On Wed, Jun 22, 2022 at 02:10:55PM +0800, Wenbin Mei wrote: > On Wed, 2022-06-22 at 09:57 +0800, Chunfeng Yun wrote: > > On Tue, 2022-06-21 at 09:14 +0200, Krzysztof Kozlowski wrote: > > > On 20/06/2022 17:50, Nícolas F. R. A. Prado wrote: > > > > On Mon, Jun 20, 2022 at 10:50:57AM +0200, Krzysztof Kozlowski > > > > wrote: > > > > > On 20/06/2022 08:59, Chunfeng Yun wrote: > > > > > > On Sun, 2022-06-19 at 14:05 +0200, Krzysztof Kozlowski wrote: > > > > > > > On 19/06/2022 09:46, Chunfeng Yun wrote: > > > > > > > > On Fri, 2022-06-17 at 18:25 -0700, Krzysztof Kozlowski > > > > > > > > wrote: > > > > > > > > > On 17/06/2022 15:29, Nícolas F. R. A. Prado wrote: > > > > > > > > > > The current clock list in the binding doesn't allow > > > > > > > > > > for > > > > > > > > > > one of > > > > > > > > > > the > > > > > > > > > > optional clocks to be missing and a subsequent clock > > > > > > > > > > to > > > > > > > > > > be > > > > > > > > > > present. > > > > > > > > > > An > > > > > > > > > > example where this is an issue is in mt8192.dtsi, > > > > > > > > > > which > > > > > > > > > > has > > > > > > > > > > "sys_ck", > > > > > > > > > > "ref_ck", "xhci_ck" and would cause dtbs_check > > > > > > > > > > warnings. > > > > > > > > > > > > > > > > > > > > Change the clock list in a way that allows the middle > > > > > > > > > > optional > > > > > > > > > > clocks to > > > > > > > > > > be missing, while still guaranteeing a fixed order. > > > > > > > > > > The > > > > > > > > > > "ref_ck" is > > > > > > > > > > kept > > > > > > > > > > as a const even though it is optional for simplicity, > > > > > > > > > > since it > > > > > > > > > > is > > > > > > > > > > present in all current dts files. > > > > > > > > > > > > > > > > > > > > Signed-off-by: Nícolas F. R. A. Prado < > > > > > > > > > > nfraprado@xxxxxxxxxxxxx> > > > > > > > > > > --- > > > > > > > > > > > > > > > > > > > > .../devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > > xhci.yaml | 9 > > > > > > > > > > +++++++-- > > > > > > > > > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > > > > > > > > > > > > > > > > > diff --git > > > > > > > > > > a/Documentation/devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > > xhci.yaml > > > > > > > > > > b/Documentation/devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > > xhci.yaml > > > > > > > > > > index 63cbc2b62d18..99a1b233ec90 100644 > > > > > > > > > > --- > > > > > > > > > > a/Documentation/devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > > xhci.yaml > > > > > > > > > > +++ > > > > > > > > > > b/Documentation/devicetree/bindings/usb/mediatek,mtk- > > > > > > > > > > xhci.yaml > > > > > > > > > > @@ -80,8 +80,13 @@ properties: > > > > > > > > > > items: > > > > > > > > > > - const: sys_ck # required, the following > > > > > > > > > > ones > > > > > > > > > > are > > > > > > > > > > optional > > > > > > > > > > - const: ref_ck > > > > > > > > > > - - const: mcu_ck > > > > > > > > > > - - const: dma_ck > > > > > > > > > > + - enum: > > > > > > > > > > + - mcu_ck > > > > > > > > > > + - dma_ck > > > > > > > > > > + - xhci_ck > > > > > > > > > > + - enum: > > > > > > > > > > + - dma_ck > > > > > > > > > > + - xhci_ck > > > > > > > > > > - const: xhci_ck > > > > > > > > > > > > > > > > > > You allow now almost any order here, including > > > > > > > > > incorrect > > > > > > > > > like > > > > > > > > > sys,ref,xhci,xhci,xhci. > > > > > > > > > > > > > > > > > > The order of clocks has to be fixed and we cannot allow > > > > > > > > > flexibility. > > > > > > > > > Are > > > > > > > > > you sure that these clocks are actually optional (not > > > > > > > > > wired to > > > > > > > > > the > > > > > > > > > device)? > > > > > > > > > > > > > > > > In fact, these optional clocks are fixed, due to no gates > > > > > > > > are > > > > > > > > provided, > > > > > > > > SW can't control them by CCF; > > > > > > > > In this case, I usually use a fixed clock, or ignore it. > > > > > > > > > > > > > > But in some versions these clocks are controllable or not? > > > > > > > > > > > > Some SoCs are controllable, some ones are not (fixed clock). > > > > > > > > > > Thanks for confirming. Then I would prefer to make these clocks > > > > > required > > > > > (not optional) and always provide them - via common clock > > > > > framework or > > > > > fixed-clock. > > > > > > > > Hi Krzysztof and Chunfeng, > > > > > > > > thank you both for the feedback. > > > > > > > > Since the solution I proposed in this patch is not acceptable I > > > > see > > > > two options: > > > > 1. Split the clocks in several if blocks matched by compatibles > > > > 2. Make the clocks required and use fixed-clock nodes for the > > > > missing clocks in > > > > the DT > > > > > > > > My understanding is that 1 is the desirable solution if the clock > > > > is really > > > > missing in some hardware variants, while 2 is desirable if all > > > > hardware variants > > > > really receive all the clocks, only that on some variants they're > > > > fixed and not > > > > controlable by SW. > > > > > > > > From what I'm reading of this discussion it seems that the latter > > > > is the case > > > > here and thus we should go for 2. Is this correct? > > > > > > This is how I understood it as well, so correct from my side. > > > > Also right for me. > > > > > > > > > > > > > Also Chunfeng, do you have information on whether the same is > > > > true > > > > for the MMC > > > > HW block? I recently submitted some changes to that binding [1] > > > > but > > > > I followed > > > > approach 1 there instead. However if all the clocks are present > > > > in > > > > the HW level > > > > there as well it would make more sense for me to change it to > > > > follow approach 2. > > > > I discussed it with Wenbin, MMC seems a little different with USB, > > > > Hi Wenbin, > > > > Please give some comments about MMC, thanks > > > Hi Chunfeng, > > As we discussed, the following change is the desirable solution for the > Mediatek MMC HW. > > https://lists.infradead.org/pipermail/linux-mediatek/2022-June/043691.html Got it, thank you both. I'll keep that approach for MMC then, and change the one here for USB. Thanks, Nícolas
