[Custom Board] CC-WST-J17D-NK – MEMS microphones not working: no clock generated, empty recording (DTS/Yocto)

Embedded Devices Linux
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1

Hi,

I developed a custom board for a CC-WST-J17D-NK module. Everything works fine except for the MEMS microphones.

I connected two microphones (CMM-4030DT-261280-TR) to the module: CLOCK to D1 and DATA to D0 (configured using the Digi ConnectCore Smart IOmux tool). One is configured as right channel and the second as left channel.

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My difficulty is configuring the DTS file for Yocto:

/ {

dummy_codec_mic: dummy-codec-mic {

    compatible = "linux,snd-soc-dummy";

    #sound-dai-cells = <0>;

};



sound_mic: sound-mic {

    compatible = "simple-audio-card";

    simple-audio-card,name = "SAI1A-Mic-Stereo";

    simple-audio-card,format = "pdm";



    sai1a_cpu: simple-audio-card,cpu {

        sound-dai = <&sai1a>;

    };



    simple-audio-card,codec {

        sound-dai = <&dummy_codec_mic>;

    };

};

};

&sai1 {

pinctrl-names = "default", "sleep";

pinctrl-0 = <&ccmp25_sai1_pins>;

pinctrl-1 = <&ccmp25_sai1_sleep_pins>;

status = "okay";



sai1a: audio-controller@4400b004 {

    dma-names = "rx";                   /\* capture uniquement \*/

    status = "okay";



    sai1a_port: port {

        sai1a_endpoint: endpoint {

            format = "pdm";

        };

    };

};

};

&pinctrl {

ccmp25_sai1_pins: ccmp25-sai1 {

    pins {

        pinmux = <STM32_PINMUX('D',  0,  AF6)>, /\* SAI1_D1 \*/

                 <STM32_PINMUX('D',  1,  AF6)>; /\* SAI1_CK2 \*/

        drive-push-pull;

        bias-disable;

        slew-rate = <1>;

    };

};



ccmp25_sai1_sleep_pins: ccmp25-sai1-sleep {

    pins {

        pinmux = <STM32_PINMUX('D',  0, ANALOG)>, /\* SAI1_D1 \*/

                 <STM32_PINMUX('D',  1, ANALOG)>; /\* SAI1_CK2 \*/

    };

};

};

under Linux I can see the sound card, but when I perform a recording it is empty and no clock is generated (verified with an oscilloscope).

If someone could help me debug this, I would appreciate it.

Thank you in advance.