Please define HF2 interface identification rules

[flit]

For HF2 you don't specify any method of recognizing an HID interface as providing HF2.

I suggest two possible methods:

1. Interface name containing "HF2".
2. Declare a HID usage page for HF2.

Ideally both would be required in an implementation, letting the host use whichever is easiest and/or supported by the USB library being used.

[mmoskal]

HID isn't ideal for HF2 (despite the name). We've been recently using just a custom USB class with two bulk end-points. This is also the approach taken by CMSIS DAP 2. It's faster and works driver-less in all modern OSes. It also allows for usage from WebUSB.