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mc13783 RTC: Handle years in a better way for the use of struct tm. Make the code less general because all years evenly divisible by 4 in the day range are leap years.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28891 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Michael Sevakis 2010-12-24 17:06:35 +00:00
parent 78a11cf648
commit c332bba905
1 changed files with 121 additions and 109 deletions
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228
firmware/drivers/rtc/rtc_mc13783.c
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@ -26,62 +26,74 @@
/* NOTE: Defined the base to be original firmware compatible if needed - /* 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. */ * ie. the day and year as it would interpret a DAY register value of zero. */
/* Days passed since midnight 01 Jan, 1601 to midnight on the base date. */ /* 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 #ifdef TOSHIBA_GIGABEAT_S
/* Gigabeat S seems to be 1 day behind the ususual - this will /* Gigabeat S seems to be 1 day behind the ususual - this will
* make the RTC match file dates created by retailos. */ * make the RTC match file dates created by retailos. */
#define RTC_BASE_DAY_COUNT 138425 #define RTC_BASE_WDAY 1 /* Monday */
#define RTC_BASE_MONTH 12 #define RTC_BASE_YDAY 364 /* 31 Dec */
#define RTC_BASE_DAY 31
#define RTC_BASE_YEAR 1979 #define RTC_BASE_YEAR 1979
#elif 1 #elif 1
#define RTC_BASE_DAY_COUNT 138426 #define RTC_BASE_WDAY 2 /* Tuesday */
#define RTC_BASE_MONTH 1 #define RTC_BASE_YDAY 0 /* 01 Jan */
#define RTC_BASE_DAY 1
#define RTC_BASE_YEAR 1980 #define RTC_BASE_YEAR 1980
#else #else
#define RTC_BASE_DAY_COUNT 134774 #define RTC_BASE_WDAY 4 /* Thursday */
#define RTC_BASE_MONTH 1 #define RTC_BASE_YDAY 0 /* 01 Jan */
#define RTC_BASE_DAY 1
#define RTC_BASE_YEAR 1970 #define RTC_BASE_YEAR 1970
#endif #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 enum rtc_registers_indexes
{ {
RTC_REG_TIME = 0, RTC_REG_TIME = 0,
RTC_REG_DAY, RTC_REG_DAY,
RTC_REG_TIME2, RTC_REG_TIME2,
RTC_NUM_REGS, RTC_NUM_REGS_RD = 3,
RTC_NUM_REGS_WR = 2,
}; };
/* was it an alarm that triggered power on ? */ static const unsigned char rtc_registers[RTC_NUM_REGS_RD] =
static bool alarm_start = false;
static const unsigned char rtc_registers[RTC_NUM_REGS] =
{ {
[RTC_REG_TIME] = MC13783_RTC_TIME, [RTC_REG_TIME] = MC13783_RTC_TIME,
[RTC_REG_DAY] = MC13783_RTC_DAY, [RTC_REG_DAY] = MC13783_RTC_DAY,
[RTC_REG_TIME2] = MC13783_RTC_TIME, [RTC_REG_TIME2] = MC13783_RTC_TIME,
}; };
static const unsigned char month_table[2][12] = /* was it an alarm that triggered power on ? */
static bool alarm_start = false;
static const unsigned short month_table[13] =
{ {
{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }, /* Since 1 Jan, how many days have passed this year? (non-leap)
{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }, +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
}; };
/* Get number of leaps since the reference date of 1601/01/01 */ static bool read_time_and_day(uint32_t regs[RTC_NUM_REGS_RD])
static int get_leap_count(int d)
{ {
int lm = (d + 1) / 146097; /* Read time, day, time - 2nd read of time should be the same or
int lc = (d + 1 - lm) / 36524; * greater */
int ly = (d + 1 - lm + lc) / 1461; do
return ly - lc + lm; {
} 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]);
static int is_leap_year(int y) return true;
{
return (y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0) ? 1 : 0;
} }
/** Public APIs **/ /** Public APIs **/
@ -97,114 +109,110 @@ void rtc_init(void)
int rtc_read_datetime(struct tm *tm) int rtc_read_datetime(struct tm *tm)
{ {
uint32_t regs[RTC_NUM_REGS]; uint32_t regs[RTC_NUM_REGS_RD];
int year, leap, month, day, hour, min; int year, month, yday, x, n;
/* Read time, day, time - 2nd read of time should be the same or if (!read_time_and_day(regs))
* greater */
do
{
if (mc13783_read_regs(rtc_registers, regs,
RTC_NUM_REGS) < RTC_NUM_REGS)
{
/* Couldn't read registers */
return 0; return 0;
}
}
/* If TOD counter turned over - reread */
while (regs[RTC_REG_TIME2] < regs[RTC_REG_TIME]);
/* TOD: = 0 to 86399 */ /* TOD: 0 to 86399 */
hour = regs[RTC_REG_TIME] / 3600; x = regs[RTC_REG_TIME];
regs[RTC_REG_TIME] -= hour*3600;
tm->tm_hour = hour;
min = regs[RTC_REG_TIME] / 60; /* Hour */
