[PATCH v4 5/6] dt-bindings: display: sii902x: Add HDMI audio bindings

[Laurent Pinchart]

Hi Jyri,

Thank you for the patch.

On Thu, Mar 14, 2019 at 01:27:51PM +0200, Jyri Sarha wrote:
> The sii902x chip family supports also HDMI audio. Add binding for
> describing the necessary i2s and mclk wiring for it.
> 
> Signed-off-by: Jyri Sarha <jsarha at ti.com>
> ---
>  .../bindings/display/bridge/sii902x.txt       | 33 +++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/bridge/sii902x.txt b/Documentation/devicetree/bindings/display/bridge/sii902x.txt
> index c4c1855ca654..1a37bbe7c597 100644
> --- a/Documentation/devicetree/bindings/display/bridge/sii902x.txt
> +++ b/Documentation/devicetree/bindings/display/bridge/sii902x.txt
> @@ -9,6 +9,33 @@ Optional properties:
>  	  about hotplug events.
>  	- reset-gpios: OF device-tree gpio specification for RST_N pin.
>  
> +	HDMI audio properties:
> +	- i2s-data-lanes: Array of up to 4 integers with values of 0-3
> +	   Each integer indicates which i2s pin is connected to which
> +	   audio fifo. The first integer selects i2s audio pin for the
> +	   first audio fifo#0 (HDMI channels 1&2), second for fifo#1
> +	   (HDMI channels 3&4), and so on. There is 4 fifos and 4 i2s
> +	   pins (SD0 - SD3). Any i2s pin can be connected to any fifo,
> +	   but there can be no gaps. E.g. an i2s pin must be mapped to
> +	   fifo#0 and fifo#1 before mapping a channel to fifo#2.
> +	   I2S HDMI audio is configured only if this property is found.

This looks good to me, but shouldn't the property be defined somewhere
in Documentation/devicetree/bindings/sound/ ? The sound bindings seem to
be a bit messy though, with little common or high-level documentation,
so I don't want to ask you to fix all that :-) Maybe just adding a
common-i2s.txt file there would be enough ? 

Apart from this the rest looks good to me, but I'd appreciate if it
could be reviewed by audio people.

> +	- clocks: phandle and clock specifier for each clock listed in
> +          the clock-names property
> +	- clock-names: "mclk"
> +	    Describes SII902x MCLK input. MCLK is used to produce
> +	    HDMI audio CTS values. This property is required if
> +	    "i2s-data-lanes"-property is present. This property follows
> +	    Documentation/devicetree/bindings/clock/clock-bindings.txt
> +	    consumer binding.
> +
> +	If HDMI audio is configured the sii902x device becomes an ASoC
> +	codec component, that can be used in configuring full audio
> +	devices with ASoC simple-card or audio-graph-card. See their
> +	binding documents on how to describe how the sii902x device is
> +	connected to the rest of the audio system:
> +	Documentation/devicetree/bindings/sound/simple-card.txt
> +	Documentation/devicetree/bindings/sound/audio-graph-card.txt
> +
>  Optional subnodes:
>  	- video input: this subnode can contain a video input port node
>  	  to connect the bridge to a display controller output (See this
> @@ -21,6 +48,12 @@ Example:
>  		compatible = "sil,sii9022";
>  		reg = <0x39>;
>  		reset-gpios = <&pioA 1 0>;
> +
> +		#sound-dai-cells = <0>;
> +		i2s-data-lanes = < 0 1 2 >;
> +		clocks = <&mclk>;
> +		clock-names = "mclk";
> +
>  		ports {
>  			#address-cells = <1>;
>  			#size-cells = <0>;

-- 
Regards,

Laurent Pinchart