Re: [PATCH RFC v2 2/6] media: v4l2-ctrls: clarify documentation of V4L2_CID_FOCUS_RELATIVE

Laurent Pinchart
2023-06-06T10:37:49Z

Hi Michael,

Thank you for the patch.

On Tue, Apr 25, 2023 at 11:45:12AM +0200, Michael Riesch wrote:
> The control V4L2_CID_FOCUS_RELATIVE only makes sense if the device cannot
> handle absolute focal point positioning with V4L2_CID_FOCUS_ABSOLUTE.
> Clarify this in the documentation.
>
> Signed-off-by: Michael Riesch <michael.riesch@wolfvision.net>
> ---
> Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> index df29150dce7b..42cf4c3cda0c 100644
> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst
> @@ -147,7 +147,9 @@ enum v4l2_exposure_metering -
> This control moves the focal point of the camera by the specified
> amount. The unit is undefined. Positive values move the focus closer
> to the camera, negative values towards infinity. This is a
> - write-only control.
> + write-only control. It should be implemented only if the device cannot
> + handle absolute values.
> +

Extra blank line.

I don't think this is right. The control was added for the UVC driver,
and there are devices that implement both absolute and relative focus.

>
> ``V4L2_CID_FOCUS_AUTO (boolean)``
> Enables continuous automatic focus adjustments. The effect of manual
>

--
Regards,

Laurent Pinchart