v4l2_dev->dev = dev;
	if (dev == NULL) {
	/* If dev == NULL, then name must be filled in by the caller */
	if (WARN_ON(!v4l2_dev->name[0]))
	return -EINVAL;
	return 0;
	}

	/* Set name to driver name + device name if it is empty. */
	if (!v4l2_dev->name[0])
	snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
	dev->driver->name, dev_name(dev));
	if (!dev_get_drvdata(dev))
	dev_set_drvdata(dev, v4l2_dev);
	return 0;
	}
	EXPORT_SYMBOL_GPL(v4l2_device_register);

	static void v4l2_device_release(struct kref *ref)
	{
	struct v4l2_device *v4l2_dev =
	container_of(ref, struct v4l2_device, ref);

	if (v4l2_dev->release)
	v4l2_dev->release(v4l2_dev);
	}

	int v4l2_device_put(struct v4l2_device *v4l2_dev)
	{
	return kref_put(&v4l2_dev->ref, v4l2_device_release);
	}
	EXPORT_SYMBOL_GPL(v4l2_device_put);

	int v4l2_device_set_name(struct v4l2_device v4l2_dev, const char basename,
	atomic_t *instance)
	{
	int num = atomic_inc_return(instance) - 1;
	int len = strlen(basename);

	if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
	snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
	"%s-%d", basename, num);
	else
	snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
	"%s%d", basename, num);
	return num;
	}
	EXPORT_SYMBOL_GPL(v4l2_device_set_name);

	void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
	{
	if (v4l2_dev->dev == NULL)
	return;

	if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
	dev_set_drvdata(v4l2_dev->dev, NULL);
	put_device(v4l2_dev->dev);
	v4l2_dev->dev = NULL;
	}
	EXPORT_SYMBOL_GPL(v4l2_device_disconnect);

	void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
	{
	struct v4l2_subdev sd, next;

	/* Just return if v4l2_dev is NULL or if it was already
	* unregistered before. */
	if (v4l2_dev == NULL \|\| !v4l2_dev->name[0])
	return;
	v4l2_device_disconnect(v4l2_dev);

	/* Unregister subdevs */
	list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
	v4l2_device_unregister_subdev(sd);
	if (sd->flags & V4L2_SUBDEV_FL_IS_I2C)
	v4l2_i2c_subdev_unregister(sd);
	else if (sd->flags & V4L2_SUBDEV_FL_IS_SPI)
	v4l2_spi_subdev_unregister(sd);
	}
	/* Mark as unregistered, thus preventing duplicate unregistrations */
	v4l2_dev->name[0] = '\0';
	}
	EXPORT_SYMBOL_GPL(v4l2_device_unregister);

	int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
	struct v4l2_subdev *sd)
	{
	int err;

	/* Check for valid input */
	if (!v4l2_dev \|\| !sd \|\| sd->v4l2_dev \|\| !sd->name[0])
	return -EINVAL;

	/*
	* The reason to acquire the module here is to avoid unloading
	* a module of sub-device which is registered to a media
	* device. To make it possible to unload modules for media
	* devices that also register sub-devices, do not
	* try_module_get() such sub-device owners.
	*/
	sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
	sd->owner == v4l2_dev->dev->driver->owner;

	if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
	return -ENODEV;

	sd->v4l2_dev = v4l2_dev;
	/* This just returns 0 if either of the two args is NULL */
	err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler,
	NULL, true);
	if (err)
	goto error_module;

	#if defined(CONFIG_MEDIA_CONTROLLER)
	/* Register the entity. */
	if (v4l2_dev->mdev) {
	err = media_device_register_entity(v4l2_dev->mdev, &sd->entity);
	if (err < 0)
	goto error_module;
	}
	#endif

	if (sd->internal_ops && sd->internal_ops->registered) {
	err = sd->internal_ops->registered(sd);
	if (err)
	goto error_unregister;
	}

	spin_lock(&v4l2_dev->lock);
	list_add_tail(&sd->list, &v4l2_dev->subdevs);
	spin_unlock(&v4l2_dev->lock);

	return 0;

	error_unregister:
	#if defined(CONFIG_MEDIA_CONTROLLER)
	media_device_unregister_entity(&sd->entity);
	#endif
	error_module:
	if (!sd->owner_v4l2_dev)
	module_put(sd->owner);
	sd->v4l2_dev = NULL;
	return err;
	}
	EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);

	static void v4l2_subdev_release(struct v4l2_subdev *sd)
	{
	struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;

	if (sd->internal_ops && sd->internal_ops->release)
	sd->internal_ops->release(sd);
	sd->devnode = NULL;
	module_put(owner);
	}

	static void v4l2_device_release_subdev_node(struct video_device *vdev)
	{
	v4l2_subdev_release(video_get_drvdata(vdev));
	kfree(vdev);
	}

	int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
	bool read_only)
	{
	struct video_device *vdev;
	struct v4l2_subdev *sd;
	int err;

	/* Register a device node for every subdev marked with the
	* V4L2_SUBDEV_FL_HAS_DEVNODE flag.
	*/
	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
	if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
	continue;

	if (sd->devnode)
	continue;

	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
	if (!vdev) {
	err = -ENOMEM;
	goto clean_up;
	}

	video_set_drvdata(vdev, sd);
	strscpy(vdev->name, sd->name, sizeof(vdev->name));
	vdev->dev_parent = sd->dev;
	vdev->v4l2_dev = v4l2_dev;
	vdev->fops = &v4l2_subdev_fops;
	vdev->release = v4l2_device_release_subdev_node;
	vdev->ctrl_handler = sd->ctrl_handler;
	if (read_only)
	set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
	sd->devnode = vdev;
	err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
	sd->owner);
	if (err < 0) {
	sd->devnode = NULL;
	kfree(vdev);
	goto clean_up;
	}
	#if defined(CONFIG_MEDIA_CONTROLLER)
	sd->entity.info.dev.major = VIDEO_MAJOR;
	sd->entity.info.dev.minor = vdev->minor;

	/* Interface is created by __video_register_device() */
	if (vdev->v4l2_dev->mdev) {
	struct media_link *link;

	link = media_create_intf_link(&sd->entity,
	&vdev->intf_devnode->intf,
	MEDIA_LNK_FL_ENABLED \|
	MEDIA_LNK_FL_IMMUTABLE);
	if (!link) {
	err = -ENOMEM;
	goto clean_up;
	}
	}
	#endif
	}
	return 0;

	clean_up:
	list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
	if (!sd->devnode)
	break;
	video_unregister_device(sd->devnode);
	}

	return err;
	}
	EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);

	void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
	{
	struct v4l2_device *v4l2_dev;

	/* return if it isn't registered */
	if (sd == NULL \|\| sd->v4l2_dev == NULL)
	return;

	v4l2_dev = sd->v4l2_dev;

	spin_lock(&v4l2_dev->lock);
	list_del(&sd->list);
	spin_unlock(&v4l2_dev->lock);

	if (sd->internal_ops && sd->internal_ops->unregistered)
	sd->internal_ops->unregistered(sd);
	sd->v4l2_dev = NULL;

	#if defined(CONFIG_MEDIA_CONTROLLER)
	if (v4l2_dev->mdev) {
	/*
	* No need to explicitly remove links, as both pads and
	* links are removed by the function below, in the right order
	*/
	media_device_unregister_entity(&sd->entity);
	}
	#endif
	if (sd->devnode)
	video_unregister_device(sd->devnode);
	else
	v4l2_subdev_release(sd);
	}
	EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);