Re: [PATCH RFC] media: v4l2-ctrl: Add digital gain controls

From: Laurent Pinchart
Date: Thu Oct 04 2012 - 18:10:16 EST


Hi Prabhakar,

Thanks for the patch.

On Monday 01 October 2012 19:33:39 Prabhakar wrote:
> From: Lad, Prabhakar <prabhakar.lad@xxxxxx>
>
> add support for per color component digital gain controls
> and also their corresponding offset.
>
> Signed-off-by: Lad, Prabhakar <prabhakar.lad@xxxxxx>
> Signed-off-by: Manjunath Hadli <manjunath.hadli@xxxxxx>
> Cc: Sakari Ailus <sakari.ailus@xxxxxx>
> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> Cc: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> Cc: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> Cc: Hans de Goede hdegoede@xxxxxxxxxx
> Cc: Chris MacGregor chris@xxxxxxxxxxxxx
> Cc: Rob Landley <rob@xxxxxxxxxxx>
> Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxx>
> ---
> Documentation/DocBook/media/v4l/controls.xml | 54 +++++++++++++++++++++++
> drivers/media/v4l2-core/v4l2-ctrls.c | 11 +++++
> include/linux/v4l2-controls.h | 11 +++++
> 3 files changed, 76 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/DocBook/media/v4l/controls.xml
> b/Documentation/DocBook/media/v4l/controls.xml index a84a08c..9bf54f3
> 100644
> --- a/Documentation/DocBook/media/v4l/controls.xml
> +++ b/Documentation/DocBook/media/v4l/controls.xml
> @@ -4277,6 +4277,60 @@ interface and may change in the future.</para>
> specific test patterns can be used to test if a device is working
> properly.</entry>
> </row>
> + <row>
> + <entry spanname="id"><constant>V4L2_CID_GAIN_RED</constant></entry>
> + <entry>integer</entry>
> + </row>
> + <row>
> + <entry
> spanname="id"><constant>V4L2_CID_GAIN_GREEN_RED</constant></entry> +
> <entry>integer</entry>
> + </row>
> + <row>
> + <entry
> spanname="id"><constant>V4L2_CID_GAIN_GREEN_BLUE</constant></entry> +
> <entry>integer</entry>
> + </row>
> + <row>
> + <entry spanname="id"><constant>V4L2_CID_GAIN_BLUE</constant></entry>
> + <entry>integer</entry>
> + </row>
> + <row>
> + <entry spanname="id"><constant>V4L2_CID_GAIN_GREEN</constant></entry>
> + <entry>integer</entry>
> + </row>
> + <row>
> + <entry spanname="descr"> Some capture/sensor devices have
> + the capability to set per color component digital gain
values.</entry>
> + </row>
> + <row>
> + <entry
spanname="id"><constant>V4L2_CID_GAIN_OFFSET</constant></entry>
> + <entry>integer</entry>
> + </row>
> + <row>
> + <entry
spanname="id"><constant>V4L2_CID_BLUE_OFFSET</constant></entry>
> + <entry>integer</entry>
> + </row>
> + <row>
> + <entry spanname="id"><constant>V4L2_CID_RED_OFFSET</constant></entry>
> + <entry>integer</entry>
> + </row>
> + <row>
> + <entry
> spanname="id"><constant>V4L2_CID_GREEN_OFFSET</constant></entry> +
> <entry>integer</entry>
> + </row>
> + <row>
> + <entry
> spanname="id"><constant>V4L2_CID_GREEN_RED_OFFSET</constant></entry> +
> <entry>integer</entry>
> + </row>
> + <row>
> + <entry
> spanname="id"><constant>V4L2_CID_GREEN_BLUE_OFFSET</constant></entry> +
> <entry>integer</entry>
> + </row>
> + <row>
> + <entry spanname="descr"> Some capture/sensor devices have the
> + capability to set per color component digital gain offset values.
> + V4L2_CID_GAIN_OFFSET is the global gain offset and the rest are per
> + color component gain offsets.</entry>
> + </row>
> <row><entry></entry></row>
> </tbody>
> </tgroup>
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c
> b/drivers/media/v4l2-core/v4l2-ctrls.c index 93cd0a4..02cc1d2 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -750,6 +750,17 @@ const char *v4l2_ctrl_get_name(u32 id)
> case V4L2_CID_LINK_FREQ: return "Link Frequency";
> case V4L2_CID_PIXEL_RATE: return "Pixel Rate";
> case V4L2_CID_TEST_PATTERN: return "Test Pattern";
> + case V4L2_CID_GAIN_RED: return "Digital Gain Red";
> + case V4L2_CID_GAIN_GREEN_RED: return "Digital Gain Green Red";
> + case V4L2_CID_GAIN_GREEN_BLUE: return "Digital Gain Green Blue";
> + case V4L2_CID_GAIN_BLUE: return "Digital Gain Blue";
> + case V4L2_CID_GAIN_GREEN: return "Digital Gain Green";
> + case V4L2_CID_GAIN_OFFSET: return "Digital Gain Offset";
> + case V4L2_CID_BLUE_OFFSET: return "Digital Gain Blue Offset";
> + case V4L2_CID_RED_OFFSET: return "Digital Gain Red Offset";
> + case V4L2_CID_GREEN_OFFSET: return "Digital Gain Green Offset";
> + case V4L2_CID_GREEN_RED_OFFSET: return "Digital Gain Green Red
Offset";
> + case V4L2_CID_GREEN_BLUE_OFFSET: return "Digital Gain Green Blue
Offset";

