diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/leds/led_hw_brightness_mon.c | |
parent | Initial commit. (diff) | |
download | linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.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/leds/led_hw_brightness_mon.c')
-rw-r--r-- | tools/leds/led_hw_brightness_mon.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/tools/leds/led_hw_brightness_mon.c b/tools/leds/led_hw_brightness_mon.c new file mode 100644 index 000000000..eb65ae988 --- /dev/null +++ b/tools/leds/led_hw_brightness_mon.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * led_hw_brightness_mon.c + * + * This program monitors LED brightness level changes having its origin + * in hardware/firmware, i.e. outside of kernel control. + * A timestamp and brightness value is printed each time the brightness changes. + * + * Usage: led_hw_brightness_mon <device-name> + * + * <device-name> is the name of the LED class device to be monitored. Pressing + * CTRL+C will exit. + */ + +#include <errno.h> +#include <fcntl.h> +#include <poll.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <time.h> +#include <unistd.h> + +#include <linux/uleds.h> + +int main(int argc, char const *argv[]) +{ + int fd, ret; + char brightness_file_path[LED_MAX_NAME_SIZE + 11]; + struct pollfd pollfd; + struct timespec ts; + char buf[11]; + + if (argc != 2) { + fprintf(stderr, "Requires <device-name> argument\n"); + return 1; + } + + snprintf(brightness_file_path, LED_MAX_NAME_SIZE, + "/sys/class/leds/%s/brightness_hw_changed", argv[1]); + + fd = open(brightness_file_path, O_RDONLY); + if (fd == -1) { + printf("Failed to open %s file\n", brightness_file_path); + return 1; + } + + /* + * read may fail if no hw brightness change has occurred so far, + * but it is required to avoid spurious poll notifications in + * the opposite case. + */ + read(fd, buf, sizeof(buf)); + + pollfd.fd = fd; + pollfd.events = POLLPRI; + + while (1) { + ret = poll(&pollfd, 1, -1); + if (ret == -1) { + printf("Failed to poll %s file (%d)\n", + brightness_file_path, ret); + ret = 1; + break; + } + + clock_gettime(CLOCK_MONOTONIC, &ts); + + ret = read(fd, buf, sizeof(buf)); + if (ret < 0) + break; + + ret = lseek(pollfd.fd, 0, SEEK_SET); + if (ret < 0) { + printf("lseek failed (%d)\n", ret); + break; + } + + printf("[%ld.%09ld] %d\n", ts.tv_sec, ts.tv_nsec, atoi(buf)); + } + + close(fd); + + return ret; +} |