mirror of https://gitee.com/openkylin/linux.git
192 lines
4.2 KiB
C
192 lines
4.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* gpio-event-mon - monitor GPIO line events from userspace
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*
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* Copyright (C) 2016 Linus Walleij
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*
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* Usage:
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* gpio-event-mon -n <device-name> -o <offset>
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <dirent.h>
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#include <errno.h>
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#include <string.h>
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#include <poll.h>
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#include <fcntl.h>
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#include <getopt.h>
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#include <inttypes.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <linux/gpio.h>
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int monitor_device(const char *device_name,
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unsigned int line,
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uint32_t handleflags,
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uint32_t eventflags,
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unsigned int loops)
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{
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struct gpioevent_request req;
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struct gpiohandle_data data;
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char *chrdev_name;
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int fd;
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int ret;
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int i = 0;
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ret = asprintf(&chrdev_name, "/dev/%s", device_name);
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if (ret < 0)
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return -ENOMEM;
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fd = open(chrdev_name, 0);
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if (fd == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to open %s\n", chrdev_name);
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goto exit_close_error;
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}
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req.lineoffset = line;
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req.handleflags = handleflags;
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req.eventflags = eventflags;
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strcpy(req.consumer_label, "gpio-event-mon");
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ret = ioctl(fd, GPIO_GET_LINEEVENT_IOCTL, &req);
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if (ret == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to issue GET EVENT "
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"IOCTL (%d)\n",
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ret);
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goto exit_close_error;
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}
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/* Read initial states */
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ret = ioctl(req.fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data);
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if (ret == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to issue GPIOHANDLE GET LINE "
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"VALUES IOCTL (%d)\n",
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ret);
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goto exit_close_error;
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}
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fprintf(stdout, "Monitoring line %d on %s\n", line, device_name);
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fprintf(stdout, "Initial line value: %d\n", data.values[0]);
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while (1) {
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struct gpioevent_data event;
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ret = read(req.fd, &event, sizeof(event));
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if (ret == -1) {
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if (errno == -EAGAIN) {
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fprintf(stderr, "nothing available\n");
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continue;
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} else {
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ret = -errno;
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fprintf(stderr, "Failed to read event (%d)\n",
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ret);
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break;
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}
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}
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if (ret != sizeof(event)) {
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fprintf(stderr, "Reading event failed\n");
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ret = -EIO;
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break;
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}
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fprintf(stdout, "GPIO EVENT %llu: ", event.timestamp);
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switch (event.id) {
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case GPIOEVENT_EVENT_RISING_EDGE:
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fprintf(stdout, "rising edge");
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break;
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case GPIOEVENT_EVENT_FALLING_EDGE:
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fprintf(stdout, "falling edge");
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break;
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default:
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fprintf(stdout, "unknown event");
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}
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fprintf(stdout, "\n");
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i++;
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if (i == loops)
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break;
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}
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exit_close_error:
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if (close(fd) == -1)
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perror("Failed to close GPIO character device file");
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free(chrdev_name);
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return ret;
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}
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void print_usage(void)
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{
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fprintf(stderr, "Usage: gpio-event-mon [options]...\n"
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"Listen to events on GPIO lines, 0->1 1->0\n"
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" -n <name> Listen on GPIOs on a named device (must be stated)\n"
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" -o <n> Offset to monitor\n"
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" -d Set line as open drain\n"
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" -s Set line as open source\n"
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" -r Listen for rising edges\n"
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" -f Listen for falling edges\n"
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" [-c <n>] Do <n> loops (optional, infinite loop if not stated)\n"
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" -? This helptext\n"
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"\n"
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"Example:\n"
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"gpio-event-mon -n gpiochip0 -o 4 -r -f\n"
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);
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}
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int main(int argc, char **argv)
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{
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const char *device_name = NULL;
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unsigned int line = -1;
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unsigned int loops = 0;
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uint32_t handleflags = GPIOHANDLE_REQUEST_INPUT;
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uint32_t eventflags = 0;
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int c;
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while ((c = getopt(argc, argv, "c:n:o:dsrf?")) != -1) {
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switch (c) {
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case 'c':
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loops = strtoul(optarg, NULL, 10);
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break;
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case 'n':
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device_name = optarg;
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break;
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case 'o':
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line = strtoul(optarg, NULL, 10);
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break;
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case 'd':
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handleflags |= GPIOHANDLE_REQUEST_OPEN_DRAIN;
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break;
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case 's':
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handleflags |= GPIOHANDLE_REQUEST_OPEN_SOURCE;
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break;
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case 'r':
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eventflags |= GPIOEVENT_REQUEST_RISING_EDGE;
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break;
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case 'f':
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eventflags |= GPIOEVENT_REQUEST_FALLING_EDGE;
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break;
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case '?':
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print_usage();
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return -1;
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}
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}
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if (!device_name || line == -1) {
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print_usage();
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return -1;
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}
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if (!eventflags) {
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printf("No flags specified, listening on both rising and "
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"falling edges\n");
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eventflags = GPIOEVENT_REQUEST_BOTH_EDGES;
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}
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return monitor_device(device_name, line, handleflags,
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eventflags, loops);
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}
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