[alsa-devel] How to select input from muxer in front of SSI on i.MX6

[Nicolin Chen]

CCed Mark and Liam.

On Fri, Sep 19, 2014 at 05:18:08PM +0200, Jean-Michel Hautbois wrote:
> Hi,
> 
> I am now working on making my audio path working completely.
> And I get some difficulties to write a DT for my needs.
> I join a picture which is not the reality but a simplified version of the board.
> 
> I have a FPGA between my codecs and my i.MX6. This FPGA is responsible
> of lots of things, and in particular of muxing signals.
> I can program it in order to get the audio signal I want on the SSI I
> want (so sgtl5000 can ben on SSI1 or SSI2 or both). This path is not a
> single codec, but a multiple codec one.
> So I can have on SSI1 LineIn from sgtl5000 or audio from hdmi (adv7611).
> 
> I don't know how to write it in DT, regarding audmux for instance, and
> the sound{} node...
> And I don't know how to drive all these peripherals (from arecord, I
> wish I have hw:0,0 is LineIn, hw:0;1 is HDMI, etc.).

This looks like a DPCM (Documentation/sound/alsa/soc/DPCM.txt) to me.

I'm not sure how to write a DT for DPCM either. But it seems that you
might need a specific machine driver (guessing).

I saw Morimoto-san plans to add DPCM into Simple Card, but not sure
when they will finish it. Otherwise, you may use Simple Card while
following their defined DT formats.

Nicolin