$ egrep -irl 'alsa.*core|core.*alsa' .
./sound/soc/soc-dapm.c
./sound/soc/soc-core.c
./sound/drivers/vx/vx_core.c
./Documentation/sound/alsa/soc/codec.txt
./Documentation/sound/alsa/ALSA-Configuration.txt
./Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl