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[media] v4l: Add a media_device pointer to the v4l2_device structure

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The pointer will later be used to register/unregister media entities
when registering/unregistering a v4l2_subdev or a video_device.

With the introduction of media devices, device drivers need to store a
pointer to a driver-specific structure in the device's drvdata.
v4l2_device can't claim ownership of the drvdata anymore.

To maintain compatibility with drivers that rely on v4l2_device storing
a pointer to itself in the device's drvdata, v4l2_device_register() will
keep doing so if the drvdata is NULL.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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 08:40:05 -03:00
committed by Mauro Carvalho Chehab
parent e02188c90f
commit 95db3a60e0
3 changed files with 23 additions and 11 deletions
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17
Documentation/video4linux/v4l2-framework.txt
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@@ -83,11 +83,17 @@ You must register the device instance:
v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
Registration will initialize the v4l2_device struct and link dev->driver_data
to v4l2_dev. If v4l2_dev->name is empty then it will be set to a value derived
from dev (driver name followed by the bus_id, to be precise). If you set it
up before calling v4l2_device_register then it will be untouched. If dev is
NULL, then you *must* setup v4l2_dev->name before calling v4l2_device_register.
Registration will initialize the v4l2_device struct. If the dev->driver_data
field is NULL, it will be linked to v4l2_dev. Drivers that use the media
device framework in addition to the V4L2 framework need to set
dev->driver_data manually to point to the driver-specific device structure
that embed the struct v4l2_device instance. This is achieved by a
dev_set_drvdata() call before registering the V4L2 device instance.
If v4l2_dev->name is empty then it will be set to a value derived from dev
(driver name followed by the bus_id, to be precise). If you set it up before
calling v4l2_device_register then it will be untouched. If dev is NULL, then
you *must* setup v4l2_dev->name before calling v4l2_device_register.
You can use v4l2_device_set_name() to set the name based on a driver name and
a driver-global atomic_t instance. This will generate names like ivtv0, ivtv1,
@@ -108,6 +114,7 @@ You unregister with:
v4l2_device_unregister(struct v4l2_device *v4l2_dev);
If the dev->driver_data field points to v4l2_dev, it will be reset to NULL.
Unregistering will also automatically unregister all subdevs from the device.
If you have a hotpluggable device (e.g. a USB device), then when a disconnect