Implements CONFIG_TIME_EXTENDED as we discussed relative to providing the last 3 members of the tm struct and support for filling them in and even using the wday in the STM32 RTC. From David Sidrane.

arch/arm/src/stm32/stm32_rtcc.c

@@ -880,6 +880,7 @@ int up_rtc_getdatetime(FAR struct tm *tp)
    * Days: 1-31 match in both cases.
    * Month: STM32 is 1-12, struct tm is 0-11.
    * Years: STM32 is 00-99, struct tm is years since 1900.
+   * WeekDay: STM32 is 1 = Mon - 7 = Sun
    *
    * Issue:  I am not sure what the STM32 years mean.  Are these the
    * years 2000-2099?  I'll assume so.
@@ -894,6 +895,13 @@ int up_rtc_getdatetime(FAR struct tm *tp)
   tmp = (dr & (RTC_DR_YU_MASK|RTC_DR_YT_MASK)) >> RTC_DR_YU_SHIFT;
   tp->tm_year = rtc_bcd2bin(tmp) + 100;
 
+#if defined(CONFIG_TIME_EXTENDED)
+  tmp = (dr & RTC_DR_WDU_MASK) >> RTC_DR_WDU_SHIFT;
+  tp->tm_wday = tmp % 7;
+  tp->tm_yday = tp->tm_mday + clock_daysbeforemonth(tp->tm_mon, clock_isleapyear(tp->tm_year + 1900));
+  tp->tm_isdst = 0
+#endif
+
 #ifdef CONFIG_STM32_HAVE_RTC_SUBSECONDS
   /* Return RTC sub-seconds if no configured and if a non-NULL value
    * of nsec has been provided to receive the sub-second value.
@@ -992,14 +1000,18 @@ int stm32_rtc_setdatetime(FAR const struct tm *tp)
    * Days: 1-31 match in both cases.
    * Month: STM32 is 1-12, struct tm is 0-11.
    * Years: STM32 is 00-99, struct tm is years since 1900.
-   *
+   * WeekDay: STM32 is 1 = Mon - 7 = Sun
    * Issue:  I am not sure what the STM32 years mean.  Are these the
    * years 2000-2099?  I'll assume so.
    */
 
   dr = (rtc_bin2bcd(tp->tm_mday) << RTC_DR_DU_SHIFT) |
        ((rtc_bin2bcd(tp->tm_mon + 1))  << RTC_DR_MU_SHIFT) |
+#if defined(CONFIG_TIME_EXTENDED)
+       ((tp->tm_wday == 0 ? 7 : (tp->tm_wday & 7))  << RTC_DR_WDU_SHIFT) |
+#endif
        ((rtc_bin2bcd(tp->tm_year - 100)) << RTC_DR_YU_SHIFT);
+
   dr &= ~RTC_DR_RESERVED_BITS;
 
   /* Disable the write protection for RTC registers */

include/nuttx/time.h

@@ -1,7 +1,7 @@
 /****************************************************************************
  * include/nuttx/time.h
  *
- *   Copyright (C) 2009, 2011 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009, 2011, 2015 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -100,6 +100,26 @@ int clock_isleapyear(int year);
 
 int clock_daysbeforemonth(int month, bool leapyear);
 
+/****************************************************************************
+ * Function:  clock_dayoftheweek
+ *
+ * Description:
+ *    Get the day of the week
+ *
+ * Input Parameters:
+ *   mday  - The day of the month 1 - 31
+ *   month - The month of the year 1 - 12
+ *   year  - the year including the 1900
+ *
+ * Returned value:
+ *   Zero based day of the week 0-6, 0 = Sunday, 1 = Monday... 6 = Saturday
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_TIME_EXTENDED)
+int clock_dayoftheweek(int mday, int month, int year);
+#endif
+
 /****************************************************************************
  * Function:  clock_calendar2utc
  *

