linux-kernel - Re: [RESEND v2 1/6] dt-bindings: power: Add JH7110 AON PMU support

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Message-ID: <20230425-resale-footrest-de667778c4fe@wendy>
Date:   Tue, 25 Apr 2023 10:35:45 +0100
From:   Conor Dooley <conor.dooley@...rochip.com>
To:     Changhuang Liang <changhuang.liang@...rfivetech.com>
CC:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Conor Dooley <conor@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Emil Renner Berthing <kernel@...il.dk>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Walker Chen <walker.chen@...rfivetech.com>,
        Hal Feng <hal.feng@...rfivetech.com>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-riscv@...ts.infradead.org>, <vkoul@...nel.org>,
        <linux-phy@...ts.infradead.org>
Subject: Re: [RESEND v2 1/6] dt-bindings: power: Add JH7110 AON PMU support

On Tue, Apr 25, 2023 at 05:18:10PM +0800, Changhuang Liang wrote:
> 
> 
> On 2023/4/25 16:19, Krzysztof Kozlowski wrote:
> > On 25/04/2023 09:57, Changhuang Liang wrote:
> >>>>>>>>  
> >>>>>>>>  description: |
> >>>>>>>>    StarFive JH7110 SoC includes support for multiple power domains which can be
> >>>>>>>> @@ -17,6 +18,7 @@ properties:
> >>>>>>>>    compatible:
> >>>>>>>>      enum:
> >>>>>>>>        - starfive,jh7110-pmu
> >>>>>>>> +      - starfive,jh7110-aon-pmu
> >>>>>
> >>>>> I was speaking to Rob about this over the weekend, he asked:
> >>>>> 'Why isn't "starfive,jh7110-aon-syscon" just the power-domain provider
> >>>>> itself?'
> >>>>
> >>>> Maybe not, this syscon only offset "0x00" configure power switch.
> >>>> other offset configure other functions, maybe not power, so this
> >>>> "starfive,jh7110-aon-syscon" not the power-domain itself.
> >>>>
> >>>>> Do we actually need to add a new binding for this at all?
> >>>>>
> >>>>> Cheers,
> >>>>> Conor.
> >>>>>
> >>>>
> >>>> Maybe this patch do that.
> >>>> https://lore.kernel.org/all/20230414024157.53203-6-xingyu.wu@starfivetech.com/
> >>>
> >>> This makes it a child-node right? I think Rob already said no to that in
> >>> and earlier revision of this series. What he meant the other day was
> >>> making the syscon itself a power domain controller, since the child node
> >>> has no meaningful properties (reg, interrupts etc).
> >>>
> >>> Cheers,
> >>> Conor.
> >>
> >> Yes, "starfive,jh7110-aon-pmu" is a child-node of "starfive,jh7110-aon-syscon".
> >> In my opinion, "0x17010000" is "aon-syscon" on JH7110 SoC, and this "aon-pmu" is just 
> >> a part of "aon-syscon" function, so I think it is inappropriate to make "aon-syscon"
> >> to a power domain controller. I think using the child-node description is closer to
> >> JH7110 SoC. 
> > 
> > Unfortunately, I do not see the correlation between these, any
> > connection. Why being a child of syscon block would mean that this
> > should no be power domain controller? Really, why? These are two
> > unrelated things.
> > 
> > Best regards,
> > Krzysztof
> > 
> 
> Let me summarize what has been discussed above. 
> 
> There has two ways to describe this "starfive,jh7110-aon-syscon"(0x17010000).
> 1. (0x17010000) is power-controller node:
> 
> 	aon_pwrc: power-controller@...10000 {
> 		compatible = "starfive,jh7110-aon-pmu", "syscon";
> 		reg = <0x0 0x17010000 0x0 0x1000>;
> 		#power-domain-cells = <1>;
> 	};
> 
> 
> 2. (0x17010000) is syscon node, power-controller is child-node of syscon:
> 
> 	aon_syscon: syscon@...10000 {
> 		compatible = "starfive,jh7110-aon-syscon", "syscon", "simple-mfd";
> 		reg = <0x0 0x17010000 0x0 0x1000>;
> 
> 		aon_pwrc: power-controller {
> 			compatible = "starfive,jh7110-aon-pmu";
> 			#power-domain-cells = <1>;
> 		};
> 	};

I thought that Rob was suggesting something like this:
	aon_syscon: syscon@...10000 {
		compatible = "starfive,jh7110-aon-syscon", ...
		reg = <0x0 0x17010000 0x0 0x1000>;
		#power-domain-cells = <1>;
	};

Cheers,
Conor.


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