text: // SPDX-License-Identifier: GPL-2.0+
  /*
   * (C) Copyright 2001, 2002, 2003
   * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   * Keith Outwater, keith_outwater@mvis.com`
   * Steven Scholz, steven.scholz@imc-berlin.de
   */
  
  /*
   * Date & Time support (no alarms) for Dallas Semiconductor (now Maxim)
   * DS1307 and DS1338/9 Real Time Clock (RTC).
   *
   * based on ds1337.c
   */
  
  #include <common.h>
  #include <command.h>
  #include <dm.h>
  #include <rtc.h>
  #include <i2c.h>
  
  enum ds_type {
  	ds_1307,
  	ds_1337,
  	ds_1340,
  	mcp794xx,
  };
  
  /*
   * RTC register addresses
   */
  #define RTC_SEC_REG_ADDR	0x00
  #define RTC_MIN_REG_ADDR	0x01
  #define RTC_HR_REG_ADDR		0x02
  #define RTC_DAY_REG_ADDR	0x03
  #define RTC_DATE_REG_ADDR	0x04
  #define RTC_MON_REG_ADDR	0x05
  #define RTC_YR_REG_ADDR		0x06
  #define RTC_CTL_REG_ADDR	0x07
  
  #define RTC_SEC_BIT_CH		0x80	/* Clock Halt (in Register 0)   */
  
  #define RTC_CTL_BIT_RS0		0x01	/* Rate select 0                */
  #define RTC_CTL_BIT_RS1		0x02	/* Rate select 1                */
  #define RTC_CTL_BIT_SQWE	0x10	/* Square Wave Enable           */
  #define RTC_CTL_BIT_OUT		0x80	/* Output Control               */
  
  /* MCP7941X-specific bits */
  #define MCP7941X_BIT_ST		0x80
  #define MCP7941X_BIT_VBATEN	0x08
  
  #ifndef CONFIG_DM_RTC
  
  #if defined(CONFIG_CMD_DATE)
  
  /*---------------------------------------------------------------------*/
  #undef DEBUG_RTC
  
  #ifdef DEBUG_RTC
  #define DEBUGR(fmt, args...) printf(fmt, ##args)
  #else
  #define DEBUGR(fmt, args...)
  #endif
  /*---------------------------------------------------------------------*/
  
  #ifndef CONFIG_SYS_I2C_RTC_ADDR
  # define CONFIG_SYS_I2C_RTC_ADDR	0x68
  #endif
  
  #if defined(CONFIG_RTC_DS1307) && (CONFIG_SYS_I2C_SPEED > 100000)
  # error The DS1307 is specified only up to 100kHz!
  #endif
  
  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, year;
  
  #ifdef CONFIG_RTC_MCP79411
  read_rtc:
  #endif
  	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 = rtc_read (RTC_MON_REG_ADDR);
  	year = rtc_read (RTC_YR_REG_ADDR);
  
  	DEBUGR ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
  		"hr: %02x min: %02x sec: %02x\n",
  		year, mon, mday, wday, hour, min, sec);
  
  #ifdef CONFIG_RTC_DS1307
  	if (sec & RTC_SEC_BIT_CH) {
  		printf ("### Warning: RTC oscillator has stopped\n");
  		/* clear the CH flag */
  		rtc_write (RTC_SEC_REG_ADDR,
  			   rtc_read (RTC_SEC_REG_ADDR) & ~RTC_SEC_BIT_CH);
  		rel = -1;
  	}
  #endif
  
  #ifdef CONFIG_RTC_MCP79411
  	/* make sure that the backup battery is enabled */
  	if (!(wday & MCP7941X_BIT_VBATEN)) {
  		rtc_write(RTC_DAY_REG_ADDR,
  			  wday | MCP7941X_BIT_VBATEN);
  	}
  
  	/* clock halted?  turn it on, so clock can tick. */
  	if (!(sec & MCP7941X_BIT_ST)) {
  		rtc_write(RTC_SEC_REG_ADDR, MCP7941X_BIT_ST);
  		printf("Started RTC\n");
  		goto read_rtc;
  	}
  #endif
  
