| 1 | |
| 2 | |
| 3 | * uledmon.c
|
| 4 | *
|
| 5 | * This program creates a new userspace LED class device and monitors it. A
|
| 6 | * timestamp and brightness value is printed each time the brightness changes.
|
| 7 | *
|
| 8 | * Usage: uledmon <device-name>
|
| 9 | *
|
| 10 | * <device-name> is the name of the LED class device to be created. Pressing
|
| 11 | * CTRL+C will exit.
|
| 12 |
|
| 13 |
|
| 14 | #include <fcntl.h>
|
| 15 | #include <stdio.h>
|
| 16 | #include <string.h>
|
| 17 | #include <time.h>
|
| 18 | #include <unistd.h>
|
| 19 |
|
| 20 | #include <linux/uleds.h>
|
| 21 |
|
| 22 | int main(int argc, char const *argv[])
|
| 23 | {
|
| 24 | struct uleds_user_dev uleds_dev;
|
| 25 | int fd, ret;
|
| 26 | int brightness;
|
| 27 | struct timespec ts;
|
| 28 |
|
| 29 | if (argc != 2) {
|
| 30 | fprintf(stderr, "Requires <device-name> argument\n");
|
| 31 | return 1;
|
| 32 | }
|
| 33 |
|
| 34 | strncpy(uleds_dev.name, argv[1], LED_MAX_NAME_SIZE);
|
| 35 | uleds_dev.max_brightness = 100;
|
| 36 |
|
| 37 | fd = open("/dev/uleds", O_RDWR);
|
| 38 | if (fd == -1) {
|
| 39 | perror("Failed to open /dev/uleds");
|
| 40 | return 1;
|
| 41 | }
|
| 42 |
|
| 43 | ret = write(fd, &uleds_dev, sizeof(uleds_dev));
|
| 44 | if (ret == -1) {
|
| 45 | perror("Failed to write to /dev/uleds");
|
| 46 | close(fd);
|
| 47 | return 1;
|
| 48 | }
|
| 49 |
|
| 50 | while (1) {
|
| 51 | ret = read(fd, &brightness, sizeof(brightness));
|
| 52 | if (ret == -1) {
|
| 53 | perror("Failed to read from /dev/uleds");
|
| 54 | close(fd);
|
| 55 | return 1;
|
| 56 | }
|
| 57 | clock_gettime(CLOCK_MONOTONIC, &ts);
|
| 58 | printf("[%ld.%09ld] %u\n", ts.tv_sec, ts.tv_nsec, brightness);
|
| 59 | }
|
| 60 |
|
| 61 | close(fd);
|
| 62 |
|
| 63 | return 0;
|
| 64 | }
|