I would remove the mention of "Digital" here, as those controls can be used
for analog gains as well. Same above in the documentation.

> /* DV controls */
> case V4L2_CID_DV_CLASS: return "Digital Video Controls";
> diff --git a/include/linux/v4l2-controls.h b/include/linux/v4l2-controls.h
> index e1b3680..087596d 100644
> --- a/include/linux/v4l2-controls.h
> +++ b/include/linux/v4l2-controls.h
> @@ -758,5 +758,16 @@ enum v4l2_jpeg_chroma_subsampling {
> #define V4L2_CID_LINK_FREQ (V4L2_CID_IMAGE_PROC_CLASS_BASE + 1)
> #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_GAIN_RED (V4L2_CID_IMAGE_PROC_CLASS_BASE + 4)
> +#define V4L2_CID_GAIN_GREEN_RED (V4L2_CID_IMAGE_PROC_CLASS_BASE +
5)
> +#define V4L2_CID_GAIN_GREEN_BLUE (V4L2_CID_IMAGE_PROC_CLASS_BASE + 6)
> +#define V4L2_CID_GAIN_BLUE (V4L2_CID_IMAGE_PROC_CLASS_BASE + 7)
> +#define V4L2_CID_GAIN_GREEN (V4L2_CID_IMAGE_PROC_CLASS_BASE + 8)
> +#define V4L2_CID_GAIN_OFFSET (V4L2_CID_IMAGE_PROC_CLASS_BASE + 9)
> +#define V4L2_CID_BLUE_OFFSET (V4L2_CID_IMAGE_PROC_CLASS_BASE + 10)
> +#define V4L2_CID_RED_OFFSET (V4L2_CID_IMAGE_PROC_CLASS_BASE + 11)
> +#define V4L2_CID_GREEN_OFFSET (V4L2_CID_IMAGE_PROC_CLASS_BASE +
12)
> +#define V4L2_CID_GREEN_RED_OFFSET (V4L2_CID_IMAGE_PROC_CLASS_BASE + 13)
> +#define V4L2_CID_GREEN_BLUE_OFFSET (V4L2_CID_IMAGE_PROC_CLASS_BASE +
14)
>
> #endif
--
Regards,

Laurent Pinchart

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