[RFC PATCH 2/2] thermal: Add generic cpu cooling implementation

[Rob Lee]

>> I don't like how ACTIVE does not have available notification callbacks
>> like HOT and CRITICAL do.  Perhaps I fail to grasp why they aren't there
>> but besides just applying a cooling device, one might want to do something
>> else as well upon hitting these trip points.  So that said, it might be nice
>> to add a notification to STATE_ACTIVE as well.
> Well I added ACTIVE_STATE trip type as just some additional features
> over trip type ACTIVE. Also each thermal zone can have more then one
> trip types so HOT notifications can still be used. But I like your
> suggestion of putting notfications in all the trip types. Lets see if
> the maintainers agree to this idea.
Thinking about it a bit more, I didn't consider HOT because it only
notifies when you cross above this trip point and not below and the
use case I had in mind would ideally want to be notified in both
cases.  Also, if ACTIVE/ACTIVE_STATE trip types will always have
cooling devices bound to them, then the notification could be put in
the cooling device code if desired.  I think these features are
separate from your main effort and can be addressed in separate future
patch.