Why no any IMX series product supporting PDM audio microphone?

[mayqueen]

My target Platform is IMX7 and IMXRT1050, both adapted Buildroot, it works very well but audio function is always failed using PDM microphone, it seems very strange when I search no any post or project, it's a good cost down way but why no anyone to do it?

I adapted simple-audio-card driver as following setting:

    sound {
        compatible = "simple-audio-card";
        simple-audio-card,name = "OnboardIM69D130";
        simple-audio-card,format = "pdm";
        simple-audio-card,bitclock-master = <&cpu_dai>;
        simple-audio-card,frame-master = <&cpu_dai>;
        simple-audio-card,widgets =
            "Microphone", "Mic Jack";
        simple-audio-card,routing =
            "MIC_IN", "Mic Jack";

        cpu_dai: simple-audio-card,cpu {
            sound-dai = <&sai1>;
            system-clock-frequency = <2400000>;
            dai-tdm-slot-num = <1>;
            dai-tdm-slot-width = <16>;
        };

        simple-audio-card,codec {
            sound-dai = <&dummy_codec>;
        };
    };

and dmesg has no error but also no generate any ALSA devices, please someone can give me directions, thanks!

Wig

[igorpadykov]

Hi May

i.MX8M Mini supports pdm

software description can be found on

i.MX Software|NXP 

fsl-imx8mq-evk-pdm.dts\freescale\dts\boot\arm64\arch - linux-imx - i.MX Linux kernel 

imx-pdm.c\fsl\soc\sound - linux-imx - i.MX Linux kernel 

Best regards
igor
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