[alsa-devel] [PATCH v3 1/3] dt-bindings: Document STM32 I2S bindings

[Rob Herring]

On Thu, May 11, 2017 at 11:45:02AM +0200, olivier moysan wrote:
> Add documentation of device tree bindings for STM32 SPI/I2S.
> 
> Signed-off-by: olivier moysan <olivier.moysan at st.com>
> ---
>  .../devicetree/bindings/sound/st,stm32-i2s.txt     | 68 ++++++++++++++++++++++
>  1 file changed, 68 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/sound/st,stm32-i2s.txt
> 
> diff --git a/Documentation/devicetree/bindings/sound/st,stm32-i2s.txt b/Documentation/devicetree/bindings/sound/st,stm32-i2s.txt
> new file mode 100644
> index 0000000..67b854a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sound/st,stm32-i2s.txt
> @@ -0,0 +1,68 @@
> +STMicroelectronics STM32 SPI/I2S Controller
> +
> +The SPI/I2S block supports I2S/PCM protocols when configured on I2S mode.
> +Only some SPI instances support I2S.
> +
> +Required properties:
> +  - compatible: Must be "st,stm32h7-i2s"
> +  - reg: Offset and length of the device's register set.
> +  - interrupts: Must contain the interrupt line id.
> +  - clocks: Must contain phandle and clock specifier pairs for each entry
> +	in clock-names.
> +  - clock-names: Must contain "i2sclk", "pclk", "x8k" and "x11k".
> +	"i2sclk": clock which feeds the internal clock generator
> +	"pclk": clock which feeds the peripheral bus interface
> +	"x8k": I2S parent clock for sampling rates multiple of 8kHz.
> +	"x11k": I2S parent clock for sampling rates multiple of 11.025kHz.
> +  - dmas: DMA specifiers for tx and rx dma.
> +    See Documentation/devicetree/bindings/dma/stm32-dma.txt.
> +  - dma-names: Identifier for each DMA request line. Must be "tx" and "rx".
> +  - pinctrl-names: should contain only value "default"
> +  - pinctrl-0: see Documentation/devicetree/bindings/pinctrl/pinctrl-stm32.txt
> +
> +Optional properties:
> +  - resets: Reference to a reset controller asserting the reset controller
> +
> +The device node should contain one 'port' child node with one child 'endpoint'
> +node, according to the bindings defined in Documentation/devicetree/bindings/
> +graph.txt.
> +
> +Example:
> +sound_card {
> +	compatible = "audio-graph-card";
> +	dais = <&i2s2_port 0>;

What is the 0 representing?

> +};
> +
> +i2s2: audio-controller at 40003800 {
> +	compatible = "st,stm32h7-i2s";
> +	#sound-dai-cells = <0>;

Should be dropped.

> +	reg = <0x40003800 0x400>;
> +	interrupts = <36>;
> +	clocks = <&rcc PCLK1>, <&rcc SPI2_CK>, <&rcc PLL1_Q>, <&rcc PLL2_P>;
> +	clock-names = "pclk", "i2sclk",  "x8k", "x11k";
> +	dmas = <&dmamux2 2 39 0x400 0x1>,
> +           <&dmamux2 3 40 0x400 0x1>;
> +	dma-names = "rx", "tx";
> +	pinctrl-names = "default";
> +	pinctrl-0 = <&pinctrl_i2s2>;
> +
> +	i2s2_port: port at 0 {
> +		#address-cells = <1>;
> +		#size-cells = <0>;

This shouldn't even compile. You don't need these because because you 
have no reg property in the endpoint. 

You have a unit-address here w/o a reg property. You don't need a reg 
prop because you only have 1 port.

> +
> +		cpu_endpoint: endpoint {
> +			remote-endpoint = <&codec_endpoint>;
> +			format = "i2s";
> +			bitclock-master = <&codec_endpoint>;
> +			frame-master = <&codec_endpoint>;
> +		};
> +	};
> +};
> +
> +audio-codec {
> +		codec_port: port at 0 {
> +			codec_endpoint: endpoint {
> +				remote-endpoint = <&cpu_endpoint>;
> +		};
> +	};
> +};
> -- 
> 1.9.1
>