/*
#include <linux/i2c-dev.h>
// Terrible portability hack between arm-linux-gnueabihf-gcc on Mac OS X and native gcc on raspbian.
#ifndef I2C_M_RD
#include <linux/i2c.h>
#endif
*/
#include <errno.h>
#include <string.h>
#include <stdio.h>
//#include <conio.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/i2c-dev.h>
#include <linux/rtc.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdint.h>

#if defined(CONFIG_CMD_DATE)

/*
 * RTC register addresses
 */
#define RTC_SEC_REG_ADDR	0x0
#define RTC_MIN_REG_ADDR	0x1
#define RTC_HR_REG_ADDR		0x2
#define RTC_DAY_REG_ADDR	0x3
#define RTC_DATE_REG_ADDR	0x4
#define RTC_MON_REG_ADDR	0x5
#define RTC_YR_REG_ADDR		0x6
#define RTC_CTL_REG_ADDR	0x0e
#define RTC_STAT_REG_ADDR	0x0f


/*
 * RTC control register bits
 */
#define RTC_CTL_BIT_A1IE	0x1	/ Alarm 1 interrupt enable     /
#define RTC_CTL_BIT_A2IE	0x2	/ Alarm 2 interrupt enable     /
#define RTC_CTL_BIT_INTCN	0x4	/ Interrupt control            /
#define RTC_CTL_BIT_RS1		0x8	/ Rate select 1                /
#define RTC_CTL_BIT_RS2		0x10	/ Rate select 2                /
#define RTC_CTL_BIT_DOSC	0x80	/ Disable Oscillator           /

/*
 * RTC status register bits
 */
#define RTC_STAT_BIT_A1F	0x1	/ Alarm 1 flag                 /
#define RTC_STAT_BIT_A2F	0x2	/ Alarm 2 flag                 /
#define RTC_STAT_BIT_OSF	0x80	/ Oscillator stop flag         /


static uchar rtc_read (uchar reg);
static void rtc_write (uchar reg, uchar val);


/*
 * Get the current time from the RTC
 */
int rtc_get (struct rtc_time *tmp)
{
	int rel = 0;
	int tm_year, tm_mon, tm_mday, tm_wday, tm_hour, tm_min, tm_sec;
	uchar sec, min, hour, mday, wday, mon_cent, year, control, status;

	control = rtc_read (RTC_CTL_REG_ADDR);
	status = rtc_read (RTC_STAT_REG_ADDR);
	sec = rtc_read (RTC_SEC_REG_ADDR);
	min = rtc_read (RTC_MIN_REG_ADDR);
	hour = rtc_read (RTC_HR_REG_ADDR);
	wday = rtc_read (RTC_DAY_REG_ADDR);
	mday = rtc_read (RTC_DATE_REG_ADDR);
	mon_cent = rtc_read (RTC_MON_REG_ADDR);
	year = rtc_read (RTC_YR_REG_ADDR);

	debug("Get RTC year: %02x mon/cent: %02x mday: %02x wday: %02x "
		"hr: %02x min: %02x sec: %02x control: %02x status: %02x\n",
		year, mon_cent, mday, wday, hour, min, sec, control, status);

	if (status & RTC_STAT_BIT_OSF) {
		printf ("### Warning: RTC oscillator has stopped\n");
		/ clear the OSF flag /
		rtc_write (RTC_STAT_REG_ADDR,
			   rtc_read (RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_OSF);
		rel = -1;
	}

	tmp->tm_sec  = bcd2bin (sec & 0x7F);
	tmp->tm_min  = bcd2bin (min & 0x7F);
	tmp->tm_hour = bcd2bin (hour & 0x3F);
	tmp->tm_mday = bcd2bin (mday & 0x3F);
	tmp->tm_mon  = bcd2bin (mon_cent & 0x1F);
	tmp->tm_year = bcd2bin (year) + ((mon_cent & 0x80) ? 2000 : 1900);
	tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
	tmp->tm_yday = 0;
	tmp->tm_isdst= 0;

	debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
	
	tm_year == tmp->tm_year; 
	tm_mon == tmp->tm_mon;
	tm_mday == tmp->tm_mday; 
	tm_wday == tmp->tm_wday;
	tm_hour == tmp->tm_hour; 
	tm_min == tmp->tm_min; 
	tm_sec == tmp->tm_sec;
	
	return rel;
	return tm_year, tm_mon, tm_mday, tm_wday, tm_hour, tm_min, tm_sec;
}


/*
 * Set the RTC
 */
int rtc_set (struct rtc_time *tmp)
{
	uchar century;

	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);

	rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));

	century = (tmp->tm_year >= 2000) ? 0x80 : 0;
	rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon) | century);

	rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
	rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
	rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour));
	rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
	rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));

	return 0;
}


/*
 * Reset the RTC.  We also enable the oscillator output on the
  SQW/INTB pin and program it for 32,768 Hz output. Note that
 * according to the datasheet, turning on the square wave output
 * increases the current drain on the backup battery from about
 * 600 nA to 2uA.
 */
void rtc_reset (void)
{
	rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS2);
}


/*
 * Helper functions
 */

static uchar rtc_read (uchar reg)
{
	return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
}


static void rtc_write (uchar reg, uchar val)
{
	i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
}

#endif

int main(int argc, char *argv[]){
	
	int file;
	const char *filename = "/dev/i2c-0";
	uint8_t id;
	int mode;
	const int mg_per_digi = 4;
	uint16_t szXYZ[3];
	int cnt=0, max_cnt=0;
	int tm_year, tm_mon, tm_mday, tm_wday, tm_hour, tm_min, tm_sec;
	
	printf("===== rtc test =====\r\n");

	if ( argc == 2){
		max_cnt = atoi(argv[1]);
	}
	
	// open bus
	if ((file = open(filename, O_RDWR)) < 0) {
  	  /* ERROR HANDLING: you can check errno to see what went wrong */
	    perror("Failed to open the i2c bus of rtc");
  	  exit(1);
	}	

	// ds3231 i2c address: 101_0011
	int addr = 0b01010011; 
	if (ioctl(file, I2C_SLAVE, addr) < 0) {
  	  printf("Failed to acquire bus access and/or talk to slave.\n");
	    /* ERROR HANDLING; you can check errno to see what went wrong */
  	  exit(1);
	}
	
/////////////////////////////////////////////////////////////////////////////////////////
	printf("======= SET MODE READ & WRITE ========\n");
	
	printf(" Enter mode 0 is READ & mode 1 Write ");	
	scanf("%d",&mode);

	// mode 0 is READ & mode 1 Write 
	if (mode == 0) {
	int rtc_get (struct rtc_time *tmp);	
	printf("Get DATE: %4d-%02d-%02d ::(wday=%0d)  TIME: %02d:%02d:%20d  \n",
		tm_year, tm_mon, tm_mday, tm_wday, tm_hour, tm_min, tm_sec);
	}
	else {
	int rtc_set (struct rtc_time *tmp);
	//reset rtc using rtc_reset
	//void rtc_reset (void);
	} 

	return 0;
	}