/*
   * (C) Copyright 2006
   * Markus Klotzbuecher, mk@denx.de
   *

   * SPDX-License-Identifier:	GPL-2.0+

   */
  
  /*
   * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
   * Extremly Accurate DS3231 Real Time Clock (RTC).
   *
   * copied from ds1337.c
   */
  
  #include <common.h>
  #include <command.h>
  #include <rtc.h>
  #include <i2c.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         */

  #define RTC_STAT_BIT_BB32KHZ	0x40	/* Battery backed 32KHz Output  */
  #define RTC_STAT_BIT_EN32KHZ	0x8	/* Enable 32KHz Output  */

  
  
  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;

  	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
  ",
  		year, mon_cent, mday, wday, hour, min, sec, control, status);
  
  	if (status & RTC_STAT_BIT_OSF) {
  		printf ("### Warning: RTC oscillator has stopped
  ");
  		/* 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
  ",

  		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);

  
  	return rel;

  }
  
  
  /*
   * Set the RTC
   */

  int rtc_set (struct rtc_time *tmp)

  {
  	uchar century;

  	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d
  ",

  		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);
  }

  /*
   * Enable 32KHz output
   */
  void rtc_enable_32khz_output(void)
  {
  	rtc_write(RTC_STAT_REG_ADDR,
  		  RTC_STAT_BIT_BB32KHZ | RTC_STAT_BIT_EN32KHZ);
  }

  
  /*
   * 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