Re: [PATCH 3/4] dt-bindings: PCI: microchip,pcie-host: fix incorrect child node name

[Krzysztof Kozlowski]

On 12/08/2022 10:55, Conor.Dooley@xxxxxxxxxxxxx wrote:
> On 12/08/2022 08:42, Krzysztof Kozlowski wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> On 11/08/2022 23:33, Conor Dooley wrote:
>>> From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
>>>
>>> v2022.08 of dt-schema improved checking of unevaluatedProperties, and
>>> exposed a previously unseen warning for the PCIe controller's interrupt
>>> controller node name:
>>>
>>> arch/riscv/boot/dts/microchip/mpfs-icicle-kit.dtb: pcie@2000000000: Unevaluated properties are not allowed ('clock-names', 'clocks', 'legacy-interrupt-controller', 'microchip,axi-m-atr0' were unexpected)
>>>          From schema: Documentation/devicetree/bindings/pci/microchip,pcie-host.yaml
>>>
>>> Make the property in the binding match the node name actually used in
>>> the dts.
>>>
>>> Fixes: dcd49679fb3a ("dt-bindings: PCI: Fix 'unevaluatedProperties' warnings")
>>> Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
>>> ---
>>> This is another one Rob where I feel like I'm doing the wrong thing.
>>> The Linux driver gets the child node without using the name, but
>>> another OS etc could in theory (or reality), right?
>>
>> Yes and we had such cases when renaming device nodes caused regression.
>> My interpretation is that node name is not part of ABI, so anyone
>> depending on it made a mistake and they need to fix their stuff. I think
>> actually that is really poor coding and poor solution to parse device
>> node names and expect specific name.
>>
>> Other folks interpretation is that we never break the users of kernel,
>> regardless what is documented in the ABI... so it depends. :)
>>
>> Here however it is not a device node name, but a property name (although
>> still a node). Bindings require these to be specific, thus such name is
>> a part of ABI.
> 
> Yup, pretty much aligned to my thoughts on this.
> 
>> For your case, I wonder why it was called "legacy-interrupt-controller"
>> in the first place? Node names - also for properties - should be
>> generic, so generic name is just "interrupt-controller".
> 
> I don't know. It's what we had in our internal tree prior to upstreaming.
> "We" don't rely on the name for the Linux driver, so I am not really that
> bothered if we change the binding or the dts.

Then I propose to change the name in DTS.

Best regards,
Krzysztof