[alsa-devel] [question] Sample rate IC followed by DAC

[Clemens Ladisch]

Matt Flax wrote:
> On 04/11/16 22:31, Clemens Ladisch wrote:
>> Matt Flax wrote:
>>> I have a sample rate converter IC, which is followed by a DAC. This kind of setup :
>>>
>>> SoC chip -> Sample rate conv. chip -> DAC chip
>>
>> What is the purpose of the converter?  What problem does it solve?
>
> It has a lower noise floor then libsamplerate.

Which chip is better than 145 dB?

>>> How do you construct a machine driver for this setup ?
>>
>> The original DAC driver will not work correctly, as far as sample rate
>> settings are concerned.
>
> Yes, I was expecting that. Tell me, even in the current ALSA version, is there
> any support for sample rate converter hardware chains ?

No.

>> Well, if your goal isn't a proper driver for upstream, just hack the
>> existing DAC driver to access the other I²C device, when needed.
>>
> Sure, I can do this. I can't find any examples on operating a codec within
> a codec. Would I export all function symbols and do it that way ?

Export to where?  You would just modify the existing DAC driver.


Regards,
Clemens