media: imx: capture: Allow event subscribe/unsubscribe

Implement the vidioc_(un)subscribe_event operations. Imx will allow
subscribing to the imx-specific frame interval error events, events
from subdevices (V4L2_EVENT_SOURCE_CHANGE), and control events.
Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/staging/media/imx/imx-media-capture.c

@@ -398,6 +398,21 @@ static int capture_s_parm(struct file *file, void *fh,
 	return 0;
 }
 
+static int capture_subscribe_event(struct v4l2_fh *fh,
+				   const struct v4l2_event_subscription *sub)
+{
+	switch (sub->type) {
+	case V4L2_EVENT_IMX_FRAME_INTERVAL_ERROR:
+		return v4l2_event_subscribe(fh, sub, 0, NULL);
+	case V4L2_EVENT_SOURCE_CHANGE:
+		return v4l2_src_change_event_subscribe(fh, sub);
+	case V4L2_EVENT_CTRL:
+		return v4l2_ctrl_subscribe_event(fh, sub);
+	default:
+		return -EINVAL;
+	}
+}
+
 static const struct v4l2_ioctl_ops capture_ioctl_ops = {
 	.vidioc_querycap	= vidioc_querycap,
 
@@ -427,6 +442,9 @@ static const struct v4l2_ioctl_ops capture_ioctl_ops = {
 	.vidioc_expbuf		= vb2_ioctl_expbuf,
 	.vidioc_streamon	= vb2_ioctl_streamon,
 	.vidioc_streamoff	= vb2_ioctl_streamoff,
+
+	.vidioc_subscribe_event = capture_subscribe_event,
+	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
 };
 
 /*