Merge from master

ChangeLog

@@ -10253,6 +10253,7 @@
 	  Parikh.  This initial commit is incomplete.  This is quite a bit more
 	  hub logic that needs to come in before the port is complete
 	  (2015-04-18).
+	* arch/arm/src/stm32/stm32_rtcounter.c: Now need to enable backup
+	  domain write access when setting the time.  From Darcy Gong (2015-04-19).
 	* include/nuttx/usb/usbhost.h:  Bring in more logic from
-          https://github.com/kaushalparikh/nuttx (2015-04-19).
-
+	  https://github.com/kaushalparikh/nuttx (2015-04-19).

arch/arm/src/stm32/stm32_rtcounter.c

@@ -589,25 +589,37 @@ int up_rtc_settime(FAR const struct timespec *tp)
 {
   struct rtc_regvals_s regvals;
   irqstate_t flags;
+  uint16_t cntl;
 
   /* Break out the time values */
 
   stm32_rtc_breakout(tp, &regvals);
 
+  /* Enable write access to the backup domain */
+
+  (void)stm32_pwr_enablebkp(true);
+
   /* Then write the broken out values to the RTC counter and BKP overflow register
    * (hi-res mode only)
    */
 
   flags = irqsave();
-  stm32_rtc_beginwr();
-  putreg16(regvals.cnth, STM32_RTC_CNTH);
-  putreg16(regvals.cntl, STM32_RTC_CNTL);
-  stm32_rtc_endwr();
+  do
+    {
+      stm32_rtc_beginwr();
+      putreg16(regvals.cnth, STM32_RTC_CNTH);
+      putreg16(regvals.cntl, STM32_RTC_CNTL);
+      cntl = getreg16(STM32_RTC_CNTL);
+      stm32_rtc_endwr();
+    }
+  while (cntl != regvals.cntl);
 
 #ifdef CONFIG_RTC_HIRES
   putreg16(regvals.ovf, RTC_TIMEMSB_REG);
 #endif
   irqrestore(flags);
+
+  (void)stm32_pwr_enablebkp(false);
   return OK;
 }