Exar USB Serial Driver
======================
#### Version 1C-AK 2023/03/17
* Fix errors in code.
* Update to work with kernel 5.15+
Version 1C 2017/1/11
Add the 9-bit mode support.
Disbale the debug messages.
Version 1B, 11/6/2015
Fixed Bug: The conditional logic to support kernel 3.9 was incorrect(line 396 in xr_usb_serial_common.c).
Version 1A, 1/9/2015
This driver will work with any USB UART function in these Exar devices:
XR21V1410/1412/1414
XR21B1411
XR21B1420/1422/1424
XR22801/802/804
The source code has been tested on various Linux kernels from 3.6.x to 3.17.x.
This may also work with newer kernels as well.
Installation
------------
* Compile and install the common usb serial driver module
# make
# insmod ./xr_usb_serial_common.ko
* Alternativley install via DKMS
# cp -a ../$(basename $(pwd)) /usr/src/xr_usb_serial_common-1c
# dkms add -m xr_usb_serial_common -v 1c
# dkms build -m xr_usb_serial_common -v 1c
# dkms install -m xr_usb_serial_common -v 1c
* Ensure that the cdc-acm module is not loaded (assumig that it is not needed)
# echo blacklist cdc-acm > /etc/modprobe.d/blacklist-cdc-acm.conf
# update-initramfs -u
* Plug the device into the USB host. You should see up to four devices created,
typically /dev/ttyXRUSB[0-3].
Tips for Debugging
------------------
* Check that the USB UART is detected by the system
# lsusb
* Check that the CDC-ACM driver was not installed for the Exar USB UART
# ls /dev/tty*
To remove the CDC-ACM driver and install the driver:
# rmmod cdc-acm
# modprobe -r usbserial
# modprobe usbserial
# insmod ./xr_usb_serial_common.ko
Technical Support
-----------------
Send any technical questions/issues to uarttechsupport@exar.com.