This option enables support for Silicon Labs C2 port used to program Silicon micro controller chips (and other 8051 compatible). If your board have no such micro controllers you don't need this interface at all. To compile this driver as a module, choose M here: the module will be called c2port_core. Note that you also need a client module usually called c2port-*. If you are not sure, say N here.
This option enables C2 support for the Eurotech's Duramar 2150 on board micro controller. To compile this driver as a module, choose M here: the module will be called c2port-duramar2150.