Quick question with regard to USB/SPI comms.  I know of this chip, and that it's been used in other designs in the past to allow SPI comms on the chip to be accessible from a PC over the USB port. 

I'm curious how this affects cgminer, specifically with zefir's driver having been written for an Rpi, which has an SPI port natively available.  My first design will just use the Rpi, but for future implementations I'd like to make it usable from a PC over standard USB.  I can handle the board changes to incorporate the chip, but I'm less sure of the changes that might be required to get the drive to encapsulate SPI commands within USB packets. 

Or is the chip/driver already smart enough to handle this on its own?