186d7f5d3SJohn Marino.\" Copyright (c) 1998, Nicolas Souchu 286d7f5d3SJohn Marino.\" All rights reserved. 386d7f5d3SJohn Marino.\" 486d7f5d3SJohn Marino.\" Redistribution and use in source and binary forms, with or without 586d7f5d3SJohn Marino.\" modification, are permitted provided that the following conditions 686d7f5d3SJohn Marino.\" are met: 786d7f5d3SJohn Marino.\" 1. Redistributions of source code must retain the above copyright 886d7f5d3SJohn Marino.\" notice, this list of conditions and the following disclaimer. 986d7f5d3SJohn Marino.\" 2. Redistributions in binary form must reproduce the above copyright 1086d7f5d3SJohn Marino.\" notice, this list of conditions and the following disclaimer in the 1186d7f5d3SJohn Marino.\" documentation and/or other materials provided with the distribution. 1286d7f5d3SJohn Marino.\" 1386d7f5d3SJohn Marino.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1486d7f5d3SJohn Marino.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1586d7f5d3SJohn Marino.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1686d7f5d3SJohn Marino.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1786d7f5d3SJohn Marino.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1886d7f5d3SJohn Marino.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 1986d7f5d3SJohn Marino.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2086d7f5d3SJohn Marino.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2186d7f5d3SJohn Marino.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2286d7f5d3SJohn Marino.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2386d7f5d3SJohn Marino.\" SUCH DAMAGE. 2486d7f5d3SJohn Marino.\" 2586d7f5d3SJohn Marino.\" $FreeBSD: src/share/man/man4/smbus.4,v 1.9.2.3 2001/08/17 13:08:39 ru Exp $ 2686d7f5d3SJohn Marino.\" $DragonFly: src/share/man/man4/smbus.4,v 1.2 2003/06/17 04:36:59 dillon Exp $ 2786d7f5d3SJohn Marino.\" 2886d7f5d3SJohn Marino.Dd August 10, 1998 2986d7f5d3SJohn Marino.Dt SMBUS 4 3086d7f5d3SJohn Marino.Os 3186d7f5d3SJohn Marino.Sh NAME 3286d7f5d3SJohn Marino.Nm smbus 3386d7f5d3SJohn Marino.Nd System Management Bus 3486d7f5d3SJohn Marino.Sh SYNOPSIS 3586d7f5d3SJohn Marino.Cd "device smbus" 3686d7f5d3SJohn Marino.Pp 3786d7f5d3SJohn Marino.Cd "device iicsmb" 3886d7f5d3SJohn Marino.Cd "device bktr" 3986d7f5d3SJohn Marino.Sh DESCRIPTION 4086d7f5d3SJohn MarinoThe 4186d7f5d3SJohn Marino.Em smbus 4286d7f5d3SJohn Marinosystem provides a uniform, modular and architecture-independent 4386d7f5d3SJohn Marinosystem for the implementation of drivers to control various SMB devices 4486d7f5d3SJohn Marinoand to utilize different SMB controllers (I2C, PIIX4, Brooktree848, vm86...). 4586d7f5d3SJohn Marino.Sh System Management Bus 4686d7f5d3SJohn MarinoThe 4786d7f5d3SJohn Marino.Em System Management Bus 4886d7f5d3SJohn Marinois a two-wire interface through which simple power-related chips can communicate 4986d7f5d3SJohn Marinowith rest of the system. 5086d7f5d3SJohn MarinoIt uses I2C as its backbone (see 5186d7f5d3SJohn Marino.Xr iicbus 4 ) . 5286d7f5d3SJohn Marino.Pp 5386d7f5d3SJohn MarinoA system using SMB passes messages to and from devices instead of tripping 5486d7f5d3SJohn Marinoindividual control lines. 5586d7f5d3SJohn Marino.Pp 5686d7f5d3SJohn MarinoWith the SMBus, a device can provide manufacturer information, tell the 5786d7f5d3SJohn Marinosystem what its model/part number is, save its state for a suspend event, 5886d7f5d3SJohn Marinoreport different types of errors, accept control parameters, and return its 5986d7f5d3SJohn Marinostatus. 6086d7f5d3SJohn Marino.Pp 6186d7f5d3SJohn MarinoThe SMBus may share the same host device and physical bus as ACCESS bus 6286d7f5d3SJohn Marinocomponents provided that an appropriate electrical bridge is provided 6386d7f5d3SJohn Marinobetween the internal SMB devices and external ACCESS bus devices. 6486d7f5d3SJohn Marino.Sh SEE ALSO 6586d7f5d3SJohn Marino.Xr bktr 4 , 6686d7f5d3SJohn Marino.Xr iicbus 4 , 6786d7f5d3SJohn Marino.Xr iicsmb 4 , 6886d7f5d3SJohn Marino.Xr smb 4 6986d7f5d3SJohn Marino.Sh HISTORY 7086d7f5d3SJohn MarinoThe 7186d7f5d3SJohn Marino.Nm 7286d7f5d3SJohn Marinomanual page first appeared in 7386d7f5d3SJohn Marino.Fx 3.0 . 7486d7f5d3SJohn Marino.Sh AUTHORS 7586d7f5d3SJohn MarinoThis 7686d7f5d3SJohn Marinomanual page was written by 7786d7f5d3SJohn Marino.An Nicolas Souchu . 78