Recording works now, although I'm sure there will be a few
things that need fine-tuning. A major issue is that writing
to the SD card creates noticable interference, which happens
on the original firmware too but seems worse under Rockbox.
(Since Rockbox waits until RAM fills up before writing data,
the interference will only be heard on >50 MiB recordings.)
Change-Id: I5561dd9668c3bdd34e92f34ef50848aef8c0b7eb
Define proper symbolic constants for power mode. Also allow
targets to define the default power mode setting.
Change-Id: Ia07cf854dce47d0a6aa88e067471f1ff9fbc45fb
Some audiohw API calls are shared between playback and recording,
eg. frequency settings. Implementing these in the DAC driver won't
work for the M3K, as it uses a separate codec for microphone input.
Change-Id: Ieb0a267f8a81b9e2bbf0bbca951c5778f8dcd203
