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

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Date:   Thu, 4 May 2023 08:13:37 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Changhuang Liang <changhuang.liang@...rfivetech.com>,
        Conor Dooley <conor@...nel.org>
Cc:     Conor Dooley <conor.dooley@...rochip.com>,
        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 04/05/2023 03:34, Changhuang Liang wrote:
> 
> 
> 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@...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>;
>>>> 	};
>>
>>> 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@...10000 {
> 	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.

Adding property from child to parent does not make any sense. Didn't you
already receive comment on this?

Best regards,
Krzysztof