How to write a driver for ARM platform

Hi, I have designed a device in FPGA. This device has only one register and this register is mapped to physical address 0x41200000. I can operate this address in kernel level. And now I want to write a driver to operate this device. Because the driver runs at application level and I can just operate virtual address. I want to know how to map this physical address 0x41200000 to driver virtual address so I can operate this device in the application driver. Thanks a lot. Best, Jian