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

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Date: Mon, 19 Feb 2024 14:11:50 +0100
From: Michal Simek <michal.simek@....com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
 linux-kernel@...r.kernel.org, monstr@...str.eu, michal.simek@...inx.com,
 git@...inx.com
Cc: Alexandre Belloni <alexandre.belloni@...tlin.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 2/17/24 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.

Thanks,
Michal