Commit | Line | Data |
---|---|---|
97f69747 | 1 | /* |
925baf39 | 2 | * gpio-event-mon - monitor GPIO line events from userspace |
97f69747 LW |
3 | * |
4 | * Copyright (C) 2016 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 | * gpio-event-mon -n <device-name> -o <offset> | |
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 <inttypes.h> | |
25 | #include <sys/ioctl.h> | |
636124c8 | 26 | #include <sys/types.h> |
97f69747 LW |
27 | #include <linux/gpio.h> |
28 | ||
29 | int monitor_device(const char *device_name, | |
30 | unsigned int line, | |
31 | u_int32_t handleflags, | |
32 | u_int32_t eventflags, | |
33 | unsigned int loops) | |
34 | { | |
35 | struct gpioevent_request req; | |
36 | struct gpiohandle_data data; | |
37 | char *chrdev_name; | |
38 | int fd; | |
39 | int ret; | |
40 | int i = 0; | |
41 | ||
42 | ret = asprintf(&chrdev_name, "/dev/%s", device_name); | |
43 | if (ret < 0) | |
44 | return -ENOMEM; | |
45 | ||
46 | fd = open(chrdev_name, 0); | |
47 | if (fd == -1) { | |
48 | ret = -errno; | |
49 | fprintf(stderr, "Failed to open %s\n", chrdev_name); | |
50 | goto exit_close_error; | |
51 | } | |
52 | ||
53 | req.lineoffset = line; | |
54 | req.handleflags = handleflags; | |
55 | req.eventflags = eventflags; | |
56 | strcpy(req.consumer_label, "gpio-event-mon"); | |
57 | ||
58 | ret = ioctl(fd, GPIO_GET_LINEEVENT_IOCTL, &req); | |
59 | if (ret == -1) { | |
60 | ret = -errno; | |
61 | fprintf(stderr, "Failed to issue GET EVENT " | |
62 | "IOCTL (%d)\n", | |
63 | ret); | |
64 | goto exit_close_error; | |
65 | } | |
66 | ||
67 | /* Read initial states */ | |
68 | ret = ioctl(req.fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data); | |
69 | if (ret == -1) { | |
70 | ret = -errno; | |
71 | fprintf(stderr, "Failed to issue GPIOHANDLE GET LINE " | |
72 | "VALUES IOCTL (%d)\n", | |
73 | ret); | |
74 | goto exit_close_error; | |
75 | } | |
76 | ||
77 | fprintf(stdout, "Monitoring line %d on %s\n", line, device_name); | |
78 | fprintf(stdout, "Initial line value: %d\n", data.values[0]); | |
79 | ||
80 | while (1) { | |
81 | struct gpioevent_data event; | |
82 | ||
83 | ret = read(req.fd, &event, sizeof(event)); | |
84 | if (ret == -1) { | |
85 | if (errno == -EAGAIN) { | |
86 | fprintf(stderr, "nothing available\n"); | |
87 | continue; | |
88 | } else { | |
89 | ret = -errno; | |
90 | fprintf(stderr, "Failed to read event (%d)\n", | |
91 | ret); | |
92 | break; | |
93 | } | |
94 | } | |
95 | ||
96 | if (ret != sizeof(event)) { | |
97 | fprintf(stderr, "Reading event failed\n"); | |
98 | ret = -EIO; | |
99 | break; | |
100 | } | |
101 | fprintf(stdout, "GPIO EVENT %" PRIu64 ": ", event.timestamp); | |
102 | switch (event.id) { | |
103 | case GPIOEVENT_EVENT_RISING_EDGE: | |
104 | fprintf(stdout, "rising edge"); | |
105 | break; | |
106 | case GPIOEVENT_EVENT_FALLING_EDGE: | |
107 | fprintf(stdout, "falling edge"); | |
108 | break; | |
109 | default: | |
110 | fprintf(stdout, "unknown event"); | |
111 | } | |
112 | fprintf(stdout, "\n"); | |
113 | ||
114 | i++; | |
115 | if (i == loops) | |
116 | break; | |
117 | } | |
118 | ||
119 | exit_close_error: | |
120 | if (close(fd) == -1) | |
121 | perror("Failed to close GPIO character device file"); | |
122 | free(chrdev_name); | |
123 | return ret; | |
124 | } | |
125 | ||
126 | void print_usage(void) | |
127 | { | |
128 | fprintf(stderr, "Usage: gpio-event-mon [options]...\n" | |
129 | "Listen to events on GPIO lines, 0->1 1->0\n" | |
130 | " -n <name> Listen on GPIOs on a named device (must be stated)\n" | |
131 | " -o <n> Offset to monitor\n" | |
132 | " -d Set line as open drain\n" | |
133 | " -s Set line as open source\n" | |
134 | " -r Listen for rising edges\n" | |
135 | " -f Listen for falling edges\n" | |
136 | " [-c <n>] Do <n> loops (optional, infinite loop if not stated)\n" | |
137 | " -? This helptext\n" | |
138 | "\n" | |
139 | "Example:\n" | |
140 | "gpio-event-mon -n gpiochip0 -o 4 -r -f\n" | |
141 | ); | |
142 | } | |
143 | ||
144 | int main(int argc, char **argv) | |
145 | { | |
146 | const char *device_name = NULL; | |
147 | unsigned int line = -1; | |
148 | unsigned int loops = 0; | |
149 | u_int32_t handleflags = GPIOHANDLE_REQUEST_INPUT; | |
150 | u_int32_t eventflags = 0; | |
151 | int c; | |
152 | ||
153 | while ((c = getopt(argc, argv, "c:n:o:dsrf?")) != -1) { | |
154 | switch (c) { | |
155 | case 'c': | |
156 | loops = strtoul(optarg, NULL, 10); | |
157 | break; | |
158 | case 'n': | |
159 | device_name = optarg; | |
160 | break; | |
161 | case 'o': | |
162 | line = strtoul(optarg, NULL, 10); | |
163 | break; | |
164 | case 'd': | |
165 | handleflags |= GPIOHANDLE_REQUEST_OPEN_DRAIN; | |
166 | break; | |
167 | case 's': | |
168 | handleflags |= GPIOHANDLE_REQUEST_OPEN_SOURCE; | |
169 | break; | |
170 | case 'r': | |
171 | eventflags |= GPIOEVENT_REQUEST_RISING_EDGE; | |
172 | break; | |
173 | case 'f': | |
174 | eventflags |= GPIOEVENT_REQUEST_FALLING_EDGE; | |
175 | break; | |
176 | case '?': | |
177 | print_usage(); | |
178 | return -1; | |
179 | } | |
180 | } | |
181 | ||
182 | if (!device_name || line == -1) { | |
183 | print_usage(); | |
184 | return -1; | |
185 | } | |
186 | if (!eventflags) { | |
187 | printf("No flags specified, listening on both rising and " | |
188 | "falling edges\n"); | |
189 | eventflags = GPIOEVENT_REQUEST_BOTH_EDGES; | |
190 | } | |
191 | return monitor_device(device_name, line, handleflags, | |
192 | eventflags, loops); | |
193 | } |