rk3588sdk/env/rootfs/etc/asound.conf

#
#
# 当前配置文件生效后会产生如下效果
# 1. 通过amixer controls,可以看到如下音量控制器,其中通过Master Volume控制的是主音量,
# default_playback用于在唤醒的时候降低背景声音。
#   root@firefly:~# amixer controls
#   numid=1,iface=MIXER,name='Master Volume'
#   numid=2,iface=MIXER,name='Ch1 Volume'
#   numid=3,iface=MIXER,name='Ch2 Volume'
#   numid=4,iface=MIXER,name='default_playback'
#   numid=5,iface=MIXER,name='wakeup_playback'
#
# 2. 通过aplay播放音频文件时，会自动通过default_playback设备播放，即其他应用程序例如chrome播放音频的时候也会自动使用这个设备
# 3. 通过amixer控制音量时候，无需通过-c指定声卡编号
# 4. 通过amixer通过default_playback控制音量来实现唤醒时降低背景声音。
# 5. 通过amixer通过Master控制音量来实现对系统音量大小的控制。
#

pcm.!default {
    type plug
    slave.pcm "default_playback"
}
ctl.!default {
  type hw
  card 2
}
pcm.default_playback {
    type softvol
    slave {
        pcm "xa8326"
    }
    control {
        name "default_playback"
        card 2
    }
    min_dB -40.0
    max_dB 0.0
    resolution 256
}
pcm.wakeup_playback {
    type softvol
    slave {
        pcm "xa8326"
    }
    control {
        name "wakeup_playback"
        card 2
    }
    min_dB -40.0
    max_dB 0.0
    resolution 256
}
# 放音设备
pcm.xa8326 {
    type plug
    slave {
        pcm {
            type dmix
            ipc_key 321456  # any unique value
            ipc_key_add_uid true
            slave {
                pcm "hw:2,0"
                period_time 100000 # 100ms
                format S16_LE
                channels 2
            }
        }
        rate 48000
        format S16_LE
        channels 2
    }
}

# 重采样
pcm.recorder {
    type plug
    slave {
        pcm {
            type multi
            slaves.xa8326.pcm "hw:2,0"
            slaves.xa8326.channels 2
            slaves.pdm.pcm "hw:1,0"
            slaves.pdm.channels 8

            bindings.0.slave pdm
            bindings.0.channel 0

            bindings.1.slave pdm
            bindings.1.channel 1

            bindings.2.slave pdm
            bindings.2.channel 2

            bindings.3.slave pdm
            bindings.3.channel 3

            bindings.4.slave xa8326
            bindings.4.channel 0
    
            # bindings.5.slave pdm
            # bindings.5.channel 5

            # bindings.6.slave pdm
            # bindings.6.channel 6

            # bindings.7.slave pdm
            # bindings.7.channel 7

            # bindings.8.slave xa8326
            # bindings.8.channel 0

            # bindings.9.slave xa8326
            # bindings.9.channel 1    
        }
        rate 48000
        format S16_LE
        channels 5
    }
}