linux-kernel - Re: [PATCH v1 1/3] dt-bindings: Document MIPID02 bindings

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Message-ID: <20190316214649.co63p5arhiwbuv3g@valkosipuli.retiisi.org.uk>
Date:   Sat, 16 Mar 2019 23:46:49 +0200
From:   Sakari Ailus <sakari.ailus@....fi>
To:     Mickael Guene <mickael.guene@...com>
Cc:     linux-media@...r.kernel.org,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>
Subject: Re: [PATCH v1 1/3] dt-bindings: Document MIPID02 bindings

Hi Mickael,

Thanks for the patchset.

On Tue, Mar 12, 2019 at 07:44:03AM +0100, Mickael Guene wrote:
> This adds documentation of device tree for MIPID02 CSI-2 to PARALLEL
> bridge.
> 
> Signed-off-by: Mickael Guene <mickael.guene@...com>
> ---
> 
>  .../bindings/media/i2c/st,st-mipid02.txt           | 69 ++++++++++++++++++++++
>  1 file changed, 69 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/st,st-mipid02.txt
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/st,st-mipid02.txt b/Documentation/devicetree/bindings/media/i2c/st,st-mipid02.txt
> new file mode 100644
> index 0000000..a1855da
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/st,st-mipid02.txt
> @@ -0,0 +1,69 @@
> +STMicroelectronics MIPID02 CSI-2 to PARALLEL bridge
> +
> +MIPID02 has two CSI-2 input ports, only one of those ports can be active at a
> +time. Active port input stream will be de-serialized and its content outputted
> +through PARALLEL output port.
> +CSI-2 first input port is a dual lane 800Mbps whereas CSI-2 second input port is

800 Mbps per lane (or total)?

> +a single lane 800Mbps. Both ports support clock and data lane polarity swap.
> +First port also supports data lane swap.
> +PARALLEL output port has a maximum width of 12 bits.
> +Supported formats are RAW6, RAW7, RAW8, RAW10, RAW12, RGB565, RGB888, RGB444,
> +YUV420 8-bit, YUV422 8-bit and YUV420 10-bit.
> +
> +Required Properties:
> +- compatible: should be "st,st-mipid02"
> +- clocks: reference to the xclk input clock.
> +- clock-names: should be "xclk".
> +- VDDE-supply: sensor digital IO supply. Must be 1.8 volts.
> +- VDDIN-supply: sensor internal regulator supply. Must be 1.8 volts.

Perhaps Rob can confirm, but AFAIR the custom is to use lower case letters.

> +
> +Optional Properties:
> +- reset-gpios: reference to the GPIO connected to the xsdn pin, if any.
> +	       This is an active low signal to the mipid02.
> +
> +Required subnodes:
> +  - ports: A ports node with one port child node per device input and output
> +	   port, in accordance with the video interface bindings defined in
> +	   Documentation/devicetree/bindings/media/video-interfaces.txt. The
> +	   port nodes are numbered as follows:
> +
> +	   Port Description
> +	   -----------------------------
> +	   0    CSI-2 first input port
> +	   1    CSI-2 second input port
> +	   2    PARALLEL output

Please document which endpoint properties are relevant. From the above
description I'd presume this to be at least clock-lanes (1st input),
data-lanes, lane-polarities (for CSI-2) as well as bus-width for the
parallel bus.

> +
> +Example:
> +
> +mipid02: mipid02@14 {

The node should be a generic name. "csi2rx" is used by a few devices now.

> +	compatible = "st,st-mipid02";
> +	reg = <0x14>;
> +	status = "okay";
> +	clocks = <&clk_ext_camera_12>;
> +	clock-names = "xclk";
> +	VDDE-supply = <&vdd>;
> +	VDDIN-supply = <&vdd>;
> +	ports {
> +		#address-cells = <1>;
> +		#size-cells = <0>;
> +		port@0 {
> +			reg = <0>;
> +
> +			ep0: endpoint {
> +				clock-lanes = <0>;
> +				data-lanes = <1 2>;
> +				remote-endpoint = <&mipi_csi2_in>;
> +			};
> +		};
> +		port@2 {
> +			reg = <2>;
> +
> +			ep2: endpoint {
> +				bus-width = <8>;
> +				hsync-active = <0>;
> +				vsync-active = <0>;
> +				remote-endpoint = <&parallel_out>;
> +			};
> +		};
> +	};
> +};

-- 
Kind regards,

Sakari Ailus