Re: [PATCH 1/2] dt-bindings: wireless: restore constraint for brcm,bcm4329-fmac compatible property

[Arend van Spriel <arend.vanspriel@broadcom.com>]

On 8/20/2024 1:39 PM, Krzysztof Kozlowski wrote:
> On 20/08/2024 13:27, Krzysztof Kozlowski wrote:
>> On Tue, Aug 20, 2024 at 12:12:15PM +0200, Arend van Spriel wrote:
>>> When extending the bindings for Apple PCIe devices the compatible property
>>> specification was changed. However, it was changed such that for these
>>> devices it was no longer necessary to have "brcm,bcm4329-fmac" listed as
>>> string in the compatible list property as it was before that extension.
>>
>> Apart that this was never tested... That statement is not true. Look at
>> "fixed" commit - it is not doing like that at all.
>>
>> I don't understand the reasoning.
>>
>>> This patch restores that constraint.
>>>
>>> Fixes: e2e37224e8b3 ("dt-bindings: net: bcm4329-fmac: Add Apple properties & chips")
>>> Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
>>> ---
>>>   .../net/wireless/brcm,bcm4329-fmac.yaml       | 19 ++++++++++---------
>>>   1 file changed, 10 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/net/wireless/brcm,bcm4329-fmac.yaml b/Documentation/devicetree/bindings/net/wireless/brcm,bcm4329-fmac.yaml
>>> index e564f20d8f41..47f90446322f 100644
>>> --- a/Documentation/devicetree/bindings/net/wireless/brcm,bcm4329-fmac.yaml
>>> +++ b/Documentation/devicetree/bindings/net/wireless/brcm,bcm4329-fmac.yaml
>>> @@ -7,7 +7,7 @@ $schema: http://devicetree.org/meta-schemas/core.yaml#
>>>   title: Broadcom BCM4329 family fullmac wireless SDIO/PCIE devices
>>>   
>>>   maintainers:
>>> -  - Arend van Spriel <arend@broadcom.com>
>>> +  - Arend van Spriel <arend.vanspriel@broadcom.com>
>>>   
>>>   description:
>>>     The Broadcom Single chip MAC part for the BCM4329 family and
>>> @@ -27,7 +27,6 @@ properties:
>>>                 - brcm,bcm4341b0-fmac
>>>                 - brcm,bcm4341b4-fmac
>>>                 - brcm,bcm4341b5-fmac
>>> -              - brcm,bcm4329-fmac
>>>                 - brcm,bcm4330-fmac
>>>                 - brcm,bcm4334-fmac
>>>                 - brcm,bcm43340-fmac
>>> @@ -46,13 +45,15 @@ properties:
>>>                 - cypress,cyw43012-fmac
>>>                 - infineon,cyw43439-fmac
>>>             - const: brcm,bcm4329-fmac
>>> -      - enum:
>>> -          - brcm,bcm4329-fmac
>>> -          - pci14e4,43dc  # BCM4355
>>> -          - pci14e4,4464  # BCM4364
>>> -          - pci14e4,4488  # BCM4377
>>> -          - pci14e4,4425  # BCM4378
>>> -          - pci14e4,4433  # BCM4387
>>> +    - items:
>>> +          - enum:
>>> +              - pci14e4,43dc  # BCM4355
>>> +              - pci14e4,4464  # BCM4364
>>> +              - pci14e4,4488  # BCM4377
>>> +              - pci14e4,4425  # BCM4378
>>> +              - pci14e4,4433  # BCM4387
>>> +          - const: brcm,bcm4329-fmac
>>> +    - const: brcm,bcm4329-fmac
>>
>> And this does not make sense... You claim that some constrained was
>> droppped and you re-add it, but in fact you still add the same code as
>> it was before.
>>
>> NAK.
> 
> Ah, the last "const" actually makes sense, I missed that.
> 
> Commit still however lacks rationale why these devices are compatible.
> Plus existing rationale that e2e37224e8b3 changed something is entirely
> WRONG. It changed nothing. ZERO. It only added new devices, which was
> claimed are not compatible with brcm,bcm4329-fmac.

So is that claim true? What does it mean that these new devices are not 
compatible. If they are they should be in a separate binding or the 
applicable properties for these devices should be made conditional.

> Now if you claim that original commit which said "these devices are not
> compatible with brcm,bcm4329-fmac", then please provide arguments, not
> just say "other commit did something". It did nothing...

Not entirely true. Indeed new devices were added for which no 
"brcm,bcm4329-fmac" string is required in the compatible property. Also 
the commit added new properties for these new devices. Now in my opinion 
a driver should not use these properties without a "compatible" check. 
Hope we can agree to that. However, the driver patch for supporting the 
binding change does no such thing. So if we leave the binding as it 
currently is the driver will have to check if compatible has any of the 
listed PCI IDs before processing the properties. As all properties old 
and new are marked as optional I can not come up with an argument that 
these new devices are *not* compatible with brcm,bcm4329-fmac.

Regards,
Arend

> Best regards,
> Krzysztof
>