ACPISMBUS(4) Kernel Interfaces Manual ACPISMBUS(4)
acpismbus -- ACPI SMBus Control Method Interface
acpismbus* at acpi?
iic* at acpismbus?
The acpismbus 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.
The acpismbus driver appeared in NetBSD 6.0.
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.
NetBSD 6.1.5 February 6, 2010 NetBSD 6.1.5