Re: [PATCH 08/13] dt-bindings: serial: fsl-linflexuart: add clock input properties

[Krzysztof Kozlowski <krzk@kernel.org>]

On 18/02/2026 14:26, Larisa Ileana Grigore wrote:
> On 2/16/2026 5:10 PM, Krzysztof Kozlowski wrote:
>> On 16/02/2026 16:02, Larisa Grigore wrote:
>>> From: Radu Pirea <radu-nicolae.pirea@nxp.com>
>>>
>>> Add optional support for the two clock inputs used by the LINFlexD UART
>>> controller:
>>> - "lin": LIN_BAUD_CLK
>>> - "ipg": LINFLEXD_CLK
>>>
>>> The clock inputs are kept optional to maintain compatibility with the
>>> S32V234 platform.
>>
>> Does S32V234 have the clocks? I don't understand the "maintain
>> compatibility" in this context. Either you have or you have not clocks,
>> which should be expressed in schema (: false, see example schema).
>>
> Hello Krzysztof,
> 
> Thanks for pointing this out! I will update both the schema and the 
> commit description.
> S32V234 does not expose these clocks in its device tree—on this platform 
> the LINFlexD clocks are set up and enabled by U‑Boot, so they are not 
> available to the kernel.

So there are clocks. DTS is being used by bootloader, so how bootloader
is going to set up clocks for S32V234 if no one provides them?

This looks like buggy/incomplete approach, although I understand that
the original binding had the issue.


> The changes in this patch are intended specifically for S32G2/G3, where 
> the clocks are provided in the DT and required by the driver.
> 
>>>
>>> Signed-off-by: Radu Pirea <radu-nicolae.pirea@nxp.com>
>>> Co-developed-by: Larisa Grigore <larisa.grigore@oss.nxp.com>
>>> Signed-off-by: Larisa Grigore <larisa.grigore@oss.nxp.com>
>>> ---
>>>   .../bindings/serial/fsl,s32-linflexuart.yaml   | 18 ++++++++++++++++++
>>>   1 file changed, 18 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.yaml b/Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.yaml
>>> index 4171f524a928..885f0b1b3492 100644
>>> --- a/Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.yaml
>>> +++ b/Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.yaml
>>> @@ -34,6 +34,14 @@ properties:
>>>     interrupts:
>>>       maxItems: 1
>>>   
>>> +  clocks:
>>> +    maxItems: 2
>>> +
>>> +  clock-names:
>>> +    items:
>>> +      - const: lin
>>> +      - const: ipg
>>> +
>>>   required:
>>>     - compatible
>>>     - reg
>>> @@ -48,3 +56,13 @@ examples:
>>>           reg = <0x40053000 0x1000>;
>>>           interrupts = <0 59 4>;
>>>       };
>>> +
>>> +  - |
>>> +    serial@401c8000 {
>>> +        compatible = "nxp,s32g2-linflexuart",
>>> +                     "fsl,s32v234-linflexuart";
>>> +        reg = <0x401C8000 0x3000>;
>>> +        interrupts = <0 82 1>;
>>> +        clocks = <&clks 14>, <&clks 13>;
>>> +        clock-names = "lin", "ipg";
>>
>> Just add the clocks to existing example. No need for new example for
>> each new property.
>>
>>> +    };
> 
> The existing node refers to S32V234 which does not expose any clock 
> properties in its device tree. Because of this, I couldn’t extend that 

You just said S32V234 has clocks...

> example with clocks and clock-names. The additional example is there 
> only to illustrate the S32G2 case, where the clocks are required and 
> actually present in the device tree. Should I remove it?
> 
> Best regards,
> Larisa
>>
>> Best regards,
>> Krzysztof
> 


Best regards,
Krzysztof