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 #include <linux/ds1742rtc.h>
  45
  46 #include <asm/time.h>
  47 #include <asm/addrspace.h>
  48
  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         unsigned long flags;
  61
  62         spin_lock_irqsave(&rtc_lock, flags);
  63         rtc_write(RTC_READ, RTC_CONTROL);
  64         second = BCD2BIN(rtc_read(RTC_SECONDS) & RTC_SECONDS_MASK);
  65         minute = BCD2BIN(rtc_read(RTC_MINUTES));
  66         hour = BCD2BIN(rtc_read(RTC_HOURS));
  67         day = BCD2BIN(rtc_read(RTC_DATE));
  68         month = BCD2BIN(rtc_read(RTC_MONTH));
  69         year = BCD2BIN(rtc_read(RTC_YEAR));
  70         century = BCD2BIN(rtc_read(RTC_CENTURY) & RTC_CENTURY_MASK);
  71         rtc_write(0, RTC_CONTROL);
  72         spin_unlock_irqrestore(&rtc_lock, flags);
  73
  74         year += century * 100;
  75
  76         return mktime(year, month, day, hour, minute, second);
  77 }
  78 extern void to_tm(unsigned long tim, struct rtc_time * tm);
  79
  80 static int
  81 rtc_ds1742_set_time(unsigned long t)
  82 {
  83         struct rtc_time tm;
  84         u8 year, month, day, hour, minute, second;
  85         u8 cmos_year, cmos_month, cmos_day, cmos_hour, cmos_minute, cmos_second;
  86         int cmos_century;
  87         unsigned long flags;
  88
  89         spin_lock_irqsave(&rtc_lock, flags);
  90         rtc_write(RTC_READ, RTC_CONTROL);
  91         cmos_second = (u8)(rtc_read(RTC_SECONDS) & RTC_SECONDS_MASK);
  92         cmos_minute = (u8)rtc_read(RTC_MINUTES);
  93         cmos_hour = (u8)rtc_read(RTC_HOURS);
  94         cmos_day = (u8)rtc_read(RTC_DATE);
  95         cmos_month = (u8)rtc_read(RTC_MONTH);
  96         cmos_year = (u8)rtc_read(RTC_YEAR);
  97         cmos_century = rtc_read(RTC_CENTURY) & RTC_CENTURY_MASK;
  98
  99         rtc_write(RTC_WRITE, RTC_CONTROL);
 100
 101         /* convert */
 102         to_tm(t, &tm);
 103
 104         /* check each field one by one */
 105         year = BIN2BCD(tm.tm_year - EPOCH);
 106         if (year != cmos_year) {
 107                 rtc_write(year,RTC_YEAR);
 108         }
 109
 110         month = BIN2BCD(tm.tm_mon);
 111         if (month != (cmos_month & 0x1f)) {
 112                 rtc_write((month & 0x1f) | (cmos_month & ~0x1f),RTC_MONTH);
 113         }
 114
 115         day = BIN2BCD(tm.tm_mday);
 116         if (day != cmos_day) {
 117
 118                 rtc_write(day, RTC_DATE);
 119         }
 120
 121         if (cmos_hour & 0x40) {
 122                 /* 12 hour format */
 123                 hour = 0x40;
 124                 if (tm.tm_hour > 12) {
 125                         hour |= 0x20 | (BIN2BCD(hour-12) & 0x1f);
 126                 } else {
 127                         hour |= BIN2BCD(tm.tm_hour);
 128                 }
 129         } else {
 130                 /* 24 hour format */
 131                 hour = BIN2BCD(tm.tm_hour) & 0x3f;
 132         }
 133         if (hour != cmos_hour) rtc_write(hour, RTC_HOURS);
 134
 135         minute = BIN2BCD(tm.tm_min);
 136         if (minute !=  cmos_minute) {
 137                 rtc_write(minute, RTC_MINUTES);
 138         }
 139
 140         second = BIN2BCD(tm.tm_sec);
 141         if (second !=  cmos_second) {
 142                 rtc_write(second & RTC_SECONDS_MASK,RTC_SECONDS);
 143         }
 144
 145         /* RTC_CENTURY and RTC_CONTROL share same address... */
 146         rtc_write(cmos_century, RTC_CONTROL);
 147         spin_unlock_irqrestore(&rtc_lock, flags);
 148
 149         return 0;
 150 }
 151
 152 void
 153 rtc_ds1742_init(unsigned long base)
 154 {
 155         u8  cmos_second;
 156
 157         /* remember the base */
 158         rtc_base = base;
 159         db_assert((rtc_base & 0xe0000000) == KSEG1);
 160
 161         /* set the function pointers */
 162         rtc_mips_get_time = rtc_ds1742_get_time;
 163         rtc_mips_set_time = rtc_ds1742_set_time;
 164
 165         /* clear oscillator stop bit */
 166         rtc_write(RTC_READ, RTC_CONTROL);
 167         cmos_second = (u8)(rtc_read(RTC_SECONDS) & RTC_SECONDS_MASK);
 168         rtc_write(RTC_WRITE, RTC_CONTROL);
 169         rtc_write(cmos_second, RTC_SECONDS); /* clear msb */
 170         rtc_write(0, RTC_CONTROL);
 171 }