gpiod.h File Reference

#include <stdbool.h>
#include <stdlib.h>
#include <time.h>

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Data Structures
struct	gpiod_ctxless_event_poll_fd
	Helper structure for the ctxless event loop poll callback. More...
struct	gpiod_line_bulk
	Helper structure for storing a set of GPIO line objects. More...
struct	gpiod_line_request_config
	Structure holding configuration of a line request. More...
struct	gpiod_line_event
	Structure holding event info. More...

Macros
#define	GPIOD_API   __attribute__((visibility("default")))
	Makes symbol visible.
#define	GPIOD_UNUSED   __attribute__((unused))
	Marks a function argument or variable as potentially unused.
#define	GPIOD_BIT(nr)   (1UL << (nr))
	Shift 1 by given offset. More...
#define	GPIOD_DEPRECATED   __attribute__((deprecated))
	Marks a public function as deprecated.
#define	GPIOD_LINE_BULK_MAX_LINES   64
	Maximum number of GPIO lines that can be requested at once.
#define	GPIOD_LINE_BULK_INITIALIZER   { { NULL }, 0 }
	Static initializer for GPIO bulk objects. More...
#define	gpiod_line_bulk_foreach_line(bulk, line, lineptr)
	Iterate over all line handles held by a line bulk object. More...
#define	gpiod_line_bulk_foreach_line_off(bulk, line, offset)
	Iterate over all line handles held by a line bulk object (integer counter variant). More...
#define	gpiod_foreach_chip(iter, chip)
	Iterate over all GPIO chips present in the system. More...
#define	gpiod_foreach_chip_noclose(iter, chip)
	Iterate over all chips present in the system without closing them. More...
#define	gpiod_foreach_line(iter, line)
	Iterate over all GPIO lines of a single chip. More...

Typedefs
typedef void(*	gpiod_ctxless_set_value_cb) (void *)
	Simple set value callback signature.
typedef int(*	gpiod_ctxless_event_handle_cb) (int, unsigned int, const struct timespec *, void *)
	Simple event callback signature. More...
typedef int(*	gpiod_ctxless_event_poll_cb) (unsigned int, struct gpiod_ctxless_event_poll_fd *, const struct timespec *, void *)
	Simple event poll callback signature. More...

Enumerations
enum	{   GPIOD_CTXLESS_FLAG_OPEN_DRAIN = GPIOD_BIT(0), GPIOD_CTXLESS_FLAG_OPEN_SOURCE = GPIOD_BIT(1), GPIOD_CTXLESS_FLAG_BIAS_DISABLE = GPIOD_BIT(2), GPIOD_CTXLESS_FLAG_BIAS_PULL_DOWN = GPIOD_BIT(3),   GPIOD_CTXLESS_FLAG_BIAS_PULL_UP = GPIOD_BIT(4) }
	Miscellaneous GPIO flags. More...
enum	{ GPIOD_CTXLESS_EVENT_RISING_EDGE = 1, GPIOD_CTXLESS_EVENT_FALLING_EDGE, GPIOD_CTXLESS_EVENT_BOTH_EDGES }
	Event types that the ctxless event monitor can wait for. More...
enum	{ GPIOD_CTXLESS_EVENT_CB_TIMEOUT = 1, GPIOD_CTXLESS_EVENT_CB_RISING_EDGE, GPIOD_CTXLESS_EVENT_CB_FALLING_EDGE }
	Event types that can be passed to the ctxless event callback. More...
enum	{ GPIOD_CTXLESS_EVENT_CB_RET_ERR = -1, GPIOD_CTXLESS_EVENT_CB_RET_OK = 0, GPIOD_CTXLESS_EVENT_CB_RET_STOP = 1 }
	Return status values that the ctxless event callback can return. More...
enum	{ GPIOD_CTXLESS_EVENT_POLL_RET_STOP = -2, GPIOD_CTXLESS_EVENT_POLL_RET_ERR = -1, GPIOD_CTXLESS_EVENT_POLL_RET_TIMEOUT = 0 }
	Return status values that the ctxless event poll callback can return. More...
