Configurable number of M106 fans (#18883)

Marlin/Configuration.h

 
 // @section extras
 
+// Set number of user-controlled fans. Disable to use all board-defined fans.
+// :[1,2,3,4,5,6,7,8]
+//#define NUM_M106_FANS 1
+
 // Increase the FAN PWM frequency. Removes the PWM noise but increases heating in the FET/Arduino
 //#define FAST_PWM_FAN
 

Marlin/src/inc/Conditionals_post.h

   #undef AUTO_POWER_CHAMBER_FAN
 #endif
 
-// Other fans
+// Print Cooling fans (limit)
+#ifdef NUM_M106_FANS
+  #define MAX_FANS NUM_M106_FANS
+#else
+  #define MAX_FANS 8  // Max supported fans
+#endif
+
+#define _NOT_E_AUTO(N,F) (E##N##_AUTO_FAN_PIN != FAN##F##_PIN)
+#define _HAS_FAN(F) (PIN_EXISTS(FAN##F) \
+                     && CONTROLLER_FAN_PIN != FAN##F##_PIN \
+                     && _NOT_E_AUTO(0,F) \
+                     && _NOT_E_AUTO(1,F) \
+                     && _NOT_E_AUTO(2,F) \
+                     && _NOT_E_AUTO(3,F) \
+                     && _NOT_E_AUTO(4,F) \
+                     && _NOT_E_AUTO(5,F) \
+                     && _NOT_E_AUTO(6,F) \
+                     && _NOT_E_AUTO(7,F) \
+                     && F < MAX_FANS)
 #if PIN_EXISTS(FAN)
   #define HAS_FAN0 1
 #endif
-#define _NOT_E_AUTO(N,F) (E##N##_AUTO_FAN_PIN != FAN##F##_PIN)
-#define _HAS_FAN(F) (PIN_EXISTS(FAN##F) && CONTROLLER_FAN_PIN != FAN##F##_PIN && _NOT_E_AUTO(0,F) && _NOT_E_AUTO(1,F) && _NOT_E_AUTO(2,F) && _NOT_E_AUTO(3,F) && _NOT_E_AUTO(4,F) && _NOT_E_AUTO(5,F) && _NOT_E_AUTO(6,F) && _NOT_E_AUTO(7,F))
 #if _HAS_FAN(1)
   #define HAS_FAN1 1
 #endif

Marlin/src/inc/SanityCheck.h

 #endif
 
 /**
+ * Limited user-controlled fans
+ */
+#if NUM_M106_FANS > FAN_COUNT
+  #error "The selected board doesn't support enough user-controlled fans. Reduce NUM_M106_FANS."
+#endif
+
+/**
  * Limited number of servos
  */
 #if NUM_SERVOS > NUM_SERVO_PLUGS

Marlin/src/module/temperature.cpp

   #endif
 
   #if ENABLED(ADAPTIVE_FAN_SLOWING)
-    uint8_t Temperature::fan_speed_scaler[FAN_COUNT] = ARRAY_N(FAN_COUNT, 128, 128, 128, 128, 128, 128);
+    uint8_t Temperature::fan_speed_scaler[FAN_COUNT] = ARRAY_N(FAN_COUNT, 128, 128, 128, 128, 128, 128, 128, 128);
   #endif
 
   /**

Marlin/src/pins/sam/pins_CNCONTROLS_15D.h

 //
 // Fans
 //
-//#define FAN0_PIN                             8
+//#define FAN_PIN                              8
 
 //
 // Auto fans