media: add V4L2_SUBDEV_CAP_STREAMS

Add a subdev capability flag to expose to userspace if a subdev supports
multiplexed streams.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/v4l2-core/v4l2-subdev.c

@@ -446,6 +446,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
 	struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
 	struct v4l2_fh *vfh = file->private_data;
 	bool ro_subdev = test_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
+	bool streams_subdev = sd->flags & V4L2_SUBDEV_FL_STREAMS;
 	int rval;
 
 	switch (cmd) {
@@ -454,7 +455,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
 
 		memset(cap->reserved, 0, sizeof(cap->reserved));
 		cap->version = LINUX_VERSION_CODE;
-		cap->capabilities = ro_subdev ? V4L2_SUBDEV_CAP_RO_SUBDEV : 0;
+		cap->capabilities =
+			(ro_subdev ? V4L2_SUBDEV_CAP_RO_SUBDEV : 0) |
+			(streams_subdev ? V4L2_SUBDEV_CAP_STREAMS : 0);
 
 		return 0;
 	}

include/uapi/linux/v4l2-subdev.h

@@ -175,6 +175,9 @@ struct v4l2_subdev_capability {
 /* The v4l2 sub-device video device node is registered in read-only mode. */
 #define V4L2_SUBDEV_CAP_RO_SUBDEV		0x00000001
 
+/* The v4l2 sub-device supports routing and multiplexed streams. */
+#define V4L2_SUBDEV_CAP_STREAMS			0x00000002
+
 /* Backwards compatibility define --- to be removed */
 #define v4l2_subdev_edid v4l2_edid