As detailed in the <Low Power Mode> section of the AK4376A
datasheet, the amp should be powered down before switching
power modes (or to a sample rate <= 12 KHz).
Change-Id: I3ab0a21c78a3ad2bb418b64c916f7dbe2a843efa
Define proper symbolic constants for power mode. Also allow
targets to define the default power mode setting.
Change-Id: Ia07cf854dce47d0a6aa88e067471f1ff9fbc45fb
According to a forum user, there's an audible click when changing
the volume between -32 and -32.5 dB with some headphones. Fix this
by not (ab)using the DAC digital mixer for volume control.
The mixer only provides an extra -6 dB of hardware volume range,
so the only side effect is that software volume will now kick in
at -32 dB instead of -38 dB.
Change-Id: If24d9bc0058eff3c1a29aefb155a2e378522623c
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
