v2.6.1 から、拡張 DI ポートに割込処理を追加しました。
select() / poll() / epoll を使用することで、DI の状態が変化するイベントを待つことができます。

<sxh C toolbar:false; title:gpio_poll.c> #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <poll.h>

int main(int argc, char **argv) {

  int fd, ret;
  char c;
  struct pollfd pfd;

  /* DI: port 0 割込極性設定 */
  fd = open("/sys/class/gpio/DI_00/edge", O_WRONLY);

  write(fd, "both", 4); /* "rising" / "falling" / "both" */
  close(fd);

  /* DI: port 0 */
  fd = open("/sys/class/gpio/DI_00/value", O_RDONLY);

  pfd.fd = fd;
  pfd.events = POLLPRI;

  while (1) {
      lseek(fd, 0, SEEK_SET);
      
      /* 割込待ち: 5000 [ms] */
      ret = poll(&pfd, 1, 5000);
      read(fd, &c, 1);

      if (ret != 0)
          /* Event */
          printf("DI: %c\n", c);
      else
          printf("timeouted...\n");
  }

  close(fd);

  return 0;

} </sxh>

<sxh python toolbar:false; title:gpio_epoll.py> #! /usr/bin/env python3

import select

def setup_gpios(nums):

  gpios = {}

  GPIO_BASE = "/sys/class/gpio/DI_%02d"

  for i in range(nums):
      # setup interrupt
      open((GPIO_BASE + "/edge") % i, 'w').write("both")

      f = open((GPIO_BASE + "/value") % i, "r")
      # dummy read
      f.readline()

      gpios[f.fileno()] = (i, f)

  return gpios

def main():

  gpios = setup_gpios(8)

  epoll = select.epoll()

  for fd, info in gpios.items():
      epoll.register(fd, select.EPOLLPRI)

  for i in range(10):
      print("waiting event...")
      events = epoll.poll()

      print(" event! nums = %d" % len(events))

      for event in events:
          fd = event[0]
          info = gpios[fd]

          print("  event in GPIO%d" % info[0])
          info[1].seek(0)
          val = int(info[1].readline().strip())
          print("  value: %d" % val)

if name == “main”:

  main()

</sxh>

root@plum:/tmp# python3 gpio_epoll.py 
waiting event...
 event! nums = 1
  event in GPIO0
  value: 1
waiting event...
 event! nums = 1
  event in GPIO0
  value: 0
waiting event...