XR21B1411 with forced rs485 mode
Inpired by this project: https://github.com/Goshik92/XR21B1411-RS-485-driver
Same patch but for 3.6+ kernels based on original Exar driver code: https://www.exar.com/content/document.ashx?id=21651
Successfully tested on BeagleBone Black Debian with 4.14.71-ti-r80 kernel
To build install linux headers for your kernel:
apt-get install linux-headers-$(uname -r)
And follow instructions from original Readme.txt
You will see /dev/ttyXRUSB0 device file