1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * gpio-event-mon - monitor GPIO line events from userspace 4 * 5 * Copyright (C) 2016 Linus Walleij 6 * 7 * Usage: 8 * gpio-event-mon -n <device-name> -o <offset> 9 */ 10 11 #include <unistd.h> 12 #include <stdlib.h> 13 #include <stdbool.h> 14 #include <stdint.h> 15 #include <stdio.h> 16 #include <dirent.h> 17 #include <errno.h> 18 #include <string.h> 19 #include <poll.h> 20 #include <fcntl.h> 21 #include <getopt.h> 22 #include <inttypes.h> 23 #include <sys/ioctl.h> 24 #include <sys/types.h> 25 #include <linux/gpio.h> 26 #include "gpio-utils.h" 27 28 int monitor_device(const char *device_name, 29 unsigned int *lines, 30 unsigned int num_lines, 31 struct gpio_v2_line_config *config, 32 unsigned int loops) 33 { 34 struct gpio_v2_line_values values; 35 char *chrdev_name; 36 int cfd, lfd; 37 int ret; 38 int i = 0; 39 40 ret = asprintf(&chrdev_name, "/dev/%s", device_name); 41 if (ret < 0) 42 return -ENOMEM; 43 44 cfd = open(chrdev_name, 0); 45 if (cfd == -1) { 46 ret = -errno; 47 fprintf(stderr, "Failed to open %s\n", chrdev_name); 48 goto exit_free_name; 49 } 50 51 ret = gpiotools_request_line(device_name, lines, num_lines, config, 52 "gpio-event-mon"); 53 if (ret < 0) 54 goto exit_device_close; 55 else 56 lfd = ret; 57 58 /* Read initial states */ 59 values.mask = 0; 60 values.bits = 0; 61 for (i = 0; i < num_lines; i++) 62 gpiotools_set_bit(&values.mask, i); 63 ret = gpiotools_get_values(lfd, &values); 64 if (ret < 0) { 65 fprintf(stderr, 66 "Failed to issue GPIO LINE GET VALUES IOCTL (%d)\n", 67 ret); 68 goto exit_line_close; 69 } 70 71 if (num_lines == 1) { 72 fprintf(stdout, "Monitoring line %d on %s\n", lines[0], device_name); 73 fprintf(stdout, "Initial line value: %d\n", 74 gpiotools_test_bit(values.bits, 0)); 75 } else { 76 fprintf(stdout, "Monitoring lines %d", lines[0]); 77 for (i = 1; i < num_lines - 1; i++) 78 fprintf(stdout, ", %d", lines[i]); 79 fprintf(stdout, " and %d on %s\n", lines[i], device_name); 80 fprintf(stdout, "Initial line values: %d", 81 gpiotools_test_bit(values.bits, 0)); 82 for (i = 1; i < num_lines - 1; i++) 83 fprintf(stdout, ", %d", 84 gpiotools_test_bit(values.bits, i)); 85 fprintf(stdout, " and %d\n", 86 gpiotools_test_bit(values.bits, i)); 87 } 88 89 i = 0; 90 while (1) { 91 struct gpio_v2_line_event event; 92 93 ret = read(lfd, &event, sizeof(event)); 94 if (ret == -1) { 95 if (errno == -EAGAIN) { 96 fprintf(stderr, "nothing available\n"); 97 continue; 98 } else { 99 ret = -errno; 100 fprintf(stderr, "Failed to read event (%d)\n", 101 ret); 102 break; 103 } 104 } 105 106 if (ret != sizeof(event)) { 107 fprintf(stderr, "Reading event failed\n"); 108 ret = -EIO; 109 break; 110 } 111 fprintf(stdout, "GPIO EVENT at %" PRIu64 " on line %d (%d|%d) ", 112 (uint64_t)event.timestamp_ns, event.offset, event.line_seqno, 113 event.seqno); 114 switch (event.id) { 115 case GPIO_V2_LINE_EVENT_RISING_EDGE: 116 fprintf(stdout, "rising edge"); 117 break; 118 case GPIO_V2_LINE_EVENT_FALLING_EDGE: 119 fprintf(stdout, "falling edge"); 120 break; 121 default: 122 fprintf(stdout, "unknown event"); 123 } 124 fprintf(stdout, "\n"); 125 126 i++; 127 if (i == loops) 128 break; 129 } 130 131 exit_line_close: 132 if (close(lfd) == -1) 133 perror("Failed to close line file"); 134 exit_device_close: 135 if (close(cfd) == -1) 136 perror("Failed to close GPIO character device file"); 137 exit_free_name: 138 free(chrdev_name); 139 return ret; 140 } 141 142 void print_usage(void) 143 { 144 fprintf(stderr, "Usage: gpio-event-mon [options]...