media: dt-bindings: media: Add Renesas CEU bindings

Add bindings documentation for Renesas Capture Engine Unit (CEU).
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/devicetree/bindings/media/renesas,ceu.txt

+Renesas Capture Engine Unit (CEU)
+----------------------------------------------
+
+The Capture Engine Unit is the image capture interface found in the Renesas
+SH Mobile and RZ SoCs.
+
+The interface supports a single parallel input with data bus width of 8 or 16
+bits.
+
+Required properties:
+- compatible: Shall be "renesas,r7s72100-ceu" for CEU units found in RZ/A1H
+  and RZ/A1M SoCs.
+- reg: Registers address base and size.
+- interrupts: The interrupt specifier.
+
+The CEU supports a single parallel input and should contain a single 'port'
+subnode with a single 'endpoint'. Connection to input devices are modeled
+according to the video interfaces OF bindings specified in:
+Documentation/devicetree/bindings/media/video-interfaces.txt
+
+Optional endpoint properties applicable to parallel input bus described in
+the above mentioned "video-interfaces.txt" file are supported.
+
+- hsync-active: Active state of the HSYNC signal, 0/1 for LOW/HIGH respectively.
+  If property is not present, default is active high.
+- vsync-active: Active state of the VSYNC signal, 0/1 for LOW/HIGH respectively.
+  If property is not present, default is active high.
+
+Example:
+
+The example describes the connection between the Capture Engine Unit and an
+OV7670 image sensor connected to i2c1 interface.
+
+ceu: ceu@e8210000 {
+	reg = <0xe8210000 0x209c>;
+	compatible = "renesas,r7s72100-ceu";
+	interrupts = <GIC_SPI 332 IRQ_TYPE_LEVEL_HIGH>;
+
+	pinctrl-names = "default";
+	pinctrl-0 = <&vio_pins>;
+
+	status = "okay";
+
+	port {
+		ceu_in: endpoint {
+			remote-endpoint = <&ov7670_out>;
+
+			hsync-active = <1>;
+			vsync-active = <0>;
+		};
+	};
+};
+
+i2c1: i2c@fcfee400 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&i2c1_pins>;
+
+	status = "okay";
+
+	clock-frequency = <100000>;
+
+	ov7670: camera@21 {
+		compatible = "ovti,ov7670";
+		reg = <0x21>;
+
+		pinctrl-names = "default";
+		pinctrl-0 = <&vio_pins>;
+
+		reset-gpios = <&port3 11 GPIO_ACTIVE_LOW>;
+		powerdown-gpios = <&port3 12 GPIO_ACTIVE_HIGH>;
+
+		port {
+			ov7670_out: endpoint {
+				remote-endpoint = <&ceu_in>;
+
+				hsync-active = <1>;
+				vsync-active = <0>;
+			};
+		};
+	};
+};