Re: [PATCH v2 0/2] PM / devfreq: add Airoha SoC Subsystem scale support

[Choi Chanwoo <cwchoi00@gmail.com>]

On 10/9/2026 4:33 PM, Christian Marangi wrote:
> Airoha SoC contains multiple subsystem that are scaled to a
> specific OPP taking the CPU clock as reference. Such sybsystem
> can enter idle or performance state based on the system load
> and power consumption conditions.
> 
> Example of such subsystem are GSW (Gigabit Switch), NPU (Custom
> Risc Co-Processor for Network acceleration), SOE (Crypto Module) BUS...
> 
> Changes v2:
> - Rename to a more symbolic name
> - Address some sashiko bot warning
> - Better describe the use of this devfreq driver
> 
> Christian Marangi (2):
>   dt-bindings: devfreq: Document support for Airoha Subsystem Scale
>   PM / devfreq: add Airoha SoC Subsystem devfreq driver
> 
>  .../devfreq/airoha,subsystem-scale.yaml       | 114 ++++++++++++++++++
>  drivers/devfreq/Kconfig                       |  10 ++
>  drivers/devfreq/Makefile                      |   1 +
>  drivers/devfreq/airoha-subsystem-devfreq.c    | 100 +++++++++++++++
>  4 files changed, 225 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/devfreq/airoha,subsystem-scale.yaml
>  create mode 100644 drivers/devfreq/airoha-subsystem-devfreq.c
> 

Hi,

The devicetree contains ths only clock information for scaling without any parent device
information even if this drier has used the passive governor as default.
I think that you better to use 'userspace' governor.

Also, are there any connected device to provide the utilization?

-- 
Best Regards,
Chanwoo Choi
Principal Engineer, Samsung Electronics