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Date:   Thu, 4 May 2023 09:34:37 +0800
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Subject: Re: [RESEND v2 1/6] dt-bindings: power: Add JH7110 AON PMU support
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To:     Conor Dooley <conor@kernel.org>
CC:     Conor Dooley <conor.dooley@microchip.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.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>
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From:   Changhuang Liang <changhuang.liang@starfivetech.com>
In-Reply-To: <20230425-commotion-prewashed-876247bed4ab@spud>
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On 2023/4/26 0:56, Conor Dooley wrote:
> On Tue, Apr 25, 2023 at 08:26:35PM +0800, Changhuang Liang wrote:
>> On 2023/4/25 17:35, Conor Dooley wrote:
>>> 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:
>>>>>> 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.
>>>>
>>>> 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 thought that Rob was suggesting something like this:
>>> 	aon_syscon: syscon@17010000 {
>>> 		compatible = "starfive,jh7110-aon-syscon", ...
>>> 		reg = <0x0 0x17010000 0x0 0x1000>;
>>> 		#power-domain-cells = <1>;
>>> 	};
> 
>> I see the kernel:
>> https://elixir.bootlin.com/linux/latest/source/arch/arm64/boot/dts/mediatek/mt8167.dtsi
>> this file line 42:
>> it's power-controller also has no meaningful properties.
>> What do you think?
> 
> I'm not sure that I follow. It has a bunch of child-nodes does it not,
> each of which is a domain?
> 
> I didn't see such domains in your dts patch, they're defined directly in
> the driver instead AFAIU. Assuming I have understood that correctly,
> your situation is different to that mediatek one?
> 
> Cheers,
> Conor.

Conor and Rob, 

How about this way:

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";
		regmap = <&aon_syscon>;
		#power-domain-cells = <1>;
	};
};

Add a "regmap" property which is phandle. And it can keep the present child-node
structure. This is more consistent with our soc design.

Best regards,
Changhuang