Exar/MxL USB Serial Driver ====================== Version 1D 2021/9/14 Add GPIO operation support Use dynamic allocate memory for usb_control_msg Avoid re-configuring the flow mode if no changes Remove obsoleted flag check for newer version Fix XR21B142x incorrect register mapping Fix baud rate setting for Big-Endian system XR2280x wide mode setting Clean up ident Version 1C 2017/1/11 Add the 9-bit mode support. Disable 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/MxL 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 5.11.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 * 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.