parport_find_base — find a parallel port by base address
| struct parport * parport_find_base ( | unsigned long base ); | 
   This returns the parallel port with the specified base
   address, or NULL if there is none.
   
   There is an implicit parport_get_port done already; to throw
   away the reference to the port that parport_find_base
   gives you, use parport_put_port.