enum	{ GPIOD_LINE_DIRECTION_INPUT = 1, GPIOD_LINE_DIRECTION_OUTPUT }
	Possible direction settings. More...
enum	{ GPIOD_LINE_ACTIVE_STATE_HIGH = 1, GPIOD_LINE_ACTIVE_STATE_LOW }
	Possible active state settings. More...
enum	{ GPIOD_LINE_BIAS_AS_IS = 1, GPIOD_LINE_BIAS_DISABLE, GPIOD_LINE_BIAS_PULL_UP, GPIOD_LINE_BIAS_PULL_DOWN }
	Possible internal bias settings. More...
enum	{   GPIOD_LINE_REQUEST_DIRECTION_AS_IS = 1, GPIOD_LINE_REQUEST_DIRECTION_INPUT, GPIOD_LINE_REQUEST_DIRECTION_OUTPUT, GPIOD_LINE_REQUEST_EVENT_FALLING_EDGE,   GPIOD_LINE_REQUEST_EVENT_RISING_EDGE, GPIOD_LINE_REQUEST_EVENT_BOTH_EDGES }
	Available types of requests. More...
enum	{   GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN = GPIOD_BIT(0), GPIOD_LINE_REQUEST_FLAG_OPEN_SOURCE = GPIOD_BIT(1), GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW = GPIOD_BIT(2), GPIOD_LINE_REQUEST_FLAG_BIAS_DISABLE = GPIOD_BIT(3),   GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_DOWN = GPIOD_BIT(4), GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_UP = GPIOD_BIT(5) }
	Miscellaneous GPIO request flags. More...
enum	{ GPIOD_LINE_EVENT_RISING_EDGE = 1, GPIOD_LINE_EVENT_FALLING_EDGE }
	Event types. More...

Functions
int	gpiod_ctxless_get_value (const char *device, unsigned int offset, bool active_low, const char *consumer) GPIOD_API
	Read current value from a single GPIO line. More...
int	gpiod_ctxless_get_value_ext (const char *device, unsigned int offset, bool active_low, const char *consumer, int flags) GPIOD_API
	Read current value from a single GPIO line. More...
int	gpiod_ctxless_get_value_multiple (const char *device, const unsigned int *offsets, int *values, unsigned int num_lines, bool active_low, const char *consumer) GPIOD_API
	Read current values from a set of GPIO lines. More...
int	gpiod_ctxless_get_value_multiple_ext (const char *device, const unsigned int *offsets, int *values, unsigned int num_lines, bool active_low, const char *consumer, int flags) GPIOD_API
	Read current values from a set of GPIO lines. More...
int	gpiod_ctxless_set_value (const char *device, unsigned int offset, int value, bool active_low, const char *consumer, gpiod_ctxless_set_value_cb cb, void *data) GPIOD_API
	Set value of a single GPIO line. More...
int	gpiod_ctxless_set_value_ext (const char *device, unsigned int offset, int value, bool active_low, const char *consumer, gpiod_ctxless_set_value_cb cb, void *data, int flags) GPIOD_API
	Set value of a single GPIO line. More...
int	gpiod_ctxless_set_value_multiple (const char *device, const unsigned int *offsets, const int *values, unsigned int num_lines, bool active_low, const char *consumer, gpiod_ctxless_set_value_cb cb, void *data) GPIOD_API
	Set values of multiple GPIO lines. More...
int	gpiod_ctxless_set_value_multiple_ext (const char *device, const unsigned int *offsets, const int *values, unsigned int num_lines, bool active_low, const char *consumer, gpiod_ctxless_set_value_cb cb, void *data, int flags) GPIOD_API
	Set values of multiple GPIO lines. More...
int	gpiod_ctxless_event_loop (const char *device, unsigned int offset, bool active_low, const char *consumer, const struct timespec *timeout, gpiod_ctxless_event_poll_cb poll_cb, gpiod_ctxless_event_handle_cb event_cb, void *data) GPIOD_API GPIOD_DEPRECATED
	Wait for events on a single GPIO line. More...