include/time.h

@@ -136,7 +136,7 @@ struct tm
   int tm_mday;    /* Day of the month (1-31) */
   int tm_mon;     /* Month (0-11) */
   int tm_year;    /* Years since 1900 */
-#ifdef CONFIG_LIBC_LOCALTIME
+#if defined(CONFIG_LIBC_LOCALTIME) || defined(CONFIG_TIME_EXTENDED)
   int tm_wday;    /* Day of the week (0-6) */
   int tm_yday;    /* Day of the year (0-365) */
   int tm_isdst;   /* Non-0 if daylight savings time is in effect */

libc/Kconfig

@@ -285,6 +285,16 @@ config LIBC_TZDIR
 
 endif
 
+config TIME_EXTENDED
+	bool "Add day of week, year support"
+	default "n"
+	---help---
+		Selecting TIME_EXTENDED adds tm_wday, tm_yday and tm_isdst
+		to the tm struct. This allows integration with 3rd party libraries
+		that expect the tm struct to contain these members.
+
+		Note: tm_isdst is always 0
+
 config LIB_SENDFILE_BUFSIZE
 	int "sendfile() buffer size"
 	default 512

libc/time/Make.defs

@@ -1,7 +1,7 @@
 ############################################################################
 # libc/time/Make.defs
 #
-#   Copyright (C) 2011-2012, 2014 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2011-2012, 2014-2015 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -42,6 +42,9 @@ ifdef CONFIG_LIBC_LOCALTIME
 CSRCS += lib_localtime.c
 else
 CSRCS += lib_mktime.c lib_gmtime.c lib_gmtimer.c
+ifdef CONFIG_TIME_EXTENDED
+CSRCS += lib_dayofweek.c
+endif
 endif
 
 # Add the time directory to the build

libc/time/lib_dayofweek.c

@@ -0,0 +1,106 @@
+/****************************************************************************
+ * libc/time/lib_dayofweek.c
+ *
+ *   Copyright (C) 2009, 2011 - 2015 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *           David Sidrane <david_s5@nscdg.com>
+ *
+ * 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.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <nuttx/time.h>
+
+#if defined(CONFIG_TIME_EXTENDED)
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Type Declarations
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Constant Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Variables
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  clock_dayoftheweek
+ *
+ * Description:
+ *    Get the day of the week
+ *
+ * Input Parameters:
+ *   mday  - The day of the month 1 - 31
+ *   month - The month of the year 1 - 12
+ *   year  - the year including the 1900
+ *
+ * Returned value:
+  * Zero based day of the week 0-6, 0 = Sunday, 1 = Monday... 6 = Saturday
+ *
+ ****************************************************************************/
+
+int clock_dayoftheweek(int mday, int month, int year)
+{
+  if (month <= 2) {
+      year--;
+      month += 12;
+  }
+  month -= 2;
+  return (mday + year + year/4 - year/100 + year/400 + ( 31 * month) / 12) % 7;
+}
+#endif /* CONFIG_TIME_EXTENDED */

libc/time/lib_gmtimer.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * libc/time/lib_gmtimer.c
  *
- *   Copyright (C) 2007, 2009, 2011 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2009, 2011, 2015 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -343,12 +343,18 @@ FAR struct tm *gmtime_r(FAR const time_t *timer, FAR struct tm *result)
 
   /* Then return the struct tm contents */
 
-  result->tm_year = (int)year - 1900; /* Relative to 1900 */
+  result->tm_year  = (int)year - 1900; /* Relative to 1900 */
-  result->tm_mon  = (int)month - 1;   /* zero-based */
+  result->tm_mon   = (int)month - 1;   /* zero-based */
-  result->tm_mday = (int)day;         /* one-based */
+  result->tm_mday  = (int)day;         /* one-based */
-  result->tm_hour = (int)hour;
+  result->tm_hour  = (int)hour;
-  result->tm_min  = (int)min;
+  result->tm_min   = (int)min;
-  result->tm_sec  = (int)sec;
+  result->tm_sec   = (int)sec;
+
+#if defined(CONFIG_TIME_EXTENDED)
+  result->tm_wday  = clock_dayoftheweek(day, month, year);
+  result->tm_yday  = day + clock_daysbeforemonth(result->tm_mon, clock_isleapyear(year));
+  result->tm_isdst = 0;
+#endif
 
   return result;
 }