Scala: Companion object with arguments

I am looking for a way to initialize a singleton object with arguments for configuration. I tried this, it has the risk for re-instantiation.

class A(in:Int) {
  def method = {}
}

object A {

  var singleton: Option[A] = None

  def getInstance(): A = {
    if(singleton.isDefined)
      singleton.get
    else {
        throw InitializationException("Object not configured")
      }
  }

  def getInstance(in:Int): A = {
    singleton = Some(new A(in))
    singleton.get
  }
}

Is there a better way?