GPIO(3)                FreeBSD Library Functions Manual                GPIO(3)

NAME
     gpio_open, gpio_close - library to handle GPIO pins

LIBRARY
     General-Purpose Input Output (GPIO) library (libgpio, -lgpio)

SYNOPSIS
     #include <sys/types.h>
     #include <libgpio.h>

     gpio_handle_t
     gpio_open(unsigned int unit);

     gpio_handle_t
     gpio_open_device(const char *device);

     void
     gpio_close(gpio_handle_t handle);

     int
     gpio_pin_list(gpio_handle_t handle, gpio_config_t **pcfgs);

     int
     gpio_pin_config(gpio_handle_t handle, gpio_config_t *cfg);

     int
     gpio_pin_set_name(gpio_handle_t handle, gpio_pin_t pin, char *name);

     int
     gpio_pin_set_flags(gpio_handle_t handle, gpio_config_t *cfg);

     gpio_value_t
     gpio_pin_get(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_set(gpio_handle_t handle, gpio_pin_t pin, gpio_value_t value);

     int
     gpio_pin_toggle(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_low(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_high(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_input(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_output(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_opendrain(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_pushpull(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_tristate(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_pullup(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_pulldown(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_invin(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_invout(gpio_handle_t handle, gpio_pin_t pin);

     int
     gpio_pin_pulsate(gpio_handle_t handle, gpio_pin_t pin);

DESCRIPTION
     The libgpio library provides an interface to configure GPIO pins.  The
     library operates with a gpio_handle_t opaque type which can be created
     with gpio_open() or gpio_open_device().  When no more GPIO operations are
     needed, this handle can be destroyed with gpio_close().

     To get a list of all available pins, one can call gpio_pin_list().  This
     function takes a pointer to a gpio_config_t which is dynamically
     allocated.  This pointer should be freed with free(3) when it is no
     longer necessary.

     The function gpio_pin_config() retrieves the current configuration of a
     pin.  The pin number should be passed in via the g_pin variable which is
     part of the gpio_config_t structure.

     The function gpio_pin_set_name() sets the name used to describe a pin.

     The function gpio_pin_set_flags() configures a pin with the flags passed
     in by the gpio_config_t structure.  The pin number should also be passed
     in through the g_pin variable.  All other structure members will be
     ignored by this function.  The list of flags can be found in
     /usr/include/sys/gpio.h.

     The get or set the state of a GPIO pin, the functions gpio_pin_get() and
     gpio_pin_set() are available, respectively.  To toggle the state, use
     gpio_pin_toggle().

     The functions gpio_pin_low() and gpio_pin_high() are wrappers around
     gpio_pin_set().

     The functions gpio_pin_input(), gpio_pin_output(), gpio_pin_opendrain(),
     gpio_pin_pushpull(), gpio_pin_tristate(), gpio_pin_pullup(),
     gpio_pin_pulldown(), gpio_pin_invin(), gpio_pin_invout() and
     gpio_pin_pulsate() are wrappers around gpio_pin_set_flags().

EXAMPLES
     The following example shows how to configure pin 16 as output and then
     drive it high:

     #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);

     The following example shows how to get a configuration of a pin:

     gpio_config_t cfg;

     cfg.g_pin = 32;
     gpio_pin_config(handle, &cfg);

     The structure will contain the name of the pin and its flags.

SEE ALSO
     gpiobus(4), gpioctl(8)

HISTORY
     The libgpio library first appeared in FreeBSD 11.0.

AUTHORS
     The libgpio library was implemented by Rui Paulo <rpaulo@FreeBSD.org>.

FreeBSD 13.1-RELEASE-p6          July 1, 2015          FreeBSD 13.1-RELEASE-p6