🏗️ Planner::busy() (#23145)

Marlin/src/module/planner.cpp

   #include "../feature/power.h"
 #endif
 
-#if ENABLED(EXTERNAL_CLOSED_LOOP_CONTROLLER)
-  #include "../feature/closedloop.h"
-#endif
-
 #if ENABLED(BACKLASH_COMPENSATION)
   #include "../feature/backlash.h"
 #endif
 }
 
 /**
- * Block until all buffered steps are executed / cleaned
+ * Block until the planner is finished processing
  */
-void Planner::synchronize() {
-  while (has_blocks_queued() || cleaning_buffer_counter
-      || TERN0(EXTERNAL_CLOSED_LOOP_CONTROLLER, CLOSED_LOOP_WAITING())
-  ) idle();
-}
+void Planner::synchronize() { while (busy()) idle(); }
 
 /**
  * Planner::_buffer_steps

Marlin/src/module/planner.h

   #define IS_PAGE(B) false
 #endif
 
+#if ENABLED(EXTERNAL_CLOSED_LOOP_CONTROLLER)
+  #include "../feature/closedloop.h"
+#endif
+
 // Feedrate for manual moves
 #ifdef MANUAL_FEEDRATE
   constexpr xyze_feedrate_t _mf = MANUAL_FEEDRATE,
     // Triggered position of an axis in mm (not core-savvy)
     static float triggered_position_mm(const AxisEnum axis);
 
+    // Blocks are queued, or we're running out moves, or the closed loop controller is waiting
+    static inline bool busy() {
+      return (has_blocks_queued() || cleaning_buffer_counter
+          || TERN0(EXTERNAL_CLOSED_LOOP_CONTROLLER, CLOSED_LOOP_WAITING())
+      );
+    }
+    
     // Block until all buffered steps are executed / cleaned
     static void synchronize();