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// SPDX-License-Identifier: GPL-2.0-only
/*
* gpio-event-mon - monitor GPIO line events from userspace
*
* Copyright (C) 2016 Linus Walleij
*
* Usage:
* gpio-event-mon -n <device-name> -o <offset>
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <dirent.h>
#include <errno.h>
#include <string.h>
#include <poll.h>
#include <fcntl.h>
#include <getopt.h>
#include <inttypes.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <linux/gpio.h>
#include "gpio-utils.h"
int monitor_device(const char *device_name,
unsigned int *lines,
unsigned int num_lines,
struct gpio_v2_line_config *config,
unsigned int loops)
{
struct gpio_v2_line_values values;
char *chrdev_name;
int cfd, lfd;
int ret;
int i = 0;
ret = asprintf(&chrdev_name, "/dev/%s", device_name);
if (ret < 0)
return -ENOMEM;
cfd = open(chrdev_name, 0);
if (cfd == -1) {
ret = -errno;
fprintf(stderr, "Failed to open %s\n", chrdev_name);
goto exit_free_name;
}
ret = gpiotools_request_line(device_name, lines, num_lines, config,
"gpio-event-mon");
if (ret < 0)
goto exit_device_close;
else
lfd = ret;
/* Read initial states */
values.mask = 0;
values.bits = 0;
for (i = 0; i < num_lines; i++)
gpiotools_set_bit(&values.mask, i);
ret = gpiotools_get_values(lfd, &values);
if (ret < 0) {
fprintf(stderr,
"Failed to issue GPIO LINE GET VALUES IOCTL (%d)\n",
ret);
goto exit_line_close;
}
if (num_lines == 1) {
fprintf(stdout, "Monitoring line %d on %s\n", lines[0], device_name);
fprintf(stdout, "Initial line value: %d\n",
gpiotools_test_bit(values.bits, 0));
} else {
fprintf(stdout, "Monitoring lines %d", lines[0]);
for (i = 1; i < num_lines - 1; i++)
fprintf(stdout, ", %d", lines[i]);
fprintf(stdout, " and %d on %s\n", lines[i], device_name);
fprintf(stdout, "Initial line values: %d",
gpiotools_test_bit(values.bits, 0));
for (i = 1; i < num_lines - 1; i++)
fprintf(stdout, ", %d",
gpiotools_test_bit(values.bits, i));
fprintf(stdout, " and %d\n",
gpiotools_test_bit(values.bits, i));
}
while (1) {
struct gpio_v2_line_event event;
ret = read(lfd, &event, sizeof(event));
if (ret == -1) {
if (errno == -EAGAIN) {
fprintf(stderr, "nothing available\n");
continue;
} else {
ret = -errno;
fprintf(stderr, "Failed to read event (%d)\n",
ret);
break;
}
}
if (ret != sizeof(event)) {
fprintf(stderr, "Reading event failed\n");
ret = -EIO;
break;
}
fprintf(stdout, "GPIO EVENT at %llu on line %d (%d|%d) ",
event.timestamp_ns, event.offset, event.line_seqno,
event.seqno);
switch (event.id) {
case GPIO_V2_LINE_EVENT_RISING_EDGE:
fprintf(stdout, "rising edge");
break;
case GPIO_V2_LINE_EVENT_FALLING_EDGE:
fprintf(stdout, "falling edge");
break;
default:
fprintf(stdout, "unknown event");
}
fprintf(stdout, "\n");
i++;
if (i == loops)
break;
}
exit_line_close:
if (close(lfd) == -1)
perror("Failed to close line file");
exit_device_close:
if (close(cfd) == -1)
perror("Failed to close GPIO character device file");
exit_free_name:
free(chrdev_name);
return ret;
}
void print_usage(void)
{
fprintf(stderr, "Usage: gpio-event-mon [options]...\n"
"Listen to events on GPIO lines, 0->1 1->0\n"
" -n <name> Listen on GPIOs on a named device (must be stated)\n"
" -o <n> Offset of line to monitor (may be repeated)\n"
" -d Set line as open drain\n"
" -s Set line as open source\n"
" -r Listen for rising edges\n"
" -f Listen for falling edges\n"
" -b <n> Debounce the line with period n microseconds\n"
" [-c <n>] Do <n> loops (optional, infinite loop if not stated)\n"
" -? This helptext\n"
"\n"
"Example:\n"
"gpio-event-mon -n gpiochip0 -o 4 -r -f -b 10000\n"
);
}
#define EDGE_FLAGS \
(GPIO_V2_LINE_FLAG_EDGE_RISING | \
GPIO_V2_LINE_FLAG_EDGE_FALLING)
int main(int argc, char **argv)
{
const char *device_name = NULL;
unsigned int lines[GPIO_V2_LINES_MAX];
unsigned int num_lines = 0;
unsigned int loops = 0;
struct gpio_v2_line_config config;
int c, attr, i;
unsigned long debounce_period_us = 0;
memset(&config, 0, sizeof(config));
config.flags = GPIO_V2_LINE_FLAG_INPUT;
while ((c = getopt(argc, argv, "c:n:o:b:dsrf?")) != -1) {
switch (c) {
case 'c':
loops = strtoul(optarg, NULL, 10);
break;
case 'n':
device_name = optarg;
break;
case 'o':
if (num_lines >= GPIO_V2_LINES_MAX) {
print_usage();
return -1;
}
lines[num_lines] = strtoul(optarg, NULL, 10);
num_lines++;
break;
case 'b':
debounce_period_us = strtoul(optarg, NULL, 10);
break;
case 'd':
config.flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
break;
case 's':
config.flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
break;
case 'r':
config.flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
break;
case 'f':
config.flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
break;
case '?':
print_usage();
return -1;
}
}
if (debounce_period_us) {
attr = config.num_attrs;
config.num_attrs++;
for (i = 0; i < num_lines; i++)
gpiotools_set_bit(&config.attrs[attr].mask, i);
config.attrs[attr].attr.id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
config.attrs[attr].attr.debounce_period_us = debounce_period_us;
}
if (!device_name || num_lines == 0) {
print_usage();
return -1;
}
if (!(config.flags & EDGE_FLAGS)) {
printf("No flags specified, listening on both rising and "
"falling edges\n");
config.flags |= EDGE_FLAGS;
}
return monitor_device(device_name, lines, num_lines, &config, loops);
}
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