linux-kernel - Re: [PATCH 1/3] arm64: dts: rockchip: Update CPU OPP voltages in RK356x SoC dtsi

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Message-Id: <D4U2PO4VF4ST.9SBVKYF6095M@cknow.org>
Date: Sat, 12 Oct 2024 21:27:16 +0200
From: "Diederik de Haas" <didi.debian@...ow.org>
To: "Dragan Simic" <dsimic@...jaro.org>,
 <linux-rockchip@...ts.infradead.org>
Cc: <heiko@...ech.de>, <linux-arm-kernel@...ts.infradead.org>,
 <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
 <robh@...nel.org>, <krzk+dt@...nel.org>, <conor+dt@...nel.org>
Subject: Re: [PATCH 1/3] arm64: dts: rockchip: Update CPU OPP voltages in
 RK356x SoC dtsi

Hi Dragan,

On Sat Oct 12, 2024 at 7:04 PM CEST, Dragan Simic wrote:
> Update the lower/upper voltage limits and the exact voltages for the Rockchip
> RK356x CPU OPPs, using the most conservative values (i.e. the highest per-OPP
> voltages) found in the vendor kernel source. [1]
>
> Using the most conservative per-OPP voltages ensures reliable CPU operation
> regardless of the actual CPU binning, with the downside of possibly using
> a bit more power for the CPU cores than absolutely needed.
>
> Additionally, fill in the missing "clock-latency-ns" CPU OPP properties, using
> the values found in the vendor kernel source. [1]
>
> [1] https://raw.githubusercontent.com/rockchip-linux/kernel/f8b9431ee38ed561650be7092ab93f564598daa9/arch/arm64/boot/dts/rockchip/rk3568.dtsi
>
> Related-to: eb665b1c06bc ("arm64: dts: rockchip: Update GPU OPP voltages in RK356x SoC dtsi")
> Signed-off-by: Dragan Simic <dsimic@...jaro.org>
> ---
>  arch/arm64/boot/dts/rockchip/rk3568.dtsi |  1 +
>  arch/arm64/boot/dts/rockchip/rk356x.dtsi | 18 ++++++++++++------
>  2 files changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm64/boot/dts/rockchip/rk3568.dtsi b/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> index 0946310e8c12..5c54898f6ed1 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3568.dtsi
> @@ -273,6 +273,7 @@ &cpu0_opp_table {
>  	opp-1992000000 {
>  		opp-hz = /bits/ 64 <1992000000>;
>  		opp-microvolt = <1150000 1150000 1150000>;
> +		clock-latency-ns = <40000>;
>  	};
>  };
>  
> diff --git a/arch/arm64/boot/dts/rockchip/rk356x.dtsi b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> index 0ee0ada6f0ab..534593f2ed0b 100644
> --- a/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> @@ -134,39 +134,45 @@ cpu0_opp_table: opp-table-0 {
>  
>  		opp-408000000 {
>  			opp-hz = /bits/ 64 <408000000>;
> -			opp-microvolt = <900000 900000 1150000>;
> +			opp-microvolt = <850000 850000 1150000>;
>  			clock-latency-ns = <40000>;
>  		};
>  
>  		opp-600000000 {
>  			opp-hz = /bits/ 64 <600000000>;
> -			opp-microvolt = <900000 900000 1150000>;
> +			opp-microvolt = <850000 850000 1150000>;
> +			clock-latency-ns = <40000>;
>  		};
>  
>  		opp-816000000 {
>  			opp-hz = /bits/ 64 <816000000>;
> -			opp-microvolt = <900000 900000 1150000>;
> +			opp-microvolt = <850000 850000 1150000>;
> +			clock-latency-ns = <40000>;
>  			opp-suspend;
>  		};

While it felt a bit much to send a patch just to remove the blank lines
between the opp nodes, this sounds like an excellent opportunity to make
it consistent with the opp list in other DT files?

Cheers,
  Diederik

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