Commit | Line | Data |
---|---|---|
2a144dd0 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-hammer -n <device-name> -o <offset1> -o <offset2> | |
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 | int hammer_device(const char *device_name, unsigned int *lines, int nlines, | |
28 | unsigned int loops) | |
29 | { | |
30 | struct gpiohandle_request req; | |
31 | struct gpiohandle_data data; | |
32 | char *chrdev_name; | |
33 | char swirr[] = "-\\|/"; | |
34 | int fd; | |
35 | int ret; | |
36 | int i, j; | |
37 | unsigned int iteration = 0; | |
38 | ||
39 | ret = asprintf(&chrdev_name, "/dev/%s", device_name); | |
40 | if (ret < 0) | |
41 | return -ENOMEM; | |
42 | ||
43 | fd = open(chrdev_name, 0); | |
44 | if (fd == -1) { | |
45 | ret = -errno; | |
46 | fprintf(stderr, "Failed to open %s\n", chrdev_name); | |
47 | goto exit_close_error; | |
48 | } | |
49 | ||
50 | /* Request lines as output */ | |
51 | for (i = 0; i < nlines; i++) | |
52 | req.lineoffsets[i] = lines[i]; | |
53 | req.flags = GPIOHANDLE_REQUEST_OUTPUT; /* Request as output */ | |
54 | strcpy(req.consumer_label, "gpio-hammer"); | |
55 | req.lines = nlines; | |
56 | ret = ioctl(fd, GPIO_GET_LINEHANDLE_IOCTL, &req); | |
57 | if (ret == -1) { | |
58 | ret = -errno; | |
59 | fprintf(stderr, "Failed to issue GET LINEHANDLE " | |
60 | "IOCTL (%d)\n", | |
61 | ret); | |
62 | goto exit_close_error; | |
63 | } | |
64 | ||
65 | /* Read initial states */ | |
66 | ret = ioctl(req.fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data); | |
67 | if (ret == -1) { | |
68 | ret = -errno; | |
69 | fprintf(stderr, "Failed to issue GPIOHANDLE GET LINE " | |
70 | "VALUES IOCTL (%d)\n", | |
71 | ret); | |
72 | goto exit_close_error; | |
73 | } | |
74 | fprintf(stdout, "Hammer lines ["); | |
75 | for (i = 0; i < nlines; i++) { | |
76 | fprintf(stdout, "%d", lines[i]); | |
77 | if (i != (nlines - 1)) | |
78 | fprintf(stdout, ", "); | |
79 | } | |
80 | fprintf(stdout, "] on %s, initial states: [", device_name); | |
81 | for (i = 0; i < nlines; i++) { | |
82 | fprintf(stdout, "%d", data.values[i]); | |
83 | if (i != (nlines - 1)) | |
84 | fprintf(stdout, ", "); | |
85 | } | |
86 | fprintf(stdout, "]\n"); | |
87 | ||
88 | /* Hammertime! */ | |
89 | j = 0; | |
90 | while (1) { | |
91 | /* Invert all lines so we blink */ | |
92 | for (i = 0; i < nlines; i++) | |
93 | data.values[i] = !data.values[i]; | |
94 | ||
95 | ret = ioctl(req.fd, GPIOHANDLE_SET_LINE_VALUES_IOCTL, &data); | |
96 | if (ret == -1) { | |
97 | ret = -errno; | |
98 | fprintf(stderr, "Failed to issue GPIOHANDLE SET LINE " | |
99 | "VALUES IOCTL (%d)\n", | |
100 | ret); | |
101 | goto exit_close_error; | |
102 | } | |
103 | /* Re-read values to get status */ | |
104 | ret = ioctl(req.fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data); | |
105 | if (ret == -1) { | |
106 | ret = -errno; | |
107 | fprintf(stderr, "Failed to issue GPIOHANDLE GET LINE " | |
108 | "VALUES IOCTL (%d)\n", | |
109 | ret); | |
110 | goto exit_close_error; | |
111 | } | |
112 | ||
113 | fprintf(stdout, "[%c] ", swirr[j]); | |
114 | j++; | |
115 | if (j == sizeof(swirr)-1) | |
116 | j = 0; | |
117 | ||
118 | fprintf(stdout, "["); | |
119 | for (i = 0; i < nlines; i++) { | |
120 | fprintf(stdout, "%d: %d", lines[i], data.values[i]); | |
121 | if (i != (nlines - 1)) | |
122 | fprintf(stdout, ", "); | |
123 | } | |
124 | fprintf(stdout, "]\r"); | |
125 | fflush(stdout); | |
126 | sleep(1); | |
127 | iteration++; | |
128 | if (loops && iteration == loops) | |
129 | break; | |
130 | } | |
131 | fprintf(stdout, "\n"); | |
132 | ret = 0; | |
133 | ||
134 | exit_close_error: | |
135 | if (close(fd) == -1) | |
136 | perror("Failed to close GPIO character device file"); | |
137 | free(chrdev_name); | |
138 | return ret; | |
139 | } | |
140 | ||
141 | void print_usage(void) | |
142 | { | |
143 | fprintf(stderr, "Usage: gpio-hammer [options]...\n" | |
144 | "Hammer GPIO lines, 0->1->0->1...\n" | |
145 | " -n <name> Hammer GPIOs on a named device (must be stated)\n" | |
146 | " -o <n> Offset[s] to hammer, at least one, several can be stated\n" | |
147 | " [-c <n>] Do <n> loops (optional, infinite loop if not stated)\n" | |
148 | " -? This helptext\n" | |
149 | "\n" | |
150 | "Example:\n" | |
151 | "gpio-hammer -n gpiochip0 -o 4\n" | |
152 | ); | |
153 | } | |
154 | ||
155 | int main(int argc, char **argv) | |
156 | { | |
157 | const char *device_name = NULL; | |
158 | unsigned int lines[GPIOHANDLES_MAX]; | |
159 | unsigned int loops = 0; | |
160 | int nlines; | |
161 | int c; | |
162 | int i; | |
163 | ||
164 | i = 0; | |
165 | while ((c = getopt(argc, argv, "c:n:o:?")) != -1) { | |
166 | switch (c) { | |
167 | case 'c': | |
168 | loops = strtoul(optarg, NULL, 10); | |
169 | break; | |
170 | case 'n': | |
171 | device_name = optarg; | |
172 | break; | |
173 | case 'o': | |
174 | lines[i] = strtoul(optarg, NULL, 10); | |
175 | i++; | |
176 | break; | |
177 | case '?': | |
178 | print_usage(); | |
179 | return -1; | |
180 | } | |
181 | } | |
182 | nlines = i; | |
183 | ||
184 | if (!device_name || !nlines) { | |
185 | print_usage(); | |
186 | return -1; | |
187 | } | |
188 | return hammer_device(device_name, lines, nlines, loops); | |
189 | } |