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authorHans Verkuil <hans.verkuil@cisco.com>2012-09-14 14:15:03 +0400
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-10-02 00:07:07 +0400
commit34a6b7d093d8fe738ada191b36648d00bc18b7eb (patch)
tree854584731068996a381af03b95884911c07074b5 /Documentation/video4linux
parenta4f64407b9b33122a58cb78afd73f86d4bb022c4 (diff)
downloadlinux-34a6b7d093d8fe738ada191b36648d00bc18b7eb.tar.xz
[media] v4l2-ctrls: add a filter function to v4l2_ctrl_add_handler
With a filter function you can control more precisely which controls are added. This is useful in particular for radio device nodes for combined TV/Radio cards where you want to show just the radio-specific controls and not controls like brightness. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'Documentation/video4linux')
-rw-r--r--Documentation/video4linux/v4l2-controls.txt6
1 files changed, 5 insertions, 1 deletions
diff --git a/Documentation/video4linux/v4l2-controls.txt b/Documentation/video4linux/v4l2-controls.txt
index 43da22b89728..54270df99d5c 100644
--- a/Documentation/video4linux/v4l2-controls.txt
+++ b/Documentation/video4linux/v4l2-controls.txt
@@ -594,7 +594,11 @@ handler and finally add the first handler to the second. For example:
v4l2_ctrl_new_std(&radio_ctrl_handler, &radio_ops, V4L2_CID_AUDIO_MUTE, ...);
v4l2_ctrl_new_std(&video_ctrl_handler, &video_ops, V4L2_CID_BRIGHTNESS, ...);
v4l2_ctrl_new_std(&video_ctrl_handler, &video_ops, V4L2_CID_CONTRAST, ...);
- v4l2_ctrl_add_handler(&video_ctrl_handler, &radio_ctrl_handler);
+ v4l2_ctrl_add_handler(&video_ctrl_handler, &radio_ctrl_handler, NULL);
+
+The last argument to v4l2_ctrl_add_handler() is a filter function that allows
+you to filter which controls will be added. Set it to NULL if you want to add
+all controls.
Or you can add specific controls to a handler: