Edit in JSFiddle

angular.module('myApp', [])
.provider('data', function() {
 
    this.msg = 'Reader';
 
    this.$get = function() {
        var msg = this.msg;
        return {
            sayGoodies: function() {
                return  "Hello, ! "+ msg
            }
        }
    };
 
    this.setMsg = function(name) {
        this.msg = name;
    };
})
.config(function(dataProvider){
    dataProvider.setMsg('Millions Of Smiles for you');
})
.controller("MainCtrl",function($scope, data) {
    $scope.vdata = data.sayGoodies();
})

<div data-ng-app="myApp">
    <div data-ng-controller="MainCtrl">
        {{vdata}}
    </div>
</div>