Merge pull request #1135 from stevew817/master

Silicon Labs - Fix for RTC: could not properly set the time.

Author: 0xc0170

libraries/mbed/targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/rtc_api.c

@@ -24,23 +24,24 @@
 #include "sleep_api.h"
 #include "sleepmodes.h"
 
-static bool rtc_inited = false;
-static time_t time_base = 0;
-static uint32_t useflags = 0;
+static bool         rtc_inited  = false;
+static time_t       time_base   = 0;
+static uint32_t     useflags    = 0;
+static uint32_t     time_extend = 0;
 
 static void (*comp0_handler)(void) = NULL;
 
-#define RTC_LEAST_ACTIVE_SLEEPMODE EM2
-
+#define RTC_LEAST_ACTIVE_SLEEPMODE  EM2
+#define RTC_NUM_BITS                (24)
 
 void RTC_IRQHandler(void)
 {
     uint32_t flags;
     flags = RTC_IntGet();
     if (flags & RTC_IF_OF) {
         RTC_IntClear(RTC_IF_OF);
-        /* RTC has overflowed (24 bits). Use time_base as software counter for upper 8 bits. */
-        time_base += 1 << 24;
+        /* RTC has overflowed (24 bits). Use time_extend as software counter for 32 more bits. */
+        time_extend += 1;
     }
     if (flags & RTC_IF_COMP0) {
         RTC_IntClear(RTC_IF_COMP0);
@@ -50,6 +51,20 @@ void RTC_IRQHandler(void)
     }
 }
 
+uint32_t rtc_get_32bit(void) 
+{
+    return (RTC_CounterGet() + (time_extend << RTC_NUM_BITS));
+}
+
+uint64_t rtc_get_full(void) 
+{
+    uint64_t ticks = 0;
+    ticks += time_extend;
+    ticks = ticks << RTC_NUM_BITS;
+    ticks += RTC_CounterGet();
+    return ticks;
+}
+
 void rtc_set_comp0_handler(uint32_t handler)
 {
     comp0_handler = (void (*)(void)) handler;
@@ -126,18 +141,23 @@ int rtc_isenabled(void)
 
 time_t rtc_read(void)
 {
-    return (time_t) ((RTC_CounterGet() + time_base) >> RTC_FREQ_SHIFT);
+    return (time_t) (rtc_get_full() >> RTC_FREQ_SHIFT) + time_base;
+}
+
+time_t rtc_read_uncompensated(void) 
+{
+    return (time_t) (rtc_get_full() >> RTC_FREQ_SHIFT);
 }
 
 void rtc_write(time_t t)
 {
     /* We have to check that the RTC did not tick while doing this. */
     /* If the RTC ticks we just redo this. */
-    uint32_t rtc_count;
+    uint32_t time;
     do {
-        rtc_count = RTC_CounterGet();
-        time_base = (t << RTC_FREQ_SHIFT) - rtc_count;
-    } while (rtc_count != RTC_CounterGet());
+        time = rtc_read_uncompensated();
+        time_base = t - time;
+    } while (time != rtc_read_uncompensated());
 }
 
 #endif