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 }
56
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