How to access parent directive controller? - angularjs

Question

I have two directives, say dir1, dir2.
dir1 is some common directive.
I transclude dir2 into dir1.
Here is the script:
<script>
var app = angular.module('myapp', []);
app.directive('dir1', function() {
return {
scope: {},
controller: D1Controller,
controllerAs: 'd1c',
transclude: true,
templateUrl: 'd1template'
}
function D1Controller() {
var vm = this;
vm.someValue = "some data";
}
});
app.directive('dir2', dir2);
function dir2() {
return {
tempalteUrl: 'dir2t',
scope: true,
bindToController: {},
controller: D2Controller,
controllerAs: 'mc',
link: link,
require: '^dir1'
}
}
D2Controller.$inject = ['$scope']; // <-- injecting something?
function D2Controller($scope) {
var vm = this;
var getDataListener = $scope.$watch('someValue', function fnGetData(someValue) {
if (!!someValue) {
vm.data = someValue;
getDataListener();
}
});
// $scope.$parent.$parent.someValue <-- this will work but seems not elegant way to do it.
}
function link(scope, iElement, iAddr, controller) {
scope.someValue = controller.someValue; // get data form parentDirective controller
}
</script>
<script type="text/ng-template" id="d1template">
<div>
...
<div ng-transclude></div>
...
</div>
</script>
I can only access D1Controller form dir2's link function(controller) and pass it to the D2Controller via scope.
Is there any way I can (like inject something to D2Controller) access D1Controller from D2Controller?
Or is there any other way to communicate between directive scope and transclude scope?
Thanks for Robert's suggestion.
Here is my solution.
I find an elegant way is to pass the D2Controller to D1Controller and let D1Controller to set the data.
I add set data function in D1Controller
vm.setData = function(controller) {
controller.data = vm.SOMEDATA;
}
In dir2's link function I call d1controller.setData.
function link(scope, iElement, iAttr, controller) {
controller.setData(scope.mc);
}