android wm9714 ASoC driver porting

reference http://www.alsa-project.org/main/index.php/Main_Page

I:(android_kernel)

ASoC由三部份组成

1)Codec驱动。由内核源代码sound/soc/codecs/wm9713.c

2)平台驱动。由内核源码sound/soc/codecs/s3c-ac97.c实现S3C6410 CPU端的DAI驱动

由sound/soc/codecs/s3c-pcm.c实现CPU端的DMA驱动

3）板驱动由内核源代码sound/soc/s3c24xx/smdk_wm9713.c实现，它将第一部分和第二部分进行绑定

II:android filesystem

1.download alsa code

cd Android/external

git clone git://Android.git.kernel.org/platform/external/alsa-lib.git

git clone git://Android.git.kernel.org/platform/external/alsa-utils.git

cd ../hardware

git clone git://Android.git.kernel.org/platform/hardware/alsa_sound.git

2.modif /home/android/device/wolf/smdk6410/BoardConfig.mk

BOARD_USES_ALSA_AUDIO := true

#BOARD_USES_GENERIC_AUDIO := true

2.build the android

W/AudioHardwareInterface( 1767): Using stubbed audio hardware. No sound will be produced.

make clean

make -j4

logcat

W/AudioHardwareALSA( 1767): Unable to attach mixer to device AndroidOut: No such file or directory

E/ALSALib ( 1767): external/alsa-lib/src/control/control.c:902:(snd_ctl_open_noupdate) Invalid CTL AndroidOut

W/AudioHardwareALSA( 1767): Unable to attach mixer to device AndroidIn: No such file or directory

E/ALSALib ( 1767): external/alsa-lib/src/control/control.c:902:(snd_ctl_open_noupdate) Invalid CTL AndroidIn

E/ALSALib ( 1767): external/alsa-lib/src/pcm/pcm.c:2210:(snd_pcm_open_noupdate) Unknown PCM AndroidPlayback_Speaker_normal

3.alsa体系提供了这样一种机制：应用层直接改变音频codec的

寄存器，具体而言：linux驱动中创建snd_kcontrol_new控制结构，并关联到codec寄存器，asound.conf文件通过控制结构名字，

就能关联到寄存器，从而改变寄存器的值。asound.conf文件主要用来做Android音频的路由控制：不同路由可以设置多个寄存器

的不同配置组合，形成不同的音频通道，从而当路由改变时，底层codec通道随之改变

在nfsdir/system/etc下新建配置文件asound.conf

# #

# # Mixer devices

# #

ctl.AndroidPlayback {

type hw

card 0 # Can replace with drivers name from /proc/asound/cards

}

ctl.AndroidCapture {

type hw

card 0

}

# #

# # Playback devices

# #

pcm.AndroidPlayback {

type hw

card 0

device 0

# #

# # Hook example

# #

# type hooks

# slave.pcm {

# type hw

# card 0

# device 0

# }

# hooks.0 {

# type ctl_elems

# hook_args [

# { name 'DAC Gain' value [ 39 39 ] }

# { name 'Mic Bias Voltage' value '1.5' }

# { name 'In Mixer Right MIC_R Switch' value false }

# { name 'Out Mixer Left DAC_L Switch' value true }

# ]

# }

}

pcm.AndroidPlayback_Earpiece {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Earpiece_normal {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Earpiece_ringtone {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Earpiece_incall {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Speaker {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Speaker_normal {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Speaker_ringtone {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Speaker_incall {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Bluetooth {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Bluetooth_normal {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Bluetooth_ringtone {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Bluetooth_incall {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Headset {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Headset_normal {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Headset_ringtone {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Headset_incall {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Bluetooth-A2DP {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Bluetooth-A2DP_normal {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Bluetooth-A2DP_ringtone {

type hw

card 0

device 0

}

pcm.AndroidPlayback_Bluetooth-A2DP_incall {

type hw

card 0

device 0

}

# #

# # Reference only

# #

pcm.AndroidPlayback_FM {

type hw

card 0

device 0

}

# #

# # Capture devices

# #

pcm.AndroidCapture {

type hw

card 0

device 0

}

---------------------------------------------------

card代表声卡号, device代表设备号

查看声卡设备对应的ID号

# cat /proc/asound/cards

0 [SMDK ]: WM9713 - SMDK

SMDK (WM9713)