1 files changed, 64 insertions, 0 deletions
diff --git a/tools/leds/uledmon.c b/tools/leds/uledmon.c
new file mode 100644
index 000000000..c15a39c1f
--- /dev/null
+++ b/tools/leds/uledmon.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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 <device-name>
+ *
+ * <device-name> is the name of the LED class device to be created. Pressing
+ * CTRL+C will exit.
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <linux/uleds.h>
+
+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 <device-name> 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;
+}