ae1f3df434
only gpiobus configured via FDT is supported. Bus enumeration is supported. Devices are created for each device found. 1-Wire temperature controllers are supported, but other drivers could be written. Temperatures are polled and reported via a sysctl. Errors are reported via sysctl counters. Mis-wired bus detection is included for more trouble shooting. See ow(4), owc(4) and ow_temp(4) for details of what's supported and known issues. This has been tested on Raspberry Pi-B, Pi2 and Beagle Bone Black with up to 7 devices. Differential Revision: https://reviews.freebsd.org/D2956 Relnotes: yes MFC after: 2 weeks Reviewed by: loos@ (with many insightful comments)
94 lines
2.9 KiB
Groff
94 lines
2.9 KiB
Groff
.\"
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.\" Copyright (c) 2015 M. Warner Losh
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.\" All rights reserved.
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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. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 20, 2015
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.Dt OWLL 9
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.Os
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.Sh NAME
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.Nm owll
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.Nm OWLL_WRITE_ONE,
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.Nm OWLL_WRITE_ZERO,
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.Nm OWLL_READ_DATA,
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.Nm OWLL_REASET_AND_PRESENCE
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.Nd Dallas Semiconductor 1-Wire Link Layer Interface
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.Sh SYNOPSIS
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.Ft int
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.Fn OWLL_WRITE_ONE "device_t lldev" "struct ow_timing *timing"
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.Ft int
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.Fn OWLL_WRITE_ZERO "device_t lldev" "struct ow_timing *timing"
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.Ft int
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.Fn OWLL_READ_DATA "device_t lldev" "struct ow_timing *timing" "int *bit"
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.Ft int
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.Fn OWLL_RESET_AND_PRESENCE "device_t lldev" "struct ow_timing *timing" "int *bit"
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.Sh DESCRIPTION
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The
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.Nm
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interface provides access to the link layer of the Dallas
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Semiconductor 1-Wire from upper layers of the protocol.
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.Pp
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.Fn OWLL_WRITE_ONE
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and
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.Fn OWLL_WRITE_ZERO
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writes a one bitor a zero bit respectively on the 1-Wire bus.
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.Pp
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.Fn OWLL_READ_DATA
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reads one bit from the 1-Wire bus.
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This is often referred to as a
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.Dq Read Time Slot
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in the 1-Wire device data sheets.
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.Pp
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The
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.Fn OWLL_RESET_AND_PRESENCE
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function starts a reset sequence and detects if any device(s) are
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present on the bus.
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This is the beginning of all 1-Wire transactions.
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.Sh NOTES
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This interface is intended to be used only by the
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.Xr ow 4
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device to talk to the low-level bus.
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By convention, the device that implements this interface is called
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.Xr owc 4 .
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Only devices that implement
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.Xr own 9
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should call these interfaces.
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.Sh SEE ALSO
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.Xr ow 4 ,
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.Xr owc 4 ,
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.Xr own 9
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.Sh LEGAL
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.Tn 1-Wire
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is a registered trademark of Maxim Integrated Products, Inc.
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.Sh HISTORY
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The
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.Nm
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driver first appeared in
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.Fx 11.0 .
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.Sh AUTHORS
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The
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.Nm
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device driver and this manual page were written by
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.An Warner Losh .
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