libFTDI is an open source library to talk to FTDI chips: FT232BM, FT245BM, FT2232C, FT2232D, FT245R, FT232H and FT230X including the popular bitbang mode. The library is linked with programs in userspace, no kernel driver required.
WWW: https://www.intra2net.com/en/developer/libftdi/