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Subject[PATCH v9 12/12] v4l: Make v4l2_subdev inherit from media_entity
Date
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>
---
Documentation/video4linux/v4l2-framework.txt | 23 ++++++++++++++++
drivers/media/video/v4l2-device.c | 36 +++++++++++++++++++++++---
drivers/media/video/v4l2-subdev.c | 28 ++++++++++++++++++-
include/media/v4l2-subdev.h | 6 ++++
4 files changed, 87 insertions(+), 6 deletions(-)
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index 0627081..77d96f4 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 0af46e4..259415b 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 9374406..29b7ddf 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 3f4e0d1..c37d6e4 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>
@@ -448,6 +449,9 @@ 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;
@@ -470,6 +474,8 @@ 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)

--
1.7.3.4


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