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 }
58
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