Patch in WM8960 support

[probonopd]

Temporary patch to add WM8960 support until rsta2/circle#286 is integrated into Circle

Thanks @matemaciek

[probonopd]

Tested with MiniDexed and a WM8960 DAC, works for me! Both the headphone jack on the WM8960 board and also the speakers connected to the built in amplifier +1

Here is the build:
https://github.com/probonopd/MiniDexed/suites/6210021520/artifacts/219385493

Now it would be good if someone with a PCM5102A or PCM5122 based DAC could also test this in order to ensure that it doesn't break those.

[probonopd]

@matemaciek I am mirroring and locally applying your patch in MiniDexed for now so that we can enjoy our WM8960s while an architecturally cleaner solution is being worked out in Circle.

[probonopd]

It would be good if someone with access to a PCM5122 DAC could test the build from this branch (linked above) to ensure this doesn't break the PCM5122 which also uses i2c. @rsta2 do you have one?

Also, since this is auto-detecting i2c addresses, should we remove the related code from MiniDexed?

[ChKK1963]

It would be good if someone with access to a PCM5122 DAC could test the build from this branch (linked above) to ensure this doesn't break the PCM5122 which also uses i2c

Just tested the build with my new Raspiaudio+ V2 DAC which has a PCM5102A DAC. Seems to work fine.

[probonopd]

Thanks for testing @ChKK1963. We still need to find someone with a PCM5122 DAC though, as that one has i2c while the PCM5102A doesn't.

[matemaciek]

Also, since this is auto-detecting i2c addresses, should we remove the related code from MiniDexed?
Is there any? I only see passing of optional I2C address, and it still makes sense - if user provides specific address, auto-detecting is skipped.

[rsta2]

I tried a PiFi DAC+ v2.0 HAT (uses a PCM5122 DAC) attached to a RPi Zero 2 W using this build:

https://github.com/probonopd/MiniDexed/suites/6210021520/artifacts/219385493

First it initialized OK, but after some seconds the sound was strange and after a restart, the I2C initialization failed (-2 from all probed addresses). I aborted the test, because I don't want to destroy something.

With a kernel image, built from the main branch, everything works OK.

[matemaciek]

I've ordered PiFi, I'll look into it. Previous version was just assuming PCM5122 is present and was blindly sending its init sequence on its two known addresses. Can you try setting DACI2CAddress=76 and if that doesn't work DACI2CAddress=77 in minidexed.ini?

[rsta2]

@matemaciek I guess the i2cdetect test, you have implemented, does not work reliable with some devices. I will wait for the license information and then merge your PR, maybe with some modifications. Then I will test again.

[matemaciek]

@rsta2 They've just added GPLv3 (-:

[probonopd]

WM8960 works. If PCM5xxx also still works, we might want to consider merging.

[probonopd]

PCM5xxx confirmed, hence merging.