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64 lines
1.3 KiB
64 lines
1.3 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* uledmon.c |
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* |
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* This program creates a new userspace LED class device and monitors it. A |
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* timestamp and brightness value is printed each time the brightness changes. |
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* |
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* Usage: uledmon <device-name> |
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* |
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* <device-name> is the name of the LED class device to be created. Pressing |
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* CTRL+C will exit. |
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*/ |
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#include <fcntl.h> |
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#include <stdio.h> |
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#include <string.h> |
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#include <time.h> |
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#include <unistd.h> |
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#include <linux/uleds.h> |
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int main(int argc, char const *argv[]) |
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{ |
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struct uleds_user_dev uleds_dev; |
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int fd, ret; |
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int brightness; |
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struct timespec ts; |
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if (argc != 2) { |
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fprintf(stderr, "Requires <device-name> argument\n"); |
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return 1; |
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} |
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strncpy(uleds_dev.name, argv[1], LED_MAX_NAME_SIZE); |
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uleds_dev.max_brightness = 100; |
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fd = open("/dev/uleds", O_RDWR); |
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if (fd == -1) { |
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perror("Failed to open /dev/uleds"); |
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return 1; |
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} |
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ret = write(fd, &uleds_dev, sizeof(uleds_dev)); |
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if (ret == -1) { |
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perror("Failed to write to /dev/uleds"); |
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close(fd); |
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return 1; |
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} |
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while (1) { |
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ret = read(fd, &brightness, sizeof(brightness)); |
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if (ret == -1) { |
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perror("Failed to read from /dev/uleds"); |
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close(fd); |
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return 1; |
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} |
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clock_gettime(CLOCK_MONOTONIC, &ts); |
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printf("[%ld.%09ld] %u\n", ts.tv_sec, ts.tv_nsec, brightness); |
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} |
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close(fd); |
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return 0; |
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}
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