On 10/15/2025, Frank Li wrote: > On Wed, Oct 15, 2025 at 05:14:02PM +0800, Liu Ying wrote: >> On 10/14/2025, Marek Vasut wrote: >>> 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 <[email protected]> >>>>>> >>>>>> 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. >> >> Yes. The design decision was made to avoid using OF graph to describe >> links between DC blocks due to the complexity. > > Any previous discuission? Using registers base address to determiate ID
Yes, you may find the discussion in https://patchwork.freedesktop.org/series/135786/ > is not solution. Well it is, based on the discussion. And it's also used by MSM DPU, see drivers/gpu/drm/msm/disp/dpu1/catalog/*.h, though IIRC someone said it's not the best solution for MSM DPU. > > Frank > >> >>> >>> 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. >> >> >> -- >> Regards, >> Liu Ying -- Regards, Liu Ying
