/* * uledmon.c * * This program creates a new userspace LED class device and monitors it. A * timestamp and brightness value is printed each time the brightness changes. * * Usage: uledmon * * is the name of the LED class device to be created. Pressing * CTRL+C will exit. */ #include #include #include #include #include #include int main(int argc, char const *argv[]) { struct uleds_user_dev uleds_dev; int fd, ret; int brightness; struct timespec ts; if (argc != 2) { fprintf(stderr, "Requires argument\n"); return 1; } strncpy(uleds_dev.name, argv[1], LED_MAX_NAME_SIZE); uleds_dev.max_brightness = 100; fd = open("/dev/uleds", O_RDWR); if (fd == -1) { perror("Failed to open /dev/uleds"); return 1; } ret = write(fd, &uleds_dev, sizeof(uleds_dev)); if (ret == -1) { perror("Failed to write to /dev/uleds"); close(fd); return 1; } while (1) { ret = read(fd, &brightness, sizeof(brightness)); if (ret == -1) { perror("Failed to read from /dev/uleds"); close(fd); return 1; } clock_gettime(CLOCK_MONOTONIC, &ts); printf("[%ld.%09ld] %u\n", ts.tv_sec, ts.tv_nsec, brightness); } close(fd); return 0; } net-next plumbingsTobias Klauser
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authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-30 09:32:26 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-30 09:32:26 -0800
commit238d1d0f79f619d75c2cc741d6770fb0986aef24 (patch)
treeed11bb89c3c61cba7aff3ebc90647f83758a982d /include/trace/events/power.h
parentf3de082c12e5e9ff43c58a7561f6ec3272d03a48 (diff)
parent36f671be1db1b17d3d4ab0c8b47f81ccb1efcb75 (diff)
Merge tag 'docs-4.10-rc1-fix' of git://git.lwn.net/linux
Pull documentation fixes from Jonathan Corbet: "Two small fixes: - A merge error on my part broke the DocBook build. I've requisitioned one of tglx's frozen sharks for appropriate disciplinary action and resolved to be more careful about testing the DocBook stuff as long as it's still around. - Fix an error in unaligned-memory-access.txt" * tag 'docs-4.10-rc1-fix' of git://git.lwn.net/linux: Documentation/unaligned-memory-access.txt: fix incorrect comparison operator docs: Fix build failure
Diffstat (limited to 'include/trace/events/power.h')