101 lines
2.1 KiB
C
101 lines
2.1 KiB
C
/*
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* Doorlockd -- Binary Kitchen's smart door opener
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*
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* Copyright (c) Binary Kitchen e.V., 2018
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*
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* Author: Ralf Ramsauer <ralf@binary-kitchen.de>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the LICENSE file in the top-level directory.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*/
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <linux/gpio.h>
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int main(int argc, const char **argv) {
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int gpiochip_fd, ret;
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struct gpioevent_request req;
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struct gpiohandle_data data;
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struct gpioevent_data event;
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if (argc != 3) {
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fprintf(stderr, "Usage: %s gpiochip pin\n", argv[0]);
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return -1;
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}
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gpiochip_fd = open(argv[1], 0);
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if (gpiochip_fd == -1) {
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perror("open");
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return -1;
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}
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req.lineoffset = atoi(argv[2]);
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req.handleflags = GPIOHANDLE_REQUEST_INPUT;
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req.eventflags = GPIOEVENT_REQUEST_RISING_EDGE | GPIOEVENT_REQUEST_FALLING_EDGE;
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req.consumer_label[0] = 0;
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ret = ioctl(gpiochip_fd, GPIO_GET_LINEEVENT_IOCTL, &req);
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if (ret == -1) {
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perror("ioctl");
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goto gpiochip_out;
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}
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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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perror("ioctl");
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goto req_fd_out;
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}
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printf("Initial Value: %u\n", data.values[0]);
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retry:
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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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printf("Nothing available, trying again\n");
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goto retry;
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}
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}
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if (ret != sizeof(event)) {
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ret = -EIO;
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goto req_fd_out;
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}
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switch (event.id) {
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case GPIOEVENT_EVENT_RISING_EDGE:
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printf("Detected rising edge\n");
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ret = 1;
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break;
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case GPIOEVENT_EVENT_FALLING_EDGE:
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printf("Detected falling edge\n");
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ret = 0;
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break;
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default:
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printf("Unknown event\n");
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ret = -EIO;
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break;
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}
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req_fd_out:
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close(req.fd);
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gpiochip_out:
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close(gpiochip_fd);
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return ret;
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}
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