On 06/09/17 15:21, Sakari Ailus wrote:
> 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@xxxxxxxxxxxxxxx>
Acked-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Regards,
Hans
> ---
> Documentation/media/uapi/v4l/extended-controls.rst | 7 +++++++
> drivers/media/v4l2-core/v4l2-ctrls.c | 1 +
> include/uapi/linux/v4l2-controls.h | 2 +-
> 3 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/media/uapi/v4l/extended-controls.rst b/Documentation/media/uapi/v4l/extended-controls.rst
> index 76c5b1a..9acc9cad 100644
> --- a/Documentation/media/uapi/v4l/extended-controls.rst
> +++ b/Documentation/media/uapi/v4l/extended-controls.rst
> @@ -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:
>
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 5aed7bd..36eede3 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -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! */
> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
> index 0d2e1e0..0cdb8eb 100644
> --- a/include/uapi/linux/v4l2-controls.h
> +++ b/include/uapi/linux/v4l2-controls.h
> @@ -893,7 +893,7 @@ 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)
>
