/* SPDX-License-Identifier: BSD-2-Clause */
/*
* 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).
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#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
*/
static 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))
static int m48t08_get_time(
int minor,
rtems_time_of_day *time
)
{
uint32_t m48t08;
getRegister_f getReg;
setRegister_f setReg;
uint8_t controlReg;
uint32_t value1;
uint32_t 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
*/
static int m48t08_set_time(
int minor,
const rtems_time_of_day *time
)
{
uint32_t m48t08;
getRegister_f getReg;
setRegister_f setReg;
uint8_t 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
};
