C172 pilot reported while on final approach they inadvertently turned on the autopilot resulting in yoke binding and aircraft wanting to roll left. Pilot turned off autopilot and flight controls functioned normally.

Narrative

On final approach for Runway XX at ZZZ; I put in a second notch (20 degrees) of flaps to slow my speed down for spacing from another aircraft a few miles ahead of me on short final. In doing so; I inadvertantly flicked the Autopilot switch; which is right next to the flap lever into the On position. The Autopilot in this aircraft will hold heading but not altitude. After putting in the flaps; I observed a binding feeling in the yoke and the aircraft wanting to roll left. Initially I thought I had a split flap situation; but I observed both flaps in the same position. I then thought I had an issue with the pulley and cable system for the flight controls and [requested priority handling] with ZZZ Tower. The approach was stabilized and the landing uneventful. After turning off Runway XX on [Taxiway] 1; I still observed a binding feeling in the yoke. I reached to put up the flap lever and noticed the Autopilot switch in the Up/On position. Upon turning the Autopilot switch off; the flight controls returned to normal operation. I believe my lack of familiarization with this particular style of Autopilot in this aircraft was the cause of the situation. Additionally; this was the first time I had flown this particular aircraft with this style of Autopilot. As the switch for the Autopilot is small and non-gated; I believe the addition of an audible tone when the Autopilot is turned on or off could prevent this from happening again. And/or the change to a gated style of switch that needs to be pulled out before moving on or off would mitigate inadvertant activation or deactivation of the Autopilot system.