\n" 145 "Listen to events on GPIO lines, 0->1 1->0\n" 146 " -n <name> Listen on GPIOs on a named device (must be stated)\n" 147 " -o <n> Offset of line to monitor (may be repeated)\n" 148 " -d Set line as open drain\n" 149 " -s Set line as open source\n" 150 " -r Listen for rising edges\n" 151 " -f Listen for falling edges\n" 152 " -w Report the wall-clock time for events\n" 153 " -t Report the hardware timestamp for events\n" 154 " -b <n> Debounce the line with period n microseconds\n" 155 " [-c <n>] Do <n> loops (optional, infinite loop if not stated)\n" 156 " -? This helptext\n" 157 "\n" 158 "Example:\n" 159 "gpio-event-mon -n gpiochip0 -o 4 -r -f -b 10000\n" 160 ); 161 } 162 163 #define EDGE_FLAGS \ 164 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 165 GPIO_V2_LINE_FLAG_EDGE_FALLING) 166 167 int main(int argc, char **argv) 168 { 169 const char *device_name = NULL; 170 unsigned int lines[GPIO_V2_LINES_MAX]; 171 unsigned int num_lines = 0; 172 unsigned int loops = 0; 173 struct gpio_v2_line_config config; 174 int c, attr, i; 175 unsigned long debounce_period_us = 0; 176 177 memset(&config, 0, sizeof(config)); 178 config.flags = GPIO_V2_LINE_FLAG_INPUT; 179 while ((c = getopt(argc, argv, "c:n:o:b:dsrfwt?")) != -1) { 180 switch (c) { 181 case 'c': 182 loops = strtoul(optarg, NULL, 10); 183 break; 184 case 'n': 185 device_name = optarg; 186 break; 187 case 'o': 188 if (num_lines >= GPIO_V2_LINES_MAX) { 189 print_usage(); 190 return -1; 191 } 192 lines[num_lines] = strtoul(optarg, NULL, 10); 193 num_lines++; 194 break; 195 case 'b': 196 debounce_period_us = strtoul(optarg, NULL, 10); 197 break; 198 case 'd': 199 config.flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 200 break; 201 case 's': 202 config.flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 203 break; 204 case 'r': 205 config.flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 206 break; 207 case 'f': 208 config.flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 209 break; 210 case 'w': 211 config.flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; 212 break; 213 case 't': 214 config.flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; 215 break; 216 case '?': 217 print_usage(); 218 return -1; 219 } 220 } 221 222 if (debounce_period_us) { 223 attr = config.num_attrs; 224 config.num_attrs++; 225 for (i = 0; i < num_lines; i++) 226 gpiotools_set_bit(&config.attrs[attr].mask, i); 227 config.attrs[attr].attr.id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 228 config.attrs[attr].attr.debounce_period_us = debounce_period_us; 229 } 230 231 if (!device_name || num_lines == 0) { 232 print_usage(); 233 return -1; 234 } 235 if (!(config.flags & EDGE_FLAGS)) { 236 printf("No flags specified, listening on both rising and " 237 "falling edges\n"); 238 config.flags |= EDGE_FLAGS; 239 } 240 return monitor_device(device_name, lines, num_lines, &config, loops); 241 } 242