Code review changes.

- Removed StopSelectedtimer()
- Removed extra Reset() call.
- Spelling errors.

src/app/clusters/ota-requestor/GenericOTARequestorDriver.cpp

@@ -85,7 +85,7 @@ void GenericOTARequestorDriver::Init(OTARequestorInterface * requestor, OTAImage
     else
     {
         // Start the first periodic query timer
-        StartPeriodicQueryTimer();
+        StartSelectedTimer(SelectedTimer::kPeriodicQueryTimer);
     }
 }
 
@@ -343,7 +343,7 @@ void GenericOTARequestorDriver::SendQueryImage()
 
     // Default provider timer only runs when there is no ongoing query/update; must stop it now.
     // TriggerImmediateQueryInternal() will cause the state to change from kIdle
-    StopSelectedTimer(SelectedTimer::kPeriodicQueryTimer);
+    StartSelectedTimer(SelectedTimer::kWatchdogTimer);
 
     mProviderRetryCount++;
 
@@ -400,8 +400,9 @@ void GenericOTARequestorDriver::WatchdogTimerHandler(System::Layer * systemLayer
     {
     case OTAUpdateStateEnum::kIdle:
     case OTAUpdateStateEnum::kUnknown:
-        // OTA Requestor is not stuck in non-idle state.  Restart watchdog timer.
-        StartWatchdogTimer();
+        // Watchdog timer should not expire in Idle state and periodic timer should already be scheduled.
+        // Scheduling periodic timer here just in case.
+        StartPeriodicQueryTimer();
         break;
     case OTAUpdateStateEnum::kQuerying:
     case OTAUpdateStateEnum::kDelayedOnQuery:
@@ -410,7 +411,6 @@ void GenericOTARequestorDriver::WatchdogTimerHandler(System::Layer * systemLayer
     case OTAUpdateStateEnum::kDelayedOnApply:
         UpdateDiscontinued();
         mRequestor->CancelImageUpdate();
-        mRequestor->Reset();
         StartPeriodicQueryTimer();
         break;
     case OTAUpdateStateEnum::kRollingBack:
@@ -457,21 +457,6 @@ void GenericOTARequestorDriver::StartSelectedTimer(SelectedTimer timer)
     }
 }
 
-void GenericOTARequestorDriver::StopSelectedTimer(SelectedTimer timer)
-{
-    switch (timer)
-    {
-    case SelectedTimer::kPeriodicQueryTimer:
-        StopPeriodicQueryTimer();
-        StartWatchdogTimer();
-        break;
-    case SelectedTimer::kWatchdogTimer:
-        StopWatchdogTimer();
-        StartPeriodicQueryTimer();
-        break;
-    }
-}
-
 /**
  * Returns the next available Provider location. The algorithm is to simply loop through the list of DefaultOtaProviders as a
  * circular list and return the next value (based on the last used provider). If the list of DefaultOtaProviders is empty, FALSE is

src/app/clusters/ota-requestor/GenericOTARequestorDriver.h

@@ -79,7 +79,6 @@ class GenericOTARequestorDriver : public OTARequestorDriver
     void StopWatchdogTimer();
     void WatchdogTimerHandler(System::Layer * systemLayer, void * appState);
     void StartSelectedTimer(SelectedTimer timer);
-    void StopSelectedTimer(SelectedTimer timer);
     void ScheduleDelayedAction(System::Clock::Seconds32 delay, System::TimerCompleteCallback action, void * aAppState);
     void CancelDelayedAction(System::TimerCompleteCallback action, void * aAppState);
     bool ProviderLocationsEqual(const ProviderLocationType & a, const ProviderLocationType & b);

src/app/clusters/ota-requestor/OTARequestor.cpp

@@ -658,15 +658,15 @@ void OTARequestor::RecordNewUpdateState(OTAUpdateStateEnum newState, OTAChangeRe
     }
     OtaRequestorServerOnStateTransition(mCurrentUpdateState, newState, reason, targetSoftwareVersion);
 
+    // Issue#16151 tracks re-factoring error and state transitioning handling.
     if ((newState == OTAUpdateStateEnum::kIdle) && (mCurrentUpdateState != OTAUpdateStateEnum::kIdle))
     {
         IdleStateReason idleStateReason = MapErrorToIdleStateReason(error);
 
         // Inform the driver that the OTARequestor has entered the Idle state
         mOtaRequestorDriver->HandleIdleState(idleStateReason);
     }
-    else if (((mCurrentUpdateState == OTAUpdateStateEnum::kIdle) || (mCurrentUpdateState == OTAUpdateStateEnum::kUnknown)) &&
-             (newState != OTAUpdateStateEnum::kIdle))
+    else if ((mCurrentUpdateState == OTAUpdateStateEnum::kIdle) && (newState != OTAUpdateStateEnum::kIdle))
     {
         mOtaRequestorDriver->HandleIdleStateExit();
     }

src/app/clusters/ota-requestor/OTARequestorDriver.h

@@ -81,9 +81,6 @@ enum class SelectedTimer
 class OTARequestorDriver
 {
 public:
-    using OTAUpdateStateEnum  = app::Clusters::OtaSoftwareUpdateRequestor::OTAUpdateStateEnum;
-    using OTAChangeReasonEnum = app::Clusters::OtaSoftwareUpdateRequestor::OTAChangeReasonEnum;
-
     using ProviderLocationType = app::Clusters::OtaSoftwareUpdateRequestor::Structs::ProviderLocation::Type;
 
     virtual ~OTARequestorDriver() = default;
@@ -97,7 +94,7 @@ class OTARequestorDriver
     /// Called when an error occurs at any OTA requestor operation
     virtual void HandleError(UpdateFailureState state, CHIP_ERROR error) = 0;
 
-    /// Called when OTA Requestor has exitted the Idle state for which the driver may need to take various actions
+    /// Called when OTA Requestor has exited the Idle state for which the driver may need to take various actions
     virtual void HandleIdleStateExit() = 0;
 
     // Called when the OTA Requestor has entered the Idle state for which the driver may need to take various actions