.\" $NetBSD: epgpio.4,v 1.3 2009/03/09 19:24:29 joerg Exp $
.\"
.\" Copyright (c) 2009 Ken Hornstein.
.\" All rights reserved
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd February 22, 2009
.Dt EPGPIO 4
.Os
.Sh NAME
.Nm epgpio
.Nd General Purpose I/O support for Cirrus EP93xx ARM processors
.Sh SYNOPSIS
.Cd "epgpio0 at epsoc? addr 0x80840000 size 0xcc intr 59"
.Cd "gpio* at epgpio?"
.Pp
.Cd options EPGPIO_PORT_A_MASK=0xXX
.Cd options EPGPIO_PORT_B_MASK=0xXX
.Cd options EPGPIO_PORT_C_MASK=0xXX
.Cd options EPGPIO_PORT_D_MASK=0xXX
.Cd options EPGPIO_PORT_E_MASK=0xXX
.Cd options EPGPIO_PORT_F_MASK=0xXX
.Cd options EPGPIO_PORT_G_MASK=0xXX
.Cd options EPGPIO_PORT_H_MASK=0xXX
.Sh DESCRIPTION
The
.Nm
driver provides support for the on-board General Purpose I/O (GPIO) pins on
the Cirrus Logic EP93xx series of processors.
There are 8 GPIO ports (Ports
A though H) each having 8 GPIO pins available (note: early revisions of
some EP9301 processors have some ports with less than eight pins available
on each port; check the documentation for your specific processor).
.Pp
The
.Nm
driver provides a
.Xr gpio 4
controller interface and will attach each port as a separate
.Xr gpio 4
device with 8 pins available.
All pins are bidirectional; when used
as inputs they should not be driven beyond TTL voltage levels, but
for exact details on the electrical interface the documentation for
the specific evbarm board should be consulted.
.Ss Kernel options
The following kernel options are available to configure the behavior of the
.Nm
driver.
.Pp
.Bl -tag -width "options" -compact
.It Cd options EPGPIO_PORT_A_MASK=0xXX
.It Cd options EPGPIO_PORT_B_MASK=0xXX
.It Cd options EPGPIO_PORT_C_MASK=0xXX
.It Cd options EPGPIO_PORT_D_MASK=0xXX
.It Cd options EPGPIO_PORT_E_MASK=0xXX
.It Cd options EPGPIO_PORT_F_MASK=0xXX
.It Cd options EPGPIO_PORT_G_MASK=0xXX
.It Cd options EPGPIO_PORT_H_MASK=0xXX
.El
.Pp
Each of these options is a bitmask specifying the pins available to the
.Xr gpio 4
controller for the corresponding port.
Pins should be disabled if they
are not available or are being used by the hardware for other purposes.
The default mask is
.Dq 0xff
for all ports.
.Sh IMPLEMENTATION NOTES
When a port bitmask configures less than 8 pins available, the remaining
pins will appear as sequentially numbered pins to the
.Xr gpio 4
interface.
For example, if
.Dv EPGPIO_PORT_A_MASK
is set to
.Dq 0x2c ,
Port A pins 1, 3, and 5 will appear as
.Xr gpio 4
pins 0, 1, and 2 respectively.
.Sh SEE ALSO
.Xr gpio 4