Common method for scaled fan speed

Marlin/src/lcd/HD44780/ultralcd_HD44780.cpp

@@ -886,7 +886,7 @@ void MarlinUI::draw_status_screen() {
               uint16_t spd = thermalManager.fan_speed[0];
               if (blink) c = 'F';
               #if ENABLED(ADAPTIVE_FAN_SLOWING)
-                else { c = '*'; spd = (spd * thermalManager.fan_speed_scaler[0]) >> 7; }
+                else { c = '*'; spd = thermalManager.scaledFanSpeed(0, spd); }
               #endif
               per = thermalManager.fanPercent(spd);
             }

Marlin/src/lcd/dogm/status_screen_DOGM.cpp

@@ -423,7 +423,7 @@ void MarlinUI::draw_status_screen() {
         if (spd) {
           #if ENABLED(ADAPTIVE_FAN_SLOWING)
             if (!blink && thermalManager.fan_speed_scaler[0] < 128) {
-              spd = (spd * thermalManager.fan_speed_scaler[0]) >> 7;
+              spd = thermalManager.scaledFanSpeed(0, spd);
               c = '*';
             }
           #endif

Marlin/src/lcd/dogm/status_screen_lite_ST7920.cpp

@@ -684,7 +684,7 @@ bool ST7920_Lite_Status_Screen::indicators_changed() {
   // them only during blinks we gain a bit of stability.
   const bool       blink             = ui.get_blink();
   const uint16_t   feedrate_perc     = feedrate_percentage;
-  const uint16_t   fs                = (thermalManager.fan_speed[0] * uint16_t(thermalManager.fan_speed_scaler[0])) >> 7;
+  const uint16_t   fs                = thermalManager.scaledFanSpeed(0);
   const int16_t    extruder_1_target = thermalManager.degTargetHotend(0);
   #if HOTENDS > 1
     const int16_t  extruder_2_target = thermalManager.degTargetHotend(1);
@@ -734,7 +734,7 @@ void ST7920_Lite_Status_Screen::update_indicators(const bool forceUpdate) {
 
     #if ENABLED(ADAPTIVE_FAN_SLOWING)
       if (!blink && thermalManager.fan_speed_scaler[0] < 128)
-        spd = (spd * thermalManager.fan_speed_scaler[0]) >> 7;
+        spd = thermalManager.scaledFanSpeed(0, spd);
     #endif
 
     draw_fan_speed(thermalManager.fanPercent(spd));

Marlin/src/lcd/extensible_ui/ui_api.cpp

@@ -246,7 +246,7 @@ namespace ExtUI {
   }
 
   float getActualFan_percent(const fan_t fan) {
-    return thermalManager.fanPercent((thermalManager.fan_speed[fan - FAN0] * uint16_t(thermalManager.fan_speed_scaler[fan - FAN0])) >> 7);
+    return thermalManager.fanPercent(thermalManager.scaledFanSpeed(fan - FAN0));
   }
 
   float getAxisPosition_mm(const axis_t axis) {

Marlin/src/module/planner.cpp

@@ -1184,7 +1184,7 @@ void Planner::check_axes_activity() {
   if (has_blocks_queued()) {
     #if FAN_COUNT > 0
       FANS_LOOP(i)
-        tail_fan_speed[i] = (block_buffer[block_buffer_tail].fan_speed[i] * uint16_t(thermalManager.fan_speed_scaler[i])) >> 7;
+        tail_fan_speed[i] = thermalManager.scaledFanSpeed(i, block_buffer[block_buffer_tail].fan_speed[i]);
     #endif
 
     block_t* block;
@@ -1207,7 +1207,7 @@ void Planner::check_axes_activity() {
   else {
     #if FAN_COUNT > 0
       FANS_LOOP(i)
-        tail_fan_speed[i] = (thermalManager.fan_speed[i] * uint16_t(thermalManager.fan_speed_scaler[i])) >> 7;
+        tail_fan_speed[i] = thermalManager.scaledFanSpeed(i);
     #endif
 
     #if ENABLED(BARICUDA)

Marlin/src/module/temperature.cpp

@@ -171,6 +171,9 @@ hotend_info_t Temperature::temp_hotend[HOTENDS
 
   #endif
 
+  /**
+   * Set the print fan speed for a target extruder
+   */
   void Temperature::set_fan_speed(uint8_t target, uint16_t speed) {
 
     NOMORE(speed, 255U);

Marlin/src/module/temperature.h

@@ -472,8 +472,12 @@ class Temperature {
         static constexpr uint8_t fan_speed_scaler[FAN_COUNT] = ARRAY_N(FAN_COUNT, 128, 128, 128, 128, 128, 128);
       #endif
 
-      static inline uint8_t lcd_fanSpeedActual(const uint8_t target) {
+      static inline uint8_t scaledFanSpeed(const uint8_t target) {
-        return (fan_speed[target] * uint16_t(fan_speed_scaler[target])) >> 7;
+        return (fs * uint16_t(fan_speed_scaler[target])) >> 7;
+      }
+
+      static inline uint8_t scaledFanSpeed(const uint8_t target, const uint8_t fs) {
+        return scaledFanSpeed(target, fan_speed[target]);
       }
 
       #if ENABLED(EXTRA_FAN_SPEED)