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

Hello Hans,

On Mon, 5 Feb 2018, Hans Verkuil wrote:

On 02/05/2018 03:29 PM, Florian Echtler wrote:

quoted

+
+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?

Best regards, Florian
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