Commit | Line | Data |
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6d591c46 LW |
1 | /* |
2 | * lsgpio - example on how to list the GPIO lines on a system | |
3 | * | |
4 | * Copyright (C) 2015 Linus Walleij | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License version 2 as published by | |
8 | * the Free Software Foundation. | |
9 | * | |
10 | * Usage: | |
11 | * lsgpio <-n device-name> | |
12 | */ | |
13 | ||
14 | #include <unistd.h> | |
15 | #include <stdlib.h> | |
16 | #include <stdbool.h> | |
17 | #include <stdio.h> | |
18 | #include <dirent.h> | |
19 | #include <errno.h> | |
20 | #include <string.h> | |
21 | #include <poll.h> | |
22 | #include <fcntl.h> | |
23 | #include <getopt.h> | |
24 | #include <sys/ioctl.h> | |
25 | #include <linux/gpio.h> | |
26 | ||
27 | #include "gpio-utils.h" | |
28 | ||
29 | int list_device(const char *device_name) | |
30 | { | |
31 | struct gpiochip_info cinfo; | |
32 | char *chrdev_name; | |
33 | int fd; | |
34 | int ret; | |
35 | ||
36 | ret = asprintf(&chrdev_name, "/dev/%s", device_name); | |
37 | if (ret < 0) | |
38 | return -ENOMEM; | |
39 | ||
40 | fd = open(chrdev_name, 0); | |
41 | if (fd == -1) { | |
42 | ret = -errno; | |
43 | fprintf(stderr, "Failed to open %s\n", chrdev_name); | |
44 | goto free_chrdev_name; | |
45 | } | |
46 | ||
47 | /* Inspect this GPIO chip */ | |
48 | ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo); | |
49 | if (ret == -1) { | |
50 | ret = -errno; | |
51 | fprintf(stderr, "Failed to retrieve GPIO fd\n"); | |
52 | if (close(fd) == -1) | |
53 | perror("Failed to close GPIO character device file"); | |
54 | ||
55 | goto free_chrdev_name; | |
56 | } | |
57 | fprintf(stdout, "GPIO chip: %s, %u GPIO lines\n", | |
58 | cinfo.name, cinfo.lines); | |
59 | ||
60 | if (close(fd) == -1) { | |
61 | ret = -errno; | |
62 | goto free_chrdev_name; | |
63 | } | |
64 | ||
65 | free_chrdev_name: | |
66 | free(chrdev_name); | |
67 | ||
68 | return ret; | |
69 | ||
70 | } | |
71 | ||
72 | void print_usage(void) | |
73 | { | |
74 | fprintf(stderr, "Usage: lsgpio [options]...\n" | |
75 | "List GPIO chips, lines and states\n" | |
76 | " -n <name> List GPIOs on a named device\n" | |
77 | " -? This helptext\n" | |
78 | ); | |
79 | } | |
80 | ||
81 | int main(int argc, char **argv) | |
82 | { | |
83 | const char *device_name; | |
84 | int ret; | |
85 | int c; | |
86 | ||
87 | while ((c = getopt(argc, argv, "n:")) != -1) { | |
88 | switch (c) { | |
89 | case 'n': | |
90 | device_name = optarg; | |
91 | break; | |
92 | case '?': | |
93 | print_usage(); | |
94 | return -1; | |
95 | } | |
96 | } | |
97 | ||
98 | if (device_name) | |
99 | ret = list_device(device_name); | |
100 | else { | |
101 | const struct dirent *ent; | |
102 | DIR *dp; | |
103 | ||
104 | /* List all GPIO devices one at a time */ | |
105 | dp = opendir("/dev"); | |
106 | if (!dp) { | |
107 | ret = -errno; | |
108 | goto error_out; | |
109 | } | |
110 | ||
111 | ret = -ENOENT; | |
112 | while (ent = readdir(dp), ent) { | |
113 | if (check_prefix(ent->d_name, "gpiochip")) { | |
114 | ret = list_device(ent->d_name); | |
115 | if (ret) | |
116 | break; | |
117 | } | |
118 | } | |
119 | ||
120 | ret = 0; | |
121 | if (closedir(dp) == -1) { | |
122 | perror("scanning devices: Failed to close directory"); | |
123 | ret = -errno; | |
124 | } | |
125 | } | |
126 | error_out: | |
127 | return ret; | |
128 | } |