[XXX_F3XX] enhance rtc api

add define to select LSI or LSE, update rtc api accordingly

libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F3/stm32f3xx_hal_rcc.h

@@ -164,7 +164,7 @@ typedef struct
   * @{
   */  
 /* LSE state change timeout */
-#define LSE_TIMEOUT_VALUE          ((uint32_t)100) /* 5 s    */
+#define LSE_TIMEOUT_VALUE          ((uint32_t)5000) /* 5 s    */
 
 /* Disable Backup domain write protection state change timeout */
 #define DBP_TIMEOUT_VALUE          ((uint32_t)100)  /* 100 ms */

libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F3/TARGET_DISCO_F303VC/device.h

@@ -48,6 +48,7 @@
 #define DEVICE_SPISLAVE         1
 
 #define DEVICE_RTC              1
+#define DEVICE_RTC_LSI          1
 
 #define DEVICE_PWMOUT           1
 

libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F3/TARGET_DISCO_F334C8/device.h

@@ -48,6 +48,7 @@
 #define DEVICE_SPISLAVE         1
 
 #define DEVICE_RTC              1
+#define DEVICE_RTC_LSI          1
 
 #define DEVICE_PWMOUT           1
 

libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F3/TARGET_NUCLEO_F302R8/device.h

@@ -48,6 +48,7 @@
 #define DEVICE_SPISLAVE         1
 
 #define DEVICE_RTC              1
+#define DEVICE_RTC_LSI          0
 
 #define DEVICE_PWMOUT           1
 

libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F3/TARGET_NUCLEO_F303K8/device.h

@@ -48,6 +48,7 @@
 #define DEVICE_SPISLAVE         1
 
 #define DEVICE_RTC              1
+#define DEVICE_RTC_LSI          0
 
 #define DEVICE_PWMOUT           1
 

libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F3/TARGET_NUCLEO_F303RE/device.h

@@ -48,6 +48,7 @@
 #define DEVICE_SPISLAVE         1
 
 #define DEVICE_RTC              1
+#define DEVICE_RTC_LSI          0
 
 #define DEVICE_PWMOUT           1
 

libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F3/TARGET_NUCLEO_F334R8/device.h

@@ -48,6 +48,7 @@
 #define DEVICE_SPISLAVE         1
 
 #define DEVICE_RTC              1
+#define DEVICE_RTC_LSI          0
 
 #define DEVICE_PWMOUT           1
 

libraries/mbed/targets/hal/TARGET_STM/TARGET_STM32F3/rtc_api.c

@@ -33,7 +33,9 @@
 
 #include "mbed_error.h"
 
+#if DEVICE_RTC_LSI
 static int rtc_inited = 0;
+#endif
 
 static RTC_HandleTypeDef RtcHandle;
 
@@ -42,11 +44,26 @@ void rtc_init(void)
     RCC_OscInitTypeDef RCC_OscInitStruct;
     uint32_t rtc_freq = 0;
 
-    if (rtc_inited) return;
+#if DEVICE_RTC_LSI
     rtc_inited = 1;
+#endif
 
     RtcHandle.Instance = RTC;
 
+#if !DEVICE_RTC_LSI
+    // Enable LSE Oscillator
+    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSE;
+    RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE; /* Mandatory, otherwise the PLL is reconfigured! */
+    RCC_OscInitStruct.LSEState       = RCC_LSE_ON; /* External 32.768 kHz clock on OSC_IN/OSC_OUT */
+    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) == HAL_OK) {
+        // Connect LSE to RTC
+        __HAL_RCC_RTC_CONFIG(RCC_RTCCLKSOURCE_LSE);
+        rtc_freq = LSE_VALUE;
+    }
+    else {
+      error("RTC error: LSE clock initialization failed.");
+    }
+#else
 	// Enable Power clock
     __PWR_CLK_ENABLE();
 
@@ -57,15 +74,6 @@ void rtc_init(void)
     __HAL_RCC_BACKUPRESET_FORCE();
     __HAL_RCC_BACKUPRESET_RELEASE();
 	
-    // Enable LSE Oscillator
-    RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSE;
-    RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE; /* Mandatory, otherwise the PLL is reconfigured! */
-    RCC_OscInitStruct.LSEState       = RCC_LSE_ON; /* External 32.768 kHz clock on OSC_IN/OSC_OUT */
-    if (HAL_RCC_OscConfig(&RCC_OscInitStruct) == HAL_OK) {
-        // Connect LSE to RTC
-        __HAL_RCC_RTC_CONFIG(RCC_RTCCLKSOURCE_LSE);
-        rtc_freq = LSE_VALUE;
-    } else {
 	// Enable LSI clock
 	RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI | RCC_OSCILLATORTYPE_LSE;
 	RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE; // Mandatory, otherwise the PLL is reconfigured!
@@ -78,10 +86,8 @@ void rtc_init(void)
 	__HAL_RCC_RTC_CONFIG(RCC_RTCCLKSOURCE_LSI);
 	// Note: The LSI clock can be measured precisely using a timer input capture.
 	rtc_freq = LSI_VALUE;
-    }
+#endif    
 
-    // Check if RTC is already initialized
-    if ((RTC->ISR & RTC_ISR_INITS) ==  RTC_ISR_INITS) return;
 
     // Enable RTC
     __HAL_RCC_RTC_ENABLE();
@@ -100,6 +106,7 @@ void rtc_init(void)
 
 void rtc_free(void)
 {
+#if DEVICE_RTC_LSI	
     // Enable Power clock
     __PWR_CLK_ENABLE();
 
@@ -112,6 +119,7 @@ void rtc_free(void)
 
     // Disable access to Backup domain
     HAL_PWR_DisableBkUpAccess();
+#endif	
 
     // Disable LSI and LSE clocks
     RCC_OscInitTypeDef RCC_OscInitStruct;
@@ -121,12 +129,19 @@ void rtc_free(void)
     RCC_OscInitStruct.LSEState       = RCC_LSE_OFF;
     HAL_RCC_OscConfig(&RCC_OscInitStruct);
 
+#if DEVICE_RTC_LSI
     rtc_inited = 0;
+#endif
 }
 
 int rtc_isenabled(void)
 {
+#if DEVICE_RTC_LSI
     return rtc_inited;
+#else
+  if ((RTC->ISR & RTC_ISR_INITS) ==  RTC_ISR_INITS) return 1;
+  else return 0;
+#endif
 }
 
 /*