.\" Copyright (c) 2001 Alexander Langer
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.\" $FreeBSD: src/share/man/man9/DEVICE_IDENTIFY.9,v 1.2.2.5 2002/03/19 18:24:16 schweikh Exp $
.\" $DragonFly: src/share/man/man9/DEVICE_IDENTIFY.9,v 1.3 2004/06/01 11:36:53 hmp Exp $
.\"
.Dd March 10, 2001
.Dt DEVICE_IDENTIFY 9
.Os
.Sh NAME
.Nm DEVICE_IDENTIFY
.Nd identify a device, register it
.Sh SYNOPSIS
.In sys/param.h
.In sys/bus.h
.Ft void
.Fn DEVICE_IDENTIFY "driver_t *driver" "device_t parent"
.Sh DESCRIPTION
The identify function for a device is only needed for devices on busses
that cannot identify their children independently, e.g. the ISA bus.
It is used to recognize the device (usually done by accessing non-ambigous
registers in the hardware) and to tell the kernel about it and thus
creating a new device instance.
.Pp
.Xr BUS_ADD_CHILD 9
is used to register the device as a child of the bus.
The device's resources (such as IRQ and I/O ports) are registered
with the kernel by calling
.Fn bus_set_resource
for each resource (refer to
.Xr bus_set_resource 9
for more information).
.Sh EXAMPLES
The following pseudo-code shows an example of a function that
probes for a piece of hardware and registers it and its resource
(an I/O port) with the kernel.
It also sets the description of the device.
.Bd -literal
void
foo_identify(driver_t *driver, device_t parent)
{
	device_t child;

	retrieve_device_information;
	if (devices matches one of your supported devices) {
		child = BUS_ADD_CHILD(parent, 0, "foo", -1);
		device_set_desc_copy(child, "foo chip ver.123");
		device_set_driver(child, driver);
		bus_set_resource(child, SYS_RES_IOPORT, 0, FOO_IOADDR, 1);
	}
}
.Ed
.Sh RETURN VALUES
Zero is returned on success,
otherwise an appropriate error is returned (see
.Xr errno 2 ) .
.Sh SEE ALSO
.Xr BUS_ADD_CHILD 9 ,
.Xr bus_set_resource 9 ,
.Xr device 9 ,
.Xr device_add_child 9 ,
.Xr DEVICE_ATTACH 9 ,
.Xr DEVICE_DETACH 9 ,
.Xr DEVICE_PROBE 9 ,
.Xr device_set_desc_copy 9 ,
.Xr device_set_driver 9 ,
.Xr DEVICE_SHUTDOWN 9
.Sh AUTHORS
This man page was written by
.An Alexander Langer Aq alex@FreeBSD.org .