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.\" $DragonFly: src/share/man/man9/device_add_child.9,v 1.3 2004/06/01 11:36:53 hmp Exp $ 29.\" 30.Dd June 16, 1998 31.Dt DEVICE_ADD_CHILD 9 32.Os 33.Sh NAME 34.Nm device_add_child , 35.Nm device_add_child_ordered 36.Nd "add a new device as a child of an existing device" 37.Sh SYNOPSIS 38.In sys/param.h 39.In sys/bus.h 40.Ft device_t 41.Fn device_add_child "device_t dev" "const char *name" "int unit" 42.Ft device_t 43.Fn device_add_child_ordered "device_t dev" "int order" "const char *name" "int unit" 44.Sh DESCRIPTION 45Create a new child device of 46.Fa dev . 47The 48.Fa name 49and 50.Fa unit 51arguments specify the name and unit number of the device. 52If the name is unknown then the caller should pass 53.Dv NULL . 54If the unit is unknown then the caller should pass 55.Dv -1 56and the system will choose the next available unit number. 57.Pp 58The name of the device is used to determine which drivers might be 59appropriate for the device. If a name is specified then only drivers 60of that name are probed. If no name is given then all drivers for the 61owning bus are probed. 62.Pp 63This allows busses which can uniquely identify device instances (such 64as PCI) to allow each driver to check each device instance for a 65match. For busses which rely on supplied probe hints where only one 66driver can have a chance of probing the device, the driver name should 67be specified as the device name. 68.Pp 69Normally unit numbers will be chosen automatically by the system and a 70unit number of 71.Dv -1 72should be given. 73When a specific unit number is desired (e.g. for wiring a particular 74piece of hardware to a pre-configured unit number), that unit should 75be passed. If the specified unit number is already allocated, a new 76unit will be allocated and a diagnostic message printed. 77.Pp 78If the devices attached to a bus must be probed in a specific order 79(e.g. for the ISA bus some devices are sensitive to failed probe attempts 80of unrelated drivers and therefore must be probed first), 81the 82.Fa order 83argument of 84.Xr device_add_child_ordered 9 85should be used to specify a partial ordering. 86The new device will be added before any existing device with a greater 87order. 88If 89.Xr device_add_child 9 90is used, then the new child will be added as if its order was zero. 91.Sh RETURN VALUES 92The new device if successful, NULL otherwise. 93.Sh SEE ALSO 94.Xr BUS_ADD_CHILD 9 , 95.Xr device 9 96.Sh AUTHORS 97This man page was written by 98.An Doug Rabson . 99