[Letux-kernel] Letux/Alpha 400: small progress with sound

[Maarten ter Huurne]

On Thursday, 29 April 2021 13:48:13 CEST H. Nikolaus Schaller wrote:
> > Am 29.04.2021 um 13:31 schrieb Maarten ter Huurne
> > <maarten at treewalker.org>:> 
> > There is a Linux driver for the JZ4770 internal codec, Paul Cercueil
> > is maintaining it. A quick look at both programming manuals
> > suggests it won't work as-is, but the 4780 codec is an evolution of
> > the 4770 one, so a lot of code could be re-used. Register numbers
> > are different, but most of the names and bit fields within the
> > registers are the same.
> Good to know! So at least this is a good starting point for
> debugging...
> 
> I'll give it a try what happens if we use the ingenic,jz4770-codec on
> the CI20.

You would have to at least update the register number enum at the top, 
since almost all of the registers got renumbered.

> Alternatively we could check if one of the other codecs (4725, 4740,
> 4760) is more similar to find the best starting point.

I would expect 4770 to be the most similar, since it's the closest on 
the timeline and it's a full-featured SoC like the 4780 is. But it 
wouldn't hurt to check.

> BTW: there seems to be a typo in the DTS node name/address of
> jz4770.dtsi
> 
> 	codec: audio-codec at 100200a0 {
> 		reg = <0x100200a4 0x8>;

I'm not sure whether that's a typo or just the address being rounded 
down. I'll ask Paul.

Bye,
		Maarten