Implement of RTC feature for Renesas mbed boards

I implemented the RTC feature.
The mainly changing is here.
- rtc_init()
  Previously, I have initialized the time information register in the function, so the time count was cleaned by every calling rtc_init().
  Currently, rtc_init() doesn't stop RTC from counting, and rtc_init() is safe to call repeatedly.
  Therefore in order to satisfy specifications,I removed the initialization process of the time information register in the function.

- rtc_free()
  Previously, I have initialized the RTC related register same as rtc_init(), so the time count was cleaned by calling rtc_free().
  Currently, rtc_free() doesn't stop RTC from counting.
  Therefore in order to satisfy specifications,I removed the process and decided not to do anything in the function.
  If powerdown the RTC, Supply of the clock to the RTC is stopped, cannot keeping the count.

Author: TomoYamanaka

targets/TARGET_RENESAS/TARGET_RZ_A1XX/rtc_api.c

@@ -82,7 +82,8 @@ static uint16_t rtc_hex16_to_dec(uint16_t hex_val);
  * [out]
  * None.
  */
-void rtc_init(void) {
+void rtc_init(void)
+{
     volatile uint8_t dummy_read;
 
     CPG.STBCR6 &= ~(CPG_STBCR6_BIT_MSTP60);
@@ -109,84 +110,27 @@ void rtc_init(void) {
     dummy_read = RTC.RCR2;
     dummy_read = RTC.RCR2;
 
-    RTC.RCR2 = RCR2_VAL_RESET; // RESET = 1
+    RTC.RCR2 = RCR2_VAL_START; // SRART = 1
 
     // Dummy read
     dummy_read = RTC.RCR2;
     dummy_read = RTC.RCR2;
 
-    // Set timer and alarm. Default value :01-01-1970 00:00:00
-    RTC.RSECCNT = 0;
-    RTC.RMINCNT = 0;
-    RTC.RHRCNT  = 0;
-    RTC.RWKCNT  = 0;
-    RTC.RDAYCNT = 1;
-    RTC.RMONCNT = 1;
-    RTC.RYRCNT  = 0x1970;
-    RTC.RSECAR  = 0;
-    RTC.RMINAR  = 0;
-    RTC.RHRAR   = 0;
-    RTC.RWKAR   = 0;
-    RTC.RDAYAR  = 1;
-    RTC.RMONAR  = 1;
-    RTC.RYRAR   = 0x1970;
-
-    // Dummy read
-    dummy_read = RTC.RYRCNT;
-    dummy_read = RTC.RYRCNT;
     (void)dummy_read;
 
 }
 
 
 /*
  * Release the RTC based on a time structure.
+ * @note This function does not stop the RTC from counting 
  * [in]
  * None.
  * [out]
  * None.
  */
-void rtc_free(void) {
-    volatile uint8_t dummy_read;
-
-    // Set control register
-    RTC.RCR2 = RCR2_VAL_ALLSTOP;
-    RTC.RCR1 = RCR1_VAL_OFF;
-    RTC.RCR3 = RCR3_VAL;
-    RTC.RCR5 = RCR5_VAL;
-    RTC.RFRH = RFRH_VAL_MAX;
-    RTC.RFRL = RFRL_VAL_MAX;
-
-    // Dummy read
-    dummy_read = RTC.RCR2;
-    dummy_read = RTC.RCR2;
-    RTC.RCR2 = RCR2_VAL_RESET; // RESET = 1
-
-    // Dummy read
-    dummy_read = RTC.RCR2;
-    dummy_read = RTC.RCR2;
-
-    // Set timer and alarm. Default value :01-01-1970 00:00:00
-    RTC.RSECCNT = 0;
-    RTC.RMINCNT = 0;
-    RTC.RHRCNT  = 0;
-    RTC.RWKCNT  = 0;
-    RTC.RDAYCNT = 1;
-    RTC.RMONCNT = 1;
-    RTC.RYRCNT  = 0x1970;
-    RTC.RSECAR  = 0;
-    RTC.RMINAR  = 0;
-    RTC.RHRAR   = 0;
-    RTC.RWKAR   = 0;
-    RTC.RDAYAR  = 1;
-    RTC.RMONAR  = 1;
-    RTC.RYRAR   = 0x1970;
-
-    // Dummy read
-    dummy_read = RTC.RYRCNT;
-    dummy_read = RTC.RYRCNT;
-    (void)dummy_read;
-
+void rtc_free(void)
+{
 }
 
