[PATCH v2 2/2] riscv: dts: spacemit: Add cpu scaling for K1 SoC

[Anand Moon]

Hi Shuwei,

On Tue, 21 Apr 2026 at 22:41, Aurelien Jarno <aurelien at aurel32.net> wrote:
>
> Hi,
>
> On 2026-04-21 16:10, Shuwei Wu wrote:
> > Hi Aurelien,
> >
> > Thanks for your addition.
> >
> > On Tue Apr 21, 2026 at 5:16 AM CST, Aurelien Jarno wrote:
> > > Hi Anand,
> > >
> > > On 2026-04-16 17:07, Anand Moon wrote:
> > >> After reviewing the Banana Pi F3 schematics, I confirmed that Buck1 and Buck2
> > >> Both supply the CORE_0V9 with 0.9V±1% rail. To resolve the restriction errors,
> > >> I expanded the voltage range in the DTS to 500,000–950,000 µV.
> > >>
sorry I was wrong from the doc below 1.2.1 CORE Power Design

The typical core voltage is 0.9 V to 1.05 V. Actual voltage is
dynamically regulated by
the **remote-sense dynamic voltage** adjustment circuit inside P1.
P1 BUCK1 and BUCK2 must be combined to supply the core rail.

[1] https://www.spacemit.com/community/document/info?nodepath=hardware/key_stone/k1/k1_hw/k1_hw_design_guide.md&lang=en

> > >> Additionally, I updated the DTS to map the second CPU cluster (cores 4–7)
> > >> to Buck2 to better align with the hardware's power distribution.
> > >
> > > Actually the output of Buck1 and Buck2 are connected together, so they
> > > should always be configured with the same output voltage. And both
> > > clusters should be mapped to both outputs.
> >
> > You are right, I received the same response from the official developers.
> >
> > Therefore, I'm wondering if an additional regulator-coupled-with: property
> > definition is also needed here?
>
correct.
> Yes, I think this is the way to go. I even wonder if this shouldn't be a
> fix with Cc: stable. This also has to be done for the Milk-V Jupiter
> board, I haven't checked the other boards yet, but I guess they all use
> the same schematics at that the PMIC level.
>
> Regards
> Aurelien
>
> --
> Aurelien Jarno                          GPG: 4096R/1DDD8C9B
> aurelien at aurel32.net                     http://aurel32.net

Thanks
-Anand