201 lines
5.4 KiB
Groff
201 lines
5.4 KiB
Groff
.\"
|
|
.\" Copyright (c) 2014 Rui Paulo
|
|
.\" 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.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd March 8, 2015
|
|
.Dt GPIO 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm gpio_open ,
|
|
.Nm gpio_close
|
|
.Nd "library to handle GPIO pins"
|
|
.Sh LIBRARY
|
|
.Lb libgpio
|
|
.Sh SYNOPSIS
|
|
.In sys/types.h
|
|
.In libgpio.h
|
|
.Ft "gpio_handle_t"
|
|
.Fn gpio_open "unsigned int unit"
|
|
.Ft "gpio_handle_t"
|
|
.Fn gpio_open_device "const char *device"
|
|
.Ft void
|
|
.Fn gpio_close "gpio_handle_t handle"
|
|
.Ft int
|
|
.Fn gpio_pin_list "gpio_handle_t handle" "gpio_config_t **pcfgs"
|
|
.Ft int
|
|
.Fn gpio_pin_config "gpio_handle_t handle" "gpio_config_t *cfg"
|
|
.Ft int
|
|
.Fn gpio_pin_set_name "gpio_handle_t handle" "gpio_pin_t pin" "char *name"
|
|
.Ft int
|
|
.Fn gpio_pin_set_flags "gpio_handle_t handle" "gpio_config_t *cfg"
|
|
.Ft gpio_value_t
|
|
.Fn gpio_pin_get "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_set "gpio_handle_t handle" "gpio_pin_t pin" "gpio_value_t value"
|
|
.Ft int
|
|
.Fn gpio_pin_toggle "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_low "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_high "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_input "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_output "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_opendrain "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_pushpull "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_tristate "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_pullup "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_pulldown "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_invin "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_invout "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Ft int
|
|
.Fn gpio_pin_pulsate "gpio_handle_t handle" "gpio_pin_t pin"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm libgpio
|
|
library provides an interface to configure GPIO pins.
|
|
The library operates with a
|
|
.Ft gpio_handle_t
|
|
opaque type which can be created with
|
|
.Fn gpio_open
|
|
or
|
|
.Fn gpio_open_device .
|
|
When no more GPIO operations are needed, this handle can be destroyed
|
|
with
|
|
.Fn gpio_close .
|
|
.Pp
|
|
To get a list of all available pins, one can call
|
|
.Fn gpio_pin_list .
|
|
This function takes a pointer to a
|
|
.Ft gpio_config_t
|
|
which is dynamically allocated.
|
|
This pointer should be freed with
|
|
.Xr free 3
|
|
when it is no longer necessary.
|
|
.Pp
|
|
The function
|
|
.Fn gpio_pin_config
|
|
retrieves the current configuration of a pin.
|
|
The pin number should be passed in via the
|
|
.Ft g_pin
|
|
variable which is part of the
|
|
.Ft gpio_config_t
|
|
structure.
|
|
.Pp
|
|
The function
|
|
.Fn gpio_pin_set_name
|
|
sets the name used to describe a pin.
|
|
.Pp
|
|
The function
|
|
.Fn gpio_pin_set_flags
|
|
configures a pin with the flags passed in by the
|
|
.Ft gpio_config_t
|
|
structure.
|
|
The pin number should also be passed in through the
|
|
.Ft g_pin
|
|
variable.
|
|
All other structure members will be ignored by this function.
|
|
The list of flags can be found in
|
|
.Pa /usr/include/sys/gpio.h .
|
|
.Pp
|
|
The get or set the state of a GPIO pin, the functions
|
|
.Fn gpio_pin_get
|
|
and
|
|
.Fn gpio_pin_set
|
|
are available, respectively.
|
|
To toggle the state, use
|
|
.Fn gpio_pin_toggle .
|
|
.Pp
|
|
The functions
|
|
.Fn gpio_pin_low
|
|
and
|
|
.Fn gpio_pin_high
|
|
are wrappers around
|
|
.Fn gpio_pin_set .
|
|
.Pp
|
|
The functions
|
|
.Fn gpio_pin_input ,
|
|
.Fn gpio_pin_output ,
|
|
.Fn gpio_pin_opendrain ,
|
|
.Fn gpio_pin_pushpull ,
|
|
.Fn gpio_pin_tristate ,
|
|
.Fn gpio_pin_pullup ,
|
|
.Fn gpio_pin_pulldown ,
|
|
.Fn gpio_pin_invin ,
|
|
.Fn gpio_pin_invout
|
|
and
|
|
.Fn gpio_pin_pulsate
|
|
are wrappers around
|
|
.Fn gpio_pin_set_flags .
|
|
.Sh EXAMPLES
|
|
The following example shows how to configure pin 16 as output and then
|
|
drive it high:
|
|
.Bd -literal
|
|
#include <sys/types.h>
|
|
#include <err.h>
|
|
#include <libgpio.h>
|
|
|
|
gpio_handle_t handle;
|
|
|
|
handle = gpio_open(0);
|
|
if (handle == GPIO_INVALID_HANDLE)
|
|
err(1, "gpio_open failed");
|
|
gpio_pin_output(handle, 16);
|
|
gpio_pin_high(handle, 16);
|
|
gpio_close(handle);
|
|
.Ed
|
|
.Pp
|
|
The following example shows how to get a configuration of a pin:
|
|
.Bd -literal
|
|
gpio_config_t cfg;
|
|
|
|
cfg.g_pin = 32;
|
|
gpio_pin_config(handle, &cfg);
|
|
.Ed
|
|
.Pp
|
|
The structure will contain the name of the pin and its flags.
|
|
.Sh SEE ALSO
|
|
.Xr gpiobus 4 ,
|
|
.Xr gpioctl 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm libgpio
|
|
library first appeared in
|
|
.Fx 11.0 .
|
|
.Sh AUTHORS
|
|
The
|
|
.Nm libgpio
|
|
library was implemented by
|
|
.An Rui Paulo Aq Mt rpaulo@FreeBSD.org .
|