Re: [PATCH v4 04/18] dt-bindings: PCI: rcar-gen4: Add optional "aer" interrupt for R-Car Gen4 SoCs

[Marek Vasut <marek.vasut@mailbox.org>]

On 10/19/26 4:31 AM, Koichiro Den wrote:
> On Sat, Oct 17, 2026 at 02:17:38PM +0200, Marek Vasut wrote:
>> On 10/15/26 5:30 AM, Koichiro Den wrote:
>>> The intreq_pcim_lperr interrupt carries Root Port AER notifications,
>>> separately from the integrated MSI receiver interrupt. Describe it with
>>> the "aer" name so the controller driver can use it for Root Port error
>>> reporting.
>>>
>>> Keep the fifth interrupt optional on R-Car Gen4 SoCs so existing device
>>> trees remain valid. Extend the example accordingly.
>>>
>>> Signed-off-by: Koichiro Den <den@valinux.co.jp>
>>> ---
>>> Changes since v3:
>>>     - Rebase on Marek's Gen5 AER binding fix:
>>>       https://lore.kernel.org/r/20261003215710.792518-1-marek.vasut+renesas@mailbox.org/
>>>       This requires "aer" for the Gen5 SoC PCIe4 controller from the
>>>       beginning. Update the subject to clarify that it is optional only
>>>       on Gen4 SoCs, for compatibility with existing DTs.
>>>     - Drop R-b tags due to the changes.
>>>
>>> v3: https://lore.kernel.org/r/20261006084638.3821710-5-den@valinux.co.jp/
>>>
>>>    .../devicetree/bindings/pci/rcar-gen4-pci-host.yaml | 13 ++++++++++---
>>>    1 file changed, 10 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/pci/rcar-gen4-pci-host.yaml b/Documentation/devicetree/bindings/pci/rcar-gen4-pci-host.yaml
>>> index 083b77d4de8f..a86c06701fa9 100644
>>> --- a/Documentation/devicetree/bindings/pci/rcar-gen4-pci-host.yaml
>>> +++ b/Documentation/devicetree/bindings/pci/rcar-gen4-pci-host.yaml
>>> @@ -26,7 +26,8 @@ properties:
>>>              - const: renesas,rcar-gen5-pcie4 # R-Car Gen5 PCIe4
>>>      interrupts:
>>> -    maxItems: 4
>>> +    minItems: 4
>>> +    maxItems: 5
>>
>> Wouldn't it be easier/cleaner keep only maxItems: 4 here and set ...
>>
>>>      clocks:
>>>        maxItems: 2
>>> @@ -93,11 +94,13 @@ allOf:
>>>                - const: config
>>>            interrupt-names:
>>> +          minItems: 4
>>
>> ... minItems/maxItems here ^ for R-Car Gen4 (because Gen4 is the only SoC
>> family which has optional non-mandatorily-described AER interrupt) ...
>>
>>>              items:
>>>                - const: msi
>>>                - const: dma
>>>                - const: sft_ce
>>>                - const: app
>>> +            - const: aer
>>>      - if:
>>>          properties:
>>>            compatible:
>>> @@ -117,6 +120,9 @@ allOf:
>>>                - const: app
>>>                - const: config
>>> +        interrupts:
>>> +          maxItems: 4
>>
>> ... and drop this interrupts: hunk here entirely (because Gen5 always has
>> mandatorily described AER interrupt) ?
>>
>>>            interrupt-names:
>>>              items:
>>>                - const: msi
>>> @@ -146,8 +152,9 @@ examples:
>>>                interrupts = <GIC_SPI 416 IRQ_TYPE_LEVEL_HIGH>,
>>>                             <GIC_SPI 417 IRQ_TYPE_LEVEL_HIGH>,
>>>                             <GIC_SPI 418 IRQ_TYPE_LEVEL_HIGH>,
>>> -                         <GIC_SPI 422 IRQ_TYPE_LEVEL_HIGH>;
>>> -            interrupt-names = "msi", "dma", "sft_ce", "app";
>>> +                         <GIC_SPI 422 IRQ_TYPE_LEVEL_HIGH>,
>>> +                         <GIC_SPI 421 IRQ_TYPE_LEVEL_HIGH>;
>>> +            interrupt-names = "msi", "dma", "sft_ce", "app", "aer";
>>>                clocks = <&cpg CPG_MOD 624>, <&pcie0_clkref>;
>>>                clock-names = "core", "ref";
>>>                power-domains = <&sysc R8A779F0_PD_ALWAYS_ON>;
>>
>> What do you think ?
> 
> Seems that wouldn't work as-is. With your proposed layout and a Gen4 DT that
> includes "aer":
> 
>    $ dt-validate -V
>    2026.9
>    $ dt-validate -s <schema-dir> -l rcar-gen4-pci-host <gen4.dtb>
>      interrupts: [[0, 416, 4], [0, 417, 4], [0, 418, 4], [0, 422, 4], [0, 421, 4]] is too long
>        from schema $id: http://devicetree.org/schemas/pci/rcar-gen4-pci-host.yaml
> 
> The top-level maxItems:4 would still apply to Gen4.
> We could instead drop the top-level interrupts limits and set them separately in
> the Gen4 and Gen5 'then' blocks, if that would be more readable.
> 
> But TBH, I don't see much benefit over the current (v4) layout, so I'd prefer to
> keep v4 as it is. I'd appreciate your thoughts on it.
I agree, please keep this patch as-is.

Thank you for checking !

-- 
Best regards,
Marek Vasut