tools/testing/selftests/gpio/gpio-chip-info.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * GPIO character device helper for reading chip information.
   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-chip-info <chip path> [name|label|num-lines]\n");
  20 }
  21
  22 int main(int argc, char **argv)
  23 {
  24         struct gpiochip_info info;
  25         int fd, ret;
  26
  27         if (argc != 3) {
  28                 print_usage();
  29                 return EXIT_FAILURE;
  30         }
  31
  32         fd = open(argv[1], O_RDWR);
  33         if (fd < 0) {
  34                 perror("unable to open the GPIO chip");
  35                 return EXIT_FAILURE;
  36         }
  37
  38         memset(&info, 0, sizeof(info));
  39         ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &info);
  40         if (ret) {
  41                 perror("chip info ioctl failed");
  42                 return EXIT_FAILURE;
  43         }
  44
  45         if (strcmp(argv[2], "name") == 0) {
  46                 printf("%s\n", info.name);
  47         } else if (strcmp(argv[2], "label") == 0) {
  48                 printf("%s\n", info.label);
  49         } else if (strcmp(argv[2], "num-lines") == 0) {
  50                 printf("%u\n", info.lines);
  51         } else {
  52                 fprintf(stderr, "unknown command: %s\n", argv[2]);
  53                 return EXIT_FAILURE;
  54         }
  55
  56         return EXIT_SUCCESS;
  57 }