The minimum flow of PCI soundcard is like the following:
define the PCI ID table (see the section PCI Entries ).
create probe() callback.
create remove() callback.
create pci_driver table which contains the three pointers above.
create init() function just calling pci_register_driver() to register the pci_driver table defined above.
create exit() function to call pci_unregister_driver() function.