95 lines
3.3 KiB
Groff
95 lines
3.3 KiB
Groff
.\" -*- nroff -*-
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.\"
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.\" Copyright (c) 2001 Alexander Langer
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.\"
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.\" All rights reserved.
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.\"
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.\" This program is free software.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd May 13, 2004
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.Dt DEVICE_IDENTIFY 9
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.Os
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.Sh NAME
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.Nm DEVICE_IDENTIFY
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.Nd identify a device, register it
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/bus.h
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.Ft void
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.Fn DEVICE_IDENTIFY "driver_t *driver" "device_t parent"
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.Sh DESCRIPTION
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The identify function for a device is only needed for devices on busses
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that cannot identify their children independently, e.g.\& the ISA bus.
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It is used to recognize the device (usually done by accessing non-ambiguous
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registers in the hardware) and to tell the kernel about it and thus
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creating a new device instance.
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.Pp
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.Xr BUS_ADD_CHILD 9
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is used to register the device as a child of the bus.
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The device's resources (such as IRQ and I/O ports) are registered
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with the kernel by calling
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.Fn bus_set_resource
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for each resource (refer to
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.Xr bus_set_resource 9
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for more information).
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.Pp
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Since the device tree and the device driver tree are disjoint, the
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.Fn DEVICE_IDENTIFY
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routine needs to take this into account.
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If you load and unload your device driver that has the identify
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routine, the child node has the potential for adding the same node
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multiple times unless specific measure are taken to preclude that
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possibility.
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.Sh EXAMPLES
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The following pseudo-code shows an example of a function that
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probes for a piece of hardware and registers it and its resource
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(an I/O port) with the kernel.
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.Bd -literal
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void
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foo_identify(driver_t *driver, device_t parent)
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{
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device_t child;
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retrieve_device_information;
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if (devices matches one of your supported devices &&
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not already in device tree) {
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child = BUS_ADD_CHILD(parent, 0, "foo", -1);
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bus_set_resource(child, SYS_RES_IOPORT, 0, FOO_IOADDR, 1);
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}
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}
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.Ed
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.Sh SEE ALSO
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.Xr BUS_ADD_CHILD 9 ,
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.Xr bus_set_resource 9 ,
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.Xr device 9 ,
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.Xr device_add_child 9 ,
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.Xr DEVICE_ATTACH 9 ,
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.Xr DEVICE_DETACH 9 ,
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.Xr DEVICE_PROBE 9 ,
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.Xr DEVICE_SHUTDOWN 9
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.Sh AUTHORS
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This manual page was written by
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.An Alexander Langer Aq Mt alex@FreeBSD.org .
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