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.Dd March 7, 2021
.Dt SMBUS 4
.Os
.Sh NAME
.Nm smbus
.Nd System Management Bus
.Sh SYNOPSIS
.Cd "device smbus"
.Pp
.Cd "device iicsmb"
.Sh DESCRIPTION
The
.Em smbus
system provides a uniform, modular and architecture-independent
system for the implementation of drivers to control various SMB devices
and to utilize different SMB controllers (I2C, PIIX4, vm86...).
.Sh System Management Bus
The
.Em System Management Bus
is a two-wire interface through which simple power-related chips can communicate
with rest of the system.
It uses I2C as its backbone (see
.Xr iicbus 4 ) .
.Pp
A system using SMB passes messages to and from devices instead of tripping
individual control lines.
.Pp
With the SMBus, a device can provide manufacturer information, tell the
system what its model/part number is, save its state for a suspend event,
report different types of errors, accept control parameters, and return its
status.
.Pp
The SMBus may share the same host device and physical bus as ACCESS bus
components provided that an appropriate electrical bridge is provided
between the internal SMB devices and external ACCESS bus devices.
.Sh SEE ALSO
.Xr iicbus 4 ,
.Xr iicsmb 4 ,
.Xr smb 4
.Rs
.%T The SMBus specification
.%U http://www.smbus.org/specs/
.Re
.Sh HISTORY
The
.Nm
manual page first appeared in
.Fx 3.0 .
.Sh AUTHORS
This
manual page was written by
.An Nicolas Souchu .