[media] uvcvideo: Add UVCIOC_CTRL_QUERY ioctl

This ioctl extends UVCIOC_CTRL_GET/SET by not only allowing to get/set
XU controls but to also send arbitrary UVC commands to XU controls,
namely GET_CUR, SET_CUR, GET_MIN, GET_MAX, GET_RES, GET_LEN, GET_INFO
and GET_DEF. This is required for applications to work with XU controls,
so that they can properly query the size and allocate the necessary
buffers.

Signed-off-by: Martin Rubli <martin_rubli@logitech.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 16 insertions, 3 deletions

diff --git a/drivers/media/video/uvc/uvc_v4l2.c b/drivers/media/video/uvc/uvc_v4l2.c
index 9005a8d..7432336 100644
--- a/drivers/media/video/uvc/uvc_v4l2.c
+++ b/drivers/media/video/uvc/uvc_v4l2.c
@@ -1029,10 +1029,23 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 					  cmd == UVCIOC_CTRL_MAP_OLD);
 
 	case UVCIOC_CTRL_GET:
-		return uvc_xu_ctrl_query(chain, arg, 0);
-
 	case UVCIOC_CTRL_SET:
-		return uvc_xu_ctrl_query(chain, arg, 1);
+	{
+		struct uvc_xu_control *xctrl = arg;
+		struct uvc_xu_control_query xqry = {
+			.unit		= xctrl->unit,
+			.selector	= xctrl->selector,
+			.query		= cmd == UVCIOC_CTRL_GET
+					? UVC_GET_CUR : UVC_SET_CUR,
+			.size		= xctrl->size,
+			.data		= xctrl->data,
+		};
+
+		return uvc_xu_ctrl_query(chain, &xqry);
+	}
+
+	case UVCIOC_CTRL_QUERY:
+		return uvc_xu_ctrl_query(chain, arg);
 
 	default:
 		uvc_trace(UVC_TRACE_IOCTL, "Unknown ioctl 0x%08x\n", cmd);