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// SPDX-License-Identifier: GPL-2.0-or-later
// SPDX-FileCopyrightText: 2023 Kent Gibson <warthog618@gmail.com>
/* Minimal example of toggling multiple lines. */
#include <errno.h>
#include <gpiod.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define NUM_LINES 3
static struct gpiod_line_request *
request_output_lines(const char *chip_path, const unsigned int *offsets,
enum gpiod_line_value *values, unsigned int num_lines,
const char *consumer)
{
struct gpiod_request_config *rconfig = NULL;
struct gpiod_line_request *request = NULL;
struct gpiod_line_settings *settings;
struct gpiod_line_config *lconfig;
struct gpiod_chip *chip;
unsigned int i;
int ret;
chip = gpiod_chip_open(chip_path);
if (!chip)
return NULL;
settings = gpiod_line_settings_new();
if (!settings)
goto close_chip;
gpiod_line_settings_set_direction(settings,
GPIOD_LINE_DIRECTION_OUTPUT);
lconfig = gpiod_line_config_new();
if (!lconfig)
goto free_settings;
for (i = 0; i < num_lines; i++) {
ret = gpiod_line_config_add_line_settings(lconfig, &offsets[i],
1, settings);
if (ret)
goto free_line_config;
}
gpiod_line_config_set_output_values(lconfig, values, num_lines);
if (consumer) {
rconfig = gpiod_request_config_new();
if (!rconfig)
goto free_line_config;
gpiod_request_config_set_consumer(rconfig, consumer);
}
request = gpiod_chip_request_lines(chip, rconfig, lconfig);
gpiod_request_config_free(rconfig);
free_line_config:
gpiod_line_config_free(lconfig);
free_settings:
gpiod_line_settings_free(settings);
close_chip:
gpiod_chip_close(chip);
return request;
}
static enum gpiod_line_value toggle_line_value(enum gpiod_line_value value)
{
return (value == GPIOD_LINE_VALUE_ACTIVE) ? GPIOD_LINE_VALUE_INACTIVE :
GPIOD_LINE_VALUE_ACTIVE;
}
static void toggle_line_values(enum gpiod_line_value *values,
unsigned int num_lines)
{
unsigned int i;
for (i = 0; i < num_lines; i++)
values[i] = toggle_line_value(values[i]);
}
static void print_values(const unsigned int *offsets,
const enum gpiod_line_value *values,
unsigned int num_lines)
{
unsigned int i;
for (i = 0; i < num_lines; i++) {
if (values[i] == GPIOD_LINE_VALUE_ACTIVE)
printf("%d=Active ", offsets[i]);
else
printf("%d=Inactive ", offsets[i]);
}
printf("\n");
}
int main(void)
{
/* Example configuration - customize to suit your situation. */
static const char *const chip_path = "/dev/gpiochip0";
static const unsigned int line_offsets[NUM_LINES] = { 5, 3, 7 };
enum gpiod_line_value values[NUM_LINES] = { GPIOD_LINE_VALUE_ACTIVE,
GPIOD_LINE_VALUE_ACTIVE,
GPIOD_LINE_VALUE_INACTIVE };
struct gpiod_line_request *request;
request = request_output_lines(chip_path, line_offsets, values,
NUM_LINES,
"toggle-multiple-line-values");
if (!request) {
fprintf(stderr, "failed to request line: %s\n",
strerror(errno));
return EXIT_FAILURE;
}
for (;;) {
print_values(line_offsets, values, NUM_LINES);
sleep(1);
toggle_line_values(values, NUM_LINES);
gpiod_line_request_set_values(request, values);
}
gpiod_line_request_release(request);
return EXIT_SUCCESS;
}
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