mt6735 Android L如何单独使用主、副mic

[DESCRIPTION]
android L上如何单独使用主、副MIC
[SOLUTION]
在AudioALSAHardware.cpp中定义
static String8 keySET_MIC_CHOOSE= String8("SET_MIC_CHOOSE");
添加
#include "AudioALSAHardwareResourceManager.h"
status_t AudioALSAHardware::setParameters(const String8 &keyValuePairs)
//add this start
if (param.getInt(keySET_MIC_CHOOSE, value) == NO_ERROR) {
param.remove(keySET_MIC_CHOOSE);
ALOGD("+%s(): %s", __FUNCTION__, "setBuiltInMicSpecificType");
if(value==2){
AudioALSAHardwareResourceManager::getInstance()->setBuiltInMicSpecificType(BUILTIN_MIC_MIC2_ONLY);
}elseif(value==1){
AudioALSAHardwareResourceManager::getInstance()->setBuiltInMicSpecificType(BUILTIN_MIC_MIC1_ONLY);
}else{
AudioALSAHardwareResourceManager::getInstance()->setBuiltInMicSpecificType(BUILTIN_MIC_DEFAULT);
}
}
//add this end
然后上层调用
AudioSystem.setParameters("SET_MIC_CHOOSE=1");//仅使用主mic
AudioSystem.setParameters("SET_MIC_CHOOSE=2");//仅使用副mic
AudioSystem.setParameters("SET_MIC_CHOOSE=0");//还原默认设置，使用双mic

想请问一下怎么能得到这些底层驱动的源代码?