summaryrefslogtreecommitdiff
path: root/tools/gpio/lsgpio.c
blob: e1430f504c139c458816c53e78266c487f31f082 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
// SPDX-License-Identifier: GPL-2.0-only
/*
 * lsgpio - example on how to list the GPIO lines on a system
 *
 * Copyright (C) 2015 Linus Walleij
 *
 * Usage:
 *	lsgpio <-n device-name>
 */

#include <unistd.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdio.h>
#include <dirent.h>
#include <errno.h>
#include <string.h>
#include <poll.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/ioctl.h>
#include <linux/gpio.h>

#include "gpio-utils.h"

struct gpio_flag {
	char *name;
	unsigned long mask;
};

struct gpio_flag flagnames[] = {
	{
		.name = "kernel",
		.mask = GPIOLINE_FLAG_KERNEL,
	},
	{
		.name = "output",
		.mask = GPIOLINE_FLAG_IS_OUT,
	},
	{
		.name = "active-low",
		.mask = GPIOLINE_FLAG_ACTIVE_LOW,
	},
	{
		.name = "open-drain",
		.mask = GPIOLINE_FLAG_OPEN_DRAIN,
	},
	{
		.name = "open-source",
		.mask = GPIOLINE_FLAG_OPEN_SOURCE,
	},
};

void print_flags(unsigned long flags)
{
	int i;
	int printed = 0;

	for (i = 0; i < ARRAY_SIZE(flagnames); i++) {
		if (flags & flagnames[i].mask) {
			if (printed)
				fprintf(stdout, " ");
			fprintf(stdout, "%s", flagnames[i].name);
			printed++;
		}
	}
}

int list_device(const char *device_name)
{
	struct gpiochip_info cinfo;
	char *chrdev_name;
	int fd;
	int ret;
	int i;

	ret = asprintf(&chrdev_name, "/dev/%s", device_name);
	if (ret < 0)
		return -ENOMEM;

	fd = open(chrdev_name, 0);
	if (fd == -1) {
		ret = -errno;
		fprintf(stderr, "Failed to open %s\n", chrdev_name);
		goto exit_close_error;
	}

	/* Inspect this GPIO chip */
	ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo);
	if (ret == -1) {
		ret = -errno;
		perror("Failed to issue CHIPINFO IOCTL\n");
		goto exit_close_error;
	}
	fprintf(stdout, "GPIO chip: %s, \"%s\", %u GPIO lines\n",
		cinfo.name, cinfo.label, cinfo.lines);

	/* Loop over the lines and print info */
	for (i = 0; i < cinfo.lines; i++) {
		struct gpioline_info linfo;

		memset(&linfo, 0, sizeof(linfo));
		linfo.line_offset = i;

		ret = ioctl(fd, GPIO_GET_LINEINFO_IOCTL, &linfo);
		if (ret == -1) {
			ret = -errno;
			perror("Failed to issue LINEINFO IOCTL\n");
			goto exit_close_error;
		}
		fprintf(stdout, "\tline %2d:", linfo.line_offset);
		if (linfo.name[0])
			fprintf(stdout, " \"%s\"", linfo.name);
		else
			fprintf(stdout, " unnamed");
		if (linfo.consumer[0])
			fprintf(stdout, " \"%s\"", linfo.consumer);
		else
			fprintf(stdout, " unused");
		if (linfo.flags) {
			fprintf(stdout, " [");
			print_flags(linfo.flags);
			fprintf(stdout, "]");
		}
		fprintf(stdout, "\n");

	}

exit_close_error:
	if (close(fd) == -1)
		perror("Failed to close GPIO character device file");
	free(chrdev_name);
	return ret;
}

void print_usage(void)
{
	fprintf(stderr, "Usage: lsgpio [options]...\n"
		"List GPIO chips, lines and states\n"
		"  -n <name>  List GPIOs on a named device\n"
		"  -?         This helptext\n"
	);
}

int main(int argc, char **argv)
{
	const char *device_name = NULL;
	int ret;
	int c;

	while ((c = getopt(argc, argv, "n:")) != -1) {
		switch (c) {
		case 'n':
			device_name = optarg;
			break;
		case '?':
			print_usage();
			return -1;
		}
	}

	if (device_name)
		ret = list_device(device_name);
	else {
		const struct dirent *ent;
		DIR *dp;

		/* List all GPIO devices one at a time */
		dp = opendir("/dev");
		if (!dp) {
			ret = -errno;
			goto error_out;
		}

		ret = -ENOENT;
		while (ent = readdir(dp), ent) {
			if (check_prefix(ent->d_name, "gpiochip")) {
				ret = list_device(ent->d_name);
				if (ret)
					break;
			}
		}

		ret = 0;
		if (closedir(dp) == -1) {
			perror("scanning devices: Failed to close directory");
			ret = -errno;
		}
	}
error_out:
	return ret;
}