linux-kernel - Re: [PATCH v12 0/8] Implement vendor resets for PSCI SYSTEM

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Message-ID: <217dfc7f-97d6-4598-ad6a-1cb48464c91c@kernel.org>
Date: Thu, 24 Jul 2025 16:38:11 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Shivendra Pratap <shivendra.pratap@....qualcomm.com>,
 Florian Fainelli <florian.fainelli@...adcom.com>,
 Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
 Bjorn Andersson <andersson@...nel.org>, Sebastian Reichel <sre@...nel.org>,
 Rob Herring <robh@...nel.org>, Sudeep Holla <sudeep.holla@....com>,
 Souvik Chakravarty <Souvik.Chakravarty@....com>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Andy Yan <andy.yan@...k-chips.com>,
 Mark Rutland <mark.rutland@....com>,
 Lorenzo Pieralisi <lpieralisi@...nel.org>, Arnd Bergmann <arnd@...db.de>,
 Konrad Dybcio <konradybcio@...nel.org>, cros-qcom-dts-watchers@...omium.org,
 Vinod Koul <vkoul@...nel.org>, Catalin Marinas <catalin.marinas@....com>,
 Will Deacon <will@...nel.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>,
 Mukesh Ojha <mukesh.ojha@....qualcomm.com>,
 Stephen Boyd <swboyd@...omium.org>, Andre Draszik
 <andre.draszik@...aro.org>, linux-pm@...r.kernel.org,
 linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
 Elliot Berman <quic_eberman@...cinc.com>,
 Srinivas Kandagatla <srini@...nel.org>,
 Elliot Berman <elliot.berman@....qualcomm.com>,
 Konrad Dybcio <konrad.dybcio@....qualcomm.com>
Subject: Re: [PATCH v12 0/8] Implement vendor resets for PSCI SYSTEM_RESET2

On 24/07/2025 16:04, Shivendra Pratap wrote:
>>>> For the sysfs bits, should not we be seeing "psci" instead of "reboot-mode" twice in this path:
>>>>
>>>> # cat /sys/class/reboot-mode/reboot-mode/reboot_modes
>>>> powercycle
>>> As per current patch, we create a class named - "reboot-mode".
>>> /sys/class/reboot-mode
>>>
>>> Then comes the DT node name of the registering driver.
>>> /sys/class/reboot-mode/<DT node name of the registering driver>/
>>
>> This means that node name becomes part of the ABI? I am not happy about
>> it. Where is such ABI documented? Because your last patch tells
>> something completely else!
>>
>> I strongly insist using compatible as way to find your device, not node
>> names.
> It will look better to switch to compatible. Will define a compatible for
> psci reboot-mode binding and align the patch to use the compatible for sysfs.
> Current patch defines reboot-mode as a property to psci, hope its fine to
> define a compatible for this property like "psci-vendor-reset" or
> "psci-reboot-modes"?


Hm, sorry, what? That's not what I ask, but considering inconsistency
mentioned here and in actual ABI document I do not even know what to
suggest.

> 
>>
>> In any case you need to document such ABI in Devicetree bindings,
>> because sysfs ABI is not enough.
> should reboot-mode Devicetree binding document this ABI? Can you
> please share some more detail on this?


The binding for the device, whose node name you are using here as ABI,
should document the ABI.

Best regards,
Krzysztof