Re: [PATCH] dt-bindings: display: bridge: Drop requirement on input port for DSI devices

Marek Vasut
2022-04-01T18:25:41Z

On 4/1/22 20:21, Rob Herring wrote:
> On Fri, Apr 1, 2022 at 1:06 PM Marek Vasut <marex@denx.de> wrote:
>>
>> On 4/1/22 19:34, Rob Herring wrote:
>>> On Fri, Apr 01, 2022 at 03:22:19AM +0200, Marek Vasut wrote:
>>>> On 4/1/22 01:52, Rob Herring wrote:
>>>>> On Wed, 23 Mar 2022 16:48:23 +0100, Maxime Ripard wrote:
>>>>>> MIPI-DSI devices, if they are controlled through the bus itself, have to
>>>>>> be described as a child node of the controller they are attached to.
>>>>>>
>>>>>> Thus, there's no requirement on the controller having an OF-Graph output
>>>>>> port to model the data stream: it's assumed that it would go from the
>>>>>> parent to the child.
>>>>>>
>>>>>> However, some bridges controlled through the DSI bus still require an
>>>>>> input OF-Graph port, thus requiring a controller with an OF-Graph output
>>>>>> port. This prevents those bridges from being used with the controllers
>>>>>> that do not have one without any particular reason to.
>>>>>>
>>>>>> Let's drop that requirement.
>>>>>>
>>>>>> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
>>>>>> ---
>>>>>> .../devicetree/bindings/display/bridge/chipone,icn6211.yaml | 1 -
>>>>>> .../devicetree/bindings/display/bridge/toshiba,tc358762.yaml | 1 -
>>>>>> 2 files changed, 2 deletions(-)
>>>>>>
>>>>>
>>>>> I tend to agree with port@0 not being needed and really like
>>>>> consistency.
>>>>
>>>> The consistent thing to do would be to always use port@0 and OF graph, no ?
>>>
>>> I guess it depends how wide our scope for consistency is. Just DSI bus
>>> controlled bridges? DSI panels? All bridges and panels? Any panel
>>> without a control interface has the same dilemma as those can be a child
>>> of the display controller (or bridge) and not even use OF graph.
>>
>> I would likely opt for the OF graph in all cases, panels, bridges,
>> controllers. Then it would be consistent.
>>
>>> All simple panels don't require 'port' either. That's presumably only
>>> consistent because we made a single schema. I'd assume 'non-simple'
>>> panels with their own schema are not consistent.
>>
>> Maybe we would start requiring that port even for simple panels ?
>> The port is physically there on that panel after all.
>
> Fix this in all the dts files and then I'll agree. Though I think this
> ship has already sailed. I'd like to someday get to platforms without
> warnings and not just keep adding new warnings.

I doubt we can fix existing DTs, but can we at least require it for new
DTs ?