[media] dt-bindings: Document STM32 DCMI bindings

STMicroelectronics STM32 Digital Camera Memory Interface (DCMI)

Required properties:

- compatible: "st,stm32-dcmi"

- reg: physical base address and length of the registers set for the device

- interrupts: should contain IRQ line for the DCMI

- resets: reference to a reset controller,

          see Documentation/devicetree/bindings/reset/st,stm32-rcc.txt

- clocks: list of clock specifiers, corresponding to entries in

          the clock-names property

- clock-names: must contain "mclk", which is the DCMI peripherial clock

- pinctrl: the pincontrol settings to configure muxing properly

           for pins that connect to DCMI device.

           See Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt.

- dmas: phandle to DMA controller node,

        see Documentation/devicetree/bindings/dma/stm32-dma.txt

- dma-names: must contain "tx", which is the transmit channel from DCMI to DMA

DCMI supports a single port node with parallel bus. It should contain one

'port' child node with child 'endpoint' node. Please refer to the bindings

defined in Documentation/devicetree/bindings/media/video-interfaces.txt.

Example:

	dcmi: dcmi@50050000 {

		compatible = "st,stm32-dcmi";

		reg = <0x50050000 0x400>;

		interrupts = <78>;

		resets = <&rcc STM32F4_AHB2_RESET(DCMI)>;

		clocks = <&rcc 0 STM32F4_AHB2_CLOCK(DCMI)>;

		clock-names = "mclk";

		pinctrl-names = "default";

		pinctrl-0 = <&dcmi_pins>;

		dmas = <&dma2 1 1 0x414 0x3>;

		dma-names = "tx";

		port {

			dcmi_0: endpoint {

				remote-endpoint = <...>;

				bus-width = <8>;

				hsync-active = <0>;

				vsync-active = <0>;

				pclk-sample = <1>;

			};

		};

	};