#include <fcntl.h>
#include <inttypes.h>
#include <linux/gpio.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <unistd.h>

#define check(e)                                                               \
  ({                                                                           \
    int ec = (e);                                                              \
    if (ec < 0) {                                                              \
      perror(#e);                                                              \
      exit(1);                                                                 \
    }                                                                          \
    ec;                                                                        \
  })

void gpio_info(int gpio_fd) {
  struct gpiochip_info chip_info;
  check(ioctl(gpio_fd, GPIO_GET_CHIPINFO_IOCTL, &chip_info));

  printf("Name: %s, Label: %s, %" PRIu32 " lines\n", chip_info.name,
         chip_info.label, chip_info.lines);

  for (__u32 i = 0; i != chip_info.lines; ++i) {
    struct gpio_v2_line_info line_info = {
        .offset = i,
    };
    check(ioctl(gpio_fd, GPIO_V2_GET_LINEINFO_IOCTL, &line_info));
    printf("Line %" PRIu32 ": '%s'. Consumer: %s\n", i, line_info.name,
           line_info.consumer[0] ? line_info.consumer : "<none>");
  }
}

int main() {
  int gpio0 = check(open("/dev/gpiochip0", O_RDWR));

  gpio_info(gpio0);

#if 0
  struct gpio_v2_line_request line_request = {
      .offsets = {18},
      .num_lines = 1,
      .consumer = "my-super-cool-gpio",
  };
  check(ioctl(gpio0, GPIO_V2_GET_LINE_IOCTL, &line_request));

  struct gpio_v2_line_info line_info = {
      .offset = 18,
  };
  check(ioctl(gpio0, GPIO_V2_GET_LINEINFO_IOCTL, &line_info));
  printf("Line 18: '%s'. Consumer: '%s'\n", line_info.name, line_info.consumer);

  close(line_request.fd);
#endif
  close(gpio0);
}