[media] Documentation: dt: Add binding documentation for S5K6A3 image sensor

Samsung S5K6A3(YX) raw image sensor

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S5K6A3(YX) is a raw image sensor with MIPI CSI-2 and CCP2 image data interfaces

and CCI (I2C compatible) control bus.

Required properties:

- compatible	: "samsung,s5k6a3";

- reg		: I2C slave address of the sensor;

- svdda-supply	: core voltage supply;

- svddio-supply	: I/O voltage supply;

- afvdd-supply	: AF (actuator) voltage supply;

- gpios		: specifier of a GPIO connected to the RESET pin;

- clocks	: should contain list of phandle and clock specifier pairs

		  according to common clock bindings for the clocks described

		  in the clock-names property;

- clock-names	: should contain "extclk" entry for the sensor's EXTCLK clock;

Optional properties:

- clock-frequency : the frequency at which the "extclk" clock should be

		    configured to operate, in Hz; if this property is not

		    specified default 24 MHz value will be used.

The common video interfaces bindings (see video-interfaces.txt) should be

used to specify link to the image data receiver. The S5K6A3(YX) device

node should contain one 'port' child node with an 'endpoint' subnode.

Following properties are valid for the endpoint node:

- data-lanes : (optional) specifies MIPI CSI-2 data lanes as covered in

  video-interfaces.txt.  The sensor supports only one data lane.