.\"
.\" SPDX-License-Identifier: BSD-2-Clause
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.\" Copyright (c) 2019 Andriy Gapon <avg@FreeBSD.org>
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.Dd October 11, 2019
.Dt SUPERIO 4
.Os
.Sh NAME
.Nm superio
.Nd Super I/O controller and bus driver
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device superio"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
superio_load="YES"
.Ed
.Sh DESCRIPTION
Super I/O is an I/O controller that combines various low-bandwidth devices
that can be functionally unrelated otherwise.
A typical Super I/O can contain devices such as
.Bl -bullet -compact
.It
a floppy disk controller
.It
a parallel port
.It
a serial port
.It
a PS/2 mouse and keyboard controller
.It
a hardware monitoring controller
.It
a watchdog timer
.It
a controller for general purpose input-output
.El
.Pp
The
.Nm
driver provides support for devices residing in the Super I/O controller
that can only be accessed or discovered using the controller's interface.
Some of the Super I/O devices have standardized interfaces.
Such devices either use well-known legacy resources or they are advertised
via ACPI or both.
They can be configured either using ISA bus hints or they are auto-configured by
.Xr acpi 4 .
The
.Nm
driver is not designed to interact with that kind of devices.
They can be handled by their respective drivers without any knowledge of the
Super I/O specifics.
For instance,
.Xr fdc 4
provides access to the floppy disk controller.
.Pp
There are other Super I/O devices that do not have any standardized interface.
Drivers for those devices can be written using facilities of the
.Nm
driver.
.Pp
The driver itself attaches to the ISA bus as all supported controllers are
accessed via LPC I/O ports.
.Pp
The
.Nm
driver is unusual as it is both a controller driver for a variety of Super I/O
controllers and a bus driver for supported devices in those controllers.
.Sh HARDWARE
The
.Nm
driver supports a multitude of Super I/O controllers produced by Nuvoton,
formerly known as Winbond, and ITE.
.Sh SEE ALSO
.Xr superio 9
.Sh HISTORY
The
.Nm
driver was written by
.An Andriy Gapon Aq Mt avg@FreeBSD.org .