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[media] v4l: subdev: Events support

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Provide v4l2_subdevs with v4l2_event support. Subdev drivers only need very
little to support events.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: David Cohen <dacohen@gmail.com>
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:
Sakari Ailus
2010-03-03 12:49:38 -03:00
committed by Mauro Carvalho Chehab
parent ea8aa4349e
commit 02adb1cc76
3 changed files with 105 additions and 1 deletions
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18
Documentation/video4linux/v4l2-framework.txt
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@ -350,6 +350,24 @@ VIDIOC_TRY_EXT_CTRLS
controls can be also be accessed through one (or several) V4L2 device
nodes.
VIDIOC_DQEVENT
VIDIOC_SUBSCRIBE_EVENT
VIDIOC_UNSUBSCRIBE_EVENT
The events ioctls are identical to the ones defined in V4L2. They
behave identically, with the only exception that they deal only with
events generated by the sub-device. Depending on the driver, those
events can also be reported by one (or several) V4L2 device nodes.
Sub-device drivers that want to use events need to set the
V4L2_SUBDEV_USES_EVENTS v4l2_subdev::flags and initialize
v4l2_subdev::nevents to events queue depth before registering the
sub-device. After registration events can be queued as usual on the
v4l2_subdev::devnode device node.
To properly support events, the poll() file operation is also
implemented.
I2C sub-device drivers
----------------------