👷 Add optimal stepper.set_e_position() (#27293)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Author: classicrocker883

Marlin/src/module/planner.cpp

@@ -3192,7 +3192,7 @@ void Planner::set_position_mm(const xyze_pos_t &xyze) {
     if (has_blocks_queued())
       buffer_sync_block(BLOCK_BIT_SYNC_POSITION);
     else
-      stepper.set_axis_position(E_AXIS, position.e);
+      stepper.set_e_position(position.e);
   }
 
 #endif // HAS_EXTRUDERS

Marlin/src/module/stepper.cpp

@@ -3407,6 +3407,18 @@ void Stepper::set_axis_position(const AxisEnum a, const int32_t &v) {
   #endif
 }
 
+#if HAS_EXTRUDERS
+
+  void Stepper::set_e_position(const int32_t &v) {
+    planner.synchronize();
+
+    AVR_ATOMIC_SECTION_START();
+    count_position.e = v;
+    AVR_ATOMIC_SECTION_END();
+  }
+
+#endif // HAS_EXTRUDERS
+
 #if ENABLED(FT_MOTION)
 
   void Stepper::ftMotion_syncPosition() {

Marlin/src/module/stepper.h

@@ -540,6 +540,11 @@ class Stepper {
     static void set_position(const xyze_long_t &spos);
     static void set_axis_position(const AxisEnum a, const int32_t &v);
 
+    #if HAS_EXTRUDERS
+      // Save a little when E is the only one used
+      static void set_e_position(const int32_t &v);
+    #endif
+
     // Report the positions of the steppers, in steps
     static void report_a_position(const xyz_long_t &pos);
     static void report_positions();