NAME
acpismbus —
ACPI SMBus Control Method
Interface
SYNOPSIS
acpismbus* at acpi?
iic* at acpismbus?
DESCRIPTION
Theacpismbus 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.
SEE ALSO
HISTORY
The acpismbus driver appeared in
NetBSD 6.0.
BUGS
Although acpismbus SMBus Alerts can be
associated with individual devices, this capability is ignored. When an
acpismbus SMBus Alert is generated, all devices on
the i2c bus segment which have registered an interrupt routine are
notified.
The SMBus CMI protocol defines a method to provide a list of
devices on an i2c bus segment and their addresses. The
acpismbus driver makes no attempt to retrieve or
process this device list.
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 acpismbus
driver should not be enabled by default. If both a native driver and the
acpismbus driver attempt to access the same i2c bus
segment, the results are undefined.