stm32RTC change the binary Mode in case the RTC is already init

When the RTC is already initialized, but RTC BIN mode must be changed
this is done by writing the RTC ICSR register on BIN[] and BCDU[]
bit-field with a new `RTC_SetBinaryConf()` function.

Signed-off-by: Francois Ramu <francois.ramu@st.com>

Author: Francois RAMU

src/rtc.c

@@ -93,6 +93,7 @@ static void RTC_computePrediv(uint32_t *asynch, uint32_t *synch);
 #endif /* !STM32F1xx */
 #if defined(RTC_BINARY_NONE)
 static void RTC_BinaryConf(binaryMode_t mode);
+static void RTC_SetBinaryConf(void);
 #endif
 
 static inline int _log2(int x)
@@ -383,6 +384,34 @@ static void RTC_BinaryConf(binaryMode_t mode)
     }
   }
 }
+
+/*
+* Function to check if the RTC ICSR register must be updated with new bit
+* field BIN and BCDU. To be called just after the RTC_BinaryConf
+* Map the LL RTC bin mode to the corresponding RtcHandle.Init.BinMode values
+* assuming the LL_RTC_BINARY_xxx is identical to RTC_BINARY_xxx (RTC_ICSR_BIN_xxx)
+* Idem for the LL_RTC_BINARY_MIX_BCDU_n and RTC_BINARY_MIX_BCDU_n
+*/
+#if (RTC_BINARY_MIX != LL_RTC_BINARY_MIX)
+#error "RTC_BINARY_MIX and LL_RTC_BINARY_MIX do not match"
+#endif
+#if (RTC_BINARY_MIX_BCDU_7 != LL_RTC_BINARY_MIX_BCDU_7)
+#error "RTC_BINARY_MIX_BCDU_n and LL_RTC_BINARY_MIX_BCDU_n do not match"
+#endif
+static void RTC_SetBinaryConf(void)
+{
+  if (LL_RTC_GetBinaryMode(RtcHandle.Instance) != RtcHandle.Init.BinMode) {
+    LL_RTC_DisableWriteProtection(RtcHandle.Instance);
+    LL_RTC_EnableInitMode(RtcHandle.Instance);
+
+    LL_RTC_SetBinaryMode(RtcHandle.Instance, RtcHandle.Init.BinMode);
+    if (RtcHandle.Init.BinMode == RTC_BINARY_MIX) {
+      LL_RTC_SetBinMixBCDU(RtcHandle.Instance, RtcHandle.Init.BinMixBcdU);
+    }
+    LL_RTC_ExitInitMode(RtcHandle.Instance);
+    LL_RTC_EnableWriteProtection(RtcHandle.Instance);
+  }
+}
 #endif /* RTC_BINARY_NONE */
 
 /**
@@ -463,6 +492,10 @@ bool RTC_init(hourFormat_t format, binaryMode_t mode, sourceClock_t source, bool
     RTC_initClock(source);
     RTC_getPrediv(&(RtcHandle.Init.AsynchPrediv), &(RtcHandle.Init.SynchPrediv));
 #if defined(RTC_BINARY_NONE)
+    /*
+     * If RTC BIN mode changed, calling the HAL_RTC_Init will
+     * force the update of the BIN register in the RTC_ICSR
+     */
     RTC_BinaryConf(mode);
 #endif /* RTC_BINARY_NONE */
 #endif  // STM32F1xx
@@ -527,11 +560,11 @@ bool RTC_init(hourFormat_t format, binaryMode_t mode, sourceClock_t source, bool
 #else
       RTC_getPrediv(&(RtcHandle.Init.AsynchPrediv), &(RtcHandle.Init.SynchPrediv));
 #endif
+#if defined(RTC_BINARY_NONE)
       /*
-       * TODO: RTC is already initialized, but RTC BIN mode is changed
+       * If RTC BIN mode changed, calling the HAL_RTC_Init will
        * force the update of the BIN register in the RTC_ICSR
        */
-#if defined(RTC_BINARY_NONE)
       RTC_BinaryConf(mode);
 #endif /* RTC_BINARY_NONE */
       HAL_RTC_Init(&RtcHandle);
@@ -558,6 +591,13 @@ bool RTC_init(hourFormat_t format, binaryMode_t mode, sourceClock_t source, bool
 #endif
 #if defined(RTC_BINARY_NONE)
       RTC_BinaryConf(mode);
+      /*
+       * RTC is already initialized, but RTC BIN mode is changed :
+       * force the update of the BIN register and BCDu in the RTC_ICSR
+       * by the RTC_SetBinaryConf function
+       */
+      RTC_SetBinaryConf();
+
 #endif /* RTC_BINARY_NONE */
 #if defined(STM32F1xx)
       memcpy(&RtcHandle.DateToUpdate, &BackupDate, 4);