This just came in: The USB adapter is confirmed to be compatible with Raspberry PI. Our collaborator “Team Splattenstein” tested it with Chameleon PI and VICE (C-64). After correctly mapped the joystick in the emulator, it works flawlessly and as he reported, without any lag or misbehavior.
Here is a link to their page. It’s in Finnish translated to English, be aware!
Raspberry PI is an open ARM platform originaly developped for academic purposes but currently gaining in popularity for multimedia and gaming.