Re: [PATCH] dt-bindings: display: bridge: lt9211: Require data-lanes on DSI input ports

[Krzysztof Kozlowski <krzk@kernel.org>]

On 07/04/2026 16:51, Marek Vasut wrote:
> On 4/7/26 10:00 AM, Krzysztof Kozlowski wrote:
> 
>>> NOTE: For example Linux kernel driver does already use that information
>>>        and fails to probe if it is missing. There are currently no intree
>>
>> The first sentence must be part of the commit msg. That is important
>> reason why you are doing this... but I don't see how you achieve any of
>> this. Look:
>>
>>
>>>        users for this binding, so no new warnings will be generated once
>>>        this is applied, but a new user is about to be added.
>>
>> What warnings? How?
> 
> There are no in-tree users of this binding, so no DT checker warnings 
> will be produced on existing in-tree DTs. I am in the process of adding 
> a DTO which uses this binding now in arm64: dts: imx8mm: imx8mp: Add 
> DTOs for Data Modul i.MX8M Mini and Plus eDM SBC

So add new user, apply this and what warnings are you seeing?

> 
>>> ---
>>>   .../display/bridge/lontium,lt9211.yaml        | 37 ++++++++++++++++++-
>>>   1 file changed, 35 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/display/bridge/lontium,lt9211.yaml b/Documentation/devicetree/bindings/display/bridge/lontium,lt9211.yaml
>>> index 9a6e9b25d14a9..5264fb2b68b78 100644
>>> --- a/Documentation/devicetree/bindings/display/bridge/lontium,lt9211.yaml
>>> +++ b/Documentation/devicetree/bindings/display/bridge/lontium,lt9211.yaml
>>> @@ -36,18 +36,50 @@ properties:
>>>   
>>>       properties:
>>>         port@0:
>>> -        $ref: /schemas/graph.yaml#/properties/port
>>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>>
>> OK, that's correct.
>>
>>> +        unevaluatedProperties: false
>>>           description:
>>>             Primary MIPI DSI port-1 for MIPI input or
>>>             LVDS port-1 for LVDS input or DPI input.
>>>   
>>> +        properties:
>>> +          endpoint:
>>> +            $ref: /schemas/media/video-interfaces.yaml#
>>> +            unevaluatedProperties: false
>>
>> That's correct.
>>
>>> +
>>> +            properties:
>>> +              data-lanes:
>>> +                description: array of physical DSI data lane indexes.
>>> +                minItems: 1
>>> +                items:
>>> +                  - const: 1
>>> +                  - const: 2
>>> +                  - const: 3
>>> +                  - const: 4
>>
>> That's almost redundant in this context - it was already there - and the
>> point is that it solves noting in the problem you had. Binding still
>> does not validate the ABI and does not match it, still.
>>
>> Since commit foo bar, driver needs data-lanes, so what you need to do is
>> allow them and to require them. You can also specify their constraints
>> if device can be configured multiple ways, up to 4 lanes.
> Please pardon my ignorance, what exactly do you propose I change in this 
> patch ?

Follow the subject - require data-lanes. That's was the main point of
this change, no?

Best regards,
Krzysztof