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f75c431e54
Add to the V4L2 core a function to register device nodes for video subdevices in read-only mode. Registering a device node in read-only mode is useful to expose to userspace the current sub-device configuration, without allowing application to change it by using the V4L2 subdevice ioctls. Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
293 lines
7.2 KiB
C
293 lines
7.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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V4L2 device support.
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Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
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*/
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#include <linux/types.h>
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#include <linux/ioctl.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/videodev2.h>
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#include <media/v4l2-device.h>
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#include <media/v4l2-ctrls.h>
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int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
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{
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if (v4l2_dev == NULL)
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return -EINVAL;
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INIT_LIST_HEAD(&v4l2_dev->subdevs);
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spin_lock_init(&v4l2_dev->lock);
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v4l2_prio_init(&v4l2_dev->prio);
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kref_init(&v4l2_dev->ref);
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get_device(dev);
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v4l2_dev->dev = dev;
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if (dev == NULL) {
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/* If dev == NULL, then name must be filled in by the caller */
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if (WARN_ON(!v4l2_dev->name[0]))
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return -EINVAL;
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return 0;
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}
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/* Set name to driver name + device name if it is empty. */
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if (!v4l2_dev->name[0])
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snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
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dev->driver->name, dev_name(dev));
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if (!dev_get_drvdata(dev))
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dev_set_drvdata(dev, v4l2_dev);
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return 0;
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}
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EXPORT_SYMBOL_GPL(v4l2_device_register);
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static void v4l2_device_release(struct kref *ref)
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{
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struct v4l2_device *v4l2_dev =
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container_of(ref, struct v4l2_device, ref);
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if (v4l2_dev->release)
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v4l2_dev->release(v4l2_dev);
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}
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int v4l2_device_put(struct v4l2_device *v4l2_dev)
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{
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return kref_put(&v4l2_dev->ref, v4l2_device_release);
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}
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EXPORT_SYMBOL_GPL(v4l2_device_put);
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int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
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atomic_t *instance)
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{
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int num = atomic_inc_return(instance) - 1;
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int len = strlen(basename);
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if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
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snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
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"%s-%d", basename, num);
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else
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snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
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"%s%d", basename, num);
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return num;
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}
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EXPORT_SYMBOL_GPL(v4l2_device_set_name);
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void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
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{
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if (v4l2_dev->dev == NULL)
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return;
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if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)
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dev_set_drvdata(v4l2_dev->dev, NULL);
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put_device(v4l2_dev->dev);
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v4l2_dev->dev = NULL;
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}
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EXPORT_SYMBOL_GPL(v4l2_device_disconnect);
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void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
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{
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struct v4l2_subdev *sd, *next;
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/* Just return if v4l2_dev is NULL or if it was already
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* unregistered before. */
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if (v4l2_dev == NULL || !v4l2_dev->name[0])
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return;
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v4l2_device_disconnect(v4l2_dev);
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/* Unregister subdevs */
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list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
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v4l2_device_unregister_subdev(sd);
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if (sd->flags & V4L2_SUBDEV_FL_IS_I2C)
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v4l2_i2c_subdev_unregister(sd);
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else if (sd->flags & V4L2_SUBDEV_FL_IS_SPI)
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v4l2_spi_subdev_unregister(sd);
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}
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/* Mark as unregistered, thus preventing duplicate unregistrations */
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v4l2_dev->name[0] = '\0';
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}
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EXPORT_SYMBOL_GPL(v4l2_device_unregister);
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int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
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struct v4l2_subdev *sd)
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{
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int err;
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/* Check for valid input */
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if (!v4l2_dev || !sd || sd->v4l2_dev || !sd->name[0])
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return -EINVAL;
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/*
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* The reason to acquire the module here is to avoid unloading
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* a module of sub-device which is registered to a media
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* device. To make it possible to unload modules for media
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* devices that also register sub-devices, do not
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* try_module_get() such sub-device owners.
