Would you please consider distributing the ADISUSB's spi firmwares (not the source just the hex files).
It is very easy to use cypress (usb controller on the ADISUSBZ) on linux. The only thing that is needed is your spi firmware that are automatically loaded during the usb-enumaration on windows.
In fact, those firmwares are already available in the mcp_spi.sys's data section (which you are freely distributing). However, it is a little bit problematic to convert them back to hex files so that they can be manually loaded on linux using fxload.
That is why, if you distribute those hex files, you will make it possible for everyone to use the ADISUSB boards under linux.