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 28int 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 131exit_line_close: 132 if (close(lfd) == -1) 133 perror("Failed to close line file"); 134exit_device_close: 135 if (close(cfd) == -1) 136 perror("Failed to close GPIO character device file"); 137exit_free_name: 138 free(chrdev_name); 139 return ret; 140} 141 142void 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 " -b <n> Debounce the line with period n microseconds\n" 153 " [-c <n>] Do <n> loops (optional, infinite loop if not stated)\n" 154 " -? This helptext\n" 155 "\n" 156 "Example:\n" 157 "gpio-event-mon -n gpiochip0 -o 4 -r -f -b 10000\n" 158 ); 159} 160 161#define EDGE_FLAGS \ 162 (GPIO_V2_LINE_FLAG_EDGE_RISING | \ 163 GPIO_V2_LINE_FLAG_EDGE_FALLING) 164 165int main(int argc, char **argv) 166{ 167 const char *device_name = NULL; 168 unsigned int lines[GPIO_V2_LINES_MAX]; 169 unsigned int num_lines = 0; 170 unsigned int loops = 0; 171 struct gpio_v2_line_config config; 172 int c, attr, i; 173 unsigned long debounce_period_us = 0; 174 175 memset(&config, 0, sizeof(config)); 176 config.flags = GPIO_V2_LINE_FLAG_INPUT; 177 while ((c = getopt(argc, argv, "c:n:o:b:dsrf?")) != -1) { 178 switch (c) { 179 case 'c': 180 loops = strtoul(optarg, NULL, 10); 181 break; 182 case 'n': 183 device_name = optarg; 184 break; 185 case 'o': 186 if (num_lines >= GPIO_V2_LINES_MAX) { 187 print_usage(); 188 return -1; 189 } 190 lines[num_lines] = strtoul(optarg, NULL, 10); 191 num_lines++; 192 break; 193 case 'b': 194 debounce_period_us = strtoul(optarg, NULL, 10); 195 break; 196 case 'd': 197 config.flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; 198 break; 199 case 's': 200 config.flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; 201 break; 202 case 'r': 203 config.flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; 204 break; 205 case 'f': 206 config.flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; 207 break; 208 case '?': 209 print_usage(); 210 return -1; 211 } 212 } 213 214 if (debounce_period_us) { 215 attr = config.num_attrs; 216 config.num_attrs++; 217 for (i = 0; i < num_lines; i++) 218 gpiotools_set_bit(&config.attrs[attr].mask, i); 219 config.attrs[attr].attr.id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; 220 config.attrs[attr].attr.debounce_period_us = debounce_period_us; 221 } 222 223 if (!device_name || num_lines == 0) { 224 print_usage(); 225 return -1; 226 } 227 if (!(config.flags & EDGE_FLAGS)) { 228 printf("No flags specified, listening on both rising and " 229 "falling edges\n"); 230 config.flags |= EDGE_FLAGS; 231 } 232 return monitor_device(device_name, lines, num_lines, &config, loops); 233} 234