There shall be a city planning commission of at least 7 members appointed by the mayor upon confirmation of council. The planning commission shall have all the power and authority conferred upon city planning commissions by general law and such other duties as may be imposed upon it by the administrative code. Council may by ordinance increase the number of members of the planning commission and provide for the method of their appointment.
   The planning commission shall provide for planning, zoning and regulations covering platting of all lands which are subject to control by the city, and shall cause an official map of such territory to be made. The commission shall carry out the municipal planning function including the preparation and updating of the master plan, and make such investigations, reports, and recommendations relating to planning and the physical development of the city as it finds necessary and desirable.