Koan: Created page with "== Manage the GPIO lines in C with libgpiod == Since linux 4.8 the GPIO sysfs interface is deprecated. User space should use the character device instead. '''libgpiod''' en..."

2024-09-12T09:07:49Z

Created page with "== Manage the GPIO lines in C with libgpiod == Since linux 4.8 the GPIO sysfs interface is deprecated. User space should use the character device instead. '''libgpiod''' en..."

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== Manage the GPIO lines in C with libgpiod ==

Since linux 4.8 the GPIO sysfs interface is deprecated. User space should use the character device instead.

'''libgpiod''' encapsulates the ioctl calls and data structures behind a straightforward API.

== Manage the GPIO using the C language ==

- [https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/tree/README libgpiod documentation]

- [https://github.com/starnight/libgpiod-example libgpiod-example git repo]

== Example ==

#include <gpiod.h>
#include <stdio.h>
#include <unistd.h>

#ifndef CONSUMER
#define CONSUMER "Consumer"
#endif

int main(int argc, char **argv)
{
char *chipname = "gpiochip0";
unsigned int line_num = 23; // GPIO Pin #23
unsigned int val;
struct gpiod_chip *chip;
struct gpiod_line *line;
int i, ret;

chip = gpiod_chip_open_by_name(chipname);
if (!chip) {
perror("Open chip failed\n");
goto end;
}

line = gpiod_chip_get_line(chip, line_num);
if (!line) {
perror("Get line failed\n");
goto close_chip;
}

ret = gpiod_line_request_output(line, CONSUMER, 0);
if (ret < 0) {
perror("Request line as output failed\n");
goto release_line;
}

/* Blink 20 times */
val = 0;
for (i = 20; i > 0; i--) {
ret = gpiod_line_set_value(line, val);
if (ret < 0) {
perror("Set line output failed\n");
goto release_line;
}
printf("Output %u on line #%u\n", val, line_num);
sleep(1);
val = !val;
}

release_line:
gpiod_line_release(line);
close_chip:
gpiod_chip_close(chip);
end:
return 0;
}

Manage the GPIO lines in C with libgpiod - Revision history

Koan: Created page with "== Manage the GPIO lines in C with libgpiod == Since linux 4.8 the GPIO sysfs interface is deprecated. User space should use the character device instead. '''libgpiod''' en..."