Drivers included in the linux kernel:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/serial/


See FTDI guide for compiling & using custom driver:
https://www.ftdichip.com/Support/Documents/AppNotes/AN_220_FTDI_Drivers_Installation_Guide_for_Linux.pdf