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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
fa7f3242 DL |
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 | } |