// SPDX-License-Identifier: GPL-2.0-only
|
/*
|
* gpio-watch - monitor unrequested lines for property changes using the
|
* character device
|
*
|
* Copyright (C) 2019 BayLibre SAS
|
* Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
|
*/
|
|
#include <ctype.h>
|
#include <errno.h>
|
#include <fcntl.h>
|
#include <inttypes.h>
|
#include <linux/gpio.h>
|
#include <poll.h>
|
#include <stdbool.h>
|
#include <stdio.h>
|
#include <stdlib.h>
|
#include <string.h>
|
#include <sys/ioctl.h>
|
#include <unistd.h>
|
|
int main(int argc, char **argv)
|
{
|
struct gpio_v2_line_info_changed chg;
|
struct gpio_v2_line_info req;
|
struct pollfd pfd;
|
int fd, i, j, ret;
|
char *event, *end;
|
ssize_t rd;
|
|
if (argc < 3)
|
goto err_usage;
|
|
fd = open(argv[1], O_RDWR | O_CLOEXEC);
|
if (fd < 0) {
|
perror("unable to open gpiochip");
|
return EXIT_FAILURE;
|
}
|
|
for (i = 0, j = 2; i < argc - 2; i++, j++) {
|
memset(&req, 0, sizeof(req));
|
|
req.offset = strtoul(argv[j], &end, 0);
|
if (*end != '\0')
|
goto err_usage;
|
|
ret = ioctl(fd, GPIO_V2_GET_LINEINFO_WATCH_IOCTL, &req);
|
if (ret) {
|
perror("unable to set up line watch");
|
return EXIT_FAILURE;
|
}
|
}
|
|
pfd.fd = fd;
|
pfd.events = POLLIN | POLLPRI;
|
|
for (;;) {
|
ret = poll(&pfd, 1, 5000);
|
if (ret < 0) {
|
perror("error polling the linechanged fd");
|
return EXIT_FAILURE;
|
} else if (ret > 0) {
|
memset(&chg, 0, sizeof(chg));
|
rd = read(pfd.fd, &chg, sizeof(chg));
|
if (rd < 0 || rd != sizeof(chg)) {
|
if (rd != sizeof(chg))
|
errno = EIO;
|
|
perror("error reading line change event");
|
return EXIT_FAILURE;
|
}
|
|
switch (chg.event_type) {
|
case GPIO_V2_LINE_CHANGED_REQUESTED:
|
event = "requested";
|
break;
|
case GPIO_V2_LINE_CHANGED_RELEASED:
|
event = "released";
|
break;
|
case GPIO_V2_LINE_CHANGED_CONFIG:
|
event = "config changed";
|
break;
|
default:
|
fprintf(stderr,
|
"invalid event type received from the kernel\n");
|
return EXIT_FAILURE;
|
}
|
|
printf("line %u: %s at %" PRIu64 "\n",
|
chg.info.offset, event, (uint64_t)chg.timestamp_ns);
|
}
|
}
|
|
return 0;
|
|
err_usage:
|
printf("%s: <gpiochip> <line0> <line1> ...\n", argv[0]);
|
return EXIT_FAILURE;
|
}
|
