new file mode 100644
@@ -0,0 +1,19 @@
+Rockchip DRM master device
+================================
+
+The Rockchip DRM master device is a virtual device needed to list all
+vop devices or other display interface nodes that comprise the
+graphics subsystem.
+
+Required properties:
+- compatible: Should be "rockchip,display-subsystem"
+- ports: Should contain a list of phandles pointing to display interface port
+ of vop devices. vop definitions as defined in
+ Documentation/devicetree/bindings/video/rockchip-vop.txt
+
+example:
+
+display-subsystem {
+ compatible = "rockchip,display-subsystem";
+ ports = <&vopl_out>, <&vopb_out>;
+};