Re: [PATCH 4/5] add V4L2 control functions

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On 02/05/2018 10:36 PM, Florian Echtler wrote:
> Hello Hans,
> 
> On Mon, 5 Feb 2018, Hans Verkuil wrote:
>> On 02/05/2018 03:29 PM, Florian Echtler wrote:
>>> +
>>> +static int sur40_vidioc_queryctrl(struct file *file, void *fh,
>>> +			       struct v4l2_queryctrl *qc)
>>
>> Sorry, but this is very wrong. Use the control framework instead. See
>> https://hverkuil.home.xs4all.nl/spec/kapi/v4l2-controls.html and pretty much all
>> media drivers (with the exception of uvc). See for example this driver:
>> drivers/media/pci/tw68/tw68-video.c (randomly chosen).
>>
>> It actually makes life a lot easier for you as you don't have to perform any
>> range checks and all control ioctls are automatically supported for you.
> 
> thanks for the quick reply, I wasn't aware of that framework at all :-) 
> Will certainly use it.
> 
> What's the earliest kernel version this is supported on, in case we want 
> to backport this for our standalone module, too?

Initial commit was in August 2010, so it's been around for quite some time :-)

Regards,

	Hans



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