1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 1998 Doug Rabson 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: src/share/man/man9/device_add_child.9,v 1.8.2.5 2001/12/17 11:30:18 ru Exp $ 30.\" $DragonFly: src/share/man/man9/device_add_child.9,v 1.2 2003/06/17 04:37:01 dillon Exp $ 31.\" 32.Dd June 16, 1998 33.Dt DEVICE_ADD_CHILD 9 34.Os 35.Sh NAME 36.Nm device_add_child , 37.Nm device_add_child_ordered 38.Nd "add a new device as a child of an existing device" 39.Sh SYNOPSIS 40.In sys/param.h 41.In sys/bus.h 42.Ft device_t 43.Fn device_add_child "device_t dev" "const char *name" "int unit" 44.Ft device_t 45.Fn device_add_child_ordered "device_t dev" "int order" "const char *name" "int unit" 46.Sh DESCRIPTION 47Create a new child device of 48.Fa dev . 49The 50.Fa name 51and 52.Fa unit 53arguments specify the name and unit number of the device. 54If the name is unknown then the caller should pass 55.Dv NULL . 56If the unit is unknown then the caller should pass 57.Dv -1 58and the system will choose the next available unit number. 59.Pp 60The name of the device is used to determine which drivers might be 61appropriate for the device. If a name is specified then only drivers 62of that name are probed. If no name is given then all drivers for the 63owning bus are probed. 64.Pp 65This allows busses which can uniquely identify device instances (such 66as PCI) to allow each driver to check each device instance for a 67match. For busses which rely on supplied probe hints where only one 68driver can have a change of probing the device, the driver name should 69specified as the device name. 70.Pp 71Normally unit numbers will be chosen automatically by the system and a 72unit number of 73.Dv -1 74should be given. 75When a specific unit number is desired (e.g. for wiring a particular 76piece of hardware to a pre-configured unit number), that unit should 77be passed. If the specified unit number is already allocated, a new 78unit will be allocated and a diagnostic message printed. 79.Pp 80If the devices attached to a bus must be probed in a specific order 81(e.g. for the ISA bus some devices are sensitive to failed probe attempts 82of unrelated drivers and therefore must be probed first), 83the 84.Fa order 85argument of 86.Xr device_add_child_ordered 9 87should be used to specify a partial ordering. 88The new device will be added before any existing device with a greater 89order. 90If 91.Xr device_add_child 9 92is used, then the new child will be added as if its order was zero. 93.Sh RETURN VALUES 94The new device if successful, NULL otherwise. 95.Sh SEE ALSO 96.Xr device 9 97.Sh AUTHORS 98This man page was written by 99.An Doug Rabson . 100