BBAI libgpiod-led P8_03 - 07/21/2020

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

#ifndef CONSUMER
#define CONSUMER        "Consumer"
#endif

int main(int argc, char **argv)
{
        // BBAI P8_03
		char *chipname = "gpiochip0";
        unsigned int line_num = 24;
        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;
}