Laravel Upload Csv File

i just have to validate csv file and store it in public folder and name in db on first step i am using

<input type="file" name="file" class="form-control" accept=".csv" required>

and in controller

$validation=Validator::make($request->all(),[
            'file'=>'required|mimes:csv,txt'
        ]);
        if($validation->fails())
        {
            return back()->with('error',"File Type needs to be of Type");
        }
        else
        {
            return back()->with('success',"File Ok");
        }

its always returning error block