ALSA for SoC audio support

modulename: snd-soc-core.ko

configname: CONFIG_SND_SOC

Linux Kernel Configuration
└─>Device Drivers
└─>Sound
└─>Advanced Linux Sound Architecture
└─>System on Chip audio support
└─>ALSA for SoC audio support
In linux kernel since version 2.6.21.1 (release Date: 2007-04-27)  
If you want ASoC support, you should say Y here and also to the
specific driver for your SoC platform below.

ASoC provides power efficient ALSA support for embedded battery powered
SoC based systems like PDA's, Phones and Personal Media Players.

This ASoC audio support can also be built as a module. If so, the module
will be called snd-soc-core.

source code:
sound/soc/