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Subject[RFC/PATCH v7 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@maxwell.research.nokia.com>
---
Documentation/video4linux/v4l2-framework.txt | 23 ++++++++++++++
drivers/media/video/v4l2-device.c | 39 ++++++++++++++++++++----
drivers/media/video/v4l2-subdev.c | 41 ++++++++++++++++++++++++-
include/media/v4l2-subdev.h | 10 ++++++
4 files changed, 104 insertions(+), 9 deletions(-)
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index f231bc20..d0fb880 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 8447466..7ac4d0f 100644
--- a/drivers/media/video/v4l2-device.c
+++ b/drivers/media/video/v4l2-device.c
@@ -115,8 +115,11 @@ 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
struct video_device *vdev;
int err;

@@ -134,7 +137,16 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
err = v4l2_ctrl_add_handler(v4l2_dev->ctrl_handler, sd->ctrl_handler);
if (err)
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) {
+ module_put(sd->owner);
+ return err;
+ }
+ }
+#endif
sd->v4l2_dev = v4l2_dev;
spin_lock(&v4l2_dev->lock);
list_add_tail(&sd->list, &v4l2_dev->subdevs);
@@ -149,26 +161,39 @@ int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
if (sd->flags & V4L2_SUBDEV_FL_HAS_DEVNODE) {
err = __video_register_device(vdev, VFL_TYPE_SUBDEV, -1, 1,
sd->owner);
- if (err < 0)
+ if (err < 0) {
v4l2_device_unregister_subdev(sd);
+ return err;
+ }
}
-
- return err;
+#if defined(CONFIG_MEDIA_CONTROLLER)
+ entity->v4l.major = VIDEO_MAJOR;
+ entity->v4l.minor = vdev->minor;
+#endif
+ return 0;
}
EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);

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);
sd->v4l2_dev = NULL;

module_put(sd->owner);
+#if defined(CONFIG_MEDIA_CONTROLLER)
+ if (v4l2_dev->mdev)
+ media_device_unregister_entity(&sd->entity);
+#endif
video_unregister_device(&sd->devnode);
}
EXPORT_SYMBOL_GPL(v4l2_device_unregister_subdev);
diff --git a/drivers/media/video/v4l2-subdev.c b/drivers/media/video/v4l2-subdev.c
index fbccefd..5e19136 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->initialized)
@@ -61,11 +64,20 @@ 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);
}
@@ -75,8 +87,16 @@ 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);
@@ -176,5 +196,22 @@ void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
sd->dev_priv = NULL;
sd->host_priv = NULL;
sd->initialized = 1;
+#if defined(CONFIG_MEDIA_CONTROLLER)
+ sd->entity.name = sd->name;
+ sd->entity.type = MEDIA_ENTITY_TYPE_V4L2_SUBDEV;
+#endif
}
EXPORT_SYMBOL(v4l2_subdev_init);
+
+#if defined(CONFIG_MEDIA_CONTROLLER)
+int v4l2_subdev_set_power(struct media_entity *entity, int power)
+{
+ struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
+
+ dev_dbg(entity->parent->dev,
+ "%s power%s\n", entity->name, power ? "on" : "off");
+
+ return v4l2_subdev_call(sd, core, s_power, power);
+}
+EXPORT_SYMBOL_GPL(v4l2_subdev_set_power);
+#endif
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 68cbe48..7d55b0c 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>
@@ -437,6 +438,9 @@ struct v4l2_subdev_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;
@@ -458,6 +462,8 @@ 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)

@@ -486,6 +492,10 @@ static inline void *v4l2_get_subdev_hostdata(const struct v4l2_subdev *sd)
void v4l2_subdev_init(struct v4l2_subdev *sd,
const struct v4l2_subdev_ops *ops);

+#if defined(CONFIG_MEDIA_CONTROLLER)
+int v4l2_subdev_set_power(struct media_entity *entity, int power);
+#endif
+
/* Call an ops of a v4l2_subdev, doing the right checks against
NULL pointers.

--
1.7.2.2


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