i2c locking for rtc & timesync streamlined

include/globals.h

@@ -99,7 +99,6 @@ typedef struct {
 
 enum sendprio_t { prio_low, prio_normal, prio_high };
 enum timesource_t { _gps, _rtc, _lora, _unsynced };
-enum mutexselect_t { no_mutex, do_mutex };
 
 extern std::set<uint16_t, std::less<uint16_t>, Mallocator<uint16_t>> macs;
 extern std::array<uint64_t, 0xff>::iterator it;

include/rtctime.h

@@ -9,7 +9,7 @@
 extern RtcDS3231<TwoWire> Rtc; // make RTC instance globally available
 
 uint8_t rtc_init(void);
-uint8_t set_rtctime(time_t t, mutexselect_t mutex);
+uint8_t set_rtctime(time_t t);
 void sync_rtctime(void);
 time_t get_rtctime(void);
 float get_rtctemp(void);

src/lorawan.cpp

@@ -507,15 +507,8 @@ void IRAM_ATTR user_request_network_time_callback(void *pVoidUserUTCTime,
     return;
   }
 
-  // begin of time critical section
+  // mask application irq to ensure accurate timing
-
-  // lock I2C bus and application irq to ensure accurate timing
   mask_user_IRQ();
-  if (!I2C_MUTEX_LOCK()) {
-    ESP_LOGW(TAG, "[%0.3f] Timesync handshake error: i2c bus locking failed",
-             millis() / 1000.0);
-    goto finish; // failure
-  }
 
   // Update userUTCTime, considering the difference between the GPS and UTC
   // time, and the leap seconds until year 2019
@@ -532,8 +525,7 @@ void IRAM_ATTR user_request_network_time_callback(void *pVoidUserUTCTime,
   setMyTime(*pUserUTCTime + requestDelaySec, 0);
 
 finish:
-  // end of time critical section: release I2C bus and app irq
+  // end of time critical section: release app irq lock
-  I2C_MUTEX_UNLOCK();
   unmask_user_IRQ();
 
 } // user_request_network_time_callback

src/rtctime.cpp

@@ -46,21 +46,20 @@ uint8_t rtc_init(void) {
 
 } // rtc_init()
 
-uint8_t set_rtctime(time_t t, mutexselect_t mutex) { // t is sec epoch time
+uint8_t set_rtctime(time_t t) { // t is sec epoch time
-  if (!mutex || I2C_MUTEX_LOCK()) {
+  if (I2C_MUTEX_LOCK()) {
 #ifdef RTC_INT // sync rtc 1Hz pulse on top of second
     Rtc.SetSquareWavePin(DS3231SquareWavePin_ModeNone);  // off
     Rtc.SetSquareWavePin(DS3231SquareWavePin_ModeClock); // start
 #endif
     Rtc.SetDateTime(RtcDateTime(t - SECS_YR_2000)); // epoch -> sec2000
-    if (mutex)
+    I2C_MUTEX_UNLOCK();
-      I2C_MUTEX_UNLOCK();
     ESP_LOGI(TAG, "RTC time synced");
     return 1; // success
   } else {
     ESP_LOGE(TAG, "RTC set time failure");
-    return 0;
+    return 0; // failure
-  } // failure
+  }
 } // set_rtctime()
 
 time_t get_rtctime(void) {
@@ -71,8 +70,11 @@ time_t get_rtctime(void) {
       t = tt.Epoch32Time(); // sec2000 -> epoch
     }
     I2C_MUTEX_UNLOCK();
+    return timeIsValid(t);
+  } else {
+    ESP_LOGE(TAG, "RTC get time failure");
+    return 0; // failure
   }
-  return timeIsValid(t);
 } // get_rtctime()
 
 float get_rtctemp(void) {

src/timekeeper.cpp

@@ -31,7 +31,7 @@ time_t timeProvider(void) {
   t = fetch_gpsTime(gps_status);
   if (t) {
 #ifdef HAS_RTC
-    set_rtctime(t, do_mutex); // calibrate RTC
+    set_rtctime(t); // calibrate RTC
 #endif
     timeSource = _gps;
     timesyncer.attach(TIME_SYNC_INTERVAL * 60, timeSync); // regular repeat

src/timesync.cpp

@@ -132,9 +132,8 @@ void process_timesync_req(void *taskparameter) {
 
   finish:
     // end of time critical section: release app irq lock
-    unmask_user_IRQ();
-
     timeSyncPending = false;
+    unmask_user_IRQ();
 
   } // infinite while(1)
 }
@@ -223,7 +222,7 @@ void IRAM_ATTR setMyTime(uint32_t t_sec, uint16_t t_msec) {
 
 // set RTC time and calibrate RTC_INT pulse on top of second
 #ifdef HAS_RTC
-    set_rtctime(time_to_set, no_mutex);
+    set_rtctime(time_to_set);
 #endif
 
 // sync pps timer to top of second