Control LED brightness with through digital pin 9 of Arduino with potentiometer

ledPot.ino

const int ledPin =9; //D9 = PWM pin

void setup(){
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT) ;
}

void loop(){
  int val  = analogRead(A0);
  Serial.print("val = "); Serial.print(val);
  int brightness = map(val, 0, 1023, 0, 255);  
  Serial.print(", brightness = "); Serial.println(brightness);
  analogWrite(ledPin, brightness);
}