drivers/rtc/pt7c4338.c

   1 /*
   2  * Copyright 2010 Freescale Semiconductor, Inc.
   3  *
   4  * Author:      Priyanka Jain <Priyanka.Jain@freescale.com>
   5  *
   6  * See file CREDITS for list of people who contributed to this
   7  * project.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  22  * MA 02111-1307 USA
  23  */
  24
  25 /*
  26  * This file provides Date & Time support (no alarms) for PT7C4338 chip.
  27  *
  28  * This file is based on drivers/rtc/ds1337.c
  29  *
  30  * PT7C4338 chip is manufactured by Pericom Technology Inc.
  31  * It is a serial real-time clock which provides
  32  * 1)Low-power clock/calendar.
  33  * 2)Programmable square-wave output.
  34  * It has 56 bytes of nonvolatile RAM.
  35  */
  36
  37 #include <common.h>
  38 #include <command.h>
  39 #include <rtc.h>
  40 #include <i2c.h>
  41
  42 /* RTC register addresses */
  43 #define RTC_SEC_REG_ADDR        0x0
  44 #define RTC_MIN_REG_ADDR        0x1
  45 #define RTC_HR_REG_ADDR         0x2
  46 #define RTC_DAY_REG_ADDR        0x3
  47 #define RTC_DATE_REG_ADDR       0x4
  48 #define RTC_MON_REG_ADDR        0x5
  49 #define RTC_YR_REG_ADDR         0x6
  50 #define RTC_CTL_STAT_REG_ADDR   0x7
  51
  52 /* RTC second register address bit */
  53 #define RTC_SEC_BIT_CH          0x80    /* Clock Halt (in Register 0) */
  54
  55 /* RTC control and status register bits */
  56 #define RTC_CTL_STAT_BIT_RS0    0x1     /* Rate select 0 */
  57 #define RTC_CTL_STAT_BIT_RS1    0x2     /* Rate select 1 */
  58 #define RTC_CTL_STAT_BIT_SQWE   0x10    /* Square Wave Enable */
  59 #define RTC_CTL_STAT_BIT_OSF    0x20    /* Oscillator Stop Flag */
  60 #define RTC_CTL_STAT_BIT_OUT    0x80    /* Output Level Control */
  61
  62 /* RTC reset value */
  63 #define RTC_PT7C4338_RESET_VAL \
  64         (RTC_CTL_STAT_BIT_RS0 | RTC_CTL_STAT_BIT_RS1 | RTC_CTL_STAT_BIT_OUT)
  65
  66 /****** Helper functions ****************************************/
  67 static u8 rtc_read(u8 reg)
  68 {
  69         return i2c_reg_read(CONFIG_SYS_I2C_RTC_ADDR, reg);
  70 }
  71
  72 static void rtc_write(u8 reg, u8 val)
  73 {
  74         i2c_reg_write(CONFIG_SYS_I2C_RTC_ADDR, reg, val);
  75 }
  76 /****************************************************************/
  77
  78 /* Get the current time from the RTC */
  79 int rtc_get(struct rtc_time *tmp)
  80 {
  81         int ret = 0;
  82         u8 sec, min, hour, mday, wday, mon, year, ctl_stat;
  83
  84         ctl_stat = rtc_read(RTC_CTL_STAT_REG_ADDR);
  85         sec = rtc_read(RTC_SEC_REG_ADDR);
  86         min = rtc_read(RTC_MIN_REG_ADDR);
  87         hour = rtc_read(RTC_HR_REG_ADDR);
  88         wday = rtc_read(RTC_DAY_REG_ADDR);
  89         mday = rtc_read(RTC_DATE_REG_ADDR);
  90         mon = rtc_read(RTC_MON_REG_ADDR);
  91         year = rtc_read(RTC_YR_REG_ADDR);
  92         debug("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
  93                 "hr: %02x min: %02x sec: %02x control_status: %02x\n",
  94                 year, mon, mday, wday, hour, min, sec, ctl_stat);
  95
  96         if (ctl_stat & RTC_CTL_STAT_BIT_OSF) {
  97                 printf("### Warning: RTC oscillator has stopped\n");
  98                 /* clear the OSF flag */
  99                 rtc_write(RTC_CTL_STAT_REG_ADDR,
 100                         rtc_read(RTC_CTL_STAT_REG_ADDR)\
 101                         & ~RTC_CTL_STAT_BIT_OSF);
 102                 ret = -1;
 103         }
 104
 105         tmp->tm_sec = bcd2bin(sec & 0x7F);
 106         tmp->tm_min = bcd2bin(min & 0x7F);
 107         tmp->tm_hour = bcd2bin(hour & 0x3F);
 108         tmp->tm_mday = bcd2bin(mday & 0x3F);
 109         tmp->tm_mon = bcd2bin(mon & 0x1F);
 110         tmp->tm_year = bcd2bin(year) + 2000;
 111         tmp->tm_wday = bcd2bin((wday - 1) & 0x07);
 112         tmp->tm_yday = 0;
 113         tmp->tm_isdst = 0;
 114         debug("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 115                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 116                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 117
 118         return ret;
 119 }
 120
 121 /* Set the RTC */
 122 int rtc_set(struct rtc_time *tmp)
 123 {
 124         debug("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
 125                 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
 126                 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
 127
 128         rtc_write(RTC_YR_REG_ADDR, bin2bcd(tmp->tm_year % 100));
 129         rtc_write(RTC_MON_REG_ADDR, bin2bcd(tmp->tm_mon));
 130         rtc_write(RTC_DAY_REG_ADDR, bin2bcd(tmp->tm_wday + 1));
 131         rtc_write(RTC_DATE_REG_ADDR, bin2bcd(tmp->tm_mday));
 132         rtc_write(RTC_HR_REG_ADDR, bin2bcd(tmp->tm_hour));
 133         rtc_write(RTC_MIN_REG_ADDR, bin2bcd(tmp->tm_min));
 134         rtc_write(RTC_SEC_REG_ADDR, bin2bcd(tmp->tm_sec));
 135
 136         return 0;
 137 }
 138
 139 /* Reset the RTC */
 140 void rtc_reset(void)
 141 {
 142         rtc_write(RTC_SEC_REG_ADDR, 0x00);      /* clearing Clock Halt  */
 143         rtc_write(RTC_CTL_STAT_REG_ADDR, RTC_PT7C4338_RESET_VAL);
 144 }