Add BOARD_PREINIT (for Longer3D open drain pins) (#21159)

Marlin/src/MarlinCore.cpp

@@ -870,6 +870,9 @@ inline void tmc_standby_setup() {
  *    • Max7219
  */
 void setup() {
+  #ifdef BOARD_PREINIT
+    BOARD_PREINIT(); // Low-level init (before serial init)
+  #endif
 
   tmc_standby_setup();  // TMC Low Power Standby pins must be set early or they're not usable
 

Marlin/src/module/temperature.cpp

@@ -1793,7 +1793,7 @@ void Temperature::updateTemperaturesFromRawValues() {
 #endif
 
 // Init fans according to whether they're native PWM or Software PWM
-#ifdef ALFAWISE_UX0
+#ifdef BOARD_OPENDRAIN_MOSFETS
   #define _INIT_SOFT_FAN(P) OUT_WRITE_OD(P, FAN_INVERTING ? LOW : HIGH)
 #else
   #define _INIT_SOFT_FAN(P) OUT_WRITE(P, FAN_INVERTING ? LOW : HIGH)
@@ -1886,7 +1886,7 @@ void Temperature::init() {
   #endif
 
   #if HAS_HEATER_0
-    #ifdef ALFAWISE_UX0
+    #ifdef BOARD_OPENDRAIN_MOSFETS
       OUT_WRITE_OD(HEATER_0_PIN, HEATER_0_INVERTING);
     #else
       OUT_WRITE(HEATER_0_PIN, HEATER_0_INVERTING);
@@ -1916,7 +1916,7 @@ void Temperature::init() {
   #endif
 
   #if HAS_HEATED_BED
-    #ifdef ALFAWISE_UX0
+    #ifdef BOARD_OPENDRAIN_MOSFETS
       OUT_WRITE_OD(HEATER_BED_PIN, HEATER_BED_INVERTING);
     #else
       OUT_WRITE(HEATER_BED_PIN, HEATER_BED_INVERTING);

Marlin/src/pins/stm32f1/pins_LONGER3D_LK.h

@@ -29,7 +29,6 @@
 #endif
 
 #define BOARD_INFO_NAME "Longer3D"
-#define ALFAWISE_UX0                              // Common to all Longer3D STM32F1 boards (used for Open drain mosfets)
 
 #define BOARD_NO_NATIVE_USB
 
@@ -96,6 +95,16 @@
 
 #define LED_PIN                             PC2   // pin 17
 
+// Longer3D board mosfets are passing by default
+// Avoid nozzle heat and fan start before serial init
+#define BOARD_OPENDRAIN_MOSFETS
+
+#define BOARD_PREINIT() { \
+  OUT_WRITE_OD(HEATER_0_PIN, 0); \
+  OUT_WRITE_OD(HEATER_BED_PIN, 0); \
+  OUT_WRITE_OD(FAN_PIN, 0); \
+}
+
 //
 // PWM for a servo probe
 // Other servo devices are not supported on this board!