Since the kernel driver doesn't support all necessary features I have written/am writing a userspace SPI based 'driver'.
It uses the libsoc library https://github.com/jackmitch/libsoc which I had to modify to handle 16-bit words for the SPI transfer (https://github.com/compiaffe/libsoc/tree/16-bit-mode).
The driver I have written can be found here: (compiaffe/ADIS-16480-Interface at c++ · GitHub)
However it is very much under development.
All the code is under development, but it might be helpful for other people trying to interface an ADIS16480 to a BeagleBone Black.