int	gpiod_ctxless_event_loop_multiple (const char *device, const unsigned int *offsets, unsigned int num_lines, bool active_low, const char *consumer, const struct timespec *timeout, gpiod_ctxless_event_poll_cb poll_cb, gpiod_ctxless_event_handle_cb event_cb, void *data) GPIOD_API GPIOD_DEPRECATED
	Wait for events on multiple GPIO lines. More...
int	gpiod_ctxless_event_monitor (const char *device, int event_type, unsigned int offset, bool active_low, const char *consumer, const struct timespec *timeout, gpiod_ctxless_event_poll_cb poll_cb, gpiod_ctxless_event_handle_cb event_cb, void *data) GPIOD_API
	Wait for events on a single GPIO line. More...
int	gpiod_ctxless_event_monitor_ext (const char *device, int event_type, unsigned int offset, bool active_low, const char *consumer, const struct timespec *timeout, gpiod_ctxless_event_poll_cb poll_cb, gpiod_ctxless_event_handle_cb event_cb, void *data, int flags) GPIOD_API
	Wait for events on a single GPIO line. More...
int	gpiod_ctxless_event_monitor_multiple (const char *device, int event_type, const unsigned int *offsets, unsigned int num_lines, bool active_low, const char *consumer, const struct timespec *timeout, gpiod_ctxless_event_poll_cb poll_cb, gpiod_ctxless_event_handle_cb event_cb, void *data) GPIOD_API
	Wait for events on multiple GPIO lines. More...
int	gpiod_ctxless_event_monitor_multiple_ext (const char *device, int event_type, const unsigned int *offsets, unsigned int num_lines, bool active_low, const char *consumer, const struct timespec *timeout, gpiod_ctxless_event_poll_cb poll_cb, gpiod_ctxless_event_handle_cb event_cb, void *data, int flags) GPIOD_API
	Wait for events on multiple GPIO lines. More...
int	gpiod_ctxless_find_line (const char *name, char *chipname, size_t chipname_size, unsigned int *offset) GPIOD_API
	Determine the chip name and line offset of a line with given name. More...
struct gpiod_chip *	gpiod_chip_open (const char *path) GPIOD_API
	Open a gpiochip by path. More...
struct gpiod_chip *	gpiod_chip_open_by_name (const char *name) GPIOD_API
	Open a gpiochip by name. More...
struct gpiod_chip *	gpiod_chip_open_by_number (unsigned int num) GPIOD_API
	Open a gpiochip by number. More...
struct gpiod_chip *	gpiod_chip_open_by_label (const char *label) GPIOD_API
	Open a gpiochip by label. More...
struct gpiod_chip *	gpiod_chip_open_lookup (const char *descr) GPIOD_API
	Open a gpiochip based on the best guess what the path is. More...
void	gpiod_chip_close (struct gpiod_chip *chip) GPIOD_API
	Close a GPIO chip handle and release all allocated resources. More...
const char *	gpiod_chip_name (struct gpiod_chip *chip) GPIOD_API
	Get the GPIO chip name as represented in the kernel. More...
const char *	gpiod_chip_label (struct gpiod_chip *chip) GPIOD_API
	Get the GPIO chip label as represented in the kernel. More...
unsigned int	gpiod_chip_num_lines (struct gpiod_chip *chip) GPIOD_API
	Get the number of GPIO lines exposed by this chip. More...
struct gpiod_line *	gpiod_chip_get_line (struct gpiod_chip *chip, unsigned int offset) GPIOD_API
	Get the handle to the GPIO line at given offset. More...
int	gpiod_chip_get_lines (struct gpiod_chip *chip, unsigned int *offsets, unsigned int num_offsets, struct gpiod_line_bulk *bulk) GPIOD_API
	Retrieve a set of lines and store them in a line bulk object. More...
int	gpiod_chip_get_all_lines (struct gpiod_chip *chip, struct gpiod_line_bulk *bulk) GPIOD_API
	Retrieve all lines exposed by a chip and store them in a bulk object. More...
