141 lines
4.6 KiB
Groff
141 lines
4.6 KiB
Groff
.\" $NetBSD: mk48txx.4,v 1.11 2003/06/27 18:36:20 wiz Exp $
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.\"
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.\" Copyright (c) 2000, 2002 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Paul Kranenburg.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd February 25, 2002
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.Dt MK48TXX 4
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.Os
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.Sh NAME
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.Nm mk48txx
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.Nd
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.Tn Mostek time-of-day clock driver
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.Sh SYNOPSIS
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.In dev/ic/mk48txxreg.h
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.Cd "define mk48txx"
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.Cd "file dev/ic/mk48txx.c mk48txx"
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.Sh DESCRIPTION
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The
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.Nm
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driver provides access to several models of
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.Tn Mostek
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time-of-day clock chips.
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Access methods to retrieve and set date and time
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are provided through the
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.Em TODR
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interface defined in
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.Xr todr 9 .
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.Pp
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To tie in instance of this device to the system, use
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.Bd -literal
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typedef uint8_t (*mk48txx_nvrd_t)(bus_space_tag_t bus_tag,
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bus_space_handle_t bus_handle, int off);
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typedef void (*mk48txx_nvwr_t)(bus_space_tag_t bus_tag,
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bus_space_handle_t bus_handle, int off, uint8_t datum);
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.Ed
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.nr nS 1
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.Ft "todr_chip_handle_t"
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.Fn mk48txx_attach "bus_space_tag_t bus_tag" "bus_space_handle_t bus_handle" \
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"const char *model" "int year0" \
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"mk48txx_nvrd_t nvread" "mk48txx_nvwr_t nvwrite"
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.Pp
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.Bl -tag -width Dv -offset indent
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.It Fa bus_tag
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.It Fa bus_handle
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Specify bus space access to the chip's non-volatile memory
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.Pq including the clock registers .
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.It Fa model
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The chip model which this instance should serve.
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Must be one of
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.Dq mk48t02 ,
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.Dq mk48t08 ,
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.Dq mk48t18
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or
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.Dq mk48t59 .
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.It Fa year0
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The actual year represented by the clock's
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.Sq year
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counter.
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This is generally dependent on the system configuration in which
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the clock device is mounted.
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For instance, on Sun Microsystems machines
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the convention is to have clock's two-digit year represent the year 1968.
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.It Fa nvread
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.It Fa nvwrite
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Specify alternate access methods for reading resp. writing clock
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device registers.
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The default, when
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.Dv NULL
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is passed as an access method, is to access the chip memory
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.Pq and clock registers
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as if they were direct-mapped with using the specified bus space.
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.Pp
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Otherwise, the driver will call the respective function to perform the
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access, passing it the specified bus space and the offset
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.Va off
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of the chip memory
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.Pq or clock register
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location to be read from or written to, respectively.
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.El
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.Pp
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Note that if the resulting date retrieved with the todr_gettime() method
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is earlier that January 1, 1970, the driver will assume that the chip's
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year counter actually represents a year in the 21st century.
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This behaviour can be overridden by setting the global variable
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.Va mk48txx_auto_century_adjust
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to zero.
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.Sh HARDWARE
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The following models are supported:
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.Pp
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.Bl -tag -width indent -offset indent -compact
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.It Tn Mostek MK48T02
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.It Tn Mostek MK48T08
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.It Tn Mostek MK48T18
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.It Tn Mostek MK48T59
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.El
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.Sh SEE ALSO
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.Xr intro 4 ,
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.Xr todr 9
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.Sh HISTORY
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The
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.Nm mk48txx
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driver first appeared in
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.Nx 1.5 .
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.Sh AUTHORS
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The
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.Nm
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driver was written by
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.An Paul Kranenburg
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.Aq pk@NetBSD.org .
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