Unfortunately, I don't have this board available, but I've just take a quick look into related firmware sources available at Microchip site. I'm sure that no additional driver is needed to be installed on RasPi, since this is HID device and required driver is already present in all distributions.
According to your post (that /dev/usb/biddev0 appears) I'd say that firmware is also preloaded, what is common, anyway.
Try to locate it as hidraw device. You could be able to open/read/write it that way, I believe.
Feel free to let me know if the issue remains unsolved or you bump into another one...
Best wishes, Ivan Zilic.
Running out of GPIO pins and/or need to read analog values?