[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 bddf431bbb72b51dbe492461ecf50d2b07a92499..9f5c0da57c9048ca9fcf98168b21e36390416a8a 100644 (file)
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -70,4 +70,6 @@ source "drivers/sn/Kconfig"
 
 source "drivers/edac/Kconfig"
 
+source "drivers/rtc/Kconfig"
+
 endmenu

diff --git a/drivers/Makefile b/drivers/Makefile
index 5c69b86db6247a3f776ce8bde0ede999fdc274d6..424955274e60c2db7fe50bb5c39ffc1d23d3dfbe 100644 (file)
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_USB_GADGET)      += usb/gadget/
 obj-$(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 (file)
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 (file)
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 (file)
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");

diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index b739ac1f7ca03f2371e16f52afe20f0c1adaf062..8454337c70580ffb0916b92e5bf86b0e66f5f56a 100644 (file)
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -95,6 +95,11 @@ struct rtc_pll_info {
 
 #include <linux/interrupt.h>
 
+extern int rtc_month_days(unsigned int month, unsigned int year);
+extern int rtc_valid_tm(struct rtc_time *tm);
+extern int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time);
+extern void rtc_time_to_tm(unsigned long time, struct rtc_time *tm);
+
 typedef struct rtc_task {
        void (*func)(void *private_data);
        void *private_data;