/*********************************************************************************
 *      Copyright:  (C) 2021 LingYun IoT System Studio
 *                  All rights reserved.
 *
 *       Filename:  led.c
 *    Description:  This file is used to control RGB 3-colors LED
 *
 *     pi@raspberrypi:~ $ gpio readall     #show RPi pin map
 *
 *                 LED     #PIN        BCM
 *                  I ----  39  ----   GND
 *                  G ----  37  ----   26
 *                  R ----  35  ----   19
 *                  B ----  33  ----   13
 *                 
 *        Version:  1.0.0(2012/11/03)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "2021/11/03 12:13:26"
 *                 
 ********************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <string.h>
#include <time.h>
#include <errno.h>

#include <gpiod.h>

#define msleep(x) usleep( 1000*(x) )
#define DELAY     500

#define ON        1
#define OFF       0

/* Three LEDs code */
enum
{
        LED_R = 0,
        LED_G,
        LED_B,
        LED_MAX,
};

/* RGB 3-color LED BCM pin number */
static int led_gpio[LED_MAX]= { 19, 26, 13 };

void init_led(void);
int turn_led(int which, int cmd);

int main(int argc, char *argv[])
{
	init_led();

	while(1)
	{
		turn_led(LED_R, ON);
		turn_led(LED_R, OFF);

		turn_led(LED_G, ON);
		turn_led(LED_G, OFF);

		turn_led(LED_B, ON);
		turn_led(LED_B, OFF);
	}

        return 0;
}


#if 1 /* Use libgpiod lowlevel API */

struct gpiod_chip* chip;

void init_led(void)
{
	chip = gpiod_chip_open_by_name("gpiochip0");
	if( !chip )
	{
		printf("gpiod open chip failure, maybe you need running as root\n");
		exit(1);
	}
}

int turn_led(int which, int cmd)
{
	int                rv = 0;
	struct gpiod_line* line;
       
	line = gpiod_chip_get_line(chip, led_gpio[which]);
	if( !line )
	{
		rv = -2;
	}
       
	gpiod_line_request_output(line, "led", 0);

	if( OFF == cmd )
	{
		gpiod_line_set_value(line, 0);
	}
	else
	{
		gpiod_line_set_value(line, 1);
	}

	msleep(DELAY);
}


#else /* use libgpiod ctxless high level API */
void init_led(void)
{
}

static void gpiod_ctxless_cb(void *data)
{
	sleep(1);
}

int turn_led(int which, int cmd)
{
	if( OFF == cmd )
		gpiod_ctxless_set_value("gpiochip0", led_gpio[which], 0, false, "led", gpiod_ctxless_cb, NULL);
	else
		gpiod_ctxless_set_value("gpiochip0", led_gpio[which], 1, false, "led", gpiod_ctxless_cb, NULL);
}
#endif