/*
 * Distributed under the terms of the GNU General Public License v2
 * $Header: $
 *
 * Portable led control interface using sysfs files.
 * Written for the TCT NailKit in 2008 by solar@gentoo.org
 */

/*
 * This program has the same net result as echoing values in the the sys files.
 * We just try to automate some of the logic for controling the items thru a common 
 * interface.
 * We have the distant advantage here that embedded vendors simply need to make sure they
 * enable the leds in the correct boardfile. And users don't have to worry about custom
 * led drivers etc..
 *
 * Examples:
 *
 * ledctl 0   (Turns all LEDS off)
 * ledctl 1   (Turns all LEDS on)
 *
 * ledctl 0 0 (Turns off LED 0)
 * ledctl 0 1 (Turns on LED 0)
 *
 * ledctl 1 1 (Turns on LED 1)
 * ledctl 1 0 (Turns off LED 1)
 *
 * ledctl 2 1 (Turns on LED 2)
 * ledctl 2 0 (Turns off LED 2)
 *
 * and so on...
 *
 * Return values:
 *	status: 0 (all good)
 *	status: 1 (usage syntax/help)
 *	status: 255/-1 (no such led)
 */

/* arm-softfloat-linux-uclibc-gcc ledctl.c -Os -fomit-frame-pointer -march=armv4t -mtune=arm920t -s -o ledctl */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>

const char *led_path = "/sys/class/leds/";

#define ledctl sysfs_ledctl
signed int sysfs_ledctl(const int led, const int val, const char *trigger) {
	FILE *fp;
	char fname[64];
	int state = -1;

	snprintf(fname, sizeof(fname), "%s/led%d/trigger", led_path, led);
	if ((fp = fopen(fname, "w")) != NULL) {
		fprintf(fp, "%s\n", trigger == NULL ? "none" : trigger);
		fclose(fp);
	}
	snprintf(fname, sizeof(fname), "%s/led%d/brightness", led_path, led);
	if (val >= 0 && val <= 255) {
		if ((fp = fopen(fname, "w")) == NULL)
			return state;
		fprintf(fp, "%d\n", val);
		fclose(fp);
	}
	if ((fp = fopen(fname, "r")) != NULL) {
		fscanf(fp, "%d", &state);
		fclose(fp);
	}
	return state;
}

int main(int argc, char **argv) {
	struct dirent **dnames;
	int state = 1, ret = 0;
	int count;

	if (argc == 1) {
		printf("Usage:\n\t%s <led> <state>\n\t%s <state>\n", *argv, *argv);
		return 1;
	}
	if (argc > 1)
		state = atoi(argv[1]);
	if (argc > 2) {
		ret = ledctl(atoi(argv[1]), atoi(argv[2]), argc > 3 ? argv[3] : NULL);
		return (ret < 0 ? ret : 0);
	}
	if ((count = scandir(led_path, &dnames, NULL, alphasort)) < 0) {
		fprintf(stderr, "No leds found in %s\n", led_path);
		return -1;
	}
	while (count--) {
		ret = ledctl(count, state, NULL);
		free(dnames[count]);
	}
        free(dnames);
	return (ret < 0 ? ret : 0);
}