[PATCH] RTC Subsystem: library functions
RTC and date/time related functions.
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/Kconfig b/drivers/Kconfig
index bddf431..9f5c0da 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -70,4 +70,6 @@
source "drivers/edac/Kconfig"
+source "drivers/rtc/Kconfig"
+
endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 5c69b86..4249552 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -56,6 +56,7 @@
obj-$(CONFIG_GAMEPORT) += input/gameport/
obj-$(CONFIG_INPUT) += input/
obj-$(CONFIG_I2O) += message/
+obj-$(CONFIG_RTC_LIB) += rtc/
obj-$(CONFIG_I2C) += i2c/
obj-$(CONFIG_W1) += w1/
obj-$(CONFIG_HWMON) += hwmon/
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
new file mode 100644
index 0000000..15df7c1
--- /dev/null
+++ b/drivers/rtc/Kconfig
@@ -0,0 +1,6 @@
+#
+# RTC class/drivers configuration
+#
+
+config RTC_LIB
+ tristate
\ No newline at end of file
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
new file mode 100644
index 0000000..eb9ad77
--- /dev/null
+++ b/drivers/rtc/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for RTC class/drivers.
+#
+
+obj-$(CONFIG_RTC_LIB) += rtc-lib.o
diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c
new file mode 100644
index 0000000..cfedc1d
--- /dev/null
+++ b/drivers/rtc/rtc-lib.c
@@ -0,0 +1,101 @@
+/*
+ * rtc and date/time utility functions
+ *
+ * Copyright (C) 2005-06 Tower Technologies
+ * Author: Alessandro Zummo <a.zummo@towertech.it>
+ *
+ * based on arch/arm/common/rtctime.c and other bits
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+
+static const unsigned char rtc_days_in_month[] = {
+ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
+};
+
+#define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400)
+#define LEAP_YEAR(year) ((!(year % 4) && (year % 100)) || !(year % 400))
+
+int rtc_month_days(unsigned int month, unsigned int year)
+{
+ return rtc_days_in_month[month] + (LEAP_YEAR(year) && month == 1);
+}
+EXPORT_SYMBOL(rtc_month_days);
+
+/*
+ * Convert seconds since 01-01-1970 00:00:00 to Gregorian date.
+ */
+void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
+{
+ register int days, month, year;
+
+ days = time / 86400;
+ time -= days * 86400;
+
+ /* day of the week, 1970-01-01 was a Thursday */
+ tm->tm_wday = (days + 4) % 7;
+
+ year = 1970 + days / 365;
+ days -= (year - 1970) * 365
+ + LEAPS_THRU_END_OF(year - 1)
+ - LEAPS_THRU_END_OF(1970 - 1);
+ if (days < 0) {
+ year -= 1;
+ days += 365 + LEAP_YEAR(year);
+ }
+ tm->tm_year = year - 1900;
+ tm->tm_yday = days + 1;
+
+ for (month = 0; month < 11; month++) {
+ int newdays;
+
+ newdays = days - rtc_month_days(month, year);
+ if (newdays < 0)
+ break;
+ days = newdays;
+ }
+ tm->tm_mon = month;
+ tm->tm_mday = days + 1;
+
+ tm->tm_hour = time / 3600;
+ time -= tm->tm_hour * 3600;
+ tm->tm_min = time / 60;
+ tm->tm_sec = time - tm->tm_min * 60;
+}
+EXPORT_SYMBOL(rtc_time_to_tm);
+
+/*
+ * Does the rtc_time represent a valid date/time?
+ */
+int rtc_valid_tm(struct rtc_time *tm)
+{
+ if (tm->tm_year < 70
+ || tm->tm_mon >= 12
+ || tm->tm_mday < 1
+ || tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900)
+ || tm->tm_hour >= 24
+ || tm->tm_min >= 60
+ || tm->tm_sec >= 60)
+ return -EINVAL;
+
+ return 0;
+}
+EXPORT_SYMBOL(rtc_valid_tm);
+
+/*
+ * Convert Gregorian date to seconds since 01-01-1970 00:00:00.
+ */
+int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
+{
+ *time = mktime(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
+ tm->tm_hour, tm->tm_min, tm->tm_sec);
+ return 0;
+}
+EXPORT_SYMBOL(rtc_tm_to_time);
+
+MODULE_LICENSE("GPL");