On 05/29/2014 05:01 PM, Laurent Pinchart wrote:
> On Thursday 29 May 2014 17:58:59 Sakari Ailus wrote:
>> Laurent Pinchart wrote:
>>> On Thursday 29 May 2014 17:40:46 Sakari Ailus wrote:
>>>> In many cases the test pattern has selectable values for each colour
>>>> component. Implement controls for raw bayer components. Additional
>>>> controls
>>>> should be defined for colour components that are not covered by these
>>>> controls.
>>>>
>>>> Signed-off-by: Sakari Ailus <sakari.ai...@linux.intel.com>
>>>> ---
>>>>
>>>> Documentation/DocBook/media/v4l/controls.xml | 34 +++++++++++++++++++++
>>>> drivers/media/v4l2-core/v4l2-ctrls.c | 4 ++++
>>>> include/uapi/linux/v4l2-controls.h | 4 ++++
>>>> 3 files changed, 42 insertions(+)
>>>>
>>>> diff --git a/Documentation/DocBook/media/v4l/controls.xml
>>>> b/Documentation/DocBook/media/v4l/controls.xml index 47198ee..bf23994
>>>> 100644
>>>> --- a/Documentation/DocBook/media/v4l/controls.xml
>>>> +++ b/Documentation/DocBook/media/v4l/controls.xml
>>>> @@ -4677,6 +4677,40 @@ interface and may change in the future.</para>
>>>> conversion.
>>>> </entry>
>>>> </row>
>>>> + <row>
>>>> + <entry
>>>> spanname="id"><constant>V4L2_CID_TEST_PATTERN_RED</constant></entry>
>>>> + <entry>integer</entry>
>>>> + </row>
>>>> + <row>
>>>> + <entry spanname="descr">Test pattern red colour component.
>>>> + </entry>
>>>> + </row>
>>>> + <row>
>>>> + <entry
>>>> spanname="id"><constant>V4L2_CID_TEST_PATTERN_GREENR</constant></entry>
>>>> + <entry>integer</entry>
>>>> + </row>
>>>> + <row>
>>>> + <entry spanname="descr">Test pattern green (next to red)
>>>> + colour component.
>>>
>>> What about non-Bayer RGB sensors ? Should they use the GREENR or the
>>> GREENB control for the green component ? Or a different control ?
>>
>> A different one. It should be simply green. I could add it to the same
>> patch if you wish.
>>
>>> I'm wondering whether we shouldn't have a single test pattern color
>>> control and create a color type using Hans' complex controls API.
>>
>> A raw bayer four-pixel value, you mean?
>
> Yes. I'll let Hans comment on that.
>
Why would you need the complex control API for that? It would fit in a s32,
and certainly in a s64.
We have done something similar to this in the past (V4L2_CID_BG_COLOR).
The main problem is that the interpretation of the s32 value has to be
clearly defined. And if different sensors might have different min/max values
for each component, then it becomes messy to use a single control. My feeling
is that it is better to go with separate controls, one for each component.
Regards,
Hans
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