Allo Digione Signature not recognized as audio device on Raspberry Pi 4 running Debian 11

[jtnn60]

I have rebuilt my Raspberry Pi 4 Model B (4GB) with Debian 11 and a 500GB USB disk.  Several applications are running fine already on the Pi, but I cannot get anything to recognized the Allo Digione Signature as an audio output device.

 

This is the section from the DigiOne Signature Tech Manual:

Debian 11 does not have a /boot/config.txt file, but instead has /boot/firmware/usercfg.txt file to which I have added:

 

 

Listing the content of /proc/asound/cards I see

 

However, playing a MP3 file via aplay or mplayer does not output anything to the S/PDIF output.

 

Ultimately I want to use the Allo Digione Signature with Plexamp Headless playing music from my Plex Media Server.  However, simply getting audio playback from command-line media players does not work yet. 

 

How do I find out if the allo-digione driver was loaded correctly?   What is the mythical snd-soc-allo-digione.ko device driver mentioned in the DigiOne Signature Tech Manual??