freebsd-dev/share/man/man9/device_add_child.9

.\" -*- nroff -*-
.\"
.\" Copyright (c) 1998 Doug Rabson
.\"
.\" All rights reserved.
.\"
.\" This program is free software.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\" $FreeBSD$
.\"
.Dd October 28, 2015
.Dt DEVICE_ADD_CHILD 9
.Os
.Sh NAME
.Nm device_add_child ,
.Nm device_add_child_ordered
.Nd "add a new device as a child of an existing device"
.Sh SYNOPSIS
.In sys/param.h
.In sys/bus.h
.Ft device_t
.Fn device_add_child "device_t dev" "const char *name" "int unit"
.Ft device_t
.Fn device_add_child_ordered "device_t dev" "int order" "const char *name" "int unit"
.Sh DESCRIPTION
Create a new child device of
.Fa dev .
The
.Fa name
and
.Fa unit
arguments specify the name and unit number of the device.
If the name is unknown then the caller should pass
.Dv NULL .
If the unit is unknown then the caller should pass
.Dv -1
and the system will choose the next available unit number.
.Pp
The name of the device is used to determine which drivers might be
appropriate for the device.
If a name is specified then only drivers of that name are probed.
If no name is given then all drivers for the owning bus are probed.
In any event, only the name of the device is stored so that one may
safely unload/load a driver bound to that name.
.Pp
This allows busses which can uniquely identify device instances (such
as PCI) to allow each driver to check each device instance for a
match.
For busses which rely on supplied probe hints where only one
driver can have a chance of probing the device, the driver name should
be specified as the device name.
.Pp
Normally unit numbers will be chosen automatically by the system and a
unit number of
.Dv -1
should be given.
When a specific unit number is desired (e.g.,\& for wiring a particular
piece of hardware to a pre-configured unit number), that unit should
be passed.
If the specified unit number is already allocated, a new
unit will be allocated and a diagnostic message printed.
.Pp
If the devices attached to a bus must be probed in a specific order
(e.g.,\& for the ISA bus some devices are sensitive to failed probe attempts
of unrelated drivers and therefore must be probed first),
the
.Fa order
argument of
.Fn device_add_child_ordered
should be used to specify a partial ordering.
The new device will be added before any existing device with a greater
order.
If
.Fn device_add_child
is used, then the new child will be added as if its order was zero.
.Pp
When adding a device in the context of
.Xr DEVICE_IDENTIFY 9
routine, the
.Xr device_find_child 9
routine should be used to ensure that the device has not already been
added to the tree.
Because the device name and
.Vt devclass_t
are associated at probe time (not child addition time), previous
instances of the driver (say in a module that was later unloaded) may
have already added the instance.
Authors of bus drivers must likewise be careful when adding children
when they are loaded and unloaded to avoid duplication of children
devices.
.Pp
When adding a child to another device node, such as in an identify
routine, use
.Xr BUS_ADD_CHILD 9
instead of
.Xr device_add_child 9 .
.Xr BUS_ADD_CHILD 9
will call
.Xr device_add_child 9
and add the proper bus-specific data to the new child.
.Fn device_add_child
does not call
.Xr BUS_ADD_CHILD 9 .
.Sh RETURN VALUES
The new device if successful, NULL otherwise.
.Sh SEE ALSO
.Xr BUS_ADD_CHILD 9 ,
.Xr device 9 ,
.Xr device_find_child 9 ,
.Xr DEVICE_IDENTIFY 9
.Sh AUTHORS
This manual page was written by
.An Doug Rabson .
