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

[Dan Scally <dan.scally@ideasonboard.com>]

On 24/03/2023 09:20, Laurent Pinchart wrote:
> 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 :-)


+1 for this vote

>
>> 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,