All disc brakes are inherently self-adjusting. No periodic adjustment is either necessary or possible.
The rear drum brakes used on Celicas are equipped with automatic adjusters actuated by the parking brake mechanism. No periodic adjustment of the drum brakes is necessary if this mechanism is working properly. If the brake shoe-to-drum clearance is incorrect, and applying and releasing the parking brake a few times does not adjust it properly, the parts will have to be disassembled for repair.