It is not only not permitted to use the mobile phone while driving, but it is also a danger to life. You endanger yourself and others. The legal - and much more comfortable - solution is to use a hands-free-kit, which is simply fastened with a clip to the rear view mirror.
Use the phone at rest while driving
Always in the view and at hand. The hands-free kit, which takes no space at all and is placed where it doesn’t disturb at all.