linux-kernel - Re: [PATCH v2 05/10] ARM: sun8i: h3: add operating-points-v2 table for CPU

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Message-ID: <20180206090656.r52hs7sk7w5iynrk@flea>
Date:   Tue, 6 Feb 2018 10:06:56 +0100
From:   Maxime Ripard <maxime.ripard@...tlin.com>
To:     Icenowy Zheng <icenowy@...c.io>
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Rob Herring <robh+dt@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-sunxi@...glegroups.com
Subject: Re: [PATCH v2 05/10] ARM: sun8i: h3: add operating-points-v2 table
 for CPU

On Tue, Feb 06, 2018 at 12:49:00PM +0800, Icenowy Zheng wrote:
> The CPU on Allwinner H3 can do dynamic frequency scaling.
> 
> Add a DVFS table based on the one shipped with Allwinner's H3 SDK. The
> voltage-frequency relationship seems to be conservative, and Armbian has
> another DVFS table which uses lower voltage at a certain frequency.
> However, the official one is chosen for safety.
> 
> Frequencies higher than 1008MHz are temporarily dropped in the table, as
> they may lead to over voltage on boards without proper regulator
> settings or over temperature on boards with proper regulator settings.
> They will be added back once regulator settings are ready and thermal
> sensor driver is merged.
> 
> In order to satisfy all different regulators (SY8106A which is 50mV per
> level, SY8113B which have two states: 1.1V and 1.3V, and some board with
> non-tweakable regulators), all the OPPs are defined with a range which has
> the target value as the minimum allowed value, and 1.3V (the highest
> VDD-CPUX voltage suggested by the datasheet) as the maximum allowed value.
> It's proven to work well with a board with SY8113B.
> 
> Signed-off-by: Icenowy Zheng <icenowy@...c.io>
> ---
> Changes in v2:
> - Switch to BSP OPP table, which is more conservative.
> 
>  arch/arm/boot/dts/sun8i-h3.dtsi | 32 +++++++++++++++++++++++++++++++-
>  1 file changed, 31 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/sun8i-h3.dtsi b/arch/arm/boot/dts/sun8i-h3.dtsi
> index 8495deecedad..36608c03f02b 100644
> --- a/arch/arm/boot/dts/sun8i-h3.dtsi
> +++ b/arch/arm/boot/dts/sun8i-h3.dtsi
> @@ -43,32 +43,62 @@
>  #include "sunxi-h3-h5.dtsi"
>  
>  / {
> +	cpu0_opp_table: opp_table0 {
> +		compatible = "operating-points-v2";
> +		opp-shared;
> +
> +		opp@...000000 {
> +			opp-hz = /bits/ 64 <648000000>;
> +			opp-microvolt = <1040000 1040000 1300000>;
> +			clock-latency-ns = <244144>; /* 8 32k periods */
> +		};
> +
> +		opp@...000000 {
> +			opp-hz = /bits/ 64 <816000000>;
> +			opp-microvolt = <1100000 1100000 1300000>;
> +			clock-latency-ns = <244144>; /* 8 32k periods */
> +		};
> +
> +		opp@...8000000 {
> +			opp-hz = /bits/ 64 <1008000000>;
> +			opp-microvolt = <1200000 1200000 1300000>;
> +			clock-latency-ns = <244144>; /* 8 32k periods */
> +		};
> +	};
> +
>  	cpus {
>  		#address-cells = <1>;
>  		#size-cells = <0>;
>  
> -		cpu@0 {
> +		cpu0: cpu@0 {
>  			compatible = "arm,cortex-a7";
>  			device_type = "cpu";
>  			reg = <0>;
> +			clocks = <&ccu CLK_CPUX>;
> +			clock-names = "cpu";
> +			operating-points-v2 = <&cpu0_opp_table>;
> +			#cooling-cells = <0x2>;

So, that would be 2?

There's this pattern on pretty much all the other patches following
this one as well, you should address them too.

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
http://bootlin.com

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