usb: gadget: uvc: add g_parm and s_parm for frame interval

The uvc gadget driver is lacking the information which frame interval
was set by the host. We add this information by implementing the g_parm
and s_parm callbacks.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v7-4-e224bb1035f0@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 54 insertions, 0 deletions

diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
index 4f44a607d9f5..099038f1088e 100644
--- a/drivers/usb/gadget/function/uvc.h
+++ b/drivers/usb/gadget/function/uvc.h
@@ -105,6 +105,7 @@ struct uvc_video {
 	unsigned int width;
 	unsigned int height;
 	unsigned int imagesize;
+	unsigned int interval;
 	struct mutex mutex;	/* protects frame parameters */
 
 	unsigned int uvc_num_requests;
diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
index 836b91c73f18..a3e2ca315101 100644
--- a/drivers/usb/gadget/function/uvc_v4l2.c
+++ b/drivers/usb/gadget/function/uvc_v4l2.c
@@ -323,6 +323,56 @@ uvc_v4l2_set_format(struct file *file, void *fh, struct v4l2_format *fmt)
 	return ret;
 }
 
+static int uvc_v4l2_g_parm(struct file *file, void *fh,
+			   struct v4l2_streamparm *parm)
+{
+	struct video_device *vdev = video_devdata(file);
+	struct uvc_device *uvc = video_get_drvdata(vdev);
+	struct uvc_video *video = &uvc->video;
+	struct v4l2_fract timeperframe;
+
+	if (!V4L2_TYPE_IS_OUTPUT(parm->type))
+		return -EINVAL;
+
+	/* Return the actual frame period. */
+	timeperframe.numerator = video->interval;
+	timeperframe.denominator = 10000000;
+	v4l2_simplify_fraction(&timeperframe.numerator,
+			       &timeperframe.denominator, 8, 333);
+
+	uvcg_dbg(&uvc->func, "Getting frame interval of %u/%u (%u)\n",
+		 timeperframe.numerator, timeperframe.denominator,
+		 video->interval);
+
+	parm->parm.output.timeperframe = timeperframe;
+	parm->parm.output.capability = V4L2_CAP_TIMEPERFRAME;
+
+	return 0;
+}
+
+static int uvc_v4l2_s_parm(struct file *file, void *fh,
+			   struct v4l2_streamparm *parm)
+{
+	struct video_device *vdev = video_devdata(file);
+	struct uvc_device *uvc = video_get_drvdata(vdev);
+	struct uvc_video *video = &uvc->video;
+	struct v4l2_fract timeperframe;
+
+	if (!V4L2_TYPE_IS_OUTPUT(parm->type))
+		return -EINVAL;
+
+	timeperframe = parm->parm.output.timeperframe;
+
+	video->interval = v4l2_fraction_to_interval(timeperframe.numerator,
+						    timeperframe.denominator);
+
+	uvcg_dbg(&uvc->func, "Setting frame interval to %u/%u (%u)\n",
+		 timeperframe.numerator, timeperframe.denominator,
+		 video->interval);
+
+	return 0;
+}
+
 static int
 uvc_v4l2_enum_frameintervals(struct file *file, void *fh,
 		struct v4l2_frmivalenum *fival)
@@ -596,6 +646,8 @@ const struct v4l2_ioctl_ops uvc_v4l2_ioctl_ops = {
 	.vidioc_dqbuf = uvc_v4l2_dqbuf,
 	.vidioc_streamon = uvc_v4l2_streamon,
 	.vidioc_streamoff = uvc_v4l2_streamoff,
+	.vidioc_s_parm = uvc_v4l2_s_parm,
+	.vidioc_g_parm = uvc_v4l2_g_parm,
 	.vidioc_subscribe_event = uvc_v4l2_subscribe_event,
 	.vidioc_unsubscribe_event = uvc_v4l2_unsubscribe_event,
 	.vidioc_default = uvc_v4l2_ioctl_default,
diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 06055959f716..ee7326029d6f 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -784,6 +784,7 @@ int uvcg_video_init(struct uvc_video *video, struct uvc_device *uvc)
 	video->width = 320;
 	video->height = 240;
 	video->imagesize = 320 * 240 * 2;
+	video->interval = 666666;
 
 	/* Initialize the video buffers queue. */
 	uvcg_queue_init(&video->queue, uvc->v4l2_dev.dev->parent,