1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * lsgpio - example on how to list the GPIO lines on a system
4 *
5 * Copyright (C) 2015 Linus Walleij
6 *
7 * Usage:
8 * lsgpio <-n device-name>
9 */
10
11 #include <unistd.h>
12 #include <stdlib.h>
13 #include <stdbool.h>
14 #include <stdio.h>
15 #include <dirent.h>
16 #include <errno.h>
17 #include <string.h>
18 #include <poll.h>
19 #include <fcntl.h>
20 #include <getopt.h>
21 #include <sys/ioctl.h>
22 #include <linux/gpio.h>
23
24 #include "gpio-utils.h"
25
26 struct gpio_flag {
27 char *name;
28 unsigned long long mask;
29 };
30
31 struct gpio_flag flagnames[] = {
32 {
33 .name = "used",
34 .mask = GPIO_V2_LINE_FLAG_USED,
35 },
36 {
37 .name = "input",
38 .mask = GPIO_V2_LINE_FLAG_INPUT,
39 },
40 {
41 .name = "output",
42 .mask = GPIO_V2_LINE_FLAG_OUTPUT,
43 },
44 {
45 .name = "active-low",
46 .mask = GPIO_V2_LINE_FLAG_ACTIVE_LOW,
47 },
48 {
49 .name = "open-drain",
50 .mask = GPIO_V2_LINE_FLAG_OPEN_DRAIN,
51 },
52 {
53 .name = "open-source",
54 .mask = GPIO_V2_LINE_FLAG_OPEN_SOURCE,
55 },
56 {
57 .name = "pull-up",
58 .mask = GPIO_V2_LINE_FLAG_BIAS_PULL_UP,
59 },
60 {
61 .name = "pull-down",
62 .mask = GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN,
63 },
64 {
65 .name = "bias-disabled",
66 .mask = GPIO_V2_LINE_FLAG_BIAS_DISABLED,
67 },
68 {
69 .name = "clock-realtime",
70 .mask = GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME,
71 },
72 };
73
print_attributes(struct gpio_v2_line_info * info)74 static void print_attributes(struct gpio_v2_line_info *info)
75 {
76 int i;
77 const char *field_format = "%s";
78
79 for (i = 0; i < ARRAY_SIZE(flagnames); i++) {
80 if (info->flags & flagnames[i].mask) {
81 fprintf(stdout, field_format, flagnames[i].name);
82 field_format = ", %s";
83 }
84 }
85
86 if ((info->flags & GPIO_V2_LINE_FLAG_EDGE_RISING) &&
87 (info->flags & GPIO_V2_LINE_FLAG_EDGE_FALLING))
88 fprintf(stdout, field_format, "both-edges");
89 else if (info->flags & GPIO_V2_LINE_FLAG_EDGE_RISING)
90 fprintf(stdout, field_format, "rising-edge");
91 else if (info->flags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
92 fprintf(stdout, field_format, "falling-edge");
93
94 for (i = 0; i < info->num_attrs; i++) {
95 if (info->attrs[i].id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE)
96 fprintf(stdout, ", debounce_period=%dusec",
97 info->attrs[i].debounce_period_us);
98 }
99 }
100
list_device(const char * device_name)101 int list_device(const char *device_name)
102 {
103 struct gpiochip_info cinfo;
104 char *chrdev_name;
105 int fd;
106 int ret;
107 int i;
108
109 ret = asprintf(&chrdev_name, "/dev/%s", device_name);
110 if (ret < 0)
111 return -ENOMEM;
112
113 fd = open(chrdev_name, 0);
114 if (fd == -1) {
115 ret = -errno;
116 fprintf(stderr, "Failed to open %s\n", chrdev_name);
117 goto exit_free_name;
118 }
119
120 /* Inspect this GPIO chip */
121 ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo);
122 if (ret == -1) {
123 ret = -errno;
124 perror("Failed to issue CHIPINFO IOCTL\n");
125 goto exit_close_error;
126 }
127 fprintf(stdout, "GPIO chip: %s, \"%s\", %u GPIO lines\n",
128 cinfo.name, cinfo.label, cinfo.lines);
129
130 /* Loop over the lines and print info */
131 for (i = 0; i < cinfo.lines; i++) {
132 struct gpio_v2_line_info linfo;
133
134 memset(&linfo, 0, sizeof(linfo));
135 linfo.offset = i;
136
137 ret = ioctl(fd, GPIO_V2_GET_LINEINFO_IOCTL, &linfo);
138 if (ret == -1) {
139 ret = -errno;
140 perror("Failed to issue LINEINFO IOCTL\n");
141 goto exit_close_error;
142 }
143 fprintf(stdout, "\tline %2d:", linfo.offset);
144 if (linfo.name[0])
145 fprintf(stdout, " \"%s\"", linfo.name);
146 else
147 fprintf(stdout, " unnamed");
148 if (linfo.consumer[0])
149 fprintf(stdout, " \"%s\"", linfo.consumer);
150 else
151 fprintf(stdout, " unused");
152 if (linfo.flags) {
153 fprintf(stdout, " [");
154 print_attributes(&linfo);
155 fprintf(stdout, "]");
156 }
157 fprintf(stdout, "\n");
158
159 }
160
161 exit_close_error:
162 if (close(fd) == -1)
163 perror("Failed to close GPIO character device file");
164 exit_free_name:
165 free(chrdev_name);
166 return ret;
167 }
168
print_usage(void)169 void print_usage(void)
170 {
171 fprintf(stderr, "Usage: lsgpio [options]...\n"
172 "List GPIO chips, lines and states\n"
173 " -n <name> List GPIOs on a named device\n"
174 " -? This helptext\n"
175 );
176 }
177
main(int argc,char ** argv)178 int main(int argc, char **argv)
179 {
180 const char *device_name = NULL;
181 int ret;
182 int c;
183
184 while ((c = getopt(argc, argv, "n:")) != -1) {
185 switch (c) {
186 case 'n':
187 device_name = optarg;
188 break;
189 case '?':
190 print_usage();
191 return -1;
192 }
193 }
194
195 if (device_name)
196 ret = list_device(device_name);
197 else {
198 const struct dirent *ent;
199 DIR *dp;
200
201 /* List all GPIO devices one at a time */
202 dp = opendir("/dev");
203 if (!dp) {
204 ret = -errno;
205 goto error_out;
206 }
207
208 ret = -ENOENT;
209 while (ent = readdir(dp), ent) {
210 if (check_prefix(ent->d_name, "gpiochip")) {
211 ret = list_device(ent->d_name);
212 if (ret)
213 break;
214 }
215 }
216
217 ret = 0;
218 if (closedir(dp) == -1) {
219 perror("scanning devices: Failed to close directory");
220 ret = -errno;
221 }
222 }
223 error_out:
224 return ret;
225 }
226