GPIOCTL(8) | System Manager's Manual | GPIOCTL(8) |
gpioctl
—
gpioctl |
[-qs ] device |
gpioctl |
[-q ] device
attach device
offset mask
[flag] |
gpioctl |
[-qs ] device
pin [0 |
1 | 2] |
gpioctl |
[-qs ] device
pin [on |
off | toggle] |
gpioctl |
[-q ] device
pin set
[flags] [name] |
gpioctl |
[-q ] device
pin unset |
gpioctl
program allows manipulation of GPIO (General
Purpose Input/Output) device pins. Such devices can be either part of the
chipset or embedded CPU, or a separate chip. The usual way of using GPIO is to
connect some simple devices such as LEDs and 1-wire thermal sensors to its
pins.
Each GPIO device has an associated device file in the /dev directory. device can be specified with or without the /dev prefix. For example, /dev/gpio0 or gpio0.
GPIO pins can be either “read” or “written” with the values of logical 0 or 1. If only a pin number is specified on the command line, the pin state will be read from the GPIO controller and displayed. To write to a pin, a value must be specified after the pin number. Values can be either 0 or 1. A value of 2 “toggles” the pin, i.e. changes its state to the opposite. Instead of the numerical values, the word on, off, or toggle can be used.
Only pins that have been configured at securelevel 0, typically
during system startup, are accessible once the securelevel has been raised.
Pins can be given symbolic names for easier use. Besides using individual
pins, device drivers that use GPIO pins can be attached to a
gpio(4) device using the
gpioctl
command. Such drivers can be detached at
runtime using the drvctl(8)
command.
The following configuration flags are supported by the GPIO framework:
Note that not all the flags may be supported by the particular GPIO controller.
When executed with only the
gpio(4) device name as argument,
gpioctl
reads information about the GPIO device and
displays it. At securelevel 0 the number of physically available pins is
displayed, at higher securelevels the number of configured (set) pins is
displayed.
The options are as follows:
-q
-s
gpioctl
is used in shell scripts to query the state of a pin.# gpioctl gpio0 20 set out
pp
Write logical 1 to pin 20:
# gpioctl gpio0 20 1
Attach a onewire(4) bus on a gpioow(4) device on pin 4:
# gpioctl gpio0 attach gpioow 4
0x01
Detach the gpioow0 device:
# drvctl -d gpioow0
Configure pin 5 as output and name it error_led:
# gpioctl gpio0 5 set out
error_led
Toggle the error_led:
# gpioctl gpio0 error_led
2
gpioctl
command first appeared in
OpenBSD 3.6 and NetBSD 4.0.
gpioctl
program was written by
Alexander Yurchenko
<grange@openbsd.org>.
Device attachment was added by Marc Balmer
<marc@msys.ch>.
February 12, 2019 | NetBSD 9.4 |