Make readTemperature always return false, when lock is not available

drivers/focuser/alluna_tcs2.cpp

@@ -26,6 +26,12 @@
  * - add handybox add/remove
  * - create a python client looking like tcs2control
  * - make serial port selection easier
+ *
+ * KNOWN PROBLEMS:
+ *    https://indilib.org/forum/focusers-filter-wheels/14173-new-zwo-eaf-first-use-experience-and-questions.html#98014
+ *    Note: When I try to enable Debug in the IndiControlPanel it immediately sets it to Disable?
+ *    Debug is controlled (set on/off) in Ekos and these individual driver debug buttons no longer work. This behaviour is "as expected".
+ *
  */
 
 #include "alluna_tcs2.h"
@@ -58,6 +64,7 @@ AllunaTCS2::AllunaTCS2() //: DustCapInterface()
                       FOCUSER_CAN_REL_MOVE ); //FIXME: maybe remove CAN_REL_MOVE
 }
 
+
 bool AllunaTCS2::initProperties()
 {
     INDI::Focuser::initProperties();
@@ -122,7 +129,7 @@ bool AllunaTCS2::updateProperties()
     {
         // turn on green Connected-LED
         if (sendCommand("Connect 1\n"))
-            LOG_INFO("Turned on Connected-LED¨");
+            ;//LOG_INFO("Turned on Connected-LED¨");
         else
             LOG_ERROR("Cannot turn on Connected-LED");
 
@@ -364,9 +371,9 @@ bool AllunaTCS2::ISNewSwitch(const char * dev, const char * name, ISState * stat
         {
             // turn off green Connected-LED
             if (sendCommand("Connect 0\n"))
-                LOG_INFO("XTurned off Connected-LED");
+                LOG_DEBUG("Turned off Connected-LED");
             else
-                LOG_ERROR("XCannot turn off Connected-LED");
+                LOG_ERROR("Cannot turn off Connected-LED");
         }
         // Stepping Mode?
         if (!strcmp(name, SteppingModeSP.name))
@@ -480,7 +487,7 @@ bool AllunaTCS2::AbortFocuser()
 
 void AllunaTCS2::TimerHit()
 {
-    LOG_DEBUG("TimerHit");
+    //LOG_INFO("TimerHit");
     if (!isConnected())
         return; // No need to reset timer if we are not connected anymore
 
@@ -623,7 +630,12 @@ bool AllunaTCS2::readTemperature()
     std::chrono::duration<double> seconds = std::chrono::system_clock::now() - last_temp_update;
     if ( !first_run && seconds.count() < 300 ) // update all 300 seconds
     {
-        return true; // use cached value
+        if (tcs.try_lock()) {
+            tcs.unlock(); // we need to get lock, to make TimerHit behave the same when we block reading temperature
+            return true; // return true, if we could get the lock
+        } else {
+            return false; // return false, if we could not get the lock
+        }
     }
     else if ( sendCommandOnly("GetTemperatures\n")  )
     {