You'd have to figure out phandle support for the I2C configuration channel, fire up I2S streaming by enabling it in the kernel and piping audio to the DAC, then playing it into some speakers.
Could expand it by adding some filtering. Many DACs have filter banks that you can populate with coefficients via I2C.
There's some decent kernel module resources and examples in this repo if this is something you're brand new to:
https://github.com/Johannes4Linux/Linux_Driver_Tutorial
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