[alsa-devel] How to set TWL4030 to Option2

[Lopez Cruz, Misael]

> > In current code, as you say, you have to directly change 
> > the value of the reg cache for setting to option2, also
> > you have to modify the REG_OPTION and REG_VOICE_IF reg for
> > voice, but this is temporary method.

> This can be done with a register write from the DAI init()
> function in the machine driver in order to avoid modifying
> twl4030.c itself.

For audio and voice interface, following things need to be configured:

Audio interface:
- Output pins state: high impendance or application mode
- Enable audio interface

Voice interface:
- Enable voice data input
- Enable voice data output
- Output pins state: high impedance or application mode
- Enable voice interface

I think that interfaces can be enabled in DAI init as Mark suggests,
but input/output should be enabled depending on whether we are doing
playback/capture or not, and then they should be handled in the codec
driver.

For the codec operation mode selection, I still think Peter's
advice is more appropriate because options1,2 are not really tight to
DAIs. For example, we can be in option2 (voice/audio) and do
transferences using both DAIs: I2S and PCM.