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

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Message-ID: <D4A773D5-E57C-4767-9D3C-0D386BF76DED@aosc.io>
Date:   Tue, 06 Feb 2018 17:10:26 +0800
From:   Icenowy Zheng <icenowy@...c.io>
To:     Maxime Ripard <maxime.ripard@...tlin.com>
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



于 2018年2月6日 GMT+08:00 下午5:06:56, Maxime Ripard <maxime.ripard@...tlin.com> 写到:
>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?

Okay.

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