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bootloader/u-boot_2015_04/drivers/rtc/pt7c4338.c 3.81 KB
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  /*
   * Copyright 2010 Freescale Semiconductor, Inc.
   *
   * Author:	Priyanka Jain <Priyanka.Jain@freescale.com>
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  /*
   * This file provides Date & Time support (no alarms) for PT7C4338 chip.
   *
   * This file is based on drivers/rtc/ds1337.c
   *
   * PT7C4338 chip is manufactured by Pericom Technology Inc.
   * It is a serial real-time clock which provides
   * 1)Low-power clock/calendar.
   * 2)Programmable square-wave output.
   * It has 56 bytes of nonvolatile RAM.
   */
  
  #include <common.h>
  #include <command.h>
  #include <rtc.h>
  #include <i2c.h>
  
  /* 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_STAT_REG_ADDR   0x7
  
  /* RTC second register address bit */
  #define RTC_SEC_BIT_CH		0x80	/* Clock Halt (in Register 0) */
  
  /* RTC control and status register bits */
  #define RTC_CTL_STAT_BIT_RS0    0x1	/* Rate select 0 */
  #define RTC_CTL_STAT_BIT_RS1    0x2	/* Rate select 1 */
  #define RTC_CTL_STAT_BIT_SQWE   0x10	/* Square Wave Enable */
  #define RTC_CTL_STAT_BIT_OSF    0x20	/* Oscillator Stop Flag */
  #define RTC_CTL_STAT_BIT_OUT    0x80	/* Output Level Control */
  
  /* RTC reset value */
  #define RTC_PT7C4338_RESET_VAL \
  	(RTC_CTL_STAT_BIT_RS0 | RTC_CTL_STAT_BIT_RS1 | RTC_CTL_STAT_BIT_OUT)
  
  /****** Helper functions ****************************************/
  static u8 rtc_read(u8 reg)
  {
  	return i2c_reg_read(CONFIG_SYS_I2C_RTC_ADDR, reg);
  }
  
  static void rtc_write(u8 reg, u8 val)
  {
  	i2c_reg_write(CONFIG_SYS_I2C_RTC_ADDR, reg, val);
  }
  /****************************************************************/
  
  /* Get the current time from the RTC */
  int rtc_get(struct rtc_time *tmp)
  {
  	int ret = 0;
  	u8 sec, min, hour, mday, wday, mon, year, ctl_stat;
  
  	ctl_stat = rtc_read(RTC_CTL_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 = rtc_read(RTC_MON_REG_ADDR);
  	year = rtc_read(RTC_YR_REG_ADDR);
  	debug("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
  		"hr: %02x min: %02x sec: %02x control_status: %02x
  ",
  		year, mon, mday, wday, hour, min, sec, ctl_stat);
  
  	if (ctl_stat & RTC_CTL_STAT_BIT_OSF) {
  		printf("### Warning: RTC oscillator has stopped
  ");
  		/* clear the OSF flag */
  		rtc_write(RTC_CTL_STAT_REG_ADDR,
  			rtc_read(RTC_CTL_STAT_REG_ADDR)\
  			& ~RTC_CTL_STAT_BIT_OSF);
  		ret = -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 & 0x1F);
  	tmp->tm_year = bcd2bin(year) + 2000;
  	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 ret;
  }
  
  /* Set the RTC */
  int rtc_set(struct rtc_time *tmp)
  {
  	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));
  	rtc_write(RTC_MON_REG_ADDR, bin2bcd(tmp->tm_mon));
  	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 */
  void rtc_reset(void)
  {
  	rtc_write(RTC_SEC_REG_ADDR, 0x00);	/* clearing Clock Halt	*/
  	rtc_write(RTC_CTL_STAT_REG_ADDR, RTC_PT7C4338_RESET_VAL);
  }