2 .\" Copyright (c) 2004 Jason L. Wright (jason@thought.net)
3 .\" Copyright (c) 2005 Marius Strobl <marius@FreeBSD.org>
4 .\" All rights reserved.
6 .\" Redistribution and use in source and binary forms, with or without
7 .\" modification, are permitted provided that the following conditions
9 .\" 1. Redistributions of source code must retain the above copyright
10 .\" notice, this list of conditions and the following disclaimer.
11 .\" 2. Redistributions in binary form must reproduce the above copyright
12 .\" notice, this list of conditions and the following disclaimer in the
13 .\" documentation and/or other materials provided with the distribution.
15 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 .\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 .\" DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
19 .\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
20 .\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 .\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
23 .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
24 .\" ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 .\" POSSIBILITY OF SUCH DAMAGE.
27 .\" from: OpenBSD: clock.4,v 1.3 2004/09/24 07:04:15 miod Exp
35 .Nd "non-volatile RAM / real time clock"
43 driver is a front-end for the machine-independent
48 MK48Txx driver provides access to the real time clock part of the chips it
51 by interfacing with the generic clock code.
54 MK48Txx chips are found on the
62 On systems where the hostid is stored in the NVRAM part of the Mostek MK48Txx
65 driver prints out the hostid on attach.
67 The following driver specific error message may be reported:
69 .It "mk48txx_attach: battery low"
70 The device signals that its battery is low and should be replaced.
73 driver refused to attach the device in this case as the time in the real time
74 clock is probably invalid.
75 This gives the generic clock code the chance to use another device as the
76 system real time clock that otherwise would not have been chosen.
86 driver first appeared in
93 .An "Thomas Moestl" Aq tmm@FreeBSD.org
96 sparc64 clock code written by
97 .An "Paul Kranenburg" .