Fix mini12864 v2.1 + PSU control + NeoPixel backlight (#21021)

Marlin/src/feature/leds/leds.cpp

@@ -147,11 +147,13 @@ void LEDLights::set_color(const LEDColor &incol
   millis_t LEDLights::led_off_time; // = 0
 
   void LEDLights::update_timeout(const bool power_on) {
-    const millis_t ms = millis();
-    if (power_on)
-      reset_timeout(ms);
-    else if (ELAPSED(ms, led_off_time))
-      set_off();
+    if (lights_on) {
+      const millis_t ms = millis();
+      if (power_on)
+        reset_timeout(ms);
+      else if (ELAPSED(ms, led_off_time))
+        set_off();
+    }
   }
 
 #endif

Marlin/src/feature/leds/leds.h

@@ -203,7 +203,7 @@ public:
     public:
       static inline void reset_timeout(const millis_t &ms) {
         led_off_time = ms + LED_BACKLIGHT_TIMEOUT;
-        if (!lights_on) set_default();
+        if (!lights_on) update();
       }
       static void update_timeout(const bool power_on);
   #endif

Marlin/src/lcd/marlinui.cpp

@@ -994,7 +994,7 @@ void MarlinUI::update() {
         refresh(LCDVIEW_REDRAW_NOW);
 
         #ifdef LED_BACKLIGHT_TIMEOUT
-          leds.reset_timeout(ms);
+          if (!powersupply_on) leds.reset_timeout(ms);
         #endif
       }
 

Marlin/src/lcd/menu/menu_led.cpp

@@ -121,11 +121,20 @@ void menu_led() {
   BACK_ITEM(MSG_MAIN);
 
   #if ENABLED(LED_CONTROL_MENU)
-    editable.state = leds.lights_on;
-    EDIT_ITEM(bool, MSG_LEDS, &editable.state, leds.toggle);
+    #if ENABLED(PSU_CONTROL)
+      extern bool powersupply_on;
+    #else
+      constexpr bool powersupply_on = true;
+    #endif
+    if (powersupply_on) {
+      editable.state = leds.lights_on;
+      EDIT_ITEM(bool, MSG_LEDS, &editable.state, leds.toggle);
+    }
+
     #if ENABLED(LED_COLOR_PRESETS)
       ACTION_ITEM(MSG_SET_LEDS_DEFAULT, leds.set_default);
     #endif
+
     #if ENABLED(NEOPIXEL2_SEPARATE)
       editable.state = leds2.lights_on;
       EDIT_ITEM(bool, MSG_LEDS2, &editable.state, leds2.toggle);