Audio and Embedded Linux Brief Last time I used wrote kernel drivers for the ASoC (ALSA System on Chip) subsystem, the functionality was split up into these parts:
Platform class driver that defines the SoC audio interface for the actual CPU itself. This includes both the DAI (Digital Audio Interface) and any potential audio muxes (e.g. i.MX6 has its AUDMUX). CODEC class driver that controls the actual CODEC. Machine drivers that is the magic glue between the SoC and the CODEC which connect the both interfaces. Such driver had to be written for each SoC-CODEC combination, and that does not scale very well. Nowadays, most of the CODEC class drivers is now adapted to be described with the simple-audio-card [1] in a device tree, which will completely replace the machine drivers.
