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

[Jean-Michel Hautbois]

Hi,

2014-09-19 19:52 GMT+02:00 Nicolin Chen <nicoleotsuka at gmail.com>:
> 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.

Thanks, that's interesting. It looks like a DPCM, but in the other
order (from FE to BE). I probably need a new driver, you are right.
But I still don't know how/what I should declare in the DT...

Thanks,
JM