stm32mp1 sai synchronous slave

[jacob-sorber]

Hi

I have stm32mp157c in my custom board i connect sai2 to codec(tlv320aic), i config sai2a as master (WITHOUT MASTER CLK OUTPUT) and sai2b as synchronous slave, mclk for codec come from rcc mco1 and this is my dts:

sound {

// compatible = "audio-graph-card", "simple-audio-card";

compatible = "audio-graph-card";

label = "AUDIOcard1";

routing =

"Playback" , "MCLK",

"Capture" , "MCLK";

dais = <&sai2a_port &sai2b_port>;

status = "okay";

};

sai2a:audio-controller@4400b004{

status = "okay";

/* USER CODE BEGIN sai2a */

dma-names = "tx";

// #clock-cells = <0>;

clocks = <&rcc SAI2_K>;

clock-names = "sai_ck";

frame-master;

bitclock-master;

sai2a_port: port {

sai2a_endpoint: endpoint {

remote-endpoint = <&tlv320_tx_endpoint>;

format = "i2s";

};

};

/* USER CODE END sai2a */

};

sai2b:audio-controller@4400b024{

status = "okay";

/* USER CODE BEGIN sai2b */

dma-names = "rx";

st,sync = <&sai2a 2>; /* Set SAI2B as slave of SAI2A. */

clocks = <&rcc SAI2_K>, <&sai2a>;

clock-names = "sai_ck", "NCLK";

sai2b_port: port {

sai2b_endpoint: endpoint {

remote-endpoint = <&tlv320_rx_endpoint>;

format = "i2s";

};

};

codec: tlv320aic32x4@18 {

compatible = "ti,tlv320aic32x4";

reg = <0x18>;

clocks = <&rcc CK_MCO1>;

clock-names = "MCLK";

ldoin-supply = <&v3v3>;

reset-gpios = <&gpioi 0 GPIO_ACTIVE_LOW>;

#sound-dai-cells = <0>;

status = "okay";

port {

#address-cells = <1>;

#size-cells = <0>;

tlv320_tx_endpoint: endpoint@0 {

reg = <0>;

remote-endpoint = <&sai2a_endpoint>;

};

tlv320_rx_endpoint: endpoint@1 {

reg = <1>;

remote-endpoint = <&sai2b_endpoint>;

};

};

now my tx path is ok and i can play sound but rx path for capture has some issue when run arecord
board ># arecord -D hw:0,1 -f S16_LE -c 2 -r 44100 -d 5 test.wav
arecord: pcm_read:2151: read error: Input/output error

i see in rx path bitclock and word clock desn't generate (from stm32mp1)

how should i config dts for this situation that can have sai2a as master WITHOUT MASTER CLOCK OUT and sai2b as synchronous slave

i read this thread:

https://www.st.com/resource/en/product_training/STM32MP1-Peripheral_Serial_Audio_Interface_SAI.pdf

https://wiki.st.com/stm32mpu/wiki/SAI_device_tree_configuration

https://wiki.st.com/stm32mpu/wiki/Soundcard_configuration#Wolfson_wm8994_output_configuration

[Christophe Guibout]

Hello @jacob-sorber,

According to my understanding of your DT, SAI provides FS and SCK, but not MCLK, which is provided by mco1 to the codec : I'am not sure we can consider SAI as master.

I would recommand to move frame-master and bitclock-master under the codec so it is fully master, and keep sai2b as slave of sai2a.

BR,

Christophe

[jacob-sorber]

Hi 
I have to use stm32mp1 as (sai2) as master beacause if set codec (tlv320)  as master it need a clock (MCLK) with special frequency that mco1 can't reproduce, (its (tlv320) drvier force mco1 to reproduce a clk and stm32mp1 mco1 can't be set to that value so mp1 hangs)

also in stm32h7 I  use this codec (tlv320) and connect sai2 and sai is master in tx and rx path  and everything is OK in capture and playback (but in baremetal)