dt-bindings: usb: hd3ss3220 device tree binding document

Add device tree binding document for TI HD3SS3220 Type-C DRP port
controller driver.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1567584941-13690-2-git-send-email-biju.das@bp.renesas.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/ti,hd3ss3220.txt

+TI HD3SS3220 TypeC DRP Port Controller.
+
+Required properties:
+ - compatible: Must be "ti,hd3ss3220".
+ - reg: I2C slave address, must be 0x47 or 0x67 based on ADDR pin.
+ - interrupts: An interrupt specifier.
+
+Required sub-node:
+ - connector: The "usb-c-connector" attached to the hd3ss3220 chip. The
+   bindings of the connector node are specified in:
+
+	Documentation/devicetree/bindings/connector/usb-connector.txt
+
+Example:
+hd3ss3220@47 {
+	compatible = "ti,hd3ss3220";
+	reg = <0x47>;
+	interrupt-parent = <&gpio6>;
+	interrupts = <3 IRQ_TYPE_LEVEL_LOW>;
+
+	connector {
+		compatible = "usb-c-connector";
+		label = "USB-C";
+		data-role = "dual";
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@1 {
+				reg = <1>;
+				hd3ss3220_ep: endpoint {
+					remote-endpoint = <&usb3_role_switch>;
+				};
+			};
+		};
+	};
+};