From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?utf-8?Q?Ond=C5=99ej?= Jirman <doudahwezomiechahtah@xff.cz>
Subject: Re: [linux-sunxi] [PATCH] ARM: dts: sun8i: a83t: Add CPU regulator
 supplies for A83T boards
Date: Wed, 27 Jun 2018 20:45:39 +0200
Message-ID: <20180627184539.3er4226lkbtudhwe@core>
References: <20180627022709.27434-1-wens@csie.org>
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To: Chen-Yu Tsai <wens@csie.org>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>, devicetree@vger.kernel.org, linux-sunxi@googlegroups.com, linux-arm-kernel@lists.infradead.org
List-Id: devicetree@vger.kernel.org

Hi,

On Wed, Jun 27, 2018 at 10:27:09AM +0800, Chen-Yu Tsai wrote:
> The OPPs for the A83T CPU cores were added in v4.17 in commit 2db639d8c166
> ("ARM: dts: sun8i: a83t: add stable OPP tables and CPUfreq"), but board
> level regulator supplies for the CPU clusters were only added for the
> TBS-A711 tablet. This means the other A83T boards do not benefit from
> voltage scaling, or worse, if the implementation does not scale the
> frequency when the voltage is fixed, no benefit at all.
> 
> Add board level CPU cluster power supplies to all the A83T development
> boards, so they can have proper dynamic CPU voltage and frequency scaling.
> 
> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
> ---
>  arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts | 8 ++++++++
>  arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts           | 8 ++++++++
>  arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts       | 8 ++++++++
>  3 files changed, 24 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts b/arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts
> index 36ecebaff3c0..1c012a4def16 100644
> --- a/arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts
> +++ b/arch/arm/boot/dts/sun8i-a83t-allwinner-h8homlet-v2.dts
> @@ -79,6 +79,14 @@
>  	};
>  };
>  
> +&cpu0 {
> +	cpu-supply = <&reg_dcdc2>;
> +};
> +
> +&cpu100 {
> +	cpu-supply = <&reg_dcdc3>;
> +};
> +

Shouldn't this be done for all CPU cores? Say you start the kernel with
maxcpus=1 and then enable CPU5 later on, will the regulator get enabled,
if it is not enabled by always-on setting?

regards,
  o.

>  &ehci0 {
>  	status = "okay";
>  };
> diff --git a/arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts b/arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts
> index 3b579d7567c8..c7ce4158d6c8 100644
> --- a/arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts
> +++ b/arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts
> @@ -107,6 +107,14 @@
>  	};
>  };
>  
> +&cpu0 {
> +	cpu-supply = <&reg_dcdc2>;
> +};
> +
> +&cpu100 {
> +	cpu-supply = <&reg_dcdc3>;
> +};
> +
>  &de {
>  	status = "okay";
>  };
> diff --git a/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts b/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts
> index 88decb0747ac..e5f0645e53a7 100644
> --- a/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts
> +++ b/arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts
> @@ -145,6 +145,14 @@
>  	};
>  };
>  
> +&cpu0 {
> +	cpu-supply = <&reg_dcdc2>;
> +};
> +
> +&cpu100 {
> +	cpu-supply = <&reg_dcdc3>;
> +};
> +
>  &ehci0 {
>  	/* GL830 USB-to-SATA bridge here */
>  	status = "okay";
> -- 
> 2.18.0
> 
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