arch/mips/jmr3927/common/rtc_ds1742.c

   1 /*
   2  * Copyright 2001 MontaVista Software Inc.
   3  * Author: MontaVista Software, Inc.
   4  *              ahennessy@mvista.com
   5  *
   6  * arch/mips/jmr3927/common/rtc_ds1742.c
   7  * Based on arch/mips/ddb5xxx/common/rtc_ds1386.c
   8  *     low-level RTC hookups for s for Dallas 1742 chip.
   9  *
  10  * Copyright (C) 2000-2001 Toshiba Corporation
  11  *
  12  *  This program is free software; you can redistribute  it and/or modify it
  13  *  under  the terms of  the GNU General  Public License as published by the
  14  *  Free Software Foundation;  either version 2 of the  License, or (at your
  15  *  option) any later version.
  16  *
  17  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  18  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  19  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  20  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  21  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  23  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  24  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  25  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  *  You should have received a copy of the  GNU General Public License along
  29  *  with this program; if not, write  to the Free Software Foundation, Inc.,
  30  *  675 Mass Ave, Cambridge, MA 02139, USA.
  31  */
  32
  33
  34 /*
  35  * This file exports a function, rtc_ds1386_init(), which expects an
  36  * uncached base address as the argument.  It will set the two function
  37  * pointers expected by the MIPS generic timer code.
  38  */
  39
  40 #include <linux/bcd.h>
  41 #include <linux/types.h>
  42 #include <linux/time.h>
  43 #include <linux/rtc.h>
  44
  45 #include <asm/time.h>
  46 #include <asm/addrspace.h>
  47
  48 #include <asm/jmr3927/ds1742rtc.h>
  49 #include <asm/debug.h>
  50
  51 #define EPOCH           2000
  52
  53 static unsigned long rtc_base;
  54
  55 static unsigned long
  56 rtc_ds1742_get_time(void)
  57 {
  58         unsigned int year, month, day, hour, minute, second;
  59         unsigned int century;
  60
  61         CMOS_WRITE(RTC_READ, RTC_CONTROL);
  62         second = BCD2BIN(CMOS_READ(RTC_SECONDS) & RTC_SECONDS_MASK);
  63         minute = BCD2BIN(CMOS_READ(RTC_MINUTES));
  64         hour = BCD2BIN(CMOS_READ(RTC_HOURS));
  65         day = BCD2BIN(CMOS_READ(RTC_DATE));
  66         month = BCD2BIN(CMOS_READ(RTC_MONTH));
  67         year = BCD2BIN(CMOS_READ(RTC_YEAR));
  68         century = BCD2BIN(CMOS_READ(RTC_CENTURY) & RTC_CENTURY_MASK);
  69         CMOS_WRITE(0, RTC_CONTROL);
  70
  71         year += century * 100;
  72
  73         return mktime(year, month, day, hour, minute, second);
  74 }
  75 extern void to_tm(unsigned long tim, struct rtc_time * tm);
  76
  77 static int
  78 rtc_ds1742_set_time(unsigned long t)
  79 {
  80         struct rtc_time tm;
  81         u8 year, month, day, hour, minute, second;
  82         u8 cmos_year, cmos_month, cmos_day, cmos_hour, cmos_minute, cmos_second;
  83         int cmos_century;
  84
  85         CMOS_WRITE(RTC_READ, RTC_CONTROL);
  86         cmos_second = (u8)(CMOS_READ(RTC_SECONDS) & RTC_SECONDS_MASK);
  87         cmos_minute = (u8)CMOS_READ(RTC_MINUTES);
  88         cmos_hour = (u8)CMOS_READ(RTC_HOURS);
  89         cmos_day = (u8)CMOS_READ(RTC_DATE);
  90         cmos_month = (u8)CMOS_READ(RTC_MONTH);
  91         cmos_year = (u8)CMOS_READ(RTC_YEAR);
  92         cmos_century = CMOS_READ(RTC_CENTURY) & RTC_CENTURY_MASK;
  93
  94         CMOS_WRITE(RTC_WRITE, RTC_CONTROL);
  95
  96         /* convert */
  97         to_tm(t, &tm);
  98
  99         /* check each field one by one */
 100         year = BIN2BCD(tm.tm_year - EPOCH);
 101         if (year != cmos_year) {
 102                 CMOS_WRITE(year,RTC_YEAR);
 103         }
 104
 105         month = BIN2BCD(tm.tm_mon);
 106         if (month != (cmos_month & 0x1f)) {
 107                 CMOS_WRITE((month & 0x1f) | (cmos_month & ~0x1f),RTC_MONTH);
 108         }
 109
 110         day = BIN2BCD(tm.tm_mday);
 111         if (day != cmos_day) {
 112
 113                 CMOS_WRITE(day, RTC_DATE);
 114         }
 115
 116         if (cmos_hour & 0x40) {
 117                 /* 12 hour format */
 118                 hour = 0x40;
 119                 if (tm.tm_hour > 12) {
 120                         hour |= 0x20 | (BIN2BCD(hour-12) & 0x1f);
 121                 } else {
 122                         hour |= BIN2BCD(tm.tm_hour);
 123                 }
 124         } else {
 125                 /* 24 hour format */
 126                 hour = BIN2BCD(tm.tm_hour) & 0x3f;
 127         }
 128         if (hour != cmos_hour) CMOS_WRITE(hour, RTC_HOURS);
 129
 130         minute = BIN2BCD(tm.tm_min);
 131         if (minute !=  cmos_minute) {
 132                 CMOS_WRITE(minute, RTC_MINUTES);
 133         }
 134
 135         second = BIN2BCD(tm.tm_sec);
 136         if (second !=  cmos_second) {
 137                 CMOS_WRITE(second & RTC_SECONDS_MASK,RTC_SECONDS);
 138         }
 139
 140         /* RTC_CENTURY and RTC_CONTROL share same address... */
 141         CMOS_WRITE(cmos_century, RTC_CONTROL);
 142
 143         return 0;
 144 }
 145
 146 void
 147 rtc_ds1742_init(unsigned long base)
 148 {
 149         u8  cmos_second;
 150
 151         /* remember the base */
 152         rtc_base = base;
 153         db_assert((rtc_base & 0xe0000000) == KSEG1);
 154
 155         /* set the function pointers */
 156         rtc_get_time = rtc_ds1742_get_time;
 157         rtc_set_time = rtc_ds1742_set_time;
 158
 159         /* clear oscillator stop bit */
 160         CMOS_WRITE(RTC_READ, RTC_CONTROL);
 161         cmos_second = (u8)(CMOS_READ(RTC_SECONDS) & RTC_SECONDS_MASK);
 162         CMOS_WRITE(RTC_WRITE, RTC_CONTROL);
 163         CMOS_WRITE(cmos_second, RTC_SECONDS); /* clear msb */
 164         CMOS_WRITE(0, RTC_CONTROL);
 165 }