projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 33f0c47b BG |
1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* | |
| 3 | * gpio-watch - monitor unrequested lines for property changes using the | |
| 4 | * character device | |
| 5 | * | |
| 6 | * Copyright (C) 2019 BayLibre SAS | |
| 7 | * Author: Bartosz Golaszewski <bgolaszewski@baylibre.com> | |
| 8 | */ | |
| 9 | ||
| 10 | #include <ctype.h> | |
| 11 | #include <errno.h> | |
| 12 | #include <fcntl.h> | |
| 13 | #include <linux/gpio.h> | |
| 14 | #include <poll.h> | |
| 15 | #include <stdbool.h> | |
| 16 | #include <stdio.h> | |
| 17 | #include <stdlib.h> | |
| 18 | #include <string.h> | |
| 19 | #include <sys/ioctl.h> | |
| 20 | #include <unistd.h> | |
| 21 | ||
| 22 | int main(int argc, char **argv) | |
| 23 | { | |
| 24 | struct gpioline_info_changed chg; | |
| 25 | struct gpioline_info req; | |
| 26 | struct pollfd pfd; | |
| 27 | int fd, i, j, ret; | |
| 28 | char *event, *end; | |
| 29 | ssize_t rd; | |
| 30 | ||
| 31 | if (argc < 3) | |
| 32 | goto err_usage; | |
| 33 | ||
| 34 | fd = open(argv[1], O_RDWR | O_CLOEXEC); | |
| 35 | if (fd < 0) { | |
| 36 | perror("unable to open gpiochip"); | |
| 37 | return EXIT_FAILURE; | |
| 38 | } | |
| 39 | ||
| 40 | for (i = 0, j = 2; i < argc - 2; i++, j++) { | |
| 41 | memset(&req, 0, sizeof(req)); | |
| 42 | ||
| 43 | req.line_offset = strtoul(argv[j], &end, 0); | |
| 44 | if (*end != '\0') | |
| 45 | goto err_usage; | |
| 46 | ||
| 47 | ret = ioctl(fd, GPIO_GET_LINEINFO_WATCH_IOCTL, &req); | |
| 48 | if (ret) { | |
| 49 | perror("unable to set up line watch"); | |
| 50 | return EXIT_FAILURE; | |
| 51 | } | |
| 52 | } | |
| 53 | ||
| 54 | pfd.fd = fd; | |
| 55 | pfd.events = POLLIN | POLLPRI; | |
| 56 | ||
| 57 | for (;;) { | |
| 58 | ret = poll(&pfd, 1, 5000); | |
| 59 | if (ret < 0) { | |
| 60 | perror("error polling the linechanged fd"); | |
| 61 | return EXIT_FAILURE; | |
| 62 | } else if (ret > 0) { | |
| 63 | memset(&chg, 0, sizeof(chg)); | |
| 64 | rd = read(pfd.fd, &chg, sizeof(chg)); | |
| 65 | if (rd < 0 || rd != sizeof(chg)) { | |
| 66 | if (rd != sizeof(chg)) | |
| 67 | errno = EIO; | |
| 68 | ||
| 69 | perror("error reading line change event"); | |
| 70 | return EXIT_FAILURE; | |
| 71 | } | |
| 72 | ||
| 73 | switch (chg.event_type) { | |
| 74 | case GPIOLINE_CHANGED_REQUESTED: | |
| 75 | event = "requested"; | |
| 76 | break; | |
| 77 | case GPIOLINE_CHANGED_RELEASED: | |
| 78 | event = "released"; | |
| 79 | break; | |
| 80 | case GPIOLINE_CHANGED_CONFIG: | |
| 81 | event = "config changed"; | |
| 82 | break; | |
| 83 | default: | |
| 84 | fprintf(stderr, | |
| 85 | "invalid event type received from the kernel\n"); | |
| 86 | return EXIT_FAILURE; | |
| 87 | } | |
| 88 | ||
| 89 | printf("line %u: %s at %llu\n", | |
| 90 | chg.info.line_offset, event, chg.timestamp); | |
| 91 | } | |
| 92 | } | |
| 93 | ||
| 94 | return 0; | |
| 95 | ||
| 96 | err_usage: | |
| 97 | printf("%s: <gpiochip> <line0> <line1> ...\n", argv[0]); | |
| 98 | return EXIT_FAILURE; | |
| 99 | } |