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