ACPISMBUS(4) | Device Drivers 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.
February 6, 2010 | NetBSD 10.99 |