[FEATURE] RPi4B audio support over I2S

[linguini1]

Is your feature request related to a problem? Please describe.

The RPi4B does not have audio support yet.

Describe the solution you'd like

Support for I2S based audio over the audio jack on the RPi4B.

Describe alternatives you've considered

This can be done via polling, interrupts or DMA. I think interrupts should be targeted first and then DMA can be added as a later modification.

Verification

• I have verified before submitting the report.

[linguini1]

https://github.com/sypstraw/rpi4-osdev/blob/master/part9-sound/kernel.c

[linguini1]

It turns out that the audio jack is not accessible over I2S/PCM, but rather via the PWM interface. I will leave this open to track I2S support for external devices, but for now I will pivot to getting the audio jack to work.