A close look at ALSA
http://www.volkerschatz.com/noise/alsa.html
Linux ALSA sound notes
http://www.sabi.co.uk/Notes/linuxSoundALSA.html
[alsa-devel] [PATCH 4/4] ASoC: probe CODECs and platforms before DAIs and links
http://mailman.alsa-project.org/pipermail/alsa-devel/2012-June/052588.html
Dynamic PCM
https://www.kernel.org/doc/Documentation/sound/alsa/soc/DPCM.txt
Adjusting ALSA ASoC driver for Beaglebone hooked w ADAU1373
https://ez.analog.com/message/49113
[RFC don't apply] ASoC: Add support for optional auxiliary dailess codecs
http://www.spinics.net/lists/alsa-devel/msg40127.html