1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * uledmon.c
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * This program creates a new userspace LED class device and monitors it. A
6*4882a593Smuzhiyun * timestamp and brightness value is printed each time the brightness changes.
7*4882a593Smuzhiyun *
8*4882a593Smuzhiyun * Usage: uledmon <device-name>
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * <device-name> is the name of the LED class device to be created. Pressing
11*4882a593Smuzhiyun * CTRL+C will exit.
12*4882a593Smuzhiyun */
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun #include <fcntl.h>
15*4882a593Smuzhiyun #include <stdio.h>
16*4882a593Smuzhiyun #include <string.h>
17*4882a593Smuzhiyun #include <time.h>
18*4882a593Smuzhiyun #include <unistd.h>
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun #include <linux/uleds.h>
21*4882a593Smuzhiyun
main(int argc,char const * argv[])22*4882a593Smuzhiyun int main(int argc, char const *argv[])
23*4882a593Smuzhiyun {
24*4882a593Smuzhiyun struct uleds_user_dev uleds_dev;
25*4882a593Smuzhiyun int fd, ret;
26*4882a593Smuzhiyun int brightness;
27*4882a593Smuzhiyun struct timespec ts;
28*4882a593Smuzhiyun
29*4882a593Smuzhiyun if (argc != 2) {
30*4882a593Smuzhiyun fprintf(stderr, "Requires <device-name> argument\n");
31*4882a593Smuzhiyun return 1;
32*4882a593Smuzhiyun }
33*4882a593Smuzhiyun
34*4882a593Smuzhiyun strncpy(uleds_dev.name, argv[1], LED_MAX_NAME_SIZE);
35*4882a593Smuzhiyun uleds_dev.max_brightness = 100;
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun fd = open("/dev/uleds", O_RDWR);
38*4882a593Smuzhiyun if (fd == -1) {
39*4882a593Smuzhiyun perror("Failed to open /dev/uleds");
40*4882a593Smuzhiyun return 1;
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun ret = write(fd, &uleds_dev, sizeof(uleds_dev));
44*4882a593Smuzhiyun if (ret == -1) {
45*4882a593Smuzhiyun perror("Failed to write to /dev/uleds");
46*4882a593Smuzhiyun close(fd);
47*4882a593Smuzhiyun return 1;
48*4882a593Smuzhiyun }
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun while (1) {
51*4882a593Smuzhiyun ret = read(fd, &brightness, sizeof(brightness));
52*4882a593Smuzhiyun if (ret == -1) {
53*4882a593Smuzhiyun perror("Failed to read from /dev/uleds");
54*4882a593Smuzhiyun close(fd);
55*4882a593Smuzhiyun return 1;
56*4882a593Smuzhiyun }
57*4882a593Smuzhiyun clock_gettime(CLOCK_MONOTONIC, &ts);
58*4882a593Smuzhiyun printf("[%ld.%09ld] %u\n", ts.tv_sec, ts.tv_nsec, brightness);
59*4882a593Smuzhiyun }
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun close(fd);
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun return 0;
64*4882a593Smuzhiyun }
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