Re: [PATCH 4/5] ARM: sun8i: h3: add operating-points-v2 table for CPU

From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: icenowy@aosc.io
Cc: linux-pm@vger.kernel.org, linux-sunxi@googlegroups.com,
	linux-kernel@vger.kernel.org,
	Quentin Schulz <quentin.schulz@free-electrons.com>,
	Chen-Yu Tsai <wens@csie.org>,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 4/5] ARM: sun8i: h3: add operating-points-v2 table for CPU
Date: Sun, 16 Apr 2017 22:57:40 +0200	[thread overview]
Message-ID: <20170416205740.b5pk3kcxwaegij6g@lukather> (raw)
In-Reply-To: <b37490ed1282f45542168701dea332bb@aosc.io>

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On Tue, Apr 11, 2017 at 09:28:55PM +0800, icenowy@aosc.io wrote:
> 在 2017-04-11 17:13，Maxime Ripard 写道：
> > On Sun, Apr 09, 2017 at 02:50:24AM +0800, Icenowy Zheng wrote:
> > > The CPU on Allwinner H3 can do dynamic frequency scaling.
> > > 
> > > Add a DVFS table based on the one tweaked by Armbian developers, which
> > > are proven to work stably on BSP kernels.
> > > 
> > > 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@aosc.io>
> > > ---
> > >  arch/arm/boot/dts/sun8i-h3.dtsi | 38
> > > +++++++++++++++++++++++++++++++++++++-
> > >  1 file changed, 37 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/arch/arm/boot/dts/sun8i-h3.dtsi
> > > b/arch/arm/boot/dts/sun8i-h3.dtsi
> > > index b36f9f423c39..a0cee17fe44b 100644
> > > --- a/arch/arm/boot/dts/sun8i-h3.dtsi
> > > +++ b/arch/arm/boot/dts/sun8i-h3.dtsi
> > > @@ -43,32 +43,68 @@
> > >  #include "sunxi-h3-h5.dtsi"
> > > 
> > >  / {
> > > +	cpu0_opp_table: opp_table0 {
> > > +		compatible = "operating-points-v2";
> > > +		opp-shared;
> > > +
> > > +		opp@480000000 {
> > > +			opp-hz = /bits/ 64 <480000000>;
> > > +			opp-microvolt = <980000 980000 1300000>;
> > > +			clock-latency-ns = <244144>; /* 8 32k periods */
> > > +		};
> > > +
> > > +		opp@648000000 {
> > > +			opp-hz = /bits/ 64 <816000000>;
> > > +			opp-microvolt = <1020000 1020000 1300000>;
> > > +			clock-latency-ns = <244144>; /* 8 32k periods */
> > > +		};
> > > +
> > > +		opp@912000000 {
> > > +			opp-hz = /bits/ 64 <960000000>;
> > > +			opp-microvolt = <1080000 1080000 1300000>;
> > > +			clock-latency-ns = <244144>; /* 8 32k periods */
> > > +		};
> > > +
> > > +		opp@1008000000 {
> > > +			opp-hz = /bits/ 64 <1008000000>;
> > > +			opp-microvolt = <1140000 1140000 1300000>;
> > > +			clock-latency-ns = <244144>; /* 8 32k periods */
> > > +		};
> > > +	};
> > > +
> > 
> > From your serie, I guess you never actually tested those OPPs on any
> > board without SY8113B, right?
> 
> Yes. But I will test them on an Orange Pi PC (newly got) soon.

The orange pi pc also uses the SY8113B.

> (After all PLL_CPUX-related things are well fixed)
> 
> P.S. how to implement such a thing:
> 
> - Before tweaking CPUX clock, first switch it to osc24M
>   (implemented yet)
> - Before tweaking PLL_CPUX clock (triggered by tweaking CPUX
>   clock), first gate it
> - After tweaking PLL_CPUX clock, ungate it and wait it to be stable
> - After tweaking PLL_CPUX clock, change CPUX mux back to PLL_CPUX
>   (implemented yet)
> 
> I think notifiers on PLL_CPUX can be used to implement the second
> and third part?

Do you still have any issues with the code we merged?

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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