linux-kernel - Re: [PATCH] dt-bindings: rtc: zynqmp: Describe power-domains property

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Date: Tue, 20 Feb 2024 12:34:18 +0100
From: Michal Simek <michal.simek@....com>
To: "Buddhabhatti, Jay" <jay.buddhabhatti@....com>,
 Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
 "monstr@...str.eu" <monstr@...str.eu>,
 "michal.simek@...inx.com" <michal.simek@...inx.com>,
 "git@...inx.com" <git@...inx.com>, Conor Dooley <conor+dt@...nel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 Rob Herring <robh@...nel.org>,
 "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
 <devicetree@...r.kernel.org>,
 "moderated list:ARM/ZYNQ ARCHITECTURE"
 <linux-arm-kernel@...ts.infradead.org>,
 "open list:REAL TIME CLOCK (RTC) SUBSYSTEM" <linux-rtc@...r.kernel.org>
Subject: Re: [PATCH] dt-bindings: rtc: zynqmp: Describe power-domains property



On 2/20/24 11:51, Buddhabhatti, Jay wrote:
> Hi Alexandre,
> 
>> -----Original Message-----
>> From: Alexandre Belloni <alexandre.belloni@...tlin.com>
>> Sent: Tuesday, February 20, 2024 1:49 AM
>> To: Simek, Michal <michal.simek@....com>
>> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>; linux-
>> kernel@...r.kernel.org; monstr@...str.eu; michal.simek@...inx.com;
>> git@...inx.com; Conor Dooley <conor+dt@...nel.org>; Krzysztof Kozlowski
>> <krzysztof.kozlowski+dt@...aro.org>; Rob Herring <robh@...nel.org>; open
>> list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS
>> <devicetree@...r.kernel.org>; moderated list:ARM/ZYNQ ARCHITECTURE
>> <linux-arm-kernel@...ts.infradead.org>; open list:REAL TIME CLOCK (RTC)
>> SUBSYSTEM <linux-rtc@...r.kernel.org>
>> Subject: Re: [PATCH] dt-bindings: rtc: zynqmp: Describe power-domains
>> property
>>
>> On 19/02/2024 14:11:50+0100, Michal Simek wrote:
>>>
>>>
>>> On 2/17/24 09:26, Krzysztof Kozlowski wrote:
>>>> On 16/02/2024 10:42, Michal Simek wrote:
>>>>>
>>>>>
>>>>> On 2/16/24 10:19, Krzysztof Kozlowski wrote:
>>>>>> On 16/02/2024 09:51, Michal Simek wrote:
>>>>>>> RTC has its own power domain on Xilinx Versal SOC that's why
>>>>>>> describe it as optional property.
>>>>>>>
>>>>>>> Signed-off-by: Michal Simek <michal.simek@....com>
>>>>>>> ---
>>>>>>>
>>>>>>>     Documentation/devicetree/bindings/rtc/xlnx,zynqmp-rtc.yaml | 3
>> +++
>>>>>>>     1 file changed, 3 insertions(+)
>>>>>>>
>>>>>>
>>>>>> But Versal is not described in this binding, is it? I see only
>>>>>> one compatible.
>>>>>
>>>>> It is the same IP only as is on zynqmp with own power rail.
>>>>
>>>> Then you should have separate compatible, because they are not
>>>> identical. It would also allow you to narrow the domains to versal
>>>> and also require it (on versal).
>>>
>>> I can double check with HW guys but I am quite sure IP itself is
>>> exactly the same. What it is different is that there is own power
>>> domain to it (not shared one as is in zynqmp case).
>>>
>>> Also Linux is non secure sw and if secure firmware won't allow to
>>> change setting of it it can't be required. I am just saying that Linux
>>> doesn't need to be owner of any power domain that's why it shouldn't
>>> be required property.
>>
>> I guess because the integration is different, you still need a differente
>> compatible so you can forbid the property on non-Versal.
> 
> [Jay] RTC has its own power domain in case of Versal and ZynqMP both that we double check it.

Thanks Jay for looking into it. I should definitely update my commit message to 
reflect it. Do you still want me to create soc specific property?

Thanks,
Michal