I am in new in Linux device driver development. We have a USB device (Multifunctional, many interfaces) and we need to develop a USB device driver for that. UserSpace application needs to talk with our USB driver using Serial Interfaces. I am unable to figure out how to do so.

I was going through code USB_Serial.c and USB_Serial.txt but I am not sure how to proceed. How can I expose such interfaces (Not FOPS but Serial Interfaces) from my Driver so that UserSpace applications can talk with my driver using SerialPort interfaces ? Basically UserSpace applications shall write some data into my driver which using one of the end points belonging to an interface shall be sending the data to the USB device and also the device shall be sending me(Driver) some data which needs to be sent to UserSpace application (Once again using Serial-Interfaces).

Maybe this is a very basic question but I am new to Linux and I will highly appreciate some help in this regard. Some pointers explaining how to do achieve that will help me a lot. Looking forward to your kind help and thanking you beforehand