On 16/08/2024 09:45, Heiko Stübner wrote: > Am Freitag, 16. August 2024, 08:52:04 CEST schrieb Krzysztof Kozlowski: >> On 15/08/2024 15:49, Heiko Stübner wrote: >>> Am Donnerstag, 15. August 2024, 00:34:00 CEST schrieb Detlev Casanova: >>>> Add the compatible string for rockchip,rk3576-dw-mshc and add support >>>> for the rockchip,v2-tuning flag, a new feature of this core. >>>> >>>> Signed-off-by: Detlev Casanova <detlev.casanova@xxxxxxxxxxxxx> >>>> --- >>>> Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml | 1 + >>>> 1 file changed, 1 insertion(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml >>>> index 211cd0b0bc5f3..0543cdb51c657 100644 >>>> --- a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml >>>> +++ b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.yaml >>>> @@ -39,6 +39,7 @@ properties: >>>> - rockchip,rk3368-dw-mshc >>>> - rockchip,rk3399-dw-mshc >>>> - rockchip,rk3568-dw-mshc >>>> + - rockchip,rk3576-dw-mshc >>>> - rockchip,rk3588-dw-mshc >>>> - rockchip,rv1108-dw-mshc >>>> - rockchip,rv1126-dw-mshc >>> >>> this would mark the rk3576-dw-mshc as being the "same" as the >> >> Not the same, but compatible. >> >>> core rk3288 variant. rk3288 was the first controller introducing the >>> clock tuning for higher speeds. with the clocks being part of the CRU. >>> >>> As we can see in later patches, this rk3576 though changes that >>> setup with moving the tunable clock configurations into the controller >>> itself. >>> >>> So please don't claim to be compatible to the 3288, but instead start >>> a new block for this new set of controllers: >> >> The question is can new device work with old compatible (without new >> features)? > > the rk3288 and following have their clock phase tuning for hs-modes in > the main soc's clock controller. Hence you have the "ciu-drive" and > "ciu-sample" clocks [0]. > > On the rk3576 (and probably following) those clock phase settings moved > inside the mmc controller itself. So there are no external phase clocks > anymore. > > So right now we have two types in the binding, the rk2928 type [1], > used on the old rk3066 and rk3188 socs, that did not support mmc hs-modes > and the rk3288-type which introduced phase tuning via clocks from the > main clock controller. > > The rk3576 now switches to having phase tuning in the mmc controller > itself. So throwing that on unmodified code for the rk3288 will get you > degraded functionality, because the tuning won't work because there are > no "ciu-drive" and "ciu-sample" anymore . One could still argue that rest of programming model is the same, thus "degraded" mode counts as compatibility, but I do not insist on that. > > > And with that separate compatible we could also "tighten" the binding > a bit to make those additional clocks more explicit for the rk3288 type. This you can, and actually should, do with existing binding. Maybe just a bit more tricky/complicated code. Anyway, fine with both compatibility-approaches. Best regards, Krzysztof
