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authorHans Verkuil <hans.verkuil@cisco.com>2013-06-12 11:28:08 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2013-06-21 11:09:01 -0300
commit7cb59509a74da98721ac169431a9a0bd372e29b0 (patch)
treedfbce6ef2cdf57461d180b9ea1b0e2b2514afaac /Documentation/video4linux
parente5715cfb2802cb5988f856f84454645772f4e2f5 (diff)
downloadkernel-7cb59509a74da98721ac169431a9a0bd372e29b0.tar.gz
[media] v4l2-framework: update documentation
'parent' was renamed to 'dev_parent'. Clarify how/when this should be used. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/video4linux')
-rw-r--r--Documentation/video4linux/v4l2-framework.txt17
1 files changed, 11 insertions, 6 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index 24353ecab197..b5e6347b720f 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -574,9 +574,13 @@ of the video device exits.
The default video_device_release() callback just calls kfree to free the
allocated memory.
+There is also a video_device_release_empty() function that does nothing
+(is empty) and can be used if the struct is embedded and there is nothing
+to do when it is released.
+
You should also set these fields:
-- v4l2_dev: set to the v4l2_device parent device.
+- v4l2_dev: must be set to the v4l2_device parent device.
- name: set to something descriptive and unique.
@@ -613,15 +617,16 @@ You should also set these fields:
If you want to have a separate priority state per (group of) device node(s),
then you can point it to your own struct v4l2_prio_state.
-- parent: you only set this if v4l2_device was registered with NULL as
+- dev_parent: you only set this if v4l2_device was registered with NULL as
the parent device struct. This only happens in cases where one hardware
device has multiple PCI devices that all share the same v4l2_device core.
The cx88 driver is an example of this: one core v4l2_device struct, but
- it is used by both an raw video PCI device (cx8800) and a MPEG PCI device
- (cx8802). Since the v4l2_device cannot be associated with a particular
- PCI device it is setup without a parent device. But when the struct
- video_device is setup you do know which parent PCI device to use.
+ it is used by both a raw video PCI device (cx8800) and a MPEG PCI device
+ (cx8802). Since the v4l2_device cannot be associated with two PCI devices
+ at the same time it is setup without a parent device. But when the struct
+ video_device is initialized you *do* know which parent PCI device to use and
+ so you set dev_device to the correct PCI device.
- flags: optional. Set to V4L2_FL_USE_FH_PRIO if you want to let the framework
handle the VIDIOC_G/S_PRIORITY ioctls. This requires that you use struct