.\"-
.\" Copyright (c) 2004 Jason L. Wright (jason@thought.net)
.\" Copyright (c) 2005 Marius Strobl <marius@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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.\" DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\"	from: OpenBSD: clock.4,v 1.3 2004/09/24 07:04:15 miod Exp
.\" $FreeBSD$
.\"
.Dd June 18, 2005
.Dt EEPROM 4 sparc64
.Os
.Sh NAME
.Nm eeprom
.Nd "non-volatile RAM / real time clock"
.Sh SYNOPSIS
.Cd "device genclock"
.Cd "device mk48txx"
.Cd "device eeprom"
.Sh DESCRIPTION
The
.Nm
driver is a front-end for the machine-independent
.Tn Mostek
MK48Txx driver.
The
.Tn Mostek
MK48Txx driver provides access to the real time clock part of the chips it
supports to
.Fx
by interfacing with the generic clock code.
.Pp
.Tn Mostek
MK48Txx chips are found on the
.Tn EBus ,
.Tn FireHose
and
.Tn SBus
busses of
.Tn UltraSPARC
systems.
On systems where the hostid is stored in the NVRAM part of the Mostek MK48Txx
chip the
.Nm
driver prints out the hostid on attach.
.Sh DIAGNOSTICS
The following driver specific error message may be reported:
.Bl -diag
.It "mk48txx_attach: battery low"
The device signals that its battery is low and should be replaced.
The
.Nm
driver refused to attach the device in this case as the time in the real time
clock is probably invalid.
This gives the generic clock code the chance to use another device as the
system real time clock that otherwise would not have been chosen.
.El
.Sh SEE ALSO
.Xr ebus 4 ,
.Xr fhc 4 ,
.Xr rtc 4 ,
.Xr sbus 4
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 5.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An "Thomas Moestl" Aq tmm@FreeBSD.org
based on the
.Nx
sparc64 clock code written by
.An "Paul Kranenburg" .