1.\" 2.\" Copyright (c) 2014 Rui Paulo 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.Dd July 1, 2015 27.Dt GPIO 3 28.Os 29.Sh NAME 30.Nm gpio_open , 31.Nm gpio_close 32.Nd "library to handle GPIO pins" 33.Sh LIBRARY 34.Lb libgpio 35.Sh SYNOPSIS 36.In sys/types.h 37.In libgpio.h 38.Ft "gpio_handle_t" 39.Fn gpio_open "unsigned int unit" 40.Ft "gpio_handle_t" 41.Fn gpio_open_device "const char *device" 42.Ft void 43.Fn gpio_close "gpio_handle_t handle" 44.Ft int 45.Fn gpio_pin_list "gpio_handle_t handle" "gpio_config_t **pcfgs" 46.Ft int 47.Fn gpio_pin_config "gpio_handle_t handle" "gpio_config_t *cfg" 48.Ft int 49.Fn gpio_pin_set_name "gpio_handle_t handle" "gpio_pin_t pin" "char *name" 50.Ft int 51.Fn gpio_pin_set_flags "gpio_handle_t handle" "gpio_config_t *cfg" 52.Ft gpio_value_t 53.Fn gpio_pin_get "gpio_handle_t handle" "gpio_pin_t pin" 54.Ft int 55.Fn gpio_pin_set "gpio_handle_t handle" "gpio_pin_t pin" "gpio_value_t value" 56.Ft int 57.Fn gpio_pin_toggle "gpio_handle_t handle" "gpio_pin_t pin" 58.Ft int 59.Fn gpio_pin_low "gpio_handle_t handle" "gpio_pin_t pin" 60.Ft int 61.Fn gpio_pin_high "gpio_handle_t handle" "gpio_pin_t pin" 62.Ft int 63.Fn gpio_pin_input "gpio_handle_t handle" "gpio_pin_t pin" 64.Ft int 65.Fn gpio_pin_output "gpio_handle_t handle" "gpio_pin_t pin" 66.Ft int 67.Fn gpio_pin_opendrain "gpio_handle_t handle" "gpio_pin_t pin" 68.Ft int 69.Fn gpio_pin_pushpull "gpio_handle_t handle" "gpio_pin_t pin" 70.Ft int 71.Fn gpio_pin_tristate "gpio_handle_t handle" "gpio_pin_t pin" 72.Ft int 73.Fn gpio_pin_pullup "gpio_handle_t handle" "gpio_pin_t pin" 74.Ft int 75.Fn gpio_pin_pulldown "gpio_handle_t handle" "gpio_pin_t pin" 76.Ft int 77.Fn gpio_pin_invin "gpio_handle_t handle" "gpio_pin_t pin" 78.Ft int 79.Fn gpio_pin_invout "gpio_handle_t handle" "gpio_pin_t pin" 80.Ft int 81.Fn gpio_pin_pulsate "gpio_handle_t handle" "gpio_pin_t pin" 82.Sh DESCRIPTION 83The 84.Nm libgpio 85library provides an interface to configure GPIO pins. 86The library operates with a 87.Ft gpio_handle_t 88opaque type which can be created with 89.Fn gpio_open 90or 91.Fn gpio_open_device . 92When no more GPIO operations are needed, this handle can be destroyed 93with 94.Fn gpio_close . 95.Pp 96To get a list of all available pins, one can call 97.Fn gpio_pin_list . 98This function takes a pointer to a 99.Ft gpio_config_t 100which is dynamically allocated. 101This pointer should be freed with 102.Xr free 3 103when it is no longer necessary. 104.Pp 105The function 106.Fn gpio_pin_config 107retrieves the current configuration of a pin. 108The pin number should be passed in via the 109.Ft g_pin 110variable which is part of the 111.Ft gpio_config_t 112structure. 113.Pp 114The function 115.Fn gpio_pin_set_name 116sets the name used to describe a pin. 117.Pp 118The function 119.Fn gpio_pin_set_flags 120configures a pin with the flags passed in by the 121.Ft gpio_config_t 122structure. 123The pin number should also be passed in through the 124.Ft g_pin 125variable. 126All other structure members will be ignored by this function. 127The list of flags can be found in 128.Pa /usr/include/sys/gpio.h . 129.Pp 130The get or set the state of a GPIO pin, the functions 131.Fn gpio_pin_get 132and 133.Fn gpio_pin_set 134are available, respectively. 135To toggle the state, use 136.Fn gpio_pin_toggle . 137.Pp 138The functions 139.Fn gpio_pin_low 140and 141.Fn gpio_pin_high 142are wrappers around 143.Fn gpio_pin_set . 144.Pp 145The functions 146.Fn gpio_pin_input , 147.Fn gpio_pin_output , 148.Fn gpio_pin_opendrain , 149.Fn gpio_pin_pushpull , 150.Fn gpio_pin_tristate , 151.Fn gpio_pin_pullup , 152.Fn gpio_pin_pulldown , 153.Fn gpio_pin_invin , 154.Fn gpio_pin_invout 155and 156.Fn gpio_pin_pulsate 157are wrappers around 158.Fn gpio_pin_set_flags . 159.Sh EXAMPLES 160The following example shows how to configure pin 16 as output and then 161drive it high: 162.Bd -literal 163#include <sys/types.h> 164#include <err.h> 165#include <libgpio.h> 166 167gpio_handle_t handle; 168 169handle = gpio_open(0); 170if (handle == GPIO_INVALID_HANDLE) 171 err(1, "gpio_open failed"); 172gpio_pin_output(handle, 16); 173gpio_pin_high(handle, 16); 174gpio_close(handle); 175.Ed 176.Pp 177The following example shows how to get a configuration of a pin: 178.Bd -literal 179gpio_config_t cfg; 180 181cfg.g_pin = 32; 182gpio_pin_config(handle, &cfg); 183.Ed 184.Pp 185The structure will contain the name of the pin and its flags. 186.Sh SEE ALSO 187.Xr gpiobus 4 , 188.Xr gpioctl 8 189.Sh HISTORY 190The 191.Nm libgpio 192library first appeared in 193.Fx 11.0 . 194.Sh AUTHORS 195The 196.Nm libgpio 197library was implemented by 198.An Rui Paulo Aq Mt rpaulo@FreeBSD.org . 199