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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
29struct gpio_flag {
30 char *name;
31 unsigned long mask;
32};
33
34struct 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
57void 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
72int 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
132exit_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
139void 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
148int main(int argc, char **argv)
149{
150 const char *device_name;
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 }
193error_out:
194 return ret;
195}
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
29struct gpio_flag {
30 char *name;
31 unsigned long mask;
32};
33
34struct 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
57void 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
72int 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
132exit_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
139void 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
148int 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 }
193error_out:
194 return ret;
195}