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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 | struct gpio_flag { | |
30 | char *name; | |
31 | unsigned long mask; | |
32 | }; | |
33 | ||
34 | struct gpio_flag flagnames[] = { | |
35 | { | |
36 | .name = "kernel", | |
37 | .mask = GPIOLINE_FLAG_KERNEL, | |
38 | }, | |
39 | { | |
40 | .name = "output", | |
41 | .mask = GPIOLINE_FLAG_IS_OUT, | |
42 | }, | |
43 | { | |
44 | .name = "active-low", | |
45 | .mask = GPIOLINE_FLAG_ACTIVE_LOW, | |
46 | }, | |
47 | { | |
48 | .name = "open-drain", | |
49 | .mask = GPIOLINE_FLAG_OPEN_DRAIN, | |
50 | }, | |
51 | { | |
52 | .name = "open-source", | |
53 | .mask = GPIOLINE_FLAG_OPEN_SOURCE, | |
54 | }, | |
55 | }; | |
56 | ||
57 | void print_flags(unsigned long flags) | |
58 | { | |
59 | int i; | |
60 | int printed = 0; | |
61 | ||
62 | for (i = 0; i < ARRAY_SIZE(flagnames); i++) { | |
63 | if (flags & flagnames[i].mask) { | |
64 | if (printed) | |
65 | fprintf(stdout, " "); | |
66 | fprintf(stdout, "%s", flagnames[i].name); | |
67 | printed++; | |
68 | } | |
69 | } | |
70 | } | |
71 | ||
72 | int list_device(const char *device_name) | |
73 | { | |
74 | struct gpiochip_info cinfo; | |
75 | char *chrdev_name; | |
76 | int fd; | |
77 | int ret; | |
78 | int i; | |
79 | ||
80 | ret = asprintf(&chrdev_name, "/dev/%s", device_name); | |
81 | if (ret < 0) | |
82 | return -ENOMEM; | |
83 | ||
84 | fd = open(chrdev_name, 0); | |
85 | if (fd == -1) { | |
86 | ret = -errno; | |
87 | fprintf(stderr, "Failed to open %s\n", chrdev_name); | |
88 | goto exit_close_error; | |
89 | } | |
90 | ||
91 | /* Inspect this GPIO chip */ | |
92 | ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo); | |
93 | if (ret == -1) { | |
94 | ret = -errno; | |
95 | perror("Failed to issue CHIPINFO IOCTL\n"); | |
96 | goto exit_close_error; | |
97 | } | |
98 | fprintf(stdout, "GPIO chip: %s, \"%s\", %u GPIO lines\n", | |
99 | cinfo.name, cinfo.label, cinfo.lines); | |
100 | ||
101 | /* Loop over the lines and print info */ | |
102 | for (i = 0; i < cinfo.lines; i++) { | |
103 | struct gpioline_info linfo; | |
104 | ||
105 | memset(&linfo, 0, sizeof(linfo)); | |
106 | linfo.line_offset = i; | |
107 | ||
108 | ret = ioctl(fd, GPIO_GET_LINEINFO_IOCTL, &linfo); | |
109 | if (ret == -1) { | |
110 | ret = -errno; | |
111 | perror("Failed to issue LINEINFO IOCTL\n"); | |
112 | goto exit_close_error; | |
113 | } | |
114 | fprintf(stdout, "\tline %2d:", linfo.line_offset); | |
115 | if (linfo.name[0]) | |
116 | fprintf(stdout, " \"%s\"", linfo.name); | |
117 | else | |
118 | fprintf(stdout, " unnamed"); | |
119 | if (linfo.consumer[0]) | |
120 | fprintf(stdout, " \"%s\"", linfo.consumer); | |
121 | else | |
122 | fprintf(stdout, " unused"); | |
123 | if (linfo.flags) { | |
124 | fprintf(stdout, " ["); | |
125 | print_flags(linfo.flags); | |
126 | fprintf(stdout, "]"); | |
127 | } | |
128 | fprintf(stdout, "\n"); | |
129 | ||
130 | } | |
131 | ||
132 | exit_close_error: | |
133 | if (close(fd) == -1) | |
134 | perror("Failed to close GPIO character device file"); | |
135 | free(chrdev_name); | |
136 | return ret; | |
137 | } | |
138 | ||
139 | void print_usage(void) | |
140 | { | |
141 | fprintf(stderr, "Usage: lsgpio [options]...\n" | |
142 | "List GPIO chips, lines and states\n" | |
143 | " -n <name> List GPIOs on a named device\n" | |
144 | " -? This helptext\n" | |
145 | ); | |
146 | } | |
147 | ||
148 | int main(int argc, char **argv) | |
149 | { | |
150 | const char *device_name = NULL; | |
151 | int ret; | |
152 | int c; | |
153 | ||
154 | while ((c = getopt(argc, argv, "n:")) != -1) { | |
155 | switch (c) { | |
156 | case 'n': | |
157 | device_name = optarg; | |
158 | break; | |
159 | case '?': | |
160 | print_usage(); | |
161 | return -1; | |
162 | } | |
163 | } | |
164 | ||
165 | if (device_name) | |
166 | ret = list_device(device_name); | |
167 | else { | |
168 | const struct dirent *ent; | |
169 | DIR *dp; | |
170 | ||
171 | /* List all GPIO devices one at a time */ | |
172 | dp = opendir("/dev"); | |
173 | if (!dp) { | |
174 | ret = -errno; | |
175 | goto error_out; | |
176 | } | |
177 | ||
178 | ret = -ENOENT; | |
179 | while (ent = readdir(dp), ent) { | |
180 | if (check_prefix(ent->d_name, "gpiochip")) { | |
181 | ret = list_device(ent->d_name); | |
182 | if (ret) | |
183 | break; | |
184 | } | |
185 | } | |
186 | ||
187 | ret = 0; | |
188 | if (closedir(dp) == -1) { | |
189 | perror("scanning devices: Failed to close directory"); | |
190 | ret = -errno; | |
191 | } | |
192 | } | |
193 | error_out: | |
194 | return ret; | |
195 | } |