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

[Matt Flax]

On 06/11/16 22:21, Clemens Ladisch wrote:
> 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?
The AK4137EQ is better. However it also offloads the processing to 
hardware.
>>>> 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.
OK, will do, thanks for the guidance.
>
> Regards,
> Clemens