struct gpiod_line *	gpiod_chip_find_line (struct gpiod_chip *chip, const char *name) GPIOD_API
	Find a GPIO line by name among lines associated with given GPIO chip. More...
int	gpiod_chip_find_lines (struct gpiod_chip *chip, const char **names, struct gpiod_line_bulk *bulk) GPIOD_API
	Find a set of GPIO lines by names among lines exposed by this chip. More...
static void	gpiod_line_bulk_init (struct gpiod_line_bulk *bulk)
	Initialize a GPIO bulk object. More...
static void	gpiod_line_bulk_add (struct gpiod_line_bulk *bulk, struct gpiod_line *line)
	Add a single line to a GPIO bulk object. More...
static struct gpiod_line *	gpiod_line_bulk_get_line (struct gpiod_line_bulk *bulk, unsigned int offset)
	Retrieve the line handle from a line bulk object at given offset. More...
static unsigned int	gpiod_line_bulk_num_lines (struct gpiod_line_bulk *bulk)
	Retrieve the number of GPIO lines held by this line bulk object. More...
unsigned int	gpiod_line_offset (struct gpiod_line *line) GPIOD_API
	Read the GPIO line offset. More...
const char *	gpiod_line_name (struct gpiod_line *line) GPIOD_API
	Read the GPIO line name. More...
const char *	gpiod_line_consumer (struct gpiod_line *line) GPIOD_API
	Read the GPIO line consumer name. More...
int	gpiod_line_direction (struct gpiod_line *line) GPIOD_API
	Read the GPIO line direction setting. More...
int	gpiod_line_active_state (struct gpiod_line *line) GPIOD_API
	Read the GPIO line active state setting. More...
int	gpiod_line_bias (struct gpiod_line *line) GPIOD_API
	Read the GPIO line bias setting. More...
bool	gpiod_line_is_used (struct gpiod_line *line) GPIOD_API
	Check if the line is currently in use. More...
bool	gpiod_line_is_open_drain (struct gpiod_line *line) GPIOD_API
	Check if the line is an open-drain GPIO. More...
bool	gpiod_line_is_open_source (struct gpiod_line *line) GPIOD_API
	Check if the line is an open-source GPIO. More...
int	gpiod_line_update (struct gpiod_line *line) GPIOD_API
	Re-read the line info. More...
bool	gpiod_line_needs_update (struct gpiod_line *line) GPIOD_API GPIOD_DEPRECATED
	Check if the line info needs to be updated. More...
int	gpiod_line_request (struct gpiod_line *line, const struct gpiod_line_request_config *config, int default_val) GPIOD_API
	Reserve a single line. More...
int	gpiod_line_request_input (struct gpiod_line *line, const char *consumer) GPIOD_API
	Reserve a single line, set the direction to input. More...
int	gpiod_line_request_output (struct gpiod_line *line, const char *consumer, int default_val) GPIOD_API
	Reserve a single line, set the direction to output. More...
int	gpiod_line_request_rising_edge_events (struct gpiod_line *line, const char *consumer) GPIOD_API
	Request rising edge event notifications on a single line. More...
int	gpiod_line_request_falling_edge_events (struct gpiod_line *line, const char *consumer) GPIOD_API
	Request falling edge event notifications on a single line. More...
int	gpiod_line_request_both_edges_events (struct gpiod_line *line, const char *consumer) GPIOD_API
	Request all event type notifications on a single line. More...
int	gpiod_line_request_input_flags (struct gpiod_line *line, const char *consumer, int flags) GPIOD_API
	Reserve a single line, set the direction to input. More...
int	gpiod_line_request_output_flags (struct gpiod_line *line, const char *consumer, int flags, int default_val) GPIOD_API
	Reserve a single line, set the direction to output. More...
int	gpiod_line_request_rising_edge_events_flags (struct gpiod_line *line, const char *consumer, int flags) GPIOD_API
	Request rising edge event notifications on a single line. More...
int	gpiod_line_request_falling_edge_events_flags (struct gpiod_line *line, const char *consumer, int flags) GPIOD_API
	Request falling edge event notifications on a single line. More...