  
  	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 & 0x1F);
  	tmp->tm_year = bcd2bin (year) + ( bcd2bin (year) >= 70 ? 1900 : 2000);
  	tmp->tm_wday = bcd2bin ((wday - 1) & 0x07);
  	tmp->tm_yday = 0;
  	tmp->tm_isdst= 0;
  
  	DEBUGR ("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);
  
  	return rel;
  }
  
  
  /*
   * Set the RTC
   */
  int rtc_set (struct rtc_time *tmp)
  {
  	DEBUGR ("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);
  
  	if (tmp->tm_year < 1970 || tmp->tm_year > 2069)
  		printf("WARNING: year should be between 1970 and 2069!\n");
  
  	rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
  	rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon));
  #ifdef CONFIG_RTC_MCP79411
  	rtc_write (RTC_DAY_REG_ADDR,
  		   bin2bcd (tmp->tm_wday + 1) | MCP7941X_BIT_VBATEN);
  #else
  	rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday + 1));
  #endif
  	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));
  #ifdef CONFIG_RTC_MCP79411
  	rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec) | MCP7941X_BIT_ST);
  #else
  	rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
  #endif
  
  	return 0;
  }
  
  
  /*
   * Reset the RTC. We setting the date back to 1970-01-01.
   * We also enable the oscillator output on the SQW/OUT 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 to something between 480nA and 800nA.
   */
  void rtc_reset (void)
  {
  	rtc_write (RTC_SEC_REG_ADDR, 0x00);	/* clearing Clock Halt	*/
  	rtc_write (RTC_CTL_REG_ADDR, RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 | RTC_CTL_BIT_RS0);
  }
  
  
  /*
   * 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 /* CONFIG_CMD_DATE*/
  
  #endif /* !CONFIG_DM_RTC */
  
  #ifdef CONFIG_DM_RTC
  static int ds1307_rtc_set(struct udevice *dev, const struct rtc_time *tm)
  {
  	int ret;
  	uchar buf[7];
  	enum ds_type type = dev_get_driver_data(dev);
  
  	debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  	      tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
  	      tm->tm_hour, tm->tm_min, tm->tm_sec);
  
  	if (tm->tm_year < 1970 || tm->tm_year > 2069)
  		printf("WARNING: year should be between 1970 and 2069!\n");
  
  	buf[RTC_YR_REG_ADDR] = bin2bcd(tm->tm_year % 100);
  	buf[RTC_MON_REG_ADDR] = bin2bcd(tm->tm_mon);
  	buf[RTC_DAY_REG_ADDR] = bin2bcd(tm->tm_wday + 1);
  	buf[RTC_DATE_REG_ADDR] = bin2bcd(tm->tm_mday);
  	buf[RTC_HR_REG_ADDR] = bin2bcd(tm->tm_hour);
  	buf[RTC_MIN_REG_ADDR] = bin2bcd(tm->tm_min);
  	buf[RTC_SEC_REG_ADDR] = bin2bcd(tm->tm_sec);
  
  	if (type == mcp794xx) {
  		buf[RTC_DAY_REG_ADDR] |= MCP7941X_BIT_VBATEN;
  		buf[RTC_SEC_REG_ADDR] |= MCP7941X_BIT_ST;
  	}
  
  	ret = dm_i2c_write(dev, 0, buf, sizeof(buf));
  	if (ret < 0)
  		return ret;
  
  	return 0;
  }
  
  static int ds1307_rtc_get(struct udevice *dev, struct rtc_time *tm)
  {
  	int ret;
  	uchar buf[7];
  	enum ds_type type = dev_get_driver_data(dev);
  
  read_rtc:
  	ret = dm_i2c_read(dev, 0, buf, sizeof(buf));
  	if (ret < 0)
  		return ret;
  
