PSU Sensors - Associations

[Shawn McCarney]

Hi,

I didn't follow all of your terminology, so I might be off base here, 
but in case it helps ...

There are two associations to power supply sensors from a Redfish/bmcweb 
perspective:

* chassis <-> all sensors in chassis (including PSU sensors).  This is 
needed because Redfish output is for a specific chassis.  We only want 
sensors (including PSU sensors) from the specified chassis.

* PSU inventory item <-> all sensors for the PSU.  This is used in 
several ways.  First, it allows us to store multiple PSU sensor values 
in a single associated Redfish PowerSupply object (PowerInputWatts, 
PowerOutputWatts).  Second, it allows us to look at the status of the 
PSU inventory item (e.g. is it functional? present?) when setting the 
status of the Redfish PSU sensor. Lastly, it allows us to access the VPD 
(PartNumber, SerialNumber) of the PSU inventory item associated with a 
PSU sensor.

This is documented here: 
https://github.com/openbmc/docs/blob/master/architecture/sensor-architecture.md#redfish

If not relevant, sorry please ignore ...

Shawn