validate two dependants fields with play framework

MultiValidation.scala

val locationReadsCreate = new Reads[(String, Option[String])] {
    def reads(json: JsValue) = {
      val subsidiary = (json \ "subsidiary").asOpt[String]
      val location = (json \ "location").asOpt[String]
      (subsidiary, location) match {
        case (None, _) => JsError(Seq(JsPath() \ "subsidiary" -> Seq(ValidationError("error.path.missing"))))
        case (Some("Autre"), None) => JsError(Seq(JsPath() \ "location" -> Seq(locationError)))
        case (Some("Autre"), loc @ Some(_)) => JsSuccess(("Autre", loc))
        case (Some(sub), loc @ Some(_)) => JsError(Seq(JsPath() \ "location" -> Seq(locationError)))
      }
    }
  }