<?php 
namespace App\Contracts; 

interface TestContract { 
 public function callMe($controller); 
}

<?php 
namespace App\Services; 
use App\Contracts\TestContract; 

class TestService implements TestContract { 
 public function callMe($controller){ 
 dd("Call me from TestServiceProvider in ".$controller); 
 } 
}

... 
App\Providers\RiakServiceProvider::class,

php artisan make:provider RiakServiceProvider 

<?php 

namespace App\Providers; 

use App\Services\TestService; 
use Illuminate\Support\ServiceProvider; 

class RiakServiceProvider extends ServiceProvider 
{ 
 /** 
 * Bootstrap the application services. 
 * 
 * @return void 
 */ 
 public function boot() 
 { 
 // 
 } 

 /** 
 * Register the application services. 
 * 
 * @return void 
 */ 
 public function register() 
 { 
 $this->app->bind("App\Contracts\TestContract",function(){ 
  return new TestService(); 
 }); 
 } 
}

<?php 

namespace App\Http\Controllers; 

use App; 
use Illuminate\Http\Request; 
use App\Contracts\TestContract; 

class IndexController extends Controller 
{ 
 public function __construct(TestContract $test){ 
 $this->test = $test; 
 } 
 public function index(){ 
 $this->test->callMe("IndexController"); 
 } 
}

public function index(){ 
 $test = App::make('test'); 
 $test->callMe('IndexController'); 
 }