Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
DRIVER(9)		 BSD Kernel Developer's	Manual		     DRIVER(9)

NAME
     driver -- structure describing a device driver

SYNOPSIS
     #include <sys/param.h>
     #include <sys/kernel.h>
     #include <sys/bus.h>
     #include <sys/module.h>

     static int	foo_probe(device_t);
     static int	foo_attach(device_t);
     static int	foo_detach(device_t);
     static int	foo_frob(device_t, int,	int);
     static int	foo_twiddle(device_t, char *);

     static device_method_t foo_methods[] = {
	     /*	Methods	from the device	interface */
	     DEVMETHOD(device_probe,	     foo_probe),
	     DEVMETHOD(device_attach,	     foo_attach),
	     DEVMETHOD(device_detach,	     foo_detach),

	     /*	Methods	from the bogo interface	*/
	     DEVMETHOD(bogo_frob,	     foo_frob),
	     DEVMETHOD(bogo_twiddle,	     foo_twiddle),

	     /*	Terminate method list */
	     DEVMETHOD_END
     };

     static driver_t foo_driver	= {
	     "foo",
	     foo_methods,
	     sizeof(struct foo_softc)
     };

     static devclass_t foo_devclass;

     DRIVER_MODULE(foo,	bogo, foo_driver, foo_devclass,	NULL, NULL);

DESCRIPTION
     Each driver in the	kernel is described by a driver_t structure.  The
     structure contains	the name of the	device,	a pointer to a list of meth-
     ods, an indication	of the kind of device which the	driver implements and
     the size of the private data which	the driver needs to associate with a
     device instance.  Each driver will	implement one or more sets of methods
     (called interfaces).  The example driver implements the standard "driver"
     interface and the fictitious "bogo" interface.

     When a driver is registered with the system (by the DRIVER_MODULE macro,
     see DRIVER_MODULE(9)), it is added	to the list of drivers contained in
     the devclass of its parent	bus type.  For instance	all PCI	drivers	would
     be	contained in the devclass named	"pci" and all ISA drivers would	be in
     the devclass named	"isa".	The reason the drivers are not held in the de-
     vice object of the	parent bus is to handle	multiple instances of a	given
     type of bus.  The DRIVER_MODULE macro will	also create the	devclass with
     the name of the driver and	can optionally call extra initialisation code
     in	the driver by specifying an extra module event handler and argument as
     the last two arguments.

SEE ALSO
     devclass(9), device(9), DEVICE_ATTACH(9), DEVICE_DETACH(9),
     DEVICE_IDENTIFY(9), DEVICE_PROBE(9), DEVICE_SHUTDOWN(9), DRIVER_MODULE(9)

AUTHORS
     This manual page was written by Doug Rabson.

BSD			       November	22, 2011			   BSD

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | AUTHORS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=driver&sektion=9&manpath=FreeBSD+12.0-RELEASE+and+Ports>

home | help