rio_get_device — Begin or continue searching for a RIO device by vid/did
| struct rio_dev * rio_get_device ( | u16 vid, | 
| u16 did, | |
| struct rio_dev * from ); | 
vid
     RIO vid to match or RIO_ANY_ID to match all vids
    
did
     RIO did to match or RIO_ANY_ID to match all dids
    
from
     Previous RIO device found in search, or NULL for new search
    
   Iterates through the list of known RIO devices. If a RIO device is
   found with a matching vid and did, the reference count to the
   device is incrememted and a pointer to its device structure is returned.
   Otherwise, NULL is returned. A new search is initiated by passing NULL
   to the from argument. Otherwise, if from is not NULL, searches
   continue from next device on the global list. The reference count for
   from is always decremented if it is not NULL.