1 .\" Copyright (c) 2001 Alexander Langer
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27 .\" $FreeBSD: src/share/man/man9/DEVICE_IDENTIFY.9,v 1.2.2.5 2002/03/19 18:24:16 schweikh Exp $
28 .\" $DragonFly: src/share/man/man9/DEVICE_IDENTIFY.9,v 1.3 2004/06/01 11:36:53 hmp Exp $
35 .Nd identify a device, register it
40 .Fn DEVICE_IDENTIFY "driver_t *driver" "device_t parent"
42 The identify function for a device is only needed for devices on busses
43 that cannot identify their children independently, e.g. the ISA bus.
44 It is used to recognize the device (usually done by accessing non-ambigous
45 registers in the hardware) and to tell the kernel about it and thus
46 creating a new device instance.
49 is used to register the device as a child of the bus.
50 The device's resources (such as IRQ and I/O ports) are registered
51 with the kernel by calling
53 for each resource (refer to
54 .Xr bus_set_resource 9
55 for more information).
57 The following pseudo-code shows an example of a function that
58 probes for a piece of hardware and registers it and its resource
59 (an I/O port) with the kernel.
60 It also sets the description of the device.
63 foo_identify(driver_t *driver, device_t parent)
67 retrieve_device_information;
68 if (devices matches one of your supported devices) {
69 child = BUS_ADD_CHILD(parent, 0, "foo", -1);
70 device_set_desc_copy(child, "foo chip ver.123");
71 device_set_driver(child, driver);
72 bus_set_resource(child, SYS_RES_IOPORT, 0, FOO_IOADDR, 1);
77 Zero is returned on success,
78 otherwise an appropriate error is returned (see
82 .Xr bus_set_resource 9 ,
84 .Xr device_add_child 9 ,
88 .Xr device_set_desc_copy 9 ,
89 .Xr device_set_driver 9 ,
92 This man page was written by
93 .An Alexander Langer Aq alex@FreeBSD.org .