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.\" -- nroff --`
			`.\"`
			`.\" Copyright (c) 1998 Doug Rabson`
			`.\"`
			`.\" All rights reserved.`
			`.\"`
			`.\" This program is free software.`
			`.\"`
			`.\" Redistribution and use in source and binary forms, with or without`
			`.\" modification, are permitted provided that the following conditions`
			`.\" are met:`
			`.\" 1. Redistributions of source code must retain the above copyright`
			`.\" notice, this list of conditions and the following disclaimer.`
			`.\" 2. Redistributions in binary form must reproduce the above copyright`
			`.\" notice, this list of conditions and the following disclaimer in the`
			`.\" documentation and/or other materials provided with the distribution.`
			`.\"`
			.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
			`.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES`
			`.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.`
			`.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,`
			`.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT`
			`.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,`
			`.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY`
			`.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT`
			`.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF`
			`.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.`
			`.\"`
$Id$ -> $FreeBSD$ 1999-08-28 00:22:10 +00:00			`.\" $FreeBSD$`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.\"`
BUS_ADD_CHILD calls device_add_child. device_add_child does not call BUS_ADD_CHILD. Make it explicit since it follows the command paradigm rather than the callback paradigm. Add other clarifying notes as well. 2015-10-28 19:11:06 +00:00			`.Dd October 28, 2015`
Various man page cleanup: - Sort xrefs - FreeBSD.ORG -> FreeBSD.org - Be consistent with section names as outlined in mdoc(7). - Other misc mdoc cleanup. PR: doc/13144 Submitted by: Alexey M. Zelkin <phantom@cris.net> 1999-08-15 10:48:36 +00:00			`.Dt DEVICE_ADD_CHILD 9`
mdoc(7) police: removed HISTORY info from the .Os call. 2001-07-10 15:31:11 +00:00			`.Os`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.Sh NAME`
			`.Nm device_add_child ,`
Replace stale references to device_add_child_after(9) with device_child_add_ordered(9) PR: 13210 Submitted by: Alexey Zelkin <phantom@cris.net> Reviewed by: mpp Forgotten by: dfr 1999-09-04 12:37:21 +00:00			`.Nm device_add_child_ordered`
Fix miscellaneous mdoc macro argument limit infringements. PR: 18465 Reported by: Kazu TAKAMUNE <takamune@avrl.mei.co.jp> 2000-05-09 14:02:06 +00:00			`.Nd "add a new device as a child of an existing device"`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.Sh SYNOPSIS`
mdoc(7) police: Use the new .In macro for #include statements. 2001-10-01 16:09:29 +00:00			`.In sys/param.h`
			`.In sys/bus.h`
Fixed wrong function types (the device_add_child() family returns a device_t, not an int). 1999-12-23 17:39:45 +00:00			`.Ft device_t`
Remove mention of 'ivars'. 1999-12-03 11:22:28 +00:00			`.Fn device_add_child "device_t dev" "const char *name" "int unit"`
Fixed wrong function types (the device_add_child() family returns a device_t, not an int). 1999-12-23 17:39:45 +00:00			`.Ft device_t`
Remove mention of 'ivars'. 1999-12-03 11:22:28 +00:00			`.Fn device_add_child_ordered "device_t dev" "int order" "const char *name" "int unit"`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.Sh DESCRIPTION`
			`Create a new child device of`
			`.Fa dev .`
			`The`
			`.Fa name`
			`and`
			`.Fa unit`
			`arguments specify the name and unit number of the device.`
			`If the name is unknown then the caller should pass`
			`.Dv NULL .`
Removed whitespace at end-of-line; no content changes. I simply did cd src/share; find man[1-9] -type f\|xargs perl -pi -e 's/[ \t]+$//' BTW, what editors are the culprits? I'm using vim and it shows me whitespace at EOL in troff files with a thick blue block... Reviewed by: Silence from cvs diff -b MFC after: 7 days 2001-07-14 19:41:16 +00:00			`If the unit is unknown then the caller should pass`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.Dv -1`
