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Subject[PATCH 1/2] [media] v4l: allow to register dev nodes for individual v4l2 subdevs
Date
Currently there's only a function to register device nodes for all subdevs
of a v4l2 device that are marked with the V4L2_SUBDEV_FL_HAS_DEVNODE flag.

But drivers may want to register device nodes for individual subdevices,
so add a v4l2_device_register_subdev_node() for this purpose.

A use case for this function is for media device drivers to register the
device nodes in the v4l2 async notifier .bound callback instead of doing
a registration for all subdevices in the .complete callback.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---

drivers/media/v4l2-core/v4l2-device.c | 90 ++++++++++++++++-----------
include/media/v4l2-device.h | 10 +++
2 files changed, 63 insertions(+), 37 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c
index 3940e55c72f1..e5fc51b6604c 100644
--- a/drivers/media/v4l2-core/v4l2-device.c
+++ b/drivers/media/v4l2-core/v4l2-device.c
@@ -222,9 +222,59 @@ static void v4l2_device_release_subdev_node(struct video_device *vdev)
kfree(vdev);
}

-int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
+int v4l2_device_register_subdev_node(struct v4l2_device *v4l2_dev,
+ struct v4l2_subdev *sd)
{
struct video_device *vdev;
+ int err;
+
+ if (!(sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE))
+ return -EINVAL;
+
+ vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
+ if (!vdev)
+ return -ENOMEM;
+
+ video_set_drvdata(vdev, sd);
+ strlcpy(vdev->name, sd->name, sizeof(vdev->name));
+ vdev->v4l2_dev = v4l2_dev;
+ vdev->fops = &v4l2_subdev_fops;
+ vdev->release = v4l2_device_release_subdev_node;
+ vdev->ctrl_handler = sd->ctrl_handler;
+ err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
+ sd->owner);
+ if (err < 0) {
+ kfree(vdev);
+ return err;
+ }
+ sd->devnode = vdev;
+#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;
+ video_unregister_device(sd->devnode);
+ return err;
+ }
+ }
+#endif
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_device_register_subdev_node);
+
+int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
+{
+
struct v4l2_subdev *sd;
int err;

@@ -238,43 +288,9 @@ int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
if (sd->devnode)
continue;

- vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
- if (!vdev) {
- err = -ENOMEM;
- goto clean_up;
- }
-
- video_set_drvdata(vdev, sd);
- strlcpy(vdev->name, sd->name, sizeof(vdev->name));
- vdev->v4l2_dev = v4l2_dev;
- vdev->fops = &v4l2_subdev_fops;
- vdev->release = v4l2_device_release_subdev_node;
- vdev->ctrl_handler = sd->ctrl_handler;
- err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
- sd->owner);
- if (err < 0) {
- kfree(vdev);
+ err = v4l2_device_register_subdev_node(v4l2_dev, sd);
+ if (err)
goto clean_up;
- }
- sd->devnode = vdev;
-#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;

diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h
index b330e4a08a6b..bf25418a1ad6 100644
--- a/include/media/v4l2-device.h
+++ b/include/media/v4l2-device.h
@@ -185,6 +185,16 @@ int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
*/
void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);

+/**
+ * v4l2_device_register_subdev_node - Registers a device node for a subdev
+ * of the v4l2 device.
+ *
+ * @v4l2_dev: pointer to struct v4l2_device
+ * @sd: pointer to &struct v4l2_subdev
+ */
+int __must_check v4l2_device_register_subdev_node(struct v4l2_device *v4l2_dev,
+ struct v4l2_subdev *sd);
+
/**
* v4l2_device_register_subdev_nodes - Registers device nodes for all subdevs
* of the v4l2 device that are marked with
--
2.17.1
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