| // 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)); |
| } |
| |
| i = 0; |
| 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 %" PRIu64 " on line %d (%d|%d) ", |
| (uint64_t)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); |
| } |