CONFIG_SND_SOC_TEGRA20_AC97 (not configurable)

modulename: snd-soc-tegra20-ac97.ko

configname: CONFIG_SND_SOC_TEGRA20_AC97

Linux Kernel Configuration
└─>Device Drivers
└─>Sound card support
└─>Advanced Linux Sound Architecture
└─>ALSA for SoC audio support
└─>SND_SOC_TEGRA20_AC97
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Say Y or M if you want to add support for codecs attached to the
Tegra20 AC97 interface. You will also need to select the individual
machine drivers to support below.

source code:
sound/soc//tegra/