Tweaks to Servo classes

Marlin/src/HAL/HAL_LPC1768/LPC1768_Servo.cpp

     this->servoIndex = INVALID_SERVO;  // too many servos
   }
 
-  int8_t Servo::attach(int pin) {
+  int8_t Servo::attach(const int pin) {
     return this->attach(pin, MIN_PULSE_WIDTH, MAX_PULSE_WIDTH);
   }
 
-  int8_t Servo::attach(int pin, int min, int max) {
+  int8_t Servo::attach(const int pin, const int min, const int max) {
 
     if (this->servoIndex >= MAX_SERVOS) return -1;
 
     servo_info[this->servoIndex].Pin.isActive = false;
   }
 
-  void Servo::write(int value) {
+  void Servo::write(const int value) {
     if (value < MIN_PULSE_WIDTH) { // treat values less than 544 as angles in degrees (valid values in microseconds are handled as microseconds)
       value = map(constrain(value, 0, 180), 0, 180, SERVO_MIN(), SERVO_MAX());
         // odd - this sets zero degrees to 544 and 180 degrees to 2400 microseconds but the literature says
     this->writeMicroseconds(value);
   }
 
-  void Servo::writeMicroseconds(int value) {
+  void Servo::writeMicroseconds(const int value) {
     // calculate and store the values for the given channel
     byte channel = this->servoIndex;
     if (channel < MAX_SERVOS) {  // ensure channel is valid
 
   bool Servo::attached() { return servo_info[this->servoIndex].Pin.isActive; }
 
-  void Servo::move(int value) {
+  void Servo::move(const int value) {
     if (this->attach(0) >= 0) {    // notice the pin number is zero here
       this->write(value);
       delay(SERVO_DELAY);

Marlin/src/HAL/HAL_LPC1768/LPC1768_Servo.h

   class Servo {
     public:
       Servo();
-      int8_t attach(int pin);            // attach the given pin to the next free channel, set pinMode, return channel number (-1 on fail)
-      int8_t attach(int pin, int min, int max); // as above but also sets min and max values for writes.
+      int8_t attach(const int pin);            // attach the given pin to the next free channel, set pinMode, return channel number (-1 on fail)
+      int8_t attach(const int pin, const int min, const int max); // as above but also sets min and max values for writes.
       void detach();
-      void write(int value);             // if value is < 200 it is treated as an angle, otherwise as pulse width in microseconds
-      void writeMicroseconds(int value); // write pulse width in microseconds
-      void move(int value);              // attach the servo, then move to value
+      void write(const int value);             // if value is < 200 it is treated as an angle, otherwise as pulse width in microseconds
+      void writeMicroseconds(const int value); // write pulse width in microseconds
+      void move(const int value);              // attach the servo, then move to value
                                          // if value is < 200 it is treated as an angle, otherwise as pulse width in microseconds
                                          // if DEACTIVATE_SERVOS_AFTER_MOVE wait SERVO_DELAY, then detach
       int read();                        // returns current pulse width as an angle between 0 and 180 degrees

Marlin/src/HAL/HAL_TEENSY35_36/HAL_Servo_Teensy.cpp

 #if defined(__MK64FX512__) || defined(__MK66FX1M0__)
 
-
 #include "HAL_Servo_Teensy.h"
 #include "../../inc/MarlinConfig.h"
 
-
-int8_t libServo::attach(int pin) {
-	if (this->servoIndex >= MAX_SERVOS) return -1;
-	return Servo::attach(pin);
+int8_t libServo::attach(const int pin) {
+  if (this->servoIndex >= MAX_SERVOS) return -1;
+  return Servo::attach(pin);
 }
 
-int8_t libServo::attach(int pin, int min, int max) {
-	return Servo::attach(pin, min, max);
+int8_t libServo::attach(const int pin, const int min, const int max) {
+  return Servo::attach(pin, min, max);
 }
 
-void libServo::move(int value) {
+void libServo::move(const int value) {
   if (this->attach(0) >= 0) {
     this->write(value);
     delay(SERVO_DELAY);
   }
 }
 
-
-#endif
+#endif // __MK64FX512__ || __MK66FX1M0__

Marlin/src/HAL/HAL_TEENSY35_36/HAL_Servo_Teensy.h

 // Inherit and expand on the official library
 class libServo : public Servo {
 	public:
-		int8_t attach(int pin);
-		int8_t attach(int pin, int min, int max);
-		void move(int value);
+		int8_t attach(const int pin);
+		int8_t attach(const int pin, const int min, const int max);
+		void move(const int value);
 	private:
 	   uint16_t min_ticks;
 	   uint16_t max_ticks;
 	   uint8_t servoIndex;               // index into the channel data for this servo
 };
 
-#endif
+#endif // HAL_Servo_Teensy_h