int	gpiod_line_request_both_edges_events_flags (struct gpiod_line *line, const char *consumer, int flags) GPIOD_API
	Request all event type notifications on a single line. More...
int	gpiod_line_request_bulk (struct gpiod_line_bulk *bulk, const struct gpiod_line_request_config *config, const int *default_vals) GPIOD_API
	Reserve a set of GPIO lines. More...
int	gpiod_line_request_bulk_input (struct gpiod_line_bulk *bulk, const char *consumer) GPIOD_API
	Reserve a set of GPIO lines, set the direction to input. More...
int	gpiod_line_request_bulk_output (struct gpiod_line_bulk *bulk, const char *consumer, const int *default_vals) GPIOD_API
	Reserve a set of GPIO lines, set the direction to output. More...
int	gpiod_line_request_bulk_rising_edge_events (struct gpiod_line_bulk *bulk, const char *consumer) GPIOD_API
	Request rising edge event notifications on a set of lines. More...
int	gpiod_line_request_bulk_falling_edge_events (struct gpiod_line_bulk *bulk, const char *consumer) GPIOD_API
	Request falling edge event notifications on a set of lines. More...
int	gpiod_line_request_bulk_both_edges_events (struct gpiod_line_bulk *bulk, const char *consumer) GPIOD_API
	Request all event type notifications on a set of lines. More...
int	gpiod_line_request_bulk_input_flags (struct gpiod_line_bulk *bulk, const char *consumer, int flags) GPIOD_API
	Reserve a set of GPIO lines, set the direction to input. More...
int	gpiod_line_request_bulk_output_flags (struct gpiod_line_bulk *bulk, const char *consumer, int flags, const int *default_vals) GPIOD_API
	Reserve a set of GPIO lines, set the direction to output. More...
int	gpiod_line_request_bulk_rising_edge_events_flags (struct gpiod_line_bulk *bulk, const char *consumer, int flags) GPIOD_API
	Request rising edge event notifications on a set of lines. More...
int	gpiod_line_request_bulk_falling_edge_events_flags (struct gpiod_line_bulk *bulk, const char *consumer, int flags) GPIOD_API
	Request falling edge event notifications on a set of lines. More...
int	gpiod_line_request_bulk_both_edges_events_flags (struct gpiod_line_bulk *bulk, const char *consumer, int flags) GPIOD_API
	Request all event type notifications on a set of lines. More...
void	gpiod_line_release (struct gpiod_line *line) GPIOD_API
	Release a previously reserved line. More...
void	gpiod_line_release_bulk (struct gpiod_line_bulk *bulk) GPIOD_API
	Release a set of previously reserved lines. More...
bool	gpiod_line_is_requested (struct gpiod_line *line) GPIOD_API
	Check if the calling user has ownership of this line. More...
bool	gpiod_line_is_free (struct gpiod_line *line) GPIOD_API
	Check if the calling user has neither requested ownership of this line nor configured any event notifications. More...
int	gpiod_line_get_value (struct gpiod_line *line) GPIOD_API
	Read current value of a single GPIO line. More...
int	gpiod_line_get_value_bulk (struct gpiod_line_bulk *bulk, int *values) GPIOD_API
	Read current values of a set of GPIO lines. More...
int	gpiod_line_set_value (struct gpiod_line *line, int value) GPIOD_API
	Set the value of a single GPIO line. More...
int	gpiod_line_set_value_bulk (struct gpiod_line_bulk *bulk, const int *values) GPIOD_API
	Set the values of a set of GPIO lines. More...
int	gpiod_line_set_config (struct gpiod_line *line, int direction, int flags, int value) GPIOD_API
	Update the configuration of a single GPIO line. More...
int	gpiod_line_set_config_bulk (struct gpiod_line_bulk *bulk, int direction, int flags, const int *values) GPIOD_API
	Update the configuration of a set of GPIO lines. More...
int	gpiod_line_set_flags (struct gpiod_line *line, int flags) GPIOD_API
	Update the configuration flags of a single GPIO line. More...
