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@xxxxxxxxxxxxxxx>
---
Documentation/media/uapi/v4l/control.rst | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/Documentation/media/uapi/v4l/control.rst b/Documentation/media/uapi/v4l/control.rst
index 51112ba..c1e6adb 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.
--
2.7.4
