how to set CYUSBS234 serial port mode in linux

Hi,

I'm working with CyUsbS234 (CY7C65211)

I have already tested the kit on Windows, it works ok.

I can also use it on my Linux platform, with linux SDK and libusb.

To get more gpio and i2c, I need to change the serial port mode from mode 0 (default) to mode 5. 

There is no API to change the serial port in the CyUSBSerial API Document. 

I need to change the serial port mode at runtime in linux system. 

Can someone help me? Thanks.