On Sun, Nov 16, 2025 at 8:00 PM Jernej Škrabec <[email protected]> wrote: > > Hi! > > Dne nedelja, 16. november 2025 ob 12:33:55 Srednjeevropski standardni čas je > Krzysztof Kozlowski napisal(a): > > On 16/11/2025 12:33, Krzysztof Kozlowski wrote: > > > On Sat, Nov 15, 2025 at 03:13:46PM +0100, Jernej Skrabec wrote: > > >> As it turns out, current H616 DE33 binding was written based on > > >> incomplete understanding of DE33 design. Namely, planes are shared > > >> resource and not tied to specific mixer, which was the case for previous > > >> generations of Display Engine (DE3 and earlier). > > >> > > >> This means that current DE33 binding doesn't properly reflect HW and > > >> using it would mean that second mixer (used for second display output) > > >> can't be supported. > > >> > > >> Update DE33 mixer binding so instead of referencing planes register > > >> space, it contains phandle to newly introduced DE33 planes node. > > >> > > >> There is no user of this binding yet, so changes can be made safely, > > >> without breaking any backward compatibility. > > > > > > And why would you configure statically - per soc - always the same plane > > > as per mixer? If you do that, it means it is really fixed and internal > > > to display engine thus should not be exposed in DT. > > Not sure I understand what you mean. H616 SoC has 6 planes which are > represented with single DE33 planes node (see previous DT binding). > Driver has to decide initial allocation. For example, 3 planes for each > mixer. However, nothing prevents to allocate 1 plane to first mixer and > 5 to other. You can even allocate all 6 planes to one mixer and none to > the other, if board has only one output enabled. > > In any case, plane allocation is runtime decision and has nothing to do > with DT. Since planes are shared resource, their register space can't be > assigned to only one mixer. > > See [1] for example how this would look like. > > > > > > > Describing each IP block resource in DT is way too granular. > > > > > > > BTW, everything is update, thus subject is really non-informative. > > I guess "fix" would be more descriptive.
Or maybe be more specific, like "split out layers register space to separate binding / node". ChenYu > Best regards, > Jernej > > [1] > https://github.com/jernejsk/linux-1/blob/d93d56d92db52c7ff228c0532a1045de02e0662c/arch/arm64/boot/dts/allwinner/sun50i-h616.dtsi#L181-L235 > > > >
