Re: [PATCH 3/8] usb: gadget: uvc: implement s/g_output ioctl

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Michael,

(CC'ing Hans)

Thank you for the patch.

On Thu, Mar 23, 2023 at 12:41:11PM +0100, Michael Tretter wrote:
> V4L2 OUTPUT devices should implement ENUM_OUTPUT, G_OUTPUT, and
> S_OUTPUT. The UVC gadget provides only a single output. Therefore, allow
> only a single output 0.
> 
> According to the documentation, "_TYPE_ANALOG" is historical and should
> be read as "_TYPE_VIDEO".

I think v4l2-compliance should be fixed to not require those ioctls. As
this patch clearly shows, they're useless :-)

> Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
> ---
>  drivers/usb/gadget/function/uvc_v4l2.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
> index 13c7ba06f994..4b8bf94e06fc 100644
> --- a/drivers/usb/gadget/function/uvc_v4l2.c
> +++ b/drivers/usb/gadget/function/uvc_v4l2.c
> @@ -377,6 +377,31 @@ uvc_v4l2_enum_format(struct file *file, void *fh, struct v4l2_fmtdesc *f)
>  	return 0;
>  }
>  
> +static int
> +uvc_v4l2_enum_output(struct file *file, void *priv_fh, struct v4l2_output *out)
> +{
> +	if (out->index != 0)
> +		return -EINVAL;
> +
> +	out->type = V4L2_OUTPUT_TYPE_ANALOG;
> +	snprintf(out->name, sizeof(out->name), "UVC");
> +
> +	return 0;
> +}
> +
> +static int
> +uvc_v4l2_g_output(struct file *file, void *priv_fh, unsigned int *i)
> +{
> +	*i = 0;
> +	return 0;
> +}
> +
> +static int
> +uvc_v4l2_s_output(struct file *file, void *priv_fh, unsigned int i)
> +{
> +	return i ? -EINVAL : 0;
> +}
> +
>  static int
>  uvc_v4l2_reqbufs(struct file *file, void *fh, struct v4l2_requestbuffers *b)
>  {
> @@ -547,6 +572,9 @@ const struct v4l2_ioctl_ops uvc_v4l2_ioctl_ops = {
>  	.vidioc_enum_frameintervals = uvc_v4l2_enum_frameintervals,
>  	.vidioc_enum_framesizes = uvc_v4l2_enum_framesizes,
>  	.vidioc_enum_fmt_vid_out = uvc_v4l2_enum_format,
> +	.vidioc_enum_output = uvc_v4l2_enum_output,
> +	.vidioc_g_output = uvc_v4l2_g_output,
> +	.vidioc_s_output = uvc_v4l2_s_output,
>  	.vidioc_reqbufs = uvc_v4l2_reqbufs,
>  	.vidioc_querybuf = uvc_v4l2_querybuf,
>  	.vidioc_qbuf = uvc_v4l2_qbuf,

-- 
Regards,

Laurent Pinchart