esp_timer: add internal function to adjust time

components/esp32/esp_timer_esp32.c

@@ -311,6 +311,18 @@ void IRAM_ATTR esp_timer_impl_update_apb_freq(uint32_t apb_ticks_per_us)
     portEXIT_CRITICAL_ISR(&s_time_update_lock);
 }
 
+void esp_timer_impl_advance(int64_t time_us)
+{
+    assert(time_us > 0 && "negative adjustments not supported yet");
+
+    portENTER_CRITICAL(&s_time_update_lock);
+    uint64_t count = REG_READ(FRC_TIMER_COUNT_REG(1));
+    REG_WRITE(FRC_TIMER_LOAD_REG(1), 0);
+    s_time_base_us += count / s_timer_ticks_per_us + time_us;
+    esp_timer_impl_set_alarm(esp_timer_get_next_alarm());
+    portEXIT_CRITICAL(&s_time_update_lock);
+}
+
 esp_err_t esp_timer_impl_init(intr_handler_t alarm_handler)
 {
     s_alarm_handler = alarm_handler;

components/esp32/esp_timer_impl.h

@@ -60,6 +60,15 @@ void esp_timer_impl_set_alarm(uint64_t timestamp);
  */
 void esp_timer_impl_update_apb_freq(uint32_t apb_ticks_per_us);
 
+/**
+ * @brief Adjust current esp_timer time by a certain value
+ *
+ * Called from light sleep code to synchronize esp_timer time with RTC time.
+ *
+ * @param time_us  adjustment to apply to esp_timer time, in microseconds
+ */
+void esp_timer_impl_advance(int64_t time_us);
+
 /**
  * @brief Get time, in microseconds, since esp_timer_impl_init was called
  * @return timestamp in microseconds