[media] v4l subdev: add dispatching for VIDIOC_DBG_G_REGISTER and VIDIOC_DBG_S_REGISTER

Ioctls on the subdevs node currently don't dispatch the register access debug
driver callbacks. Add the dispatching with the same security checks are for
non subdev video nodes (i.e. only capable(CAP_SYS_ADMIN may call the register
access ioctls).

Signed-off-by: Martin Hostettler <martin@neutronstar.dyndns.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/v4l2-subdev.c

@@ -173,6 +173,25 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 
 	case VIDIOC_UNSUBSCRIBE_EVENT:
 		return v4l2_subdev_call(sd, core, unsubscribe_event, vfh, arg);
+
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+	case VIDIOC_DBG_G_REGISTER:
+	{
+		struct v4l2_dbg_register *p = arg;
+
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		return v4l2_subdev_call(sd, core, g_register, p);
+	}
+	case VIDIOC_DBG_S_REGISTER:
+	{
+		struct v4l2_dbg_register *p = arg;
+
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		return v4l2_subdev_call(sd, core, s_register, p);
+	}
+#endif
 #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
 	case VIDIOC_SUBDEV_G_FMT: {
 		struct v4l2_subdev_format *format = arg;