Hi,
I'm Bortoluzzi Daniele, and I'm developing, for my master's thesis with University of Turin, a project using platformio and zephyr, helped by my thesis advisor and co-supervisor.

I would like to use the microphone (MP34DT01) of the B-L475E-IOT01A (ST Discovery kit IoT node) in a zephyr project. This mcu is supported by zephyr, but the .dts file doesn't configure the interface used by mic.

According with the hardware specs [1], I tried to start from zephyr example using st_mpxxdtyy driver [2] and configure:

- prj.conf:

CONFIG_AUDIO=y
CONFIG_AUDIO_DMIC=y
CONFIG_AUDIO_MPXXDTYY=y

- app.overlay:

&XXXX {
     status = "okay";
     pinctrl-0 = <&YYYY &ZZZZ>;
     pinctrl-names = "default";

     mp34dt01: mp34dt01@0 {
            compatible = "st,mpxxdtyy";
            reg = <0>;
            label = "MP34DT01";
     };
};

According with the specs [1] and analyzing the ST function pack FP-AI-SENSING1 [4], we think we should use:
- DFSDM1_CKOUT —» pin PE9
- DFSDM1_DATIN2 —» pin PE7
but we don't know how to write the DTS file.

In particular, about the app.overlay, we are not sure:
- which interface to use (XXXX field)
- which pin variables to use (YYYY, ZZZZ fields).

Could you please help us?

Thank you very much for your support.

Daniele

Some infos:

- Zephyr version: 2.7.0
- Sources:
[1] https://www.digikey.com/htmldatasheets/production/2263149/0/0/1/b-l475e-iot01a-user-manual.html : electric schema of the iot node
[2] https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/shields/x_nucleo_iks02a1/microphone : st mpxxdtyy example project
[3] https://github.com/zephyrproject-rtos/zephyr/blob/main/boards/arm/96b_argonkey/96b_argonkey.dts : similar dtsi (MP34DT05 module)
[4] https://www.st.com/content/st_com/en/products/embedded-software/mcu-mpu-embedded-software/stm32-embedded-software/stm32-ode-function-pack-sw/fp-ai-sensing1.html : ST FP-AI-SENSING1