1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 2001 Alexander Langer 4.\" 5.\" All rights reserved. 6.\" 7.\" This program is free software. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28.\" 29.\" $FreeBSD$ 30.\" 31.Dd May 13, 2004 32.Dt DEVICE_IDENTIFY 9 33.Os 34.Sh NAME 35.Nm DEVICE_IDENTIFY 36.Nd identify a device, register it 37.Sh SYNOPSIS 38.In sys/param.h 39.In sys/bus.h 40.Ft void 41.Fn DEVICE_IDENTIFY "driver_t *driver" "device_t parent" 42.Sh DESCRIPTION 43The identify function for a device is only needed for devices on busses 44that cannot identify their children independently, e.g.\& the ISA bus. 45It is used to recognize the device (usually done by accessing non-ambiguous 46registers in the hardware) and to tell the kernel about it and thus 47creating a new device instance. 48.Pp 49.Xr BUS_ADD_CHILD 9 50is used to register the device as a child of the bus. 51The device's resources (such as IRQ and I/O ports) are registered 52with the kernel by calling 53.Fn bus_set_resource 54for each resource (refer to 55.Xr bus_set_resource 9 56for more information). 57.Pp 58Since the device tree and the device driver tree are disjoint, the 59.Fn DEVICE_IDENTIFY 60routine needs to take this into account. 61If you load and unload your device driver that has the identify 62routine, the child node has the potential for adding the same node 63multiple times unless specific measure are taken to preclude that 64possibility. 65.Sh EXAMPLES 66The following pseudo-code shows an example of a function that 67probes for a piece of hardware and registers it and its resource 68(an I/O port) with the kernel. 69.Bd -literal 70void 71foo_identify(driver_t *driver, device_t parent) 72{ 73 device_t child; 74 75 retrieve_device_information; 76 if (devices matches one of your supported devices && 77 not already in device tree) { 78 child = BUS_ADD_CHILD(parent, 0, "foo", -1); 79 bus_set_resource(child, SYS_RES_IOPORT, 0, FOO_IOADDR, 1); 80 } 81} 82.Ed 83.Sh SEE ALSO 84.Xr BUS_ADD_CHILD 9 , 85.Xr bus_set_resource 9 , 86.Xr device 9 , 87.Xr device_add_child 9 , 88.Xr DEVICE_ATTACH 9 , 89.Xr DEVICE_DETACH 9 , 90.Xr DEVICE_PROBE 9 , 91.Xr DEVICE_SHUTDOWN 9 92.Sh AUTHORS 93This manual page was written by 94.An Alexander Langer Aq Mt alex@FreeBSD.org . 95