[PATCH 05/39] drm/imx: dc: Rework dc_subdev_get_id() to drop ARRAY_SIZE() use

[Marek Vasut]

On 10/14/25 5:11 PM, Frank Li wrote:
> On Tue, Oct 14, 2025 at 04:03:37PM +0200, Marek Vasut wrote:
>> On 10/13/25 6:56 PM, Frank Li wrote:
>>> On Sat, Oct 11, 2025 at 06:51:20PM +0200, Marek Vasut wrote:
>>>> Rework dc_subdev_get_id() to drop ARRAY_SIZE() use and use empty trailing
>>>> entry in each ID look up array instead. This allows passing of those arrays
>>>> around as OF match data, which will be useful when using this pipeline on
>>>> i.MX95, which has different address-to-ID mapping.
>>>>
>>>> Signed-off-by: Marek Vasut <marek.vasut at mailbox.org>
>>>
>>> This change is okay. but my questions is why need map register to id.
>>
>> This seems to be a recurring pattern in the driver, where some components
>> need to find other components to link with them. The mapping is fixed, and
>> since the DT does not encode link IDs, the resolution of the mapping has to
>> happen by mapping the component base addresses to the IDs first.
> 
> In graphic link, port@<n>, n should be id? why not use it?
I suspect you could model the relationships between the DC blocks using 
OF graph, yes. I also suspect that description would be very complex in 
DT, considering the amount of blocks and links this device contains. I 
suspect this is why there is no such DT description using OF graph.

I think it might also be good to talk to Liu directly about the original 
design decision and why this id mapping was done the way it was done, 
they should know better than me.