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

Petr Kulhavy petr at barix.com
Thu May 22 15:49:41 CEST 2014

Hi Benoit,

thank you, I will try them out. At the moment I need to focus on other 
projects, but in a few weeks I should be able to get back to the drivers.


On 21.05.2014 13:29, Benoit Cousson wrote:
> 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.
> Regards,
> Benoit
> 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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