Re: [RFC PATCH 0/4] Add some new camera controls

[Sylwester Nawrocki <snjw23@gmail.com>]

Hi everybody,

On 01/04/2012 10:07 PM, Sakari Ailus wrote:
> On Fri, Dec 30, 2011 at 12:18:40PM +0100, Sylwester Nawrocki wrote:
>> Thus we would three levels of controls for camera,
>>   1) image source class (lowest possible level), dealing mostly with hardware
>>      registers;
> 
> I intended the image source class for controls which only deal with the a/d
> conversion itself. Other controls would be elsewhere.
> 
> There hasn't been a final decision on this yet, but an alternative which has
> been also discussed is just to call this a "low level" control class.
> 
>>   2) "normal" camera controls (V4L2_CID_CAMERA_CLASS) [2];
>>   3) high level camera controls (for camera software algorithms)
...
> 
>> I'm afraid a little it might be hard to distinguish if some control should
>> belong to 2) or 3), as sensors' logic complexity and advancement varies.
> 
> I can see two main use cases:
> 
> 1. V4L2 / V4L2 subdev / MC as the low level API for camera control and
> 
> 2. Regular V4L2 applications.
> 
> For most controls it's clear which of the two classes they belong to.

Have you any ideas on what the class' name could be ? I thought about 
V4L2_CTRL_CLASS_HIGH_LEVEL_CAMERA or V4L2_CTRL_CLASS_CAMERA_USER although 
I'm not too happy with any of them and it seems hard to make up some 
reasonable name, when we already have V4L2_CTRL_CLASS_CAMERA.

>> Although I can see an advantage of logically separating controls which have
>> influence on one or more other (lower level) controls. And separate control
>> class would be helpful in that.
>>
>> The candidates to such control class might be:
>>
>> * V4L2_CID_METERING_MODE,
>> * V4L2_CID_EXPOSURE_BIAS,
>> * V4L2_CID_ISO,
>> * V4L2_CID_WHITE_BALANCE_PRESET,
>> * V4L2_CID_SCENEMODE,
>> * V4L2_CID_WDR,
>> * V4L2_CID_ANTISHAKE,
> 
> The list looks good to me.

--

Thanks,
Sylwester