On 02/12/2021 15:42, Ulf Hansson wrote:

On Wed, 1 Dec 2021 at 17:41, Daniel Lezcano [off-list ref] wrote:

quoted

The proposed bindings are describing a set of powerzones.

A power zone is the logical name for a component which is capable of
power capping and where we can measure the power consumption.

A power zone can aggregate several power zones in terms of power
measurement and power limitations. That allows to apply power
constraint to a group of components and let the system balance the
allocated power in order to comply with the constraint.

The ARM System Control and Management Interface (SCMI) can provide a
power zone description.

The powerzone semantic is also found on the Intel platform with the
RAPL register.

The Linux kernel powercap framework deals with the powerzones:

https://www.kernel.org/doc/html/latest/power/powercap/powercap.html

The powerzone can also represent a group of children powerzones, hence
the description can result on a hierarchy. Such hierarchy already
exists with the hardware or can be represented and computed from the
kernel.

The hierarchical description was initially proposed but not desired
given there are other descriptions like the power domain proposing
almost the same description.

https://lore.kernel.org/all/CAL_JsqLuLcHj7525tTUmh7pLqe7T2j6UcznyhV7joS8ipyb_VQ@mail.gmail.com/ (local)

The description gives the power constraint dependencies to apply on a
specific group of logically or physically aggregated devices. They do
not represent the physical location or the power domains of the SoC
even if the description could be similar.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ulf Hansson <redacted>
Cc: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Daniel Lezcano <redacted>

This looks good to me, feel free to add:

Reviewed-by: Ulf Hansson <redacted>

Thanks Ulf for your time to review these bindings



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