[media] v4l: Make video_device inherit from media_entity

V4L2 devices are media entities. As such they need to inherit from
(include) the media_entity structure.

When registering/unregistering the device, the media entity is
automatically registered/unregistered. The entity is acquired on device
open and released on device close.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 45 insertions, 4 deletions

diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
index abe04ef38066..e405b8094b94 100644
--- a/drivers/media/video/v4l2-dev.c
+++ b/drivers/media/video/v4l2-dev.c
@@ -303,6 +303,9 @@ static int v4l2_mmap(struct file *filp, struct vm_area_struct *vm)
 static int v4l2_open(struct inode *inode, struct file *filp)
 {
         struct video_device *vdev;
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        struct media_entity *entity = NULL;
+#endif
         int ret = 0;
 
         /* Check if the video device is available */
@@ -316,6 +319,16 @@ static int v4l2_open(struct inode *inode, struct file *filp)
         /* and increase the device refcount */
         video_get(vdev);
         mutex_unlock(&videodev_lock);
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        if (vdev->v4l2_dev && vdev->v4l2_dev->mdev) {
+                entity = media_entity_get(&vdev->entity);
+                if (!entity) {
+                        ret = -EBUSY;
+                        video_put(vdev);
+                        return ret;
+                }
+        }
+#endif
         if (vdev->fops->open) {
                 if (vdev->lock && mutex_lock_interruptible(vdev->lock)) {
                         ret = -ERESTARTSYS;
@@ -331,8 +344,13 @@ static int v4l2_open(struct inode *inode, struct file *filp)
 
 err:
         /* decrease the refcount in case of an error */
-        if (ret)
+        if (ret) {
+#if defined(CONFIG_MEDIA_CONTROLLER)
+                if (vdev->v4l2_dev && vdev->v4l2_dev->mdev)
+                        media_entity_put(entity);
+#endif
                 video_put(vdev);
+        }
         return ret;
 }
 
@@ -349,7 +367,10 @@ static int v4l2_release(struct inode *inode, struct file *filp)
                 if (vdev->lock)
                         mutex_unlock(vdev->lock);
         }
-
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        if (vdev->v4l2_dev && vdev->v4l2_dev->mdev)
+                media_entity_put(&vdev->entity);
+#endif
         /* decrease the refcount unconditionally since the release()
            return value is ignored. */
         video_put(vdev);
@@ -585,12 +606,27 @@ int __video_register_device(struct video_device *vdev, int type, int nr,
         if (nr != -1 && nr != vdev->num && warn_if_nr_in_use)
                 printk(KERN_WARNING "%s: requested %s%d, got %s\n", __func__,
                         name_base, nr, video_device_node_name(vdev));
-
-        /* Part 5: Activate this minor. The char device can now be used. */
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        /* Part 5: Register the entity. */
+        if (vdev->v4l2_dev && vdev->v4l2_dev->mdev) {
+                vdev->entity.type = MEDIA_ENT_T_DEVNODE_V4L;
+                vdev->entity.name = vdev->name;
+                vdev->entity.v4l.major = VIDEO_MAJOR;
+                vdev->entity.v4l.minor = vdev->minor;
+                ret = media_device_register_entity(vdev->v4l2_dev->mdev,
+                        &vdev->entity);
+                if (ret < 0)
+                        printk(KERN_WARNING
+                               "%s: media_device_register_entity failed\n",
+                               __func__);
+        }
+#endif
+        /* Part 6: Activate this minor. The char device can now be used. */
         set_bit(V4L2_FL_REGISTERED, &vdev->flags);
         mutex_lock(&videodev_lock);
         video_device[vdev->minor] = vdev;
         mutex_unlock(&videodev_lock);
+
         return 0;
 
 cleanup:
@@ -618,6 +654,11 @@ void video_unregister_device(struct video_device *vdev)
         if (!vdev || !video_is_registered(vdev))
                 return;
 
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        if (vdev->v4l2_dev && vdev->v4l2_dev->mdev)
+                media_device_unregister_entity(&vdev->entity);
+#endif
+
         mutex_lock(&videodev_lock);
         /* This must be in a critical section to prevent a race with v4l2_open.
          * Once this bit has been cleared video_get may never be called again.