Re: [PATCH] ARM: dts: stm32: add audio codec support on stm32mp157a-dk1 board

[Olivier MOYSAN <olivier.moysan@st.com>]

On 7/24/19 6:40 PM, Alexandre Torgue wrote:
> Hi Olivier
> 
> On 7/5/19 1:53 PM, Olivier Moysan wrote:
>> Add support of Cirrus cs42l51 audio codec on stm32mp157a-dk1 board.
>> Configuration overview:
>> - SAI2A is the CPU interface used for the codec audio playback
>> - SAI2B is the CPU interface used for the codec audio record
>> - SAI2A is configured as a clock provider for the audio codec
>> - SAI2A&B are configured as slave of the audio codec
>> - SAI2A&B share the same interface of the audio codec
>>
>> Note:
>> In master mode, cs42l51 audio codec provides a bitclock
>> at 64 x FS, regardless of data width. This means that
>> slot width is always 32 bits.
>> Set slot width to 32 bits and slot number to 2
>> in SAI2A&B endpoint nodes, to match this constraint.
>> dai-tdm-slot-num and dai-tdm-slot-width properties are used here,
>> assuming that i2s is a special case of tdm, where slot number is 2.
>>
>> Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
>> ---
>>    arch/arm/boot/dts/stm32mp157a-dk1.dts | 89 +++++++++++++++++++++++++++++++++++
>>    1 file changed, 89 insertions(+)
>>
> 
> ...
> 
>>    
>> +&sai2 {
>> +	clocks = <&rcc SAI2>, <&rcc PLL3_Q>, <&rcc PLL3_R>;
>> +	clock-names = "pclk", "x8k", "x11k";
>> +	pinctrl-names = "default", "sleep";
>> +	pinctrl-0 = <&sai2a_pins_a>, <&sai2b_pins_b>;
>> +	pinctrl-1 = <&sai2a_sleep_pins_a>, <&sai2b_sleep_pins_b>;
>> +	status = "okay";
>> +
>> +	sai2a: audio-controller@4400b004 {
>> +		#clock-cells = <0>;
>> +		dma-names = "tx";
>> +		clocks = <&rcc SAI2_K>;
>> +		clock-names = "sai_ck";
>> +		status = "okay";
>> +
>> +		sai2a_port: port {
>> +			sai2a_endpoint: endpoint {
>> +				remote-endpoint = <&cs42l51_tx_endpoint>;
>> +				format = "i2s";
>> +				mclk-fs = <256>;
>> +				dai-tdm-slot-num = <2>;
>> +				dai-tdm-slot-width = <32>;
>> +			};
>> +		};
>> +	};
>> +
> You could use label to overload sai2a and sai2b. no ?
I propose to keep it unchanged for better readability
> 
>> +	sai2b: audio-controller@4400b024 {
>> +		dma-names = "rx";
>> +		st,sync = <&sai2a 2>;
>> +		clocks = <&rcc SAI2_K>, <&sai2a>;
>> +		clock-names = "sai_ck", "MCLK";
>> +		status = "okay";
>> +
>> +		sai2b_port: port {
>> +			sai2b_endpoint: endpoint {
>> +				remote-endpoint = <&cs42l51_rx_endpoint>;
>> +				format = "i2s";
>> +				mclk-fs = <256>;
>> +				dai-tdm-slot-num = <2>;
>> +				dai-tdm-slot-width = <32>;
>> +			};
>> +		};
>> +	};
>> +};
>> +
>>    &sdmmc1 {
>>    	pinctrl-names = "default", "opendrain", "sleep";
>>    	pinctrl-0 = <&sdmmc1_b4_pins_a>;
>>