linux-kernel - Re: [PATCH] rockchip: dts: rk3588: add missing OPP nodes for lower frequencies

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Message-ID: <2652016.Lt9SDvczpP@diego>
Date: Thu, 03 Apr 2025 11:24:25 +0200
From: Heiko Stübner <heiko@...ech.de>
To: devicetree@...r.kernel.org, Daniele Briguglio <hello@...erkali.me>
Cc: robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
 alchark@...il.com, linux-arm-kernel@...ts.infradead.org,
 linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org,
 Daniele Briguglio <daniele.briguglio@...oud.com>,
 Daniele Briguglio <hello@...erkali.me>
Subject:
 Re: [PATCH] rockchip: dts: rk3588: add missing OPP nodes for lower
 frequencies

Hi,

Am Donnerstag, 3. April 2025, 11:18:40 MESZ schrieb Daniele Briguglio:
> From: Daniele Briguglio <daniele.briguglio@...oud.com>
> 
> This Patch adds missing Operating Performance Point (OPP) nodes for lower
> frequencies to the RK3588 device tree. These additions improve power
> management by enabling the CPU clusters to scale down to lower
> frequencies when under light loads, which should improve energy
> efficiency and reduce power consumption.
> 
> The changes add OPP nodes for 408MHz, 600MHz, 816MHz, and 1008MHz
> (for cluster1 and cluster2 only, as cluster0 already had 1008MHz)
> with appropriate voltage settings across all three CPU clusters in
> the RK3588 SoC.

the general consensus is that you don't save energy when you're not
reducing the voltage together with the frequency.

For example cluster0 @1GHz runs at 675mV already, so reducing just the
frequency, when you're not allowed to reduce the voltage with it won't
save energy, just make things slow.


Heiko

> Signed-off-by: Daniele Briguglio <hello@...erkali.me>
> ---
>  arch/arm64/boot/dts/rockchip/rk3588-opp.dtsi | 58 ++++++++++++++++++++
>  1 file changed, 58 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3588-opp.dtsi b/arch/arm64/boot/dts/rockchip/rk3588-opp.dtsi
> index 0f1a77697351..1b018823d5d3 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3588-opp.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3588-opp.dtsi
> @@ -5,6 +5,22 @@ cluster0_opp_table: opp-table-cluster0 {
>  		compatible = "operating-points-v2";
>  		opp-shared;
>  
> +		opp-408000000 {
> +			opp-hz = /bits/ 64 <408000000>;
> +			opp-microvolt = <675000 675000 950000>;
> +			clock-latency-ns = <40000>;
> +			opp-suspend;
> +		};
> +		opp-600000000 {
> +			opp-hz = /bits/ 64 <600000000>;
> +			opp-microvolt = <675000 675000 950000>;
> +			clock-latency-ns = <40000>;
> +		};
> +		opp-816000000 {
> +			opp-hz = /bits/ 64 <816000000>;
> +			opp-microvolt = <675000 675000 950000>;
> +			clock-latency-ns = <40000>;
> +		};
>  		opp-1008000000 {
>  			opp-hz = /bits/ 64 <1008000000>;
>  			opp-microvolt = <675000 675000 950000>;
> @@ -37,6 +53,27 @@ cluster1_opp_table: opp-table-cluster1 {
>  		compatible = "operating-points-v2";
>  		opp-shared;
>  
> +		opp-408000000 {
> +			opp-hz = /bits/ 64 <408000000>;
> +			opp-microvolt = <675000 675000 1000000>;
> +			clock-latency-ns = <40000>;
> +			opp-suspend;
> +		};
> +		opp-600000000 {
> +			opp-hz = /bits/ 64 <600000000>;
> +			opp-microvolt = <675000 675000 1000000>;
> +			clock-latency-ns = <40000>;
> +		};
> +		opp-816000000 {
> +			opp-hz = /bits/ 64 <816000000>;
> +			opp-microvolt = <675000 675000 1000000>;
> +			clock-latency-ns = <40000>;
> +		};
> +		opp-1008000000 {
> +			opp-hz = /bits/ 64 <1008000000>;
> +			opp-microvolt = <675000 675000 1000000>;
> +			clock-latency-ns = <40000>;
> +		};
>  		opp-1200000000 {
>  			opp-hz = /bits/ 64 <1200000000>;
>  			opp-microvolt = <675000 675000 1000000>;
> @@ -78,6 +115,27 @@ cluster2_opp_table: opp-table-cluster2 {
>  		compatible = "operating-points-v2";
>  		opp-shared;
>  
> +		opp-408000000 {
> +			opp-hz = /bits/ 64 <408000000>;
> +			opp-microvolt = <675000 675000 1000000>;
> +			clock-latency-ns = <40000>;
> +			opp-suspend;
> +		};
> +		opp-600000000 {
> +			opp-hz = /bits/ 64 <600000000>;
> +			opp-microvolt = <675000 675000 1000000>;
> +			clock-latency-ns = <40000>;
> +		};
> +		opp-816000000 {
> +			opp-hz = /bits/ 64 <816000000>;
> +			opp-microvolt = <675000 675000 1000000>;
> +			clock-latency-ns = <40000>;
> +		};
> +		opp-1008000000 {
> +			opp-hz = /bits/ 64 <1008000000>;
> +			opp-microvolt = <675000 675000 1000000>;
> +			clock-latency-ns = <40000>;
> +		};
>  		opp-1200000000 {
>  			opp-hz = /bits/ 64 <1200000000>;
>  			opp-microvolt = <675000 675000 1000000>;
>