firmware/drivers/rtc/rtc_s35390a.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2009 by Bertrik Sikken
  11  * Copyright (C) 2008 by Robert Kukla
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19  * KIND, either express or implied.
  20  *
  21  ****************************************************************************/
  22 #include "config.h"
  23 #include "rtc.h"
  24 #include "i2c-s5l8700.h"
  25
  26 /*  Driver for the Seiko S35390A real-time clock chip with i2c interface
  27
  28     This driver was derived from rtc_mr100.c and adapted for the S35390A
  29     used in the Meizu M3 (and possibly others).
  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
  44 static void reverse_bits(unsigned char* v, int size)
  45 {
  46     static const unsigned char flipnibble[] =
  47         {0x00, 0x08, 0x04, 0x0C, 0x02, 0x0A, 0x06, 0x0E,
  48          0x01, 0x09, 0x05, 0x0D, 0x03, 0x0B, 0x07, 0x0F};
  49     int i;
  50
  51     for (i = 0; i < size; i++) {
  52         v[i] = (flipnibble[v[i] & 0x0F] << 4) |
  53                 flipnibble[(v[i] >> 4) & 0x0F];
  54     }
  55 }
  56
  57 void rtc_init(void)
  58 {
  59 }
  60
  61 int rtc_read_datetime(struct tm *tm)
  62 {
  63     unsigned char buf[7];
  64     unsigned int i;
  65     int ret;
  66
  67     ret = i2c_read(RTC_ADDR | (REALTIME_DATA1 << 1), -1, sizeof(buf), buf);
  68     reverse_bits(buf, sizeof(buf));
  69
  70     buf[4] &= 0x3f; /* mask out p.m. flag */
  71
  72     for (i = 0; i < sizeof(buf); i++)
  73         buf[i] = BCD2DEC(buf[i]);
  74
  75     tm->tm_sec = buf[6];
  76     tm->tm_min = buf[5];
  77     tm->tm_hour = buf[4];
  78     tm->tm_wday = buf[3];
  79     tm->tm_mday = buf[2];
  80     tm->tm_mon = buf[1] - 1;
  81     tm->tm_year = buf[0] + 100;
  82
  83     return ret;
  84 }
  85
  86 int rtc_write_datetime(const struct tm *tm)
  87 {
  88     unsigned char buf[7];
  89     unsigned int i;
  90     int ret;
  91
  92     buf[6] = tm->tm_sec;
  93     buf[5] = tm->tm_min;
  94     buf[4] = tm->tm_hour;
  95     buf[3] = tm->tm_wday;
  96     buf[2] = tm->tm_mday;
  97     buf[1] = tm->tm_mon + 1;
  98     buf[0] = tm->tm_year - 100;
  99
 100     for (i = 0; i < sizeof(buf); i++)
 101         buf[i] = DEC2BCD(buf[i]);
 102
 103     reverse_bits(buf, sizeof(buf));
 104     ret = i2c_write(RTC_ADDR | (REALTIME_DATA1 << 1), -1, sizeof(buf), buf);
 105
 106     return ret;
 107 }
 108