int parport_negotiate (struct parport * port, int mode);
Use this to negotiate to a particular IEEE 1284 transfer mode. The mode parameter should be one of the constants in parport.h starting IEEE1284_MODE_xxx.
The return value is 0 if the peripheral has accepted the negotiation to the mode specified, -1 if the peripheral is not IEEE 1284 compliant (or not present), or 1 if the peripheral has rejected the negotiation.