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authorSakari Ailus <sakari.ailus@linux.intel.com>2017-06-09 10:15:50 -0300
committerMauro Carvalho Chehab <mchehab@s-opensource.com>2017-06-20 08:14:57 -0300
commit371f94490ea97e1bf766ba0d33ffb62f5f5a4ed1 (patch)
treea3a91347503bb0df050dbf8b382916af14ee504b /Documentation/media
parente72cb0e79475b0d26625e802846e281a84304c07 (diff)
[media] v4l: controls: Improve documentation for V4L2_CID_GAIN
Elaborate the differences between V4L2_CID_GAIN and gain-type specific V4L2_CID_DIGITAL_GAIN and V4L2_CID_ANALOGUE_GAIN. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'Documentation/media')
-rw-r--r--Documentation/media/uapi/v4l/control.rst6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/control.rst b/Documentation/media/uapi/v4l/control.rst
index 51112badb804..c1e6adbe83d7 100644
--- a/Documentation/media/uapi/v4l/control.rst
+++ b/Documentation/media/uapi/v4l/control.rst
@@ -137,6 +137,12 @@ Control IDs
``V4L2_CID_GAIN`` ``(integer)``
Gain control.
+ Primarily used to control gain on e.g. TV tuners but also on
+ webcams. Most devices control only digital gain with this control
+ but on some this could include analogue gain as well. Devices that
+ recognise the difference between digital and analogue gain use
+ controls ``V4L2_CID_DIGITAL_GAIN`` and ``V4L2_CID_ANALOGUE_GAIN``.
+
``V4L2_CID_HFLIP`` ``(boolean)``
Mirror the picture horizontally.