regs[RTC_REG_TIME] -= min*60; n = x / 3600;
tm->tm_min = min; tm->tm_hour = n;
tm->tm_sec = regs[RTC_REG_TIME]; /* Minute */
x -= n*3600;
n = x / 60;
tm->tm_min = n;
/* Second */
x -= n*60;
tm->tm_sec = x;
/* DAY: 0 to 32767 */ /* DAY: 0 to 32767 */
day = regs[RTC_REG_DAY] + RTC_BASE_DAY_COUNT; x = regs[RTC_REG_DAY];
/* Weekday */ /* Weekday */
tm->tm_wday = (day + 1) % 7; /* 1601/01/01 = Monday */ tm->tm_wday = (x + RTC_BASE_WDAY) % 7;
/* Get number of leaps for today */ /* Year */
leap = get_leap_count(day); x += RTC_REF_YEAR_OFFS*365 + RTC_BASE_YDAY;
year = (day - leap) / 365;
/* Get number of leaps for yesterday */ /* Lag year increment by subtracting leaps since the reference year
leap = get_leap_count(day - 1); * on 31 Dec of each leap year, essentially removing them from the
* calculation */
n = (x + 1) / 1461;
year = (x - n) / 365;
/* Get day number for year 0-364|365 */ /* Year day */
day = day - leap - year * 365; yday = x - n - year*365;
year += 1601; /* If (x + 1) mod 1461 == 0, then it is yday 365 of a leap year */
if (n * 1461 - 1 == x)
yday++;
/* Get the current month */ tm->tm_yday = x = yday;
leap = is_leap_year(year);
for (month = 0; month < 12; month++) if (((year + RTC_REF_YEAR) & 3) == 0 && x >= month_table[2])
{ {
int days = month_table[leap][month]; if (x > month_table[2])
yday--; /* 1 Mar or after; lag date by one day */
if (day < days) x--; /* 29 Feb or after, lag month by one day */
break;
day -= days;
} }
tm->tm_mday = day + 1; /* 1 to 31 */ /* 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 */ tm->tm_mon = month; /* 0 to 11 */
tm->tm_year = year % 100 + 100;
/* {BY to (BY+89 or 90)} - 1900 */
tm->tm_year = year + RTC_REF_YEAR - 1900;
return 7; return 7;
} }
int rtc_write_datetime(const struct tm *tm) int rtc_write_datetime(const struct tm *tm)
{ {
uint32_t regs[2]; uint32_t regs[RTC_NUM_REGS_WR];
int year, leap, month, day, i, base_yearday; int year, month, x;
regs[RTC_REG_TIME] = tm->tm_sec + /* Convert time of day into seconds since midnight */
tm->tm_min*60 + x = tm->tm_sec + tm->tm_min*60 + tm->tm_hour*3600;
tm->tm_hour*3600;
year = tm->tm_year - 100; /* Keep in range (it throws off the PMIC counters otherwise) */
regs[RTC_REG_TIME] = MAX(0, MIN(86399, x));
if (year < RTC_BASE_YEAR - 1900) year = tm->tm_year + 1900;
year += 2000;
else
year += 1900;
/* Get number of leaps for day before base */ /* Get the number of days elapsed from 1 Jan of reference year to 1 Jan of
leap = get_leap_count(RTC_BASE_DAY_COUNT - 1); * this year */
x = year - RTC_REF_YEAR;
x = x*365 + (x >> 2);
/* Get day number for base year 0-364|365 */ /* Add the number of days passed this year since 1 Jan and offset by the
base_yearday = RTC_BASE_DAY_COUNT - leap - * base yearday and the reference offset in days from the base */
(RTC_BASE_YEAR - 1601) * 365;
/* Get the number of days elapsed from reference */
for (i = RTC_BASE_YEAR, day = 0; i < year; i++)
{
day += is_leap_year(i) ? 366 : 365;
}
/* Find the number of days passed this year up to the 1st of the
* month. */
leap = is_leap_year(year);
month = tm->tm_mon; month = tm->tm_mon;
x += month_table[month] + tm->tm_mday - RTC_REF_YEAR_OFFS*365
- RTC_BASE_YDAY;
for (i = 0; i < month; i++) if ((year & 3) != 0 || month < 2) {
{ /* Sub one day because tm_mday starts at 1, otherwise the offset is
day += month_table[leap][i]; * required because of 29 Feb */
x--;
} }
regs[RTC_REG_DAY] = day + tm->tm_mday - 1 - base_yearday; /* Keep in range */
regs[RTC_REG_DAY] = MAX(0, MIN(32767, x));
if (mc13783_write_regs(rtc_registers, regs, 2) == 2) if (mc13783_write_regs(rtc_registers, regs, RTC_NUM_REGS_WR)
== RTC_NUM_REGS_WR)
{ {
return 7; return 7;
} }
@ -238,20 +246,24 @@ bool rtc_check_alarm_started(bool release_alarm)
void rtc_set_alarm(int h, int m) void rtc_set_alarm(int h, int m)
{ {
int day = mc13783_read(MC13783_RTC_DAY); uint32_t regs[RTC_NUM_REGS_RD];
int tod = mc13783_read(MC13783_RTC_TIME); uint32_t tod;
if (h*3600 + m*60 < tod) if (!read_time_and_day(regs))
day++; return;
mc13783_write(MC13783_RTC_DAY_ALARM, day); tod = h*3600 + m*60;
mc13783_write(MC13783_RTC_ALARM, 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) void rtc_get_alarm(int *h, int *m)
{ {
int tod = mc13783_read(MC13783_RTC_ALARM); uint32_t tod = mc13783_read(MC13783_RTC_ALARM);
*h = tod / 3600; *h = tod / 3600;
*m = tod % 3600 / 60; *m = tod % 3600 / 60;
} }