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/device_add_child.9,v 1.8.2.5 2001/12/17 11:30:18 ru Exp $ 28.\" 29.Dd June 16, 1998 30.Dt DEVICE_ADD_CHILD 9 31.Os 32.Sh NAME 33.Nm device_add_child , 34.Nm device_add_child_ordered 35.Nd "add a new device as a child of an existing device" 36.Sh SYNOPSIS 37.In sys/param.h 38.In sys/bus.h 39.Ft device_t 40.Fn device_add_child "device_t dev" "const char *name" "int unit" 41.Ft device_t 42.Fn device_add_child_ordered "device_t dev" "int order" "const char *name" "int unit" 43.Sh DESCRIPTION 44Create a new child device of 45.Fa dev . 46The 47.Fa name 48and 49.Fa unit 50arguments specify the name and unit number of the device. 51If the name is unknown then the caller should pass 52.Dv NULL . 53If the unit is unknown then the caller should pass 54.Dv -1 55and the system will choose the next available unit number. 56.Pp 57The name of the device is used to determine which drivers might be 58appropriate for the device. If a name is specified then only drivers 59of that name are probed. If no name is given then all drivers for the 60owning bus are probed. 61.Pp 62This allows busses which can uniquely identify device instances (such 63as PCI) to allow each driver to check each device instance for a 64match. For busses which rely on supplied probe hints where only one 65driver can have a chance of probing the device, the driver name should 66be specified as the device name. 67.Pp 68Normally unit numbers will be chosen automatically by the system and a 69unit number of 70.Dv -1 71should be given. 72When a specific unit number is desired (e.g. for wiring a particular 73piece of hardware to a pre-configured unit number), that unit should 74be passed. If the specified unit number is already allocated, a new 75unit will be allocated and a diagnostic message printed. 76.Pp 77If the devices attached to a bus must be probed in a specific order 78(e.g. for the ISA bus some devices are sensitive to failed probe attempts 79of unrelated drivers and therefore must be probed first), 80the 81.Fa order 82argument of 83.Fn device_add_child_ordered 84should be used to specify a partial ordering. 85The new device will be added before any existing device with a greater 86order. 87If 88.Fn device_add_child 89is used, then the new child will be added as if its order was zero. 90.Sh RETURN VALUES 91The new device if successful, NULL otherwise. 92.Sh SEE ALSO 93.Xr BUS_ADD_CHILD 9 , 94.Xr device 9 95.Sh AUTHORS 96This man page was written by 97.An Doug Rabson . 98