tools/testing/selftests/gpio/gpio-line-name.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * GPIO character device helper for reading line names.
   4  *
   5  * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
   6  */
   7
   8 #include <fcntl.h>
   9 #include <linux/gpio.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/ioctl.h>
  14 #include <sys/types.h>
  15
  16 static void print_usage(void)
  17 {
  18         printf("usage:\n");
  19         printf("  gpio-line-name <chip path> <line offset>\n");
  20 }
  21
  22 int main(int argc, char **argv)
  23 {
  24         struct gpio_v2_line_info info;
  25         int fd, ret;
  26         char *endp;
  27
  28         if (argc != 3) {
  29                 print_usage();
  30                 return EXIT_FAILURE;
  31         }
  32
  33         fd = open(argv[1], O_RDWR);
  34         if (fd < 0) {
  35                 perror("unable to open the GPIO chip");
  36                 return EXIT_FAILURE;
  37         }
  38
  39         memset(&info, 0, sizeof(info));
  40         info.offset = strtoul(argv[2], &endp, 10);
  41         if (*endp != '\0') {
  42                 print_usage();
  43                 return EXIT_FAILURE;
  44         }
  45
  46         ret = ioctl(fd, GPIO_V2_GET_LINEINFO_IOCTL, &info);
  47         if (ret) {
  48                 perror("line info ioctl failed");
  49                 return EXIT_FAILURE;
  50         }
  51
  52         printf("%s\n", info.name);
  53
  54         return EXIT_SUCCESS;
  55 }