242 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * gpio-event-mon - monitor GPIO line events from userspace4 *5 * Copyright (C) 2016 Linus Walleij6 *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 else56 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 " -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 167int 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