[PATCH 0/5] ASoC: ti: davinci-mcasp: Fix the DIT mode and OMAP4 support

[H. Nikolaus Schaller]

> Am 05.07.2021 um 16:10 schrieb Péter Ujfalusi <peter.ujfalusi at gmail.com>:
> 
> Hi Nikolaus,
> 
>> 
>> Yes, definitively.
>> 
>> I just wonder how compatible it is with the "old" omap-mcasp driver we carry
>> along for the Pyra:
>> 
>> https://git.goldelico.com/?p=letux-kernel.git;a=blob;f=sound/soc/ti/omap-mcasp.c;h=24d839a24f34ec02456176744d3690016592b5a3;hb=7789ab635e56a2fd9fe04ca2e9ccfeaccb8e0f52
>> 
>> Does it now have additional functionality or robustness?
> 
> The davinci-mcasp with series does work on OMAP4. I could not made the
> omap-mcasp working. I have picked the driver from pyra in hopes that it
> is working so I will ahve a stable base.
> Have you tested it?

AFAIR it was not tested. e have the sound system working (with some glitches)
but that goes through McPDM I think.

> 
> the omap-mcasp supports only 48KHz and 16bit, no passthrough, no 24bit,
> all is hardwired for the Galaxy Nexus setup, afaik.
> 
> The davinci-mcasp should be better all around, I think the PM side is
> also more robust.
> 
> The other point is that I would not accept the omap-mcasp driver
> upstream. The IP is the same so the driver should be also...

:)

> 
>> And does it need changes of the OMAP5 device tree?
> 
> In a similar way as the dts patches in this series.
> fwiw:
> https://github.com/omap-audio/linux-audio/commit/2f0a632db0b52321f1fc3623d088a741aeb72ef7
> is the patch I have for PandaES to get S/PDIF working.

If I find a little time it should not be difficult to replace your
new driver and fix the DTS in our ABE/AESS branch.

> 
>> And also important seems to be the ABE/AESS integration where we so far failed
>> to make it work again on more recent kernels.
> 
> The McASP is not routed via ABE/AESS, it has been always handled outside
> of the firmware, so it is just a simple link outside.

Ah, ok. Makes it easier to test :)

> 
>> Our most recent patch set is here:
>> 
>> https://git.goldelico.com/?p=letux-kernel.git;a=shortlog;h=refs/heads/letux/aess-v5
> 
> Yes, I'm following it ;)
> 
>> Anyways I am happy to see a little progress on the omap4/5 audio subsystem.
> 
> It is in maintenance mode as there is not much of an interest outside of
> a small group of people, but I try to help to get it better for Pyra.

And a lot of public information has been lost (OMAPpedia). But there are some backups:

https://web.archive.org/web/20181111114134/http://omappedia.org/wiki/Audio_Drive_Arch

BR and thanks,
Nikolaus