Abstract USB device implementation

[r4gus]

I've extracted the platform independent code from the rp2040 device impl (see ZigEmbeddedGroup/raspberrypi-rp2040#40).

One can create a concrete implementation by calling Usb(F), where F is a struct that contains a set of functions to handle the low level details (register access etc.).

Check out the usb examples in the rp2040 repo!

@MasterQ32 @mattnite

[mattnite]

🤌

[mattnite]

In general I would prefer removing Usb from the beginning of the identifiers since they're in a usb namespace. That being said, I'm also for keeping them as is since I know that's how the USB standard refers to them. What do you think?

[r4gus]

In general I would prefer removing Usb from the beginning of the identifiers since they're in a usb namespace. That being said, I'm also for keeping them as is since I know that's how the USB standard refers to them. What do you think?

You're right, usb.XYZ looks better than usb.UsbXYZ

[r4gus]

Just write everything down you dislike, I'll take care of it

[mattnite]

The only other change I'd like to see is to ensure that the unit tests run when you execute zig build test, once that's done with the removal of Usb we're good to merge :)

[mattnite]

@r4gus is this ready to merge?

[r4gus]

@mattnite yes. Sending multiple packets between Host and Client seems to Work fine (with the rp2040). Adding Support for other Chips will probably reveal some shortcomings.

[mattnite]

Awesome