Using USB-Serial device; e.g. Prolific

Hello All,

I tried to use USB-serial device on mini6410 then I came to building
usbserial and ftdi_sio as module. I have both .ko file then insmod to the
kernel.

Both drivers are inserted and also the usb-serial converter (prolific), but
then I am puzzled on how to use it. On Ubuntu normally once this device
loaded it will be available as /dev/ttyUSBx. 

In addition I am using BuildRoot as system builder.

Does anyone know how to achieve it?

Thanks in advance,
DWI