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[media] v4l: ctrls: Add a control for digital gain

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Add V4L2_CID_DIGITAL_GAIN to control explicitly digital gain.

We already have analogue gain control which the digital gain control
complements. Typically higher quality images are obtained using analogue
gain only as the digital gain does not add information to the image
(rather it may remove it).

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>
This commit is contained in:
Sakari Ailus 2017-06-08 16:59:58 -03:00 committed by Mauro Carvalho Chehab
parent 8e792f5287
commit e72cb0e794
3 changed files with 9 additions and 1 deletions
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7
Documentation/media/uapi/v4l/extended-controls.rst
View file

@ -3021,6 +3021,13 @@ Image Process Control IDs
The video deinterlacing mode (such as Bob, Weave, ...). The menu items are
driver specific and are documented in :ref:`v4l-drivers`.
``V4L2_CID_DIGITAL_GAIN (integer)``
Digital gain is the value by which all colour components
are multiplied by. Typically the digital gain applied is the
control value divided by e.g. 0x100, meaning that to get no
digital gain the control value needs to be 0x100. The no-gain
configuration is also typically the default.
.. _dv-controls:

1
drivers/media/v4l2-core/v4l2-ctrls.c
View file

@ -886,6 +886,7 @@ const char *v4l2_ctrl_get_name(u32 id)
case V4L2_CID_PIXEL_RATE: return "Pixel Rate";
case V4L2_CID_TEST_PATTERN: return "Test Pattern";
case V4L2_CID_DEINTERLACING_MODE: return "Deinterlacing Mode";
case V4L2_CID_DIGITAL_GAIN: return "Digital Gain";
/* DV controls */
/* Keep the order of the 'case's the same as in v4l2-controls.h! */

2
include/uapi/linux/v4l2-controls.h
View file

@ -902,7 +902,7 @@ enum v4l2_jpeg_chroma_subsampling {
#define V4L2_CID_PIXEL_RATE (V4L2_CID_IMAGE_PROC_CLASS_BASE + 2)
#define V4L2_CID_TEST_PATTERN (V4L2_CID_IMAGE_PROC_CLASS_BASE + 3)
#define V4L2_CID_DEINTERLACING_MODE (V4L2_CID_IMAGE_PROC_CLASS_BASE + 4)
#define V4L2_CID_DIGITAL_GAIN (V4L2_CID_IMAGE_PROC_CLASS_BASE + 5)
/* DV-class control IDs defined by V4L2 */
#define V4L2_CID_DV_CLASS_BASE (V4L2_CTRL_CLASS_DV | 0x900)