dt-bindings: tc358767: add DT documentation

Add DT binding documentation for the Toshiba TC358767 eDP bridge.
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Archit Taneja <architt@codeaurora.org>

Documentation/devicetree/bindings/display/bridge/toshiba,tc358767.txt

+Toshiba TC358767 eDP bridge bindings
+
+Required properties:
+ - compatible: "toshiba,tc358767"
+ - reg: i2c address of the bridge, 0x68 or 0x0f, depending on bootstrap pins
+ - clock-names: should be "ref"
+ - clocks: OF device-tree clock specification for refclk input. The reference
+   clock rate must be 13 MHz, 19.2 MHz, 26 MHz, or 38.4 MHz.
+
+Optional properties:
+ - shutdown-gpios: OF device-tree gpio specification for SD pin
+                   (active high shutdown input)
+ - reset-gpios: OF device-tree gpio specification for RSTX pin
+                (active low system reset)
+ - ports: the ports node can contain video interface port nodes to connect
+   to a DPI/DSI source and to an eDP/DP sink according to [1][2]:
+    - port@0: DSI input port
+    - port@1: DPI input port
+    - port@2: eDP/DP output port
+
+[1]: Documentation/devicetree/bindings/graph.txt
+[2]: Documentation/devicetree/bindings/media/video-interfaces.txt
+
+Example:
+	edp-bridge@68 {
+		compatible = "toshiba,tc358767";
+		reg = <0x68>;
+		shutdown-gpios = <&gpio3 23 GPIO_ACTIVE_HIGH>;
+		reset-gpios = <&gpio3 24 GPIO_ACTIVE_LOW>;
+		clock-names = "ref";
+		clocks = <&edp_refclk>;
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@1 {
+				reg = <1>;
+
+				bridge_in: endpoint {
+					remote-endpoint = <&dpi_out>;
+				};
+			};
+
+			port@2 {
+				reg = <2>;
+
+				bridge_out: endpoint {
+					remote-endpoint = <&panel_in>;
+				};
+			};
+		};
+	};