掌機 - Gaviar (小志掌機) - 移植Kernel audio


先紀錄一下Tina-Linux如何配置Audio，之後司徒找時間來寫一個精簡的Audio PCM Driver，因為Tina-Linux Audio的架構是符合Linux ASoC，有點太複雜了，我們短小精幹的小志掌機應該使用極致精簡的Audio PCM Driver就可以




Device Tree 

&codec {
    mic1gain = <0x1F>;
    mic2gain = <0x1F>;
    mic3gain = <0x1F>;
    adcdrc_cfg = <0x0>;
    adchpf_cfg = <0x1>;
    dacdrc_cfg = <0x0>;
    dachpf_cfg = <0x0>;
    digital_vol = <0x00>;
    lineout_vol = <0x1a>;
    headphonegain = <0x03>;
    pa_level = <0x01>;
    pa_pwr_level = <0x01>;
    pa_msleep_time = <0x78>;
    playback_cma = <128>;
    capture_cma = <256>;
    status = "okay";
};

&sndcodec {
    hp_detect_case = <0x00>;
    jack_enable = <0x01>;
    status = "okay";
};

&dummy_cpudai {
    status = "okay";
};

Buildroot選擇amixer


Kernel Log 

ALSA device list:
  #0: audiocodec

Audio Device 

# ls /dev/snd/
    controlC0  pcmC0D0c   pcmC0D0p

測試 

# amixer set Headphone on
    Simple mixer control 'Headphone',0
      Capabilities: pswitch pswitch-joined
      Playback channels: Mono
      Mono: Playback [on]

# speaker-test 
    speaker-test 1.2.16

    Playback device is default
    Stream parameters are 48000Hz, S16_LE, 1 channels
    Using 16 octaves of pink noise
    Rate set to 48000Hz (requested 48000Hz)
    Buffer size range from 64 to 32768
    Period size range from 63 to 16385
    Periods = 4
    [SNDCODEC][sunxi_card_hw_params][620]:stream_flag: 0
    was set period_size = 12000
    was set buffer_size = 24000
     0 - Front Left
    Time per period = 2.575911
     0 - Front Left
    Time per period = 2.997710
     0 - Front Left

# aplay Front_Center.wav 
    Playing WAVE 'Front_Center.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Mono
    [SNDCODEC][sunxi_card_hw_params][620]:stream_flag: 0