firmware/drivers/rtc/rtc_s35380a.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * adopted for HD300 by Marcin Bukat
  11  * Copyright (C) 2009 by Bertrik Sikken
  12  * Copyright (C) 2008 by Robert Kukla
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23 #include "config.h"
  24 #include "rtc.h"
  25 #include "i2c-coldfire.h"
  26
  27 /*  Driver for the Seiko S35380A real-time clock chip with i2c interface
  28
  29     This driver was derived from rtc_s3539a.c and adapted for the MPIO HD300
  30  */
  31
  32 #define RTC_ADDR   0x60
  33
  34 #define STATUS_REG1     0
  35 #define STATUS_REG2     1
  36 #define REALTIME_DATA1  2
  37 #define REALTIME_DATA2  3
  38 #define INT1_REG        4
  39 #define INT2_REG        5
  40 #define CLOCK_CORR_REG  6
  41 #define FREE_REG        7
  42
  43 /* STATUS_REG1 flags
  44  * bits order is reversed
  45  */
  46 #define STATUS_REG1_POC   0x01
  47 #define STATUS_REG1_BLD   0x02
  48 #define STATUS_REG1_INT2  0x04
  49 #define STATUS_REG1_INT1  0x08
  50 #define STATUS_REG1_SC1   0x10
  51 #define STATUS_REG1_SC0   0x20
  52 #define STATUS_REG1_H1224 0x40
  53 #define STATUS_REG1_RESET 0x80
  54
  55
  56 static void reverse_bits(unsigned char* v, int size)
  57 {
  58     static const unsigned char flipnibble[] =
  59         {0x00, 0x08, 0x04, 0x0C, 0x02, 0x0A, 0x06, 0x0E,
  60          0x01, 0x09, 0x05, 0x0D, 0x03, 0x0B, 0x07, 0x0F};
  61     int i;
  62
  63     for (i = 0; i < size; i++) {
  64         v[i] = (flipnibble[v[i] & 0x0F] << 4) |
  65                 flipnibble[(v[i] >> 4) & 0x0F];
  66     }
  67 }
  68
  69 void rtc_init(void)
  70 {
  71     unsigned char status_reg;
  72     i2c_read(I2C_IFACE_1, RTC_ADDR | (STATUS_REG1<<1), &status_reg, 1);
  73
  74     if ( (status_reg & STATUS_REG1_POC) ||
  75          (status_reg & STATUS_REG1_BLD) )
  76     {
  77         /* perform rtc reset*/
  78         status_reg |= STATUS_REG1_RESET;
  79         i2c_write(I2C_IFACE_1, RTC_ADDR | (STATUS_REG1<<1), &status_reg, 1);
  80     }
  81
  82     /* setup 24h time format */
  83     status_reg = STATUS_REG1_H1224;
  84     i2c_write(I2C_IFACE_1, RTC_ADDR | (STATUS_REG1<<1), &status_reg, 1);
  85 }
  86
  87 int rtc_read_datetime(struct tm *tm)
  88 {
  89     unsigned char buf[7];
  90     unsigned int i;
  91     int ret;
  92
  93     ret = i2c_read(I2C_IFACE_1, RTC_ADDR | (REALTIME_DATA1<<1), buf, sizeof(buf));
  94     reverse_bits(buf, sizeof(buf));
  95
  96     buf[4] &= 0x3f; /* mask out p.m. flag */
  97
  98     for (i = 0; i < sizeof(buf); i++)
  99         buf[i] = BCD2DEC(buf[i]);
 100
 101     tm->tm_sec = buf[6];
 102     tm->tm_min = buf[5];
 103     tm->tm_hour = buf[4];
 104     tm->tm_wday = buf[3];
 105     tm->tm_mday = buf[2];
 106     tm->tm_mon = buf[1] - 1;
 107     tm->tm_year = buf[0] + 100;
 108
 109     return ret;
 110 }
 111
 112 int rtc_write_datetime(const struct tm *tm)
 113 {
 114     unsigned char buf[7];
 115     unsigned int i;
 116     int ret;
 117
 118     buf[6] = tm->tm_sec;
 119     buf[5] = tm->tm_min;
 120     buf[4] = tm->tm_hour;
 121     buf[3] = tm->tm_wday;
 122     buf[2] = tm->tm_mday;
 123     buf[1] = tm->tm_mon + 1;
 124     buf[0] = tm->tm_year - 100;
 125
 126     for (i = 0; i < sizeof(buf); i++)
 127         buf[i] = DEC2BCD(buf[i]);
 128
 129     reverse_bits(buf, sizeof(buf));
 130     ret = i2c_write(I2C_IFACE_1, RTC_ADDR | (REALTIME_DATA1<<1), buf, sizeof(buf));
 131
 132     return ret;
 133 }
 134