Re: [PATCH v2 1/2] dt-bindings: can: renesas,rcar-canfd: Document renesas,fd-only property

[Krzysztof Kozlowski <krzk@kernel.org>]

On 23/11/2025 16:15, Biju Das wrote:
> Hi Krzysztof Kozlowski,
> 
>> -----Original Message-----
>> From: Krzysztof Kozlowski <krzk@kernel.org>
>> Sent: 23 November 2025 14:22
>> Subject: Re: [PATCH v2 1/2] dt-bindings: can: renesas,rcar-canfd: Document renesas,fd-only property
>>
>> On 23/11/2025 15:17, Biju Das wrote:
>>> Hi Krzysztof Kozlowski,
>>>
>>>> -----Original Message-----
>>>> From: Biju Das
>>>> Sent: 23 November 2025 14:06
>>>> Subject: RE: [PATCH v2 1/2] dt-bindings: can: renesas,rcar-canfd:
>>>> Document renesas,fd-only property
>>>>
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: Krzysztof Kozlowski <krzk@kernel.org>
>>>>> Sent: 23 November 2025 13:26
>>>>> Subject: Re: [PATCH v2 1/2] dt-bindings: can: renesas,rcar-canfd:
>>>>> Document renesas,fd-only property
>>>>>
>>>>> On 23/11/2025 12:23, Biju wrote:
>>>>>> From: Biju Das <biju.das.jz@bp.renesas.com>
>>>>>>
>>>>>> The CANFD on RZ/{G2L,G3E} and R-Car Gen4 support 3 modes FD-Only
>>>>>> mode, Classical CAN mode and CAN-FD mode. In FD-Only mode,
>>>>>> communication in Classical CAN frame format is disabled. Document
>>>>>> renesas,fd-only to handle this mode. As these SoCs support 3 modes,
>>>>>> update the description of renesas,no-can-fd property and disallow it for R-Car Gen3.
>>>>>>
>>>>>> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
>>>>>> ---
>>>>>>  v1->v2:
>>>>>>   * Added conditional check to disallow fd-only mode for R-Car Gen3.
>>>>>> ---
>>>>>>  .../bindings/net/can/renesas,rcar-canfd.yaml  | 24
>>>>>> ++++++++++++++++---
>>>>>>  1 file changed, 21 insertions(+), 3 deletions(-)
>>>>>>
>>>>>> diff --git
>>>>>> a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
>>>>>> b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
>>>>>> index f4ac21c68427..a52244f0b5d1 100644
>>>>>> ---
>>>>>> a/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml
>>>>>> +++ b/Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.
>>>>>> +++ y
>>>>>> +++ am
>>>>>> +++ l
>>>>>> @@ -125,9 +125,17 @@ properties:
>>>>>>    renesas,no-can-fd:
>>>>>>      $ref: /schemas/types.yaml#/definitions/flag
>>>>>>      description:
>>>>>> -      The controller can operate in either CAN FD only mode (default) or
>>>>>> -      Classical CAN only mode.  The mode is global to all channels.
>>>>>> -      Specify this property to put the controller in Classical CAN only mode.
>>>>>> +      The controller can operate in either CAN-FD mode (default) or FD-Only
>>>>>> +      mode (RZ/{G2L,G3E} and R-Car Gen4) or Classical CAN mode. Specify this
>>>>>> +      property to put the controller in Classical CAN mode.
>>>>>> +
>>>>>> +  renesas,fd-only:
>>>>>> +    $ref: /schemas/types.yaml#/definitions/flag
>>>>>> +    description:
>>>>>> +      The CANFD on RZ/{G2L,G3E} and R-Car Gen4 SoCs support 3 modes FD-Only
>>>>>> +      mode, Classical CAN mode and CAN-FD mode (default). In FD-Only mode,
>>>>>> +      communication in Classical CAN frame format is disabled. Specify this
>>>>>> +      property to put the controller in FD-Only mode.
>>>>>>
>>>>>>    assigned-clocks:
>>>>>>      description:
>>>>>> @@ -267,6 +275,16 @@ allOf:
>>>>>>        patternProperties:
>>>>>>          "^channel[6-7]$": false
>>>>>>
>>>>>> +  - if:
>>>>>> +      properties:
>>>>>> +        compatible:
>>>>>> +          contains:
>>>>>> +            enum:
>>>>>> +              - renesas,rcar-gen3-canfd
>>>>>> +    then:
>>>>>> +      properties:
>>>>>> +        renesas,fd-only: false
>>>>>> +
>>>>>
>>>>> You did not respond to my first paragraph from previous version. As
>>>>> I said, you now need oneOf to restrict these, since you are not using simple enum.
>>>>
>>>> This is restricting for R-Car Gen3. DT binding check returns error if 'renesas,fd-only"
>>>> is defined for R-Car Gen3.
>>>>
>>>> Am I missing anything here?
>>
>> Add on G2L no-can-fd and fd-only. What do you see? What is expected?
> 
> Can you please point me to an example where two boolean properties handled
> like this? I did not find one.
> 
> In my case, oneOf check is not valid under allOf??
> 
> For eg: RS485, We cannot set both boolean properties active-high and active-low together.
> 


I none of them are required then indeed not oneOf, but some if:then:.

https://elixir.bootlin.com/linux/v6.4-rc7/source/Documentation/devicetree/bindings/net/qcom,ipa.yaml#L174

And that's why you should have used enum in the first place for the
first property.

Best regards,
Krzysztof