As well as defining the connections the machine interface also provides constraints defining the operations that clients are allowed to perform and the parameters that may be set. This is required since generally regulator devices will offer more flexibility than it is safe to use on a given system, for example supporting higher supply voltages than the consumers are rated for.

This is done at driver registration time by providing a struct regulation_constraints.

The constraints may also specify an initial configuration for the regulator in the constraints, which is particularly useful for use with static consumers.