.\" Written by Landon Fuller for the FreeBSD Project.
.\" Based on the miibus(4) manual page written by Tom Rhodes.
.\" Please see the /usr/src/COPYRIGHT file for copyright information.
.\"
.\" $FreeBSD: head/share/man/man4/mdio.4 301589 2016-06-08 08:50:35Z trasz $
.\"
.Dd December 17, 2015
.Dt MDIO 4
.Os
.Sh NAME
.Nm mdio
.Nd IEEE 802.3 Management Data Input/Output interface
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device mdio"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides an interconnection between the Media Access Control (MAC)
sublayer and Physical Layer (PHY) entities' control and status registers,
as defined by the IEEE 802.3 Standard.
.Pp
The
.Nm
layer allows device drivers to share common support code for various
external PHY devices.
.Pp
.Tn MDIO
is one of two signal interfaces that comprise the
Media Independent Interface (MII) defined by the IEEE 802.3
Standard.
The
.Xr miibus 4
driver provides support for devices that require full
.Tn MII
support.
.Sh SEE ALSO
.Xr miibus 4
.Sh STANDARDS
More information on
.Tn MDIO
can be found in the IEEE 802.3 Standard.
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 10.0 .
.Sh AUTHORS
The driver was written by
.An Stefan Bethke Aq Mt stb@lassitu.de .