drivers/rtc/pt7c4338.c

   1 /*
   2  * Copyright 2010 Freescale Semiconductor, Inc.
   3  *
   4  * Author:      Priyanka Jain <Priyanka.Jain@freescale.com>
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 /*
  10  * This file provides Date & Time support (no alarms) for PT7C4338 chip.
  11  *
  12  * This file is based on drivers/rtc/ds1337.c
  13  *
  14  * PT7C4338 chip is manufactured by Pericom Technology Inc.
  15  * It is a serial real-time clock which provides
  16  * 1)Low-power clock/calendar.
  17  * 2)Programmable square-wave output.
  18  * It has 56 bytes of nonvolatile RAM.
  19  */
  20
  21 #include <common.h>
  22 #include <command.h>
  23 #include <rtc.h>
  24 #include <i2c.h>
  25
  26 /* RTC register addresses */
  27 #define RTC_SEC_REG_ADDR        0x0
  28 #define RTC_MIN_REG_ADDR        0x1
  29 #define RTC_HR_REG_ADDR         0x2
  30 #define RTC_DAY_REG_ADDR        0x3
  31 #define RTC_DATE_REG_ADDR       0x4
  32 #define RTC_MON_REG_ADDR        0x5
  33 #define RTC_YR_REG_ADDR         0x6
  34 #define RTC_CTL_STAT_REG_ADDR   0x7
  35
  36 /* RTC second register address bit */
  37 #define RTC_SEC_BIT_CH          0x80    /* Clock Halt (in Register 0) */
  38
  39 /* RTC control and status register bits */
  40 #define RTC_CTL_STAT_BIT_RS0    0x1     /* Rate select 0 */
  41 #define RTC_CTL_STAT_BIT_RS1    0x2     /* Rate select 1 */
  42 #define RTC_CTL_STAT_BIT_SQWE   0x10    /* Square Wave Enable */
  43 #define RTC_CTL_STAT_BIT_OSF    0x20    /* Oscillator Stop Flag */
  44 #define RTC_CTL_STAT_BIT_OUT    0x80    /* Output Level Control */
  45
  46 /* RTC reset value */
  47 #define RTC_PT7C4338_RESET_VAL \
  48         (RTC_CTL_STAT_BIT_RS0 | RTC_CTL_STAT_BIT_RS1 | RTC_CTL_STAT_BIT_OUT)
  49
  50 /****** Helper functions ****************************************/
  51 static u8 rtc_read(u8 reg)
  52 {
  53         return i2c_reg_read(CONFIG_SYS_I2C_RTC_ADDR, reg);
  54 }
  55
  56 static void rtc_write(u8 reg, u8 val)
  57 {
  58         i2c_reg_write(CONFIG_SYS_I2C_RTC_ADDR, reg, val);
  59 }
  60 /****************************************************************/
  61
  62 /* Get the current time from the RTC */
  63 int rtc_get(struct rtc_time *tmp)
  64 {
  65         int ret = 0;
  66         u8 sec, min, hour, mday, wday, mon, year, ctl_stat;
  67
  68         ctl_stat = rtc_read(RTC_CTL_STAT_REG_ADDR);
  69         sec = rtc_read(RTC_SEC_REG_ADDR);
  70         min = rtc_read(RTC_MIN_REG_ADDR);
  71         hour = rtc_read(RTC_HR_REG_ADDR);
  72         wday = rtc_read(RTC_DAY_REG_ADDR);
  73         mday = rtc_read(RTC_DATE_REG_ADDR);
  74         mon = rtc_read(RTC_MON_REG_ADDR);
  75         year = rtc_read(RTC_YR_REG_ADDR);
  76         debug("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
  77                 "hr: %02x min: %02x sec: %02x control_status: %02x\n",
  78                 year, mon, mday, wday, hour, min, sec, ctl_stat);
  79
  80         if (ctl_stat & RTC_CTL_STAT_BIT_OSF) {
  81                 printf("### Warning: RTC oscillator has stopped\n");
  82                 /* clear the OSF flag */
  83                 rtc_write(RTC_CTL_STAT_REG_ADDR,
  84                         rtc_read(RTC_CTL_STAT_REG_ADDR)\
  85                         & ~RTC_CTL_STAT_BIT_OSF);
  86                 ret = -1;
  87         }
  88
  89         tmp->tm_sec = bcd2bin(sec & 0x7F);
  90         tmp->tm_min = bcd2bin(min & 0x7F);
  91         tmp->tm_hour = bcd2bin(hour & 0x3F);
  92         tmp->tm_mday = bcd2bin(mday & 0x3F);
  93         tmp->tm_mon = bcd2bin(mon & 0x1F);
  94         tmp->tm_year = bcd2bin(year) + 2000;
  95         tmp->tm_wday = bcd2bin((wday - 1) & 0x07);
  96         tmp->tm_yday = 0;
  97         tmp->tm_isdst = 0;
  98         debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
  99                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 100                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 101
 102         return ret;
 103 }
 104
 105 /* Set the RTC */
 106 int rtc_set(struct rtc_time *tmp)
 107 {
 108         debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 109                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 110                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 111
 112         rtc_write(RTC_YR_REG_ADDR, bin2bcd(tmp->tm_year % 100));
 113         rtc_write(RTC_MON_REG_ADDR, bin2bcd(tmp->tm_mon));
 114         rtc_write(RTC_DAY_REG_ADDR, bin2bcd(tmp->tm_wday + 1));
 115         rtc_write(RTC_DATE_REG_ADDR, bin2bcd(tmp->tm_mday));
 116         rtc_write(RTC_HR_REG_ADDR, bin2bcd(tmp->tm_hour));
 117         rtc_write(RTC_MIN_REG_ADDR, bin2bcd(tmp->tm_min));
 118         rtc_write(RTC_SEC_REG_ADDR, bin2bcd(tmp->tm_sec));
 119
 120         return 0;
 121 }
 122
 123 /* Reset the RTC */
 124 void rtc_reset(void)
 125 {
 126         rtc_write(RTC_SEC_REG_ADDR, 0x00);      /* clearing Clock Halt  */
 127         rtc_write(RTC_CTL_STAT_REG_ADDR, RTC_PT7C4338_RESET_VAL);
 128 }