From 16a7ecee58d17e16cb266e458a458e527592f413 Mon Sep 17 00:00:00 2001
From: jeromecoutant <jerome.coutant@st.com>
Date: Tue, 7 Nov 2017 17:50:56 +0100
Subject: [PATCH] STM32 LOW_POWER_TIMER update : sleep

RSF synchro after deepsleep is not specific to Low Power Timer feature
And we have to check if RTC is configured before synchro
---
 targets/TARGET_STM/sleep.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/targets/TARGET_STM/sleep.c b/targets/TARGET_STM/sleep.c
index d41edfe5b7..fb232ec8b7 100644
--- a/targets/TARGET_STM/sleep.c
+++ b/targets/TARGET_STM/sleep.c
@@ -68,16 +68,16 @@ void hal_deepsleep(void)
 #if TARGET_STM32L4
     int pwrClockEnabled = __HAL_RCC_PWR_IS_CLK_ENABLED();
     int lowPowerModeEnabled = PWR->CR1 & PWR_CR1_LPR;
-    
+
     if (!pwrClockEnabled) {
         __HAL_RCC_PWR_CLK_ENABLE();
     }
     if (lowPowerModeEnabled) {
         HAL_PWREx_DisableLowPowerRunMode();
     }
-    
+
     HAL_PWREx_EnterSTOP2Mode(PWR_STOPENTRY_WFI);
-    
+
     if (lowPowerModeEnabled) {
         HAL_PWREx_EnableLowPowerRunMode();
     }
@@ -101,8 +101,15 @@ void hal_deepsleep(void)
     TimMasterHandle.Instance = TIM_MST;
     __HAL_TIM_SET_COUNTER(&TimMasterHandle, EnterTimeUS);
 
-#if DEVICE_LOWPOWERTIMER
-    rtc_synchronize();
+#if DEVICE_RTC
+    /* Wait for RTC RSF bit synchro if RTC is configured */
+#if (TARGET_STM32F2) || (TARGET_STM32F4) || (TARGET_STM32F7)
+    if (READ_BIT(RCC->BDCR, RCC_BDCR_RTCSEL)) {
+#else /* (TARGET_STM32F2) || (TARGET_STM32F4) || (TARGET_STM32F7) */
+    if (__HAL_RCC_GET_RTC_SOURCE()) {
+#endif  /* (TARGET_STM32F2) || (TARGET_STM32F4) || (TARGET_STM32F7) */
+        rtc_synchronize();
+    }
 #endif
 }