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[media] v4l: Make v4l2_subdev inherit from media_entity

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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>
This commit is contained in:
Laurent Pinchart
2009-12-09 08:40:08 -03:00
committed by Mauro Carvalho Chehab
parent 2c0ab67be1
commit 61f5db549d
4 changed files with 87 additions and 6 deletions
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23
Documentation/video4linux/v4l2-framework.txt
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@@ -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);