NetBSD/share/man/man4/intersil7170.4

.\"	$NetBSD: intersil7170.4,v 1.6 2002/02/13 08:17:37 ross Exp $
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.\" Copyright (c) 2000 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Paul Kranenburg.
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.Dd July 20, 2000
.Dt INTERSIL7170 4
.Os
.Sh NAME
.Nm intersil7170
.Nd
.Tn Intersil time-of-day clock driver
.Sh SYNOPSIS
.Fd #include \*[Lt]dev/ic/intersil7170.h\*[Gt]
.Cd "define intersil7170"
.Cd "file   dev/ic/intersil7170.c    intersil7170"
.Sh DESCRIPTION
The
.Nm
driver provides access to the
.Tn Intersil 7170
time-of-day clock chip. Access methods to retrieve and set date and time
are provided through the
.Em TODR
interface defined in
.Xr todr 9 .
.Pp
To tie in instance of this device to the system, use
.nr nS 1
.Ft "todr_chip_handle_t"
.Fn intersil7170_attach "bus_space_tag_t bus_tag" \
"bus_space_handle_t bus_handle" "int year0"
.Pp
.Bl -tag -width Dv -offset indent
.It Fa bus_tag
.It Fa bus_handle
Specify bus space access to the chip's non-volatile memory
.Pq including the clock registers .
.It Fa year0
The actual year represented by the clock's
.Sq year
counter. This is generally dependent on the system configuration in which
the clock device is mounted. For instance, on Sun Microsystems machines
the convention is to have clock's two-digit year represent the year 1968.
.El
.Pp
Note that if the resulting date retrieved with the todr_gettime() method
is earlier that January 1, 1970, the driver will assume that the chip's
year counter actually represents a year in the 21st century. This
behaviour can be overridden by setting the global variable
.Va intersil7170_auto_century_adjust
to zero.
.Sh SEE ALSO
.Xr intro 4 ,
.Xr todr 9
.Sh HISTORY
The
.Nm
driver first appeared in
.Nx 1.5 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Paul Kranenburg
.Aq pk@netbsd.org .