1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
.\" $OpenBSD: gpioctl.8,v 1.2 2004/06/04 14:00:00 jmc Exp $
.\"
.\" Copyright (c) 2004 Alexander Yurchenko <grange@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd May 3, 2004
.Dt GPIOCTL 8
.Os
.Sh NAME
.Nm gpioctl
.Nd control GPIO devices
.Sh SYNOPSIS
.Nm gpioctl
.Op Fl hq
.Op Fl d Ar device
.Op Ar pin
.Op Ar 0 | 1 | 2
.Nm gpioctl
.Op Fl hq
.Op Fl d Ar device
.Fl c
.Ar pin
.Op Ar flags
.Sh DESCRIPTION
The
.Nm
program allows manipulation of
.Tn GPIO
(General Purpose Input/Output) device pins.
Such devices can be either part of the chipset or embedded
.Tn CPU ,
or a separate chip.
The usual way of using
.Tn GPIO
is to connect some simple devices such as LEDs, 1-wire termal sensors,
etc., to its pins.
.Pp
Each
.Tn GPIO
device has an associated device file in the
.Pa /dev
directory.
By default
.Nm
uses
.Pa /dev/gpio0 ,
which corresponds to the first found
.Tn GPIO
device in the system.
If more than one
.Tn GPIO
device is present, an alternative device file can be specified with the
.Fl d
option
in order to access a particular
.Tn GPIO
device.
.Pp
When executed without any arguments,
.Nm
reads information about the
.Tn GPIO
device and displays it.
.Pp
.Tn GPIO
pins can be either
.Dq read
or
.Dq written
with the values of logical 0 or 1.
If only a
.Ar pin
number is specified on the command line, the pin state will be read
from the
.Tn GPIO
controller and displayed.
To write to a pin, a value must be specified after the
.Ar pin
number.
Values can be either 0 or 1.
A value of 2 has a special meaning: it
.Dq toggles
the pin, i.e. changes its state to the opposite.
.Pp
Each pin can be configured with different flags with the
.Fl c
option.
The following configuration flags are supported by the
.Tn GPIO
framework:
.Pp
.Bl -tag -width XXXXXXX -offset indent -compact
.It in
input direction
.It out
output direction
.It inout
bi-directional
.It od
open-drain output
.It pp
push-pull output
.It tri
tri-state (output disabled)
.It pu
internal pull-up enabled
.El
.Pp
Note that not all the flags can be supported by the particular
.Tn GPIO
controller.
The list of supported flags is always displayed when executing
.Nm
with the
.Fl c
option.
If only a
.Ar pin
number is specified on the command line, the current pin flags will be
displayed.
To change pin flags, a new flags set separated by spaces must be
specified after the
.Ar pin
number.
.Sh FILES
.Bl -tag -width "/dev/gpiou" -compact
.It /dev/gpio Ns Ar u
GPIO device unit
.Ar u
file.
.El
.Sh EXAMPLES
Configure pin 20 to have push-pull output:
.Pp
.Dl # gpioctl -c 20 out pp
.Pp
Write logical 1 to pin 20:
.Pp
.Dl # gpioctl 20 1
.Sh SEE ALSO
.Xr gpio 4 ,
.Xr gscpcib 4 ,
.Xr nsclpcsio 4
.Sh HISTORY
The
.Nm
command first appeared in
.Ox 3.6 .
.Sh AUTHORS
The
.Nm
program was written by
.An Alexander Yurchenko Aq grange@openbsd.org .
|
