summaryrefslogtreecommitdiff
path: root/tools/gpio/gpio-event-mon.c
blob: 1a303a81aeef10f5445f0db321386eaffbfbafd7 (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
/*
 * gpio-event-mon - monitor GPIO line events from userspace
 *
 * Copyright (C) 2016 Linus Walleij
 *
 * Usage:
 *	gpio-event-mon -n <device-name> -o <offset>
 */

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

int monitor_device(const char *device_name,
		   unsigned int line,
		   uint32_t handleflags,
		   uint32_t eventflags,
		   unsigned int loops)
{
	struct gpioevent_request req;
	struct gpiohandle_data data;
	char *chrdev_name;
	int fd;
	int ret;
	int i = 0;

	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_free_name;
	}

	req.lineoffset = line;
	req.handleflags = handleflags;
	req.eventflags = eventflags;
	strcpy(req.consumer_label, "gpio-event-mon");

	ret = ioctl(fd, GPIO_GET_LINEEVENT_IOCTL, &req);
	if (ret == -1) {
		ret = -errno;
		fprintf(stderr, "Failed to issue GET EVENT "
			"IOCTL (%d)\n",
			ret);
		goto exit_close_error;
	}

	/* Read initial states */
	ret = ioctl(req.fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data);
	if (ret == -1) {
		ret = -errno;
		fprintf(stderr, "Failed to issue GPIOHANDLE GET LINE "
			"VALUES IOCTL (%d)\n",
			ret);
		goto exit_close_error;
	}

	fprintf(stdout, "Monitoring line %d on %s\n", line, device_name);
	fprintf(stdout, "Initial line value: %d\n", data.values[0]);

	while (1) {
		struct gpioevent_data event;

		ret = read(req.fd, &event, sizeof(event));
		if (ret == -1) {
			if (errno == -EAGAIN) {
				fprintf(stderr, "nothing available\n");
				continue;
			} else {
				ret = -errno;
				fprintf(stderr, "Failed to read event (%d)\n",
					ret);
				break;
			}
		}

		if (ret != sizeof(event)) {
			fprintf(stderr, "Reading event failed\n");
			ret = -EIO;
			break;
		}
		fprintf(stdout, "GPIO EVENT %llu: ", event.timestamp);
		switch (event.id) {
		case GPIOEVENT_EVENT_RISING_EDGE:
			fprintf(stdout, "rising edge");
			break;
		case GPIOEVENT_EVENT_FALLING_EDGE:
			fprintf(stdout, "falling edge");
			break;
		default:
			fprintf(stdout, "unknown event");
		}
		fprintf(stdout, "\n");

		i++;
		if (i == loops)
			break;
	}

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

void print_usage(void)
{
	fprintf(stderr, "Usage: gpio-event-mon [options]...\n"
		"Listen to events on GPIO lines, 0->1 1->0\n"
		"  -n <name>  Listen on GPIOs on a named device (must be stated)\n"
		"  -o <n>     Offset to monitor\n"
		"  -d         Set line as open drain\n"
		"  -s         Set line as open source\n"
		"  -r         Listen for rising edges\n"
		"  -f         Listen for falling edges\n"
		" [-c <n>]    Do <n> loops (optional, infinite loop if not stated)\n"
		"  -?         This helptext\n"
		"\n"
		"Example:\n"
		"gpio-event-mon -n gpiochip0 -o 4 -r -f\n"
	);
}

int main(int argc, char **argv)
{
	const char *device_name = NULL;
	unsigned int line = -1;
	unsigned int loops = 0;
	uint32_t handleflags = GPIOHANDLE_REQUEST_INPUT;
	uint32_t eventflags = 0;
	int c;

	while ((c = getopt(argc, argv, "c:n:o:dsrf?")) != -1) {
		switch (c) {
		case 'c':
			loops = strtoul(optarg, NULL, 10);
			break;
		case 'n':
			device_name = optarg;
			break;
		case 'o':
			line = strtoul(optarg, NULL, 10);
			break;
		case 'd':
			handleflags |= GPIOHANDLE_REQUEST_OPEN_DRAIN;
			break;
		case 's':
			handleflags |= GPIOHANDLE_REQUEST_OPEN_SOURCE;
			break;
		case 'r':
			eventflags |= GPIOEVENT_REQUEST_RISING_EDGE;
			break;
		case 'f':
			eventflags |= GPIOEVENT_REQUEST_FALLING_EDGE;
			break;
		case '?':
			print_usage();
			return -1;
		}
	}

	if (!device_name || line == -1) {
		print_usage();
		return -1;
	}
	if (!eventflags) {
		printf("No flags specified, listening on both rising and "
		       "falling edges\n");
		eventflags = GPIOEVENT_REQUEST_BOTH_EDGES;
	}
	return monitor_device(device_name, line, handleflags,
			      eventflags, loops);
}