[RFC 1/2] [media] dt-bindings: Document BCM283x CSI2/CCP2 receiver

[Stefan Wahren]

Hi Dave,

Am 14.06.2017 um 17:15 schrieb Dave Stevenson:
> Document the DT bindings for the CSI2/CCP2 receiver peripheral
> (known as Unicam) on BCM283x SoCs.
>
> Signed-off-by: Dave Stevenson <dave.stevenson at raspberrypi.org>

please add the devicetree guys in CC for the binding.

> ---
>  .../devicetree/bindings/media/bcm2835-unicam.txt   | 76 ++++++++++++++++++++++
>  1 file changed, 76 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/bcm2835-unicam.txt
>
> diff --git a/Documentation/devicetree/bindings/media/bcm2835-unicam.txt b/Documentation/devicetree/bindings/media/bcm2835-unicam.txt
> new file mode 100644
> index 0000000..cc5a451
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/bcm2835-unicam.txt
> @@ -0,0 +1,76 @@
> +Broadcom BCM283x Camera Interface (Unicam)
> +------------------------------------------
> +
> +The Unicam block on BCM283x SoCs is the receiver for either
> +CSI-2 or CCP2 data from image sensors or similar devices.

It would be nice to add some of your explanations to Hans in this
document or into the driver.

> +
> +Required properties:
> +===================
> +- compatible	: must be "brcm,bcm2835-unicam".
> +- reg		: physical base address and length of the register sets for the
> +		  device.
> +- interrupts	: should contain the IRQ line for this Unicam instance.
> +- clocks	: list of clock specifiers, corresponding to entries in
> +		  clock-names property.
> +- clock-names	: must contain an "lp_clock" entry, matching entries
> +		  in the clocks property.
> +
> +Optional properties
> +===================
> +- max-data-lanes: the hardware can support varying numbers of clock lanes.
> +		  This value is the maximum number supported by this instance.
> +		  Known values of 2 or 4. Default is 2.

AFAIK, this isn't a common property yet. So possibly a vendor prefix
must be added.

> +
> +
> +Unicam supports a single port node. 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:
> +	csi1: csi at 7e801000 {
> +		compatible = "brcm,bcm2835-unicam";
> +		reg = <0x7e801000 0x800>,
> +		      <0x7e802004 0x4>;
> +		interrupts = <2 7>;
> +		clocks = <&clocks BCM2835_CLOCK_CAM1>;
> +		clock-names = "lp_clock";
> +
> +		port {
> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +
> +			endpoint {
> +				remote-endpoint = <&tc358743_0>;
> +
> +			};
> +		};
> +	};
> +
> +	i2c0: i2c at 7e205000 {
> +
> +		tc358743: tc358743 at 0f {

Usually the node name should describe the function of the node for example:

tc358743: csi-hdmi-bridge at 0f

Best regards
Stefan

> +			compatible = "toshiba,tc358743";
> +			reg = <0x0f>;
> +			status = "okay";
> +
> +			clocks = <&tc358743_clk>;
> +			clock-names = "refclk";
> +
> +			tc358743_clk: bridge-clk {
> +				compatible = "fixed-clock";
> +				#clock-cells = <0>;
> +				clock-frequency = <27000000>;
> +			};
> +
> +			port {
> +				tc358743_0: endpoint {
> +					remote-endpoint = <&csi1>;
> +					clock-lanes = <0>;
> +					data-lanes = <1 2 3 4>;
> +					clock-noncontinuous;
> +					link-frequencies =
> +						/bits/ 64 <297000000>;
> +				};
> +			};
> +		};
> +	};