Subversion Repositories openrisc_2011-10-31

/*

 *  This file interfaces with the real-time clock found in

 *  a Mostek M48T08 or M48T18 or compatibles.

 *

 *  Year 2K Notes:

 *

 *  This chip only uses a two digit field to store the year.  This

 *  code uses the RTEMS Epoch as a pivot year.  This lets us map the

 *  two digit year field as follows:

 *

 *    + two digit years 0-87 are mapped to 2000-2087.

 *    + two digit years 88-99 are mapped to 1988-1999.

 *

 *  This is less than the time span supported by RTEMS.

 *

 *  COPYRIGHT (c) 1989-1999.

 *  On-Line Applications Research Corporation (OAR).

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  $Id: m48t08.c,v 1.2 2001-09-27 12:01:42 chris Exp $

 */

#include <rtems.h>

#include <libchip/rtc.h>

#include <libchip/m48t08.h>

/*

 *  Control register bits

 */

#define M48T08_CONTROL_WRITE  0x80

#define M48T08_CONTROL_READ   0x40

#define M48T08_CONTROL_SIGN   0x20

/*

 *  m48t08_initialize

 */

void m48t08_initialize(

  int minor

)

{

}

/*

 *  m48t08_get_time

 */

#define From_BCD( _x ) ((((_x) >> 4) * 10) + ((_x) & 0x0F))

#define To_BCD( _x )   ((((_x) / 10) << 4) + ((_x) % 10))

int m48t08_get_time(

  int                minor,

  rtems_time_of_day *time

)

{

  unsigned32     m48t08;

  getRegister_f  getReg;

  setRegister_f  setReg;

  unsigned8      controlReg;

  unsigned32     value1;

  unsigned32     value2;

  m48t08 = RTC_Table[ minor ].ulCtrlPort1;

  getReg = RTC_Table[ minor ].getRegister;

  setReg = RTC_Table[ minor ].setRegister;

  /*

   *  Put the RTC into read mode

   */

  controlReg = (*getReg)( m48t08, M48T08_CONTROL );

  (*setReg)( m48t08, M48T08_CONTROL, controlReg | M48T08_CONTROL_READ );

  value1 = (*getReg)( m48t08, M48T08_YEAR );

  value2 = From_BCD( value1 );

  if ( value2 < 88 )

    time->year = 2000 + value2;

  else

    time->year = 1900 + value2;

  value1 = (*getReg)( m48t08, M48T08_MONTH );

  time->month = From_BCD( value1 );

  value1 = (*getReg)( m48t08, M48T08_DATE );

  time->day = From_BCD( value1 );

  value1 = (*getReg)( m48t08, M48T08_HOUR );

  time->hour = From_BCD( value1 );

  value1 = (*getReg)( m48t08, M48T08_MINUTE );

  time->minute = From_BCD( value1 );

  value1 = (*getReg)( m48t08, M48T08_SECOND );

  time->second = From_BCD( value1 );

  time->ticks  = 0;

  /*

   *  Put the RTC back into normal mode.

   */

  (*setReg)( m48t08, M48T08_CONTROL, controlReg );

  return 0;

}

/*

 *  m48t08_set_time

 */

int m48t08_set_time(

  int                minor,

  rtems_time_of_day *time

)

{

  unsigned32     m48t08;

  getRegister_f  getReg;

  setRegister_f  setReg;

  unsigned8      controlReg;

  m48t08 = RTC_Table[ minor ].ulCtrlPort1;

  getReg = RTC_Table[ minor ].getRegister;

  setReg = RTC_Table[ minor ].setRegister;

  /*

   *  Put the RTC into read mode

   */

  controlReg = (*getReg)( m48t08, M48T08_CONTROL );

  (*setReg)( m48t08, M48T08_CONTROL, controlReg | M48T08_CONTROL_WRITE );

  if ( time->year >= 2088 )

    rtems_fatal_error_occurred( RTEMS_INVALID_NUMBER );

  (*setReg)( m48t08, M48T08_YEAR,    To_BCD(time->year % 100) );

  (*setReg)( m48t08, M48T08_MONTH,   To_BCD(time->month) );

  (*setReg)( m48t08, M48T08_DATE,    To_BCD(time->day) );

  (*setReg)( m48t08, M48T08_HOUR,    To_BCD(time->hour) );

  (*setReg)( m48t08, M48T08_MINUTE,  To_BCD(time->minute) );

  (*setReg)( m48t08, M48T08_SECOND,  To_BCD(time->second) );

  /*

   *  Put the RTC back into normal mode.

   */

  (*setReg)( m48t08, M48T08_CONTROL, controlReg );

  return 0;

}

/*

 *  Driver function table

 */

rtc_fns m48t08_fns = {

  m48t08_initialize,

  m48t08_get_time,

  m48t08_set_time

};