Re: [PATCH v2 1/3] dt-bindings: power: limits: Describe Qualcomm SPEL hardware
From: Daniel Lezcano
Date: Wed Jun 24 2026 - 16:42:19 EST
Hi Krzysztof,
Le 24/06/2026 à 12:45, Krzysztof Kozlowski a écrit :
On 23/06/2026 11:47, Manaf Meethalavalappu Pallikunhi wrote:Right, it is relatively new in the device tree bindings. There is the Intel RAPL which is the same device but it does not belong to the DT namespace.
Hi Krzysztof,
On 6/22/2026 5:58 PM, Krzysztof Kozlowski wrote:
On Sat, Jun 20, 2026 at 02:09:08AM +0530, Manaf Meethalavalappu Pallikunhi wrote:
The Qualcomm SoC Power and Electrical Limits (SPEL) provides hardware
based power monitoring and limiting capabilities for various domains.
Add a DeviceTree binding to describe the SPEL block on Qualcomm's SoC.
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manaf.pallikunhi@xxxxxxxxxxxxxxxx>
---
.../bindings/power/limits/qcom,spel.yaml | 47 ++++++++++++++++++++++
MAINTAINERS | 6 +++
2 files changed, 53 insertions(+)
diff --git a/Documentation/devicetree/bindings/power/limits/qcom,spel.yaml b/Documentation/devicetree/bindings/power/limits/qcom,spel.yaml
What is "limits" directory for? What sort of class of devices fit there?
Added for devices that integrate with the powercap framework (exposed
via sys/class/powercap). These devices are responsible for enforcing and
That's a driver answer. I asked about class of devices. powercap
framework is Linux thing, not a class of devices.
Please describe hardware, not Linux frameworks.>>> monitoring power consumption limits across different domains, such as
the system, SoC, or specific subsystems. Any other better directory ?
I don't know what is this hardware doing and commit msg is quite short
on explanation. Power monitoring is usually hwmon, but probably this is
not a hwmon.
RAPL : Running Average Power Limit
SPEL : SoC Power and Electrical Limits
It allows power capping and read the average power consumption for a specific device (or/and an energy counter)
Basically you can set a power constraint (power limit) to a device and this one won't consume more than that power (the power limitation strategy is managed under the hood by the firmware depending on the device - lower OPP, idle injection, modem weaker signal, etc ...).
The RAPL or the SPEL have a hierarchical power limitation. For example:
SoC
|
------------------------
| |
Cluster0 Cluster1
| |
----------------- -----------------
| | | | | | | |
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
If you specify a power limit to 'SoC', then the power consumption of Cluster0 + Cluster1 <= SoC
If Cluster0 power consumption decreases, then Cluster1 is allowed to use more power until Cluster0 + Cluster1 <= SoC
For me it sounds reasonable to put the device description under power/limits