[Letux-kernel] jz4730 sound

[H. Nikolaus Schaller]

Hi Paul,

> Am 21.03.2021 um 21:16 schrieb Paul Boddie <paul at boddie.org.uk>:
> 
> On Sunday, 21 March 2021 20:24:15 CET H. Nikolaus Schaller wrote:
>>>> 
>>>> Maybe we should change simple-audio-card,format = "i2s";
>>>> if that makes the Reset being controlled?
>>> 
>>> The old 2.6 kernel uses I2S format.
>> 
>> and the ak4642 is i2s master.
> 
> Indeed, the only thing I have in my notes is this...
> 
> The schematic shows an AK4642EN device. This requires the "I2S master" pins to
> be configured.

I am currently experimenting a little with adding pinctrl. It is possible
to define the clocks as inputs and outputs i.e. master or slave codec.

But that will take a little more time for results (I think I should check
with our old devmem traces if the pinctrl functions are correctly set up).

> I2C control over the device is performed via address 0x13.

Yes, that is how we set up the i2c node of the codec driver.
And this is where it responds...

> I didn't go any further as there were plenty of other things to look at, many 
> of them now thankfully reviewed and supported. :-)

No problem, we still have enough work. Even if we manage to get i2s working
it is likely that we are then hit by the sluggish scheduling effect. But it
may reveal another hint what could go wrong there...

BR,
Nikolaus