VR control from the BMC

[Ed Tanous <edtanous@google.com>]

In the near future, I'm going to have some needs for OpenBMC to be
able to control VRs.  These VRs might be on the baseboard itself, or
on detected PCIe add-in-cards, and controlled over PMBus.
Additionally, I will need a "hardware safe" way for the host to be
able to modify the behavior of these VRs (usually different voltage
settings), and to have that interface be constrained in such a way
that the host can never set a value that's outside of a predefined
range that's known to be safe for the hardware, which the BMC will own
the definition of for security purposes.

Does anyone else have similar needs?  I've been pointed to
phosphor-regulators which has some similar parallels;  As-is, that
solution won't work for me, because it's relying on fixed, platform
specific json scripting to accomplish its goals.  My hope would be for
a more generalized linux devicetree based solution, as well as a
representation on dbus that could be modified at runtime by
Redfish/IPMI in band.

Is there any other work I should look into that's similar?  Does
anyone have any strong opinions on how this should be organized or how
it could be built?

Thanks,

-Ed