Re: [PATCH 1/5] riscv: dts: allwinner: Update opp table to allow CPU frequency scaling

From: Conor Dooley
Date: Thu Dec 14 2023 - 08:47:26 EST


On Thu, Dec 14, 2023 at 04:44:46PM +0530, Viresh Kumar wrote:
> On 14-12-23, 11:33, Brandon Cheo Fusi wrote:
> > Two OPPs are currently defined for the D1/D1s; one at 408MHz and
> > another at 1.08GHz. Switching between these can be done with the
> > "sun50i-cpufreq-nvmem" driver. This patch populates the opp table
> > appropriately, with inspiration from
> > https://github.com/Tina-Linux/linux-5.4/blob/master/arch/riscv/boot/dts/sunxi/sun20iw1p1.dtsi
> >
> > The supply voltages are PWM-controlled, but support for that IP
> > is still in the works. So stick to a fixed 0.9V vdd-cpu supply,
> > which seems to be the default on most D1 boards.
> >
> > Signed-off-by: Brandon Cheo Fusi <fusibrandon13@xxxxxxxxx>
> > ---
> > arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi | 18 +++++++++++++++---
> > 1 file changed, 15 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi b/arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi
> > index 64c3c2e6c..e211fe4c7 100644
> > --- a/arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi
> > +++ b/arch/riscv/boot/dts/allwinner/sun20i-d1s.dtsi
> > @@ -39,16 +39,22 @@ cpu0_intc: interrupt-controller {
> > };
> >
> > opp_table_cpu: opp-table-cpu {
> > - compatible = "operating-points-v2";
> > + compatible = "allwinner,sun20i-d1-operating-points",
>
> I don't think you should add a new compatible for every SoC that needs
> to be supported by a DT bindings and cpufreq driver. Maybe you should
> just reuse "allwinner,sun50i-h6-operating-points" and it will work
> fine for you ?
>
> Rob ?

The driver can definitely just reuse sun50i-h6, but the binding and
devicetree should have a soc-specific compatible for the sun20i-d1.

That said, the compatible does need to be documented, there's a
dt-bindings patch missing from this series.

Cheers,
Conor.

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