Passing ng-model in nested directives

You can set up a bi-directional binding (see the documentation, section "Directive Definition Object") with the variable in ngModel attribute, as with any other directives:

<my-directive ng-model="foo"></my-directive>

myApp.directive('myDirective', function () {
    return {
        template: '<div><input type="text" ng-model="ngModel" /></div>',
        replace: true,
        scope: {
            ngModel : '=',
        },
    };
});

Fiddle