  	if (type == ds_1307) {
  		if (buf[RTC_SEC_REG_ADDR] & RTC_SEC_BIT_CH) {
  			printf("### Warning: RTC oscillator has stopped\n");
  			/* clear the CH flag */
  			buf[RTC_SEC_REG_ADDR] &= ~RTC_SEC_BIT_CH;
  			dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
  					 buf[RTC_SEC_REG_ADDR]);
  			return -1;
  		}
  	}
  
  	if (type == mcp794xx) {
  		/* make sure that the backup battery is enabled */
  		if (!(buf[RTC_DAY_REG_ADDR] & MCP7941X_BIT_VBATEN)) {
  			dm_i2c_reg_write(dev, RTC_DAY_REG_ADDR,
  					 buf[RTC_DAY_REG_ADDR] |
  					 MCP7941X_BIT_VBATEN);
  		}
  
  		/* clock halted?  turn it on, so clock can tick. */
  		if (!(buf[RTC_SEC_REG_ADDR] & MCP7941X_BIT_ST)) {
  			dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR,
  					 MCP7941X_BIT_ST);
  			printf("Started RTC\n");
  			goto read_rtc;
  		}
  	}
  
  	tm->tm_sec  = bcd2bin(buf[RTC_SEC_REG_ADDR] & 0x7F);
  	tm->tm_min  = bcd2bin(buf[RTC_MIN_REG_ADDR] & 0x7F);
  	tm->tm_hour = bcd2bin(buf[RTC_HR_REG_ADDR] & 0x3F);
  	tm->tm_mday = bcd2bin(buf[RTC_DATE_REG_ADDR] & 0x3F);
  	tm->tm_mon  = bcd2bin(buf[RTC_MON_REG_ADDR] & 0x1F);
  	tm->tm_year = bcd2bin(buf[RTC_YR_REG_ADDR]) +
  			      (bcd2bin(buf[RTC_YR_REG_ADDR]) >= 70 ?
  			       1900 : 2000);
  	tm->tm_wday = bcd2bin((buf[RTC_DAY_REG_ADDR] - 1) & 0x07);
  	tm->tm_yday = 0;
  	tm->tm_isdst = 0;
  
  	debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  	      tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday,
  	      tm->tm_hour, tm->tm_min, tm->tm_sec);
  
  	return 0;
  }
  
  static int ds1307_rtc_reset(struct udevice *dev)
  {
  	int ret;
  
  	/* clear Clock Halt */
  	ret = dm_i2c_reg_write(dev, RTC_SEC_REG_ADDR, 0x00);
  	if (ret < 0)
  		return ret;
  	ret = dm_i2c_reg_write(dev, RTC_CTL_REG_ADDR,
  			       RTC_CTL_BIT_SQWE | RTC_CTL_BIT_RS1 |
  			       RTC_CTL_BIT_RS0);
  	if (ret < 0)
  		return ret;
  
  	return 0;
  }
  
  static int ds1307_probe(struct udevice *dev)
  {
  	i2c_set_chip_flags(dev, DM_I2C_CHIP_RD_ADDRESS |
  			   DM_I2C_CHIP_WR_ADDRESS);
  
  	return 0;
  }
  
  static const struct rtc_ops ds1307_rtc_ops = {
  	.get = ds1307_rtc_get,
  	.set = ds1307_rtc_set,
  	.reset = ds1307_rtc_reset,
  };
  
  static const struct udevice_id ds1307_rtc_ids[] = {
  	{ .compatible = "dallas,ds1307", .data = ds_1307 },
  	{ .compatible = "dallas,ds1337", .data = ds_1337 },
  	{ .compatible = "dallas,ds1340", .data = ds_1340 },
  	{ .compatible = "microchip,mcp7941x", .data = mcp794xx },
  	{ }
  };
  
  U_BOOT_DRIVER(rtc_ds1307) = {
  	.name	= "rtc-ds1307",
  	.id	= UCLASS_RTC,
  	.probe	= ds1307_probe,
  	.of_match = ds1307_rtc_ids,
  	.ops	= &ds1307_rtc_ops,
  };
  #endif /* CONFIG_DM_RTC */
  