[alsa-devel] ASoC: Two codecs on a single CPU DAI

Benoit Cousson bcousson at baylibre.com
Wed May 21 13:29:37 CEST 2014

Hi Petr,

I'm about to release a v4, but you can used the previous version that 
was working fine for my setup.

I'm glad to have more users for the series, because my setup is so 
simple that I cannot validate all the code I'm about to change :-(

Bottom line; The more, the merrier.


On 20/05/2014 15:46, Lars-Peter Clausen wrote:
> On 05/20/2014 03:08 PM, Petr Kulhavy wrote:
>> Hi,
>> I'm writing a driver for a custom DaVinci board, which has two codecs
>> (Wolfson and STA323 amplifier) connected to the same CPU DAI. The
>> intention
>> is that both codecs always play the same audio, only the volume/mixer
>> settings are controlled separately. In addition to that the design is
>> atypical by the fact, that the Wolfson is the clock master. So in
>> order to
>> play audio on the amplifier the Wolfson must be initialized as well.
>> My question is: how to reflect this architecture in a SOC platform
>> driver?
>> As the first approach I tried to create two DAI links, one for each
>> codec.
>> That worked if audio was first played on the Wolfson link (clock
>> master was
>> initialized) and then on the second link, using the same sampling rate.
>> But in fact I would need only one DAI link to both. So then I tried to
>> make
>> just one link to Wolfson and put the amplifier as an "aux_dev". However
>> there I need to set hw_params and format for the amplifier codec DAI and
>> those functions were not called. In fact there was no codec DAI
>> created for
>> the amplifier. I've also seen that one can define rtd_aux runtimes,
>> but have
>> nowhere found how to use it.
>> Could someone please help me?
> Hi,
> Benoit is currently working on adding support for this to the ASoC
> framework, see this patch series:
> http://comments.gmane.org/gmane.linux.alsa.devel/122160
> - Lars
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Benoît Cousson
Embedded Linux Technology Lab

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