struct pci_dev * pci_get_class (unsigned int class, struct pci_dev * from);
Iterates through the list of known PCI devices. If a PCI device is found with a matching class, the reference count to the device is incremented 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.