1.\" Copyright (c) 1998 Doug Rabson 2.\" 3.\" All rights reserved. 4.\" 5.\" This program is free software. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.\" $FreeBSD: src/share/man/man9/driver.9,v 1.3.2.3 2001/08/17 13:08:54 ru Exp $ 28.\" $DragonFly: src/share/man/man9/driver.9,v 1.3 2004/06/01 11:36:53 hmp Exp $ 29.\" 30.Dd June 16, 1998 31.Dt DRIVER 9 32.Os 33.Sh NAME 34.Nm driver 35.Nd structure describing a device driver 36.Sh SYNOPSIS 37.Bd -literal 38#include <sys/param.h> 39#include <sys/bus.h> 40#include <sys/kernel.h> 41#include <sys/module.h> 42 43static int foo_probe(device_t); 44static int foo_attach(device_t); 45static int foo_detach(device_t); 46static int foo_frob(device_t, int, int); 47static int foo_twiddle(device_t, char *); 48 49struct foo_softc { 50}; 51 52static device_method_t foo_methods[] = { 53 /* Methods from the device interface */ 54 DEVMETHOD(device_probe, foo_probe), 55 DEVMETHOD(device_attach, foo_attach), 56 DEVMETHOD(device_detach, foo_detach), 57 58 /* Methods from the bogo interface */ 59 DEVMETHOD(bogo_frob, foo_frob), 60 DEVMETHOD(bogo_twiddle, foo_twiddle), 61 62 /* Terminate method list */ 63 { 0, 0 } 64}; 65 66static driver_t foo_driver = { 67 "foo", 68 foo_methods, 69 sizeof(struct foo_softc) 70}; 71 72static devclass_t foo_devclass; 73 74DRIVER_MODULE(foo, bogo, foo_driver, foo_devclass, 0, 0); 75.Ed 76.Sh DESCRIPTION 77Each driver in the kernel is described by a 78.Vt driver_t 79structure. The structure contains the name of the device, a pointer 80to a list of methods, an indication of the kind of device which the 81driver implements and the size of the private data which the driver 82needs to associate with a device instance. Each driver will implement 83one or more sets of methods (called interfaces). The example driver 84implements the standard "driver" interface and the fictitious "bogo" 85interface. 86.Pp 87When a driver is registered with the system (by the 88.Dv DRIVER_MODULE 89macro, see 90.Xr DRIVER_MODULE 9 ) , 91it is added to the list of drivers contained in the devclass 92of its parent bus type. For instance all PCI drivers would be 93contained in the devclass named "pci" and all ISA drivers would be 94in the devclass named "isa". 95The reason the drivers are not held in the device object of the parent 96bus is to handle multiple instances of a given type of bus. 97The 98.Dv DRIVER_MODULE 99macro will also create the devclass with the name of the driver and 100can optionally call extra initialisation code in the driver by 101specifying an extra module event handler and argument as the last two 102arguments. 103.Sh SEE ALSO 104.Xr devclass 9 , 105.Xr device 9 , 106.Xr DRIVER_MODULE 9 107.Sh AUTHORS 108This man page was written by 109.An Doug Rabson . 110