			`and the system will choose the next available unit number.`
			`.Pp`
			`The name of the device is used to determine which drivers might be`
Mdoc Janitor: * Fix hard sentence breaks. * NOTE: devstat(9) requires more mdoc(7) work. 2003-10-23 01:54:06 +00:00			`appropriate for the device.`
			`If a name is specified then only drivers of that name are probed.`
Add caveats about adding devices in the IDENTIFY context. 2004-05-13 20:29:40 +00:00			`If no name is given then all drivers for the owning bus are probed.`
			`In any event, only the name of the device is stored so that one may`
			`safely unload/load a driver bound to that name.`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.Pp`
			`This allows busses which can uniquely identify device instances (such`
			`as PCI) to allow each driver to check each device instance for a`
Mdoc Janitor: * Fix hard sentence breaks. * NOTE: devstat(9) requires more mdoc(7) work. 2003-10-23 01:54:06 +00:00			`match.`
			`For busses which rely on supplied probe hints where only one`
Fix a couple of typos 2005-08-09 10:30:25 +00:00			`driver can have a chance of probing the device, the driver name should`
			`be specified as the device name.`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.Pp`
Removed whitespace at end-of-line; no content changes. I simply did cd src/share; find man[1-9] -type f\|xargs perl -pi -e 's/[ \t]+$//' BTW, what editors are the culprits? I'm using vim and it shows me whitespace at EOL in troff files with a thick blue block... Reviewed by: Silence from cvs diff -b MFC after: 7 days 2001-07-14 19:41:16 +00:00			`Normally unit numbers will be chosen automatically by the system and a`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`unit number of`
			`.Dv -1`
			`should be given.`
BUS_ADD_CHILD calls device_add_child. device_add_child does not call BUS_ADD_CHILD. Make it explicit since it follows the command paradigm rather than the callback paradigm. Add other clarifying notes as well. 2015-10-28 19:11:06 +00:00			`When a specific unit number is desired (e.g.,\& for wiring a particular`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`piece of hardware to a pre-configured unit number), that unit should`
Mdoc Janitor: * Fix hard sentence breaks. * NOTE: devstat(9) requires more mdoc(7) work. 2003-10-23 01:54:06 +00:00			`be passed.`
			`If the specified unit number is already allocated, a new`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`unit will be allocated and a diagnostic message printed.`
			`.Pp`
			`If the devices attached to a bus must be probed in a specific order`
BUS_ADD_CHILD calls device_add_child. device_add_child does not call BUS_ADD_CHILD. Make it explicit since it follows the command paradigm rather than the callback paradigm. Add other clarifying notes as well. 2015-10-28 19:11:06 +00:00			`(e.g.,\& for the ISA bus some devices are sensitive to failed probe attempts`
Document device_add_child_ordered(). 1999-05-28 09:38:25 +00:00			`of unrelated drivers and therefore must be probed first),`
			`the`
			`.Fa order`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`argument of`
mdoc(7) police: Deal with self-xrefs. 2002-12-24 13:41:48 +00:00			`.Fn device_add_child_ordered`
Document device_add_child_ordered(). 1999-05-28 09:38:25 +00:00			`should be used to specify a partial ordering.`
Removed whitespace at end-of-line; no content changes. I simply did cd src/share; find man[1-9] -type f\|xargs perl -pi -e 's/[ \t]+$//' BTW, what editors are the culprits? I'm using vim and it shows me whitespace at EOL in troff files with a thick blue block... Reviewed by: Silence from cvs diff -b MFC after: 7 days 2001-07-14 19:41:16 +00:00			`The new device will be added before any existing device with a greater`
Document device_add_child_ordered(). 1999-05-28 09:38:25 +00:00			`order.`
