i see this card has analog input. In your alsamixer screenshot, i see the control at the right, capture is set to "line", does it allow you to set to "IEC958" or "toslink" or something like that?
Another suggestion. I am no expert, but from the screenshot it seems that camilladsp is just not receiving any signal. As it is now, do you get any sound if you plug a source to the analog inputs? just to troubleshoot...
In alsamixer I can toggle the PCM capture source in the middle of the window between ”IEC958 IN“ and ”Line In“.
Both options don’t give any input if I plug in a signal. Thanks for noting.
On my Mac both inputs on the interface do work.