83 lines
2.9 KiB
Groff
83 lines
2.9 KiB
Groff
.\" $NetBSD: acpismbus.4,v 1.2 2010/02/06 21:57:08 wiz Exp $
|
|
.\"
|
|
.\" Copyright (c) 2009 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by Paul Goyette
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
|
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
|
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
.\" POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.Dd February 6, 2010
|
|
.Dt ACPISMBUS 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm acpismbus
|
|
.Nd ACPI SMBus Control Method Interface
|
|
.Sh SYNOPSIS
|
|
.Cd "acpismbus* at acpi?"
|
|
.Cd "iic* at acpismbus?"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
driver supports instances of the ACPI SMBus Control Method Interface.
|
|
This enables i2c access to bus segments which might not otherwise be
|
|
accessible due to missing "native" driver support.
|
|
The SMBus Process Call protocol is not supported.
|
|
All other SMBus protocols are supported to the extent that the underlying
|
|
controller supports them.
|
|
.Sh SEE ALSO
|
|
.Xr acpi 4 ,
|
|
.Xr iic 4
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
driver
|
|
appeared in
|
|
.Nx 6.0 .
|
|
.Sh BUGS
|
|
Although
|
|
.Nm
|
|
SMBus Alerts can be associated with individual devices, this
|
|
capability is ignored.
|
|
When an
|
|
.Nm
|
|
SMBus Alert is generated, all devices on the i2c bus segment which have
|
|
registered an interrupt routine are notified.
|
|
.Pp
|
|
The SMBus CMI protocol defines a method to provide a list of devices on an
|
|
i2c bus segment and their addresses.
|
|
The
|
|
.Nm
|
|
driver makes no attempt to retrieve or process this device list.
|
|
.Pp
|
|
There is currently no way to determine if the i2c controller managed by
|
|
an instance of the ACPI SMBus CMI can also be accessed using a native
|
|
device driver.
|
|
Therefore, the
|
|
.Nm
|
|
driver should not be enabled by default.
|
|
If both a native driver and the
|
|
.Nm
|
|
driver attempt to access the same i2c bus segment, the results are
|
|
undefined.
|