Removed whitespace at end-of-line; no content changes. I simply did cd src/share; find man[1-9] -type f\|xargs perl -pi -e 's/[ \t]+$//' BTW, what editors are the culprits? I'm using vim and it shows me whitespace at EOL in troff files with a thick blue block... Reviewed by: Silence from cvs diff -b MFC after: 7 days 2001-07-14 19:41:16 +00:00			`If`
mdoc(7) police: Deal with self-xrefs. 2002-12-24 13:41:48 +00:00			`.Fn device_add_child`
Document device_add_child_ordered(). 1999-05-28 09:38:25 +00:00			`is used, then the new child will be added as if its order was zero.`
Add caveats about adding devices in the IDENTIFY context. 2004-05-13 20:29:40 +00:00			`.Pp`
			`When adding a device in the context of`
			`.Xr DEVICE_IDENTIFY 9`
Mention how to ensure that a device hasn't already been identified 2005-08-09 11:14:21 +00:00			`routine, the`
Fix a misspelled reference. 2006-01-13 11:24:08 +00:00			`.Xr device_find_child 9`
Mention how to ensure that a device hasn't already been identified 2005-08-09 11:14:21 +00:00			`routine should be used to ensure that the device has not already been`
			`added to the tree.`
Add caveats about adding devices in the IDENTIFY context. 2004-05-13 20:29:40 +00:00			`Because the device name and`
Assorted markup, spelling, and grammar fixes. 2004-06-16 08:33:57 +00:00			`.Vt devclass_t`
Add caveats about adding devices in the IDENTIFY context. 2004-05-13 20:29:40 +00:00			`are associated at probe time (not child addition time), previous`
			`instances of the driver (say in a module that was later unloaded) may`
			`have already added the instance.`
			`Authors of bus drivers must likewise be careful when adding children`
			`when they are loaded and unloaded to avoid duplication of children`
			`devices.`
Add note about identify routines needing to use BUS_ADD_CHILD rather than device_add_child. The latter is only for busses adding children, not children drivers telling a bus that they have an instance... 2006-09-11 22:17:18 +00:00			`.Pp`
BUS_ADD_CHILD calls device_add_child. device_add_child does not call BUS_ADD_CHILD. Make it explicit since it follows the command paradigm rather than the callback paradigm. Add other clarifying notes as well. 2015-10-28 19:11:06 +00:00			`When adding a child to another device node, such as in an identify`
			`routine, use`
Add note about identify routines needing to use BUS_ADD_CHILD rather than device_add_child. The latter is only for busses adding children, not children drivers telling a bus that they have an instance... 2006-09-11 22:17:18 +00:00			`.Xr BUS_ADD_CHILD 9`
			`instead of`
			`.Xr device_add_child 9 .`
BUS_ADD_CHILD calls device_add_child. device_add_child does not call BUS_ADD_CHILD. Make it explicit since it follows the command paradigm rather than the callback paradigm. Add other clarifying notes as well. 2015-10-28 19:11:06 +00:00			`.Xr BUS_ADD_CHILD 9`
			`will call`
			`.Xr device_add_child 9`
			`and add the proper bus-specific data to the new child.`
			`.Fn device_add_child`
			`does not call`
			`.Xr BUS_ADD_CHILD 9 .`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.Sh RETURN VALUES`
			`The new device if successful, NULL otherwise.`
			`.Sh SEE ALSO`
Add note about identify routines needing to use BUS_ADD_CHILD rather than device_add_child. The latter is only for busses adding children, not children drivers telling a bus that they have an instance... 2006-09-11 22:17:18 +00:00			`.Xr BUS_ADD_CHILD 9 ,`
-mdoc sweep. 2005-11-18 10:56:28 +00:00			`.Xr device 9 ,`
Fix a misspelled reference. 2006-01-13 11:24:08 +00:00			`.Xr device_find_child 9 ,`
Mention how to ensure that a device hasn't already been identified 2005-08-09 11:14:21 +00:00			`.Xr DEVICE_IDENTIFY 9`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.Sh AUTHORS`
Mdoc Janitor: * Use 'manual' instead of 'man' for consistency. 2003-10-23 06:24:55 +00:00			`This manual page was written by`
Add manpages for the new device framework. 1998-09-03 21:52:05 +00:00			`.An Doug Rabson .`