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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/gpio/gpio-watch.c | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/gpio/gpio-watch.c')
-rw-r--r-- | tools/gpio/gpio-watch.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/tools/gpio/gpio-watch.c b/tools/gpio/gpio-watch.c new file mode 100644 index 000000000..41e76d244 --- /dev/null +++ b/tools/gpio/gpio-watch.c @@ -0,0 +1,100 @@ +// 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; +} |