DMIC

DMIC

First of all, according to the selected GPIO of 87-89, in SSD201HWCheckListV6.xlsx, we can see that the mode value is 2.

Therefore, modify the DTS Sound node and set the value of digmic-padmux to 2 according to the selected pins:

        sound {
            compatible = "sstar,audio";
//          reg = <0x1F000000 0x1000000>;
            interrupts=<GIC_SPI INT_IRQ_BACH IRQ_TYPE_LEVEL_HIGH>;
            playback-volume-level=<64>;    //0~94
            capture-volume-level=<64>;
           // micin-pregain-level=<1>;    //0~3
            micin-pregain-level=<0>;    //0~3
            micin-gain-level=<3>;    //0~7
            linein-gain-level=<2>;  //0~7
            amp-gpio = <PAD_FUART_RX 1>;
            clocks = <&CLK_upll_384m>;
           // playback-dma-buffer=<98304>; //512(ms)*48(kHz)*2(ch)*2(16bits)
           // capture-dma-buffer=<122880>; //640(ms)*48(kHz)*2(ch)*2(16bits)
            digmic-padmux = <2>;
            i2s-padmux = <2>;
            keep-i2s-clk = <0>;
            status = "ok";
        }

At the same time, modify the corresponding Infinity2M-SSC011A-S01A-PADMUX-XXX. DTSI and set the GPIO used to DMIC_MODE:

    <PAD_HDMITX_SCL PINMUX_FOR_DMIC_MODE_2 MDRV_PUSE_DMIC_D1 >,
    <PAD_HDMITX_SDA PINMUX_FOR_DMIC_MODE_2 MDRV_PUSE_DMIC_D0 >,
    <PAD_HDMITX_HPD PINMUX_FOR_DMIC_MODE_2 MDRV_PUSE_DMIC_CLK >,

Of course, the kernel also needs to load the corresponding driver:

# cd kernel
# ARCH=arm make menuconfig

Now that the DMIC interface is configured, let’s test it using audio_all_test_case:

# ./audio_all_test_case -t 20 -I -o /tmp -d 1 -m 0 -c 2 -s 48000

The chn0_dmic_48k_16bit_mono.wav and chn1_dmic_48k_16bit_mono.wav will be generated in the/TMP/directory.If there is a LineOut interface, you can directly play the recording file and judge whether the recording is successful.