[media] v4l: Make v4l2_subdev inherit from media_entity

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

When registering/unregistering the subdevice, 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>

4 files changed, 87 insertions, 6 deletions

diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index 062708169def..77d96f4e3f50 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -268,6 +268,26 @@ A sub-device driver initializes the v4l2_subdev struct using:
 Afterwards you need to initialize subdev->name with a unique name and set the
 module owner. This is done for you if you use the i2c helper functions.
 
+If integration with the media framework is needed, you must initialize the
+media_entity struct embedded in the v4l2_subdev struct (entity field) by
+calling media_entity_init():
+
+        struct media_pad *pads = &my_sd->pads;
+        int err;
+
+        err = media_entity_init(&sd->entity, npads, pads, 0);
+
+The pads array must have been previously initialized. There is no need to
+manually set the struct media_entity type and name fields, but the revision
+field must be initialized if needed.
+
+A reference to the entity will be automatically acquired/released when the
+subdev device node (if any) is opened/closed.
+
+Don't forget to cleanup the media entity before the sub-device is destroyed:
+
+        media_entity_cleanup(&sd->entity);
+
 A device (bridge) driver needs to register the v4l2_subdev with the
 v4l2_device:
 
@@ -277,6 +297,9 @@ This can fail if the subdev module disappeared before it could be registered.
 After this function was called successfully the subdev->dev field points to
 the v4l2_device.
 
+If the v4l2_device parent device has a non-NULL mdev field, the sub-device
+entity will be automatically registered with the media device.
+
 You can unregister a sub-device using:
 
         v4l2_device_unregister_subdev(sd);
diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c
index cfbd8a38991d..a1afda352d08 100644
--- a/drivers/media/video/v4l2-device.c
+++ b/drivers/media/video/v4l2-device.c
@@ -118,8 +118,11 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
 EXPORT_SYMBOL_GPL(v4l2_device_unregister);
 
 int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
-                                                struct v4l2_subdev *sd)
+                                struct v4l2_subdev *sd)
 {
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        struct media_entity *entity = &sd->entity;
+#endif
         int err;
 
         /* Check for valid input */
@@ -147,6 +150,19 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
                 return err;
         }
 
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        /* Register the entity. */
+        if (v4l2_dev->mdev) {
+                err = media_device_register_entity(v4l2_dev->mdev, entity);
+                if (err < 0) {
+                        if (sd->internal_ops && sd->internal_ops->unregistered)
+                                sd->internal_ops->unregistered(sd);
+                        module_put(sd->owner);
+                        return err;
+                }
+        }
+#endif
+
         spin_lock(&v4l2_dev->lock);
         list_add_tail(&sd->list, &v4l2_dev->subdevs);
         spin_unlock(&v4l2_dev->lock);
@@ -177,25 +193,37 @@ int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev)
                                               sd->owner);
                 if (err < 0)
                         return err;
+#if defined(CONFIG_MEDIA_CONTROLLER)
+                sd->entity.v4l.major = VIDEO_MAJOR;
+                sd->entity.v4l.minor = vdev->minor;
+#endif
         }
-
         return 0;
 }
 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;
 
-        spin_lock(&sd->v4l2_dev->lock);
+        v4l2_dev = sd->v4l2_dev;
+
+        spin_lock(&v4l2_dev->lock);
         list_del(&sd->list);
-        spin_unlock(&sd->v4l2_dev->lock);
+        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)
+                media_device_unregister_entity(&sd->entity);
+#endif
         video_unregister_device(&sd->devnode);
         module_put(sd->owner);
 }
diff --git a/drivers/media/video/v4l2-subdev.c b/drivers/media/video/v4l2-subdev.c
index 0c67f5a278fb..85573638aa1e 100644
--- a/drivers/media/video/v4l2-subdev.c
+++ b/drivers/media/video/v4l2-subdev.c
@@ -35,7 +35,10 @@ static int subdev_open(struct file *file)
 {
         struct video_device *vdev = video_devdata(file);
         struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
-        struct v4l2_fh *vfh;
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        struct media_entity *entity;
+#endif
+        struct v4l2_fh *vfh = NULL;
         int ret;
 
         if (sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS) {
@@ -58,11 +61,20 @@ static int subdev_open(struct file *file)
                 v4l2_fh_add(vfh);
                 file->private_data = vfh;
         }
-
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        if (sd->v4l2_dev->mdev) {
+                entity = media_entity_get(&sd->entity);
+                if (!entity) {
+                        ret = -EBUSY;
+                        goto err;
+                }
+        }
+#endif
         return 0;
 
 err:
         if (vfh != NULL) {
+                v4l2_fh_del(vfh);
                 v4l2_fh_exit(vfh);
                 kfree(vfh);
         }
@@ -72,8 +84,16 @@ err:
 
 static int subdev_close(struct file *file)
 {
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        struct video_device *vdev = video_devdata(file);
+        struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
+#endif
         struct v4l2_fh *vfh = file->private_data;
 
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        if (sd->v4l2_dev->mdev)
+                media_entity_put(&sd->entity);
+#endif
         if (vfh != NULL) {
                 v4l2_fh_del(vfh);
                 v4l2_fh_exit(vfh);
@@ -172,5 +192,9 @@ void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
         sd->grp_id = 0;
         sd->dev_priv = NULL;
         sd->host_priv = NULL;
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        sd->entity.name = sd->name;
+        sd->entity.type = MEDIA_ENT_T_V4L2_SUBDEV;
+#endif
 }
 EXPORT_SYMBOL(v4l2_subdev_init);
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 0f9937be53d2..6f51ce4d7ee7 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -21,6 +21,7 @@
 #ifndef _V4L2_SUBDEV_H
 #define _V4L2_SUBDEV_H
 
+#include <media/media-entity.h>
 #include <media/v4l2-common.h>
 #include <media/v4l2-dev.h>
 #include <media/v4l2-mediabus.h>
@@ -450,6 +451,9 @@ struct v4l2_subdev_internal_ops {
    stand-alone or embedded in a larger struct.
  */
 struct v4l2_subdev {
+#if defined(CONFIG_MEDIA_CONTROLLER)
+        struct media_entity entity;
+#endif
         struct list_head list;
         struct module *owner;
         u32 flags;
@@ -472,6 +476,8 @@ struct v4l2_subdev {
         unsigned int nevents;
 };
 
+#define media_entity_to_v4l2_subdev(ent) \
+        container_of(ent, struct v4l2_subdev, entity)
 #define vdev_to_v4l2_subdev(vdev) \
         container_of(vdev, struct v4l2_subdev, devnode)