 
@@ -198,7 +142,8 @@ void rtc_free(void) {
  * [out]
  * 0:Disabled, 1:Enabled.
  */
-int rtc_isenabled(void) {
+int rtc_isenabled(void)
+{
     int ret_val = 0;
 
     if ((RTC.RCR1 & RCR1_VAL_ON) != 0) { // RTC ON ?
@@ -216,7 +161,8 @@ int rtc_isenabled(void) {
  * [out]
  * UNIX timestamp value.
  */
-time_t rtc_read(void) {
+time_t rtc_read(void)
+{
 
     struct tm timeinfo;
     int    err = 0;
@@ -267,7 +213,8 @@ time_t rtc_read(void) {
  * 0:Success
  * 1:Error
  */
-static int rtc_dec8_to_hex(uint8_t dec_val, uint8_t offset, int *hex_val) {
+static int rtc_dec8_to_hex(uint8_t dec_val, uint8_t offset, int *hex_val)
+{
     int err = 0;
     uint8_t ret_val;
 
@@ -301,7 +248,8 @@ static int rtc_dec8_to_hex(uint8_t dec_val, uint8_t offset, int *hex_val) {
  * 0:Success
  * 1:Error
  */
-static int rtc_dec16_to_hex(uint16_t dec_val, uint16_t offset, int *hex_val) {
+static int rtc_dec16_to_hex(uint16_t dec_val, uint16_t offset, int *hex_val)
+{
     int err = 0;
     uint16_t ret_val;
 
@@ -336,7 +284,8 @@ static int rtc_dec16_to_hex(uint16_t dec_val, uint16_t offset, int *hex_val) {
  * [out]
  * None.
  */
-void rtc_write(time_t t) {
+void rtc_write(time_t t)
+{
 
     struct tm timeinfo;
     if (_rtc_localtime(t, &timeinfo, RTC_FULL_LEAP_YEAR_SUPPORT) == false) {
@@ -377,7 +326,8 @@ void rtc_write(time_t t) {
  * [out]
  * decimal value:From 0x00 to 0x99.
  */
-static uint8_t rtc_hex8_to_dec(uint8_t hex_val) {
+static uint8_t rtc_hex8_to_dec(uint8_t hex_val)
+{
     uint32_t calc_data;
 
     calc_data  = hex_val / 10 * 0x10;
@@ -397,7 +347,8 @@ static uint8_t rtc_hex8_to_dec(uint8_t hex_val) {
  * [out]
  * decimal value:From 0x0000 to 0x9999.
  */
-static uint16_t rtc_hex16_to_dec(uint16_t hex_val) {
+static uint16_t rtc_hex16_to_dec(uint16_t hex_val)
+{
     uint32_t calc_data;
     calc_data  =   hex_val / 1000       * 0x1000;
     calc_data += ((hex_val / 100) % 10) * 0x100;

targets/targets.json

@@ -2785,7 +2785,7 @@
         "core": "Cortex-A9",
         "supported_toolchains": ["ARM", "GCC_ARM", "IAR"],
         "extra_labels": ["RENESAS", "RZ_A1XX"],
-        "device_has": ["SLEEP", "USTICKER", "ANALOGIN", "CAN", "ETHERNET", "I2C", "I2CSLAVE", "I2C_ASYNCH", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SPI", "SPISLAVE", "SPI_ASYNCH", "STDIO_MESSAGES"],
+        "device_has": ["SLEEP", "USTICKER", "RTC", "ANALOGIN", "CAN", "ETHERNET", "I2C", "I2CSLAVE", "I2C_ASYNCH", "INTERRUPTIN", "PORTIN", "PORTINOUT", "PORTOUT", "PWMOUT", "SERIAL", "SERIAL_ASYNCH", "SERIAL_FC", "SPI", "SPISLAVE", "SPI_ASYNCH", "STDIO_MESSAGES"],
         "features": ["LWIP"],
         "program_cycle_s": 2,
         "overrides": {