Documentation on voltage control in NVML

It seems from this page there is no ability for voltage control under nvml. This means users cannot set a maximum voltage for their graphics card. Is there a possibility this is just undocumented, or is there truly no possibility for voltage control, like a VF-Curve, or a voltage limit in NVML?

If not in NVML, is there any other way to control voltage under a linux system without using display server dependent method like nvidia-settings? Could a new API be added to allow control of the maximum voltage of the card?