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*/
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sd->owner_v4l2_dev = v4l2_dev->dev && v4l2_dev->dev->driver &&
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sd->owner == v4l2_dev->dev->driver->owner;
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if (!sd->owner_v4l2_dev && !try_module_get(sd->owner))
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return -ENODEV;
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sd->v4l2_dev = v4l2_dev;
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/* This just returns 0 if either of the two args is NULL */
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err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler,
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NULL, true);
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if (err)
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goto error_module;
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#if defined(CONFIG_MEDIA_CONTROLLER)
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/* Register the entity. */
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if (v4l2_dev->mdev) {
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err = media_device_register_entity(v4l2_dev->mdev, &sd->entity);
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if (err < 0)
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goto error_module;
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}
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#endif
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if (sd->internal_ops && sd->internal_ops->registered) {
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err = sd->internal_ops->registered(sd);
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if (err)
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goto error_unregister;
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}
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spin_lock(&v4l2_dev->lock);
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list_add_tail(&sd->list, &v4l2_dev->subdevs);
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spin_unlock(&v4l2_dev->lock);
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return 0;
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error_unregister:
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#if defined(CONFIG_MEDIA_CONTROLLER)
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media_device_unregister_entity(&sd->entity);
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#endif
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error_module:
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if (!sd->owner_v4l2_dev)
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module_put(sd->owner);
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sd->v4l2_dev = NULL;
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return err;
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}
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EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);
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static void v4l2_subdev_release(struct v4l2_subdev *sd)
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{
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struct module *owner = !sd->owner_v4l2_dev ? sd->owner : NULL;
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if (sd->internal_ops && sd->internal_ops->release)
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sd->internal_ops->release(sd);
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sd->devnode = NULL;
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module_put(owner);
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}
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static void v4l2_device_release_subdev_node(struct video_device *vdev)
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{
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v4l2_subdev_release(video_get_drvdata(vdev));
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kfree(vdev);
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}
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int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev,
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bool read_only)
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{
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struct video_device *vdev;
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struct v4l2_subdev *sd;
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int err;
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/* Register a device node for every subdev marked with the
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* V4L2_SUBDEV_FL_HAS_DEVNODE flag.
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*/
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list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
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if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
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continue;
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if (sd->devnode)
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continue;
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vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
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if (!vdev) {
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err = -ENOMEM;
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goto clean_up;
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}
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video_set_drvdata(vdev, sd);
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strscpy(vdev->name, sd->name, sizeof(vdev->name));
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vdev->dev_parent = sd->dev;
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vdev->v4l2_dev = v4l2_dev;
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vdev->fops = &v4l2_subdev_fops;
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vdev->release = v4l2_device_release_subdev_node;
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vdev->ctrl_handler = sd->ctrl_handler;
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if (read_only)
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set_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
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err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
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sd->owner);
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if (err < 0) {
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kfree(vdev);
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goto clean_up;
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}
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sd->devnode = vdev;
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#if defined(CONFIG_MEDIA_CONTROLLER)
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sd->entity.info.dev.major = VIDEO_MAJOR;
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sd->entity.info.dev.minor = vdev->minor;
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/* Interface is created by __video_register_device() */
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if (vdev->v4l2_dev->mdev) {
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struct media_link *link;
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link = media_create_intf_link(&sd->entity,
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&vdev->intf_devnode->intf,
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MEDIA_LNK_FL_ENABLED |
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MEDIA_LNK_FL_IMMUTABLE);
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if (!link) {
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err = -ENOMEM;
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goto clean_up;
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}
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}
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#endif
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}
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return 0;
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clean_up:
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list_for_each_entry(sd, &v4l2_dev->subdevs, list) {
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if (!sd->devnode)
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break;
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video_unregister_device(sd->devnode);
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}
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return err;
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}
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EXPORT_SYMBOL_GPL(__v4l2_device_register_subdev_nodes);
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void v4l2_device_unregister_subdev(struct v4l2_subdev *sd)
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{
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struct v4l2_device *v4l2_dev;
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/* return if it isn't registered */
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if (sd == NULL || sd->v4l2_dev == NULL)
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return;
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v4l2_dev = sd->v4l2_dev;
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spin_lock(&v4l2_dev->lock);
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list_del(&sd->list);
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spin_unlock(&v4l2_dev->lock);
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if (sd->internal_ops && sd->internal_ops->unregistered)
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sd->internal_ops->unregistered(sd);
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sd->v4l2_dev = NULL;
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#if defined(CONFIG_MEDIA_CONTROLLER)
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if (v4l2_dev->mdev) {
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/*
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* No need to explicitly remove links, as both pads and
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* links are removed by the function below, in the right order
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*/
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media_device_unregister_entity(&sd->entity);
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}
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#endif
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if (sd->devnode)
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video_unregister_device(sd->devnode);
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else
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v4l2_subdev_release(sd);
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}
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EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
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