rockbox/firmware/drivers/rtc/rtc_mc13783.c
2010-12-24 17:06:35 +00:00

269 lines
7.2 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2008 by Michael Sevakis
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "system.h"
#include "rtc.h"
#include "mc13783.h"
/* NOTE: Defined the base to be original firmware compatible if needed -
* ie. the day and year as it would interpret a DAY register value of zero. */
/* None of this code concerns itself with (year mod 100) = 0 leap year
* exceptions because all (year mod 4) = 0 years in the relevant range are
* leap years. A base year of 1901 to an end date of 28 Feb 2100 are ok. */
#ifdef TOSHIBA_GIGABEAT_S
/* Gigabeat S seems to be 1 day behind the ususual - this will
* make the RTC match file dates created by retailos. */
#define RTC_BASE_WDAY 1 /* Monday */
#define RTC_BASE_YDAY 364 /* 31 Dec */
#define RTC_BASE_YEAR 1979
#elif 1
#define RTC_BASE_WDAY 2 /* Tuesday */
#define RTC_BASE_YDAY 0 /* 01 Jan */
#define RTC_BASE_YEAR 1980
#else
#define RTC_BASE_WDAY 4 /* Thursday */
#define RTC_BASE_YDAY 0 /* 01 Jan */
#define RTC_BASE_YEAR 1970
#endif
/* Reference year for leap calculation - year that is on or before the base
* year and immediately follows a leap year */
#define RTC_REF_YEAR_OFFS ((RTC_BASE_YEAR - 1) & 3)
#define RTC_REF_YEAR (RTC_BASE_YEAR - RTC_REF_YEAR_OFFS)
enum rtc_registers_indexes
{
RTC_REG_TIME = 0,
RTC_REG_DAY,
RTC_REG_TIME2,
RTC_NUM_REGS_RD = 3,
RTC_NUM_REGS_WR = 2,
};
static const unsigned char rtc_registers[RTC_NUM_REGS_RD] =
{
[RTC_REG_TIME] = MC13783_RTC_TIME,
[RTC_REG_DAY] = MC13783_RTC_DAY,
[RTC_REG_TIME2] = MC13783_RTC_TIME,
};
/* was it an alarm that triggered power on ? */
static bool alarm_start = false;
static const unsigned short month_table[13] =
{
/* Since 1 Jan, how many days have passed this year? (non-leap)
+31 28 31 30 31 30 31 31 30 31 30 31 */
0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365
};
static bool read_time_and_day(uint32_t regs[RTC_NUM_REGS_RD])
{
/* Read time, day, time - 2nd read of time should be the same or
* greater */
do
{
if (mc13783_read_regs(rtc_registers, regs,
RTC_NUM_REGS_RD) < RTC_NUM_REGS_RD)
{
/* Couldn't read registers */
return false;
}
}
/* If TOD counter turned over - reread */
while (regs[RTC_REG_TIME2] < regs[RTC_REG_TIME]);
return true;
}
/** Public APIs **/
void rtc_init(void)
{
/* only needs to be polled on startup */
if (mc13783_read(MC13783_INTERRUPT_STATUS1) & MC13783_TODAI)
{
alarm_start = true;
mc13783_write(MC13783_INTERRUPT_STATUS1, MC13783_TODAI);
}
}
int rtc_read_datetime(struct tm *tm)
{
uint32_t regs[RTC_NUM_REGS_RD];
int year, month, yday, x, n;
if (!read_time_and_day(regs))
return 0;
/* TOD: 0 to 86399 */
x = regs[RTC_REG_TIME];
/* Hour */
n = x / 3600;
tm->tm_hour = n;
/* Minute */
x -= n*3600;
n = x / 60;
tm->tm_min = n;
/* Second */
x -= n*60;
tm->tm_sec = x;
/* DAY: 0 to 32767 */
x = regs[RTC_REG_DAY];
/* Weekday */
tm->tm_wday = (x + RTC_BASE_WDAY) % 7;
/* Year */
x += RTC_REF_YEAR_OFFS*365 + RTC_BASE_YDAY;
/* Lag year increment by subtracting leaps since the reference year
* on 31 Dec of each leap year, essentially removing them from the
* calculation */
n = (x + 1) / 1461;
year = (x - n) / 365;
/* Year day */
yday = x - n - year*365;
/* If (x + 1) mod 1461 == 0, then it is yday 365 of a leap year */
if (n * 1461 - 1 == x)
yday++;
tm->tm_yday = x = yday;
if (((year + RTC_REF_YEAR) & 3) == 0 && x >= month_table[2])
{
if (x > month_table[2])
yday--; /* 1 Mar or after; lag date by one day */
x--; /* 29 Feb or after, lag month by one day */
}
/* Get the current month */
month = x >> 5; /* yday / 32, close enough */
if (month_table[month + 1] <= x)
month++; /* Round to next */
tm->tm_mday = yday - month_table[month] + 1; /* 1 to 31 */
tm->tm_mon = month; /* 0 to 11 */
/* {BY to (BY+89 or 90)} - 1900 */
tm->tm_year = year + RTC_REF_YEAR - 1900;
return 7;
}
int rtc_write_datetime(const struct tm *tm)
{
uint32_t regs[RTC_NUM_REGS_WR];
int year, month, x;
/* Convert time of day into seconds since midnight */
x = tm->tm_sec + tm->tm_min*60 + tm->tm_hour*3600;
/* Keep in range (it throws off the PMIC counters otherwise) */
regs[RTC_REG_TIME] = MAX(0, MIN(86399, x));
year = tm->tm_year + 1900;
/* Get the number of days elapsed from 1 Jan of reference year to 1 Jan of
* this year */
x = year - RTC_REF_YEAR;
x = x*365 + (x >> 2);
/* Add the number of days passed this year since 1 Jan and offset by the
* base yearday and the reference offset in days from the base */
month = tm->tm_mon;
x += month_table[month] + tm->tm_mday - RTC_REF_YEAR_OFFS*365
- RTC_BASE_YDAY;
if ((year & 3) != 0 || month < 2) {
/* Sub one day because tm_mday starts at 1, otherwise the offset is
* required because of 29 Feb */
x--;
}
/* Keep in range */
regs[RTC_REG_DAY] = MAX(0, MIN(32767, x));
if (mc13783_write_regs(rtc_registers, regs, RTC_NUM_REGS_WR)
== RTC_NUM_REGS_WR)
{
return 7;
}
return 0;
}
bool rtc_check_alarm_flag(void)
{
/* We don't need to do anything special if it has already fired */
return false;
}
void rtc_enable_alarm(bool enable)
{
if (enable)
mc13783_clear(MC13783_INTERRUPT_MASK1, MC13783_TODAM);
else
mc13783_set(MC13783_INTERRUPT_MASK1, MC13783_TODAM);
}
bool rtc_check_alarm_started(bool release_alarm)
{
bool rc = alarm_start;
if (release_alarm)
alarm_start = false;
return rc;
}
void rtc_set_alarm(int h, int m)
{
uint32_t regs[RTC_NUM_REGS_RD];
uint32_t tod;
if (!read_time_and_day(regs))
return;
tod = h*3600 + m*60;
if (tod < regs[RTC_REG_TIME])
regs[RTC_REG_DAY]++;
mc13783_write(MC13783_RTC_DAY_ALARM, regs[RTC_REG_DAY]);
mc13783_write(MC13783_RTC_ALARM, tod);
}
void rtc_get_alarm(int *h, int *m)
{
uint32_t tod = mc13783_read(MC13783_RTC_ALARM);
*h = tod / 3600;
*m = tod % 3600 / 60;
}