int	gpiod_line_set_flags_bulk (struct gpiod_line_bulk *bulk, int flags) GPIOD_API
	Update the configuration flags of a set of GPIO lines. More...
int	gpiod_line_set_direction_input (struct gpiod_line *line) GPIOD_API
	Set the direction of a single GPIO line to input. More...
int	gpiod_line_set_direction_input_bulk (struct gpiod_line_bulk *bulk) GPIOD_API
	Set the direction of a set of GPIO lines to input. More...
int	gpiod_line_set_direction_output (struct gpiod_line *line, int value) GPIOD_API
	Set the direction of a single GPIO line to output. More...
int	gpiod_line_set_direction_output_bulk (struct gpiod_line_bulk *bulk, const int *values) GPIOD_API
	Set the direction of a set of GPIO lines to output. More...
int	gpiod_line_event_wait (struct gpiod_line *line, const struct timespec *timeout) GPIOD_API
	Wait for an event on a single line. More...
int	gpiod_line_event_wait_bulk (struct gpiod_line_bulk *bulk, const struct timespec *timeout, struct gpiod_line_bulk *event_bulk) GPIOD_API
	Wait for events on a set of lines. More...
int	gpiod_line_event_read (struct gpiod_line *line, struct gpiod_line_event *event) GPIOD_API
	Read next pending event from the GPIO line. More...
int	gpiod_line_event_read_multiple (struct gpiod_line *line, struct gpiod_line_event *events, unsigned int num_events) GPIOD_API
	Read up to a certain number of events from the GPIO line. More...
int	gpiod_line_event_get_fd (struct gpiod_line *line) GPIOD_API
	Get the event file descriptor. More...
int	gpiod_line_event_read_fd (int fd, struct gpiod_line_event *event) GPIOD_API
	Read the last GPIO event directly from a file descriptor. More...
int	gpiod_line_event_read_fd_multiple (int fd, struct gpiod_line_event *events, unsigned int num_events) GPIOD_API
	Read up to a certain number of events directly from a file descriptor. More...
struct gpiod_line *	gpiod_line_get (const char *device, unsigned int offset) GPIOD_API
	Get a GPIO line handle by GPIO chip description and offset. More...
struct gpiod_line *	gpiod_line_find (const char *name) GPIOD_API
	Find a GPIO line by its name. More...
void	gpiod_line_close_chip (struct gpiod_line *line) GPIOD_API
	Close a GPIO chip owning this line and release all resources. More...
struct gpiod_chip *	gpiod_line_get_chip (struct gpiod_line *line) GPIOD_API
	Get the handle to the GPIO chip controlling this line. More...
struct gpiod_chip_iter *	gpiod_chip_iter_new (void) GPIOD_API
	Create a new gpiochip iterator. More...
void	gpiod_chip_iter_free (struct gpiod_chip_iter *iter) GPIOD_API
	Release all resources allocated for the gpiochip iterator and close the most recently opened gpiochip (if any). More...
void	gpiod_chip_iter_free_noclose (struct gpiod_chip_iter *iter) GPIOD_API
	Release all resources allocated for the gpiochip iterator but don't close the most recently opened gpiochip (if any). More...
struct gpiod_chip *	gpiod_chip_iter_next (struct gpiod_chip_iter *iter) GPIOD_API
	Get the next gpiochip handle. More...
struct gpiod_chip *	gpiod_chip_iter_next_noclose (struct gpiod_chip_iter *iter) GPIOD_API
	Get the next gpiochip handle without closing the previous one. More...
struct gpiod_line_iter *	gpiod_line_iter_new (struct gpiod_chip *chip) GPIOD_API
	Create a new line iterator. More...
void	gpiod_line_iter_free (struct gpiod_line_iter *iter) GPIOD_API
	Free all resources associated with a GPIO line iterator. More...
struct gpiod_line *	gpiod_line_iter_next (struct gpiod_line_iter *iter) GPIOD_API
	Get the next GPIO line handle. More...
const char *	gpiod_version_string (void) GPIOD_API
	Get the API version of the library as a human-readable string. More...