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Message-ID: <0988495f-b87a-7f69-f222-37c67d6eae23@starfivetech.com>
Date:   Tue, 25 Apr 2023 17:18:10 +0800
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Subject: Re: [RESEND v2 1/6] dt-bindings: power: Add JH7110 AON PMU support
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To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Conor Dooley <conor.dooley@microchip.com>
CC:     Conor Dooley <conor@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Emil Renner Berthing <kernel@esmil.dk>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Walker Chen <walker.chen@starfivetech.com>,
        Hal Feng <hal.feng@starfivetech.com>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-riscv@lists.infradead.org>, <vkoul@kernel.org>,
        <linux-phy@lists.infradead.org>
References: <20230419035646.43702-1-changhuang.liang@starfivetech.com>
 <20230419035646.43702-2-changhuang.liang@starfivetech.com>
 <20230419-labored-camper-644d51a7ca96@spud>
 <1a5b15fa-4f20-51c2-2ba1-a04a2911a694@starfivetech.com>
 <20230424-baffle-punch-ec73098f2b6a@spud>
 <d685a1d4-c07d-7dfa-f1fb-b35ceb2aa0eb@starfivetech.com>
 <20230425-unquote-eligible-09f743d81981@wendy>
 <a7cdfabf-2312-eaf3-f462-5bda7f0a120d@starfivetech.com>
 <68cb565d-bf39-10b0-9e3e-35ba7f54b90b@linaro.org>
From:   Changhuang Liang <changhuang.liang@starfivetech.com>
In-Reply-To: <68cb565d-bf39-10b0-9e3e-35ba7f54b90b@linaro.org>
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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@17010000 {
		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@17010000 {
		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 prefer the way of 2.
This is more in line with the hardware description of JH7110.