Hi Geert, On Thursday 20 Apr 2017 12:55:28 Geert Uytterhoeven wrote: > On Thu, Apr 20, 2017 at 12:42 PM, Laurent Pinchart wrote: > > On Thursday 20 Apr 2017 11:36:59 Geert Uytterhoeven wrote: > >> On Mon, Mar 27, 2017 at 10:48 AM, Laurent Pinchart wrote: > >>> On Friday 24 Mar 2017 14:37:44 Geert Uytterhoeven wrote: > >>>> Update r8a7795.dtsi so it corresponds to R-Car H3 ES2.0 or later: > >>>> - The following devices no longer exist on ES2.0, and are thus > >>>> removed: > >>>> fcpf2, fcpvd3, fcpvi2, fdp1-2, usb3-if1, vspd3, vspi2. > >>>> > >>>> - The DU <-> VSPD topology is different on ES2.0, hence remove the > >>>> "vsps" property from the DU node until the driver can handle this. > >>> > >>> I think I'll need a different compatible string between ES1.x and ES2 > >>> for the DU. It could make sense to move the whole DU node to *-es1.dtsi. > >>> We can decide about that later when I'll have a DU driver prototype > >>> ready. > >> > >> Why would you need a different compatible string? > >> Can't you use soc_device_match() to handle ES1.x SoCs? > >> > >> The different DU <-> VSPD topology is handled through the vsps property > >> in > >> DTS. Are the ports different, too? That can be handled in DTS. > > > > My point (not expressed clearly) was that, as I'll need a different vsps > > property, I can as well go for a different compatible string. > > Do you need a different vsps property? > AFAIK, the current array links each DU channel to a VSPD. > When a VSPD is shared between multiple channels, you can still link these > channels to the same VSPD. > > Or is my understanding incorrect? Do you mean listing the same VSP multiple times in the vsps array ? Yes, from a bindings point of view I think that would work too. That is, until we get a ES2.1 that will have a completely different hardware topology :-) > >> The main reason why I kept the DU node in r8a7795.dtsi is that the board > >> DTS refers to it. Sharing board DTS means there needs to be at least a > >> placeholder node for the DU in r8a7795.dtsi, unless you want to keep on > >> shuffling board overrides around. > > > > As the ports are identical it makes sense to share the same board DTS, I > > agree with you. We could override the compatible string in > > r8a7795-es1.dtsi and leave it blank in r8a7795.dtsi for now, as there's > > no driver support for ES2.0. That's a bit of a workaround as it shouldn't > > matter to DT whether driver support is available or not. On the other > > hand, leaving the vsps property out is a workaround too. > > > > The current driver will fail probing if the number of VSPs is different > > than the number of CRTCs, so I believe you can keep the vsps property in > > r8a7795.dtsi with 3 VSPS without causing any problem. However, there's no > > DT bindings for the H3 ES2.0 DU yet, so we would end up merging DT > > without bindings, which is not good. I think that regardless of how we > > proceed, keeping the DU node in the ES2.0 .dtsi will be a violation of > > that policy. > > What does the current driver do if the number of VSPs is the same as the > number of CRTCs, but some VSPs are listed more than once? > I guess it will break in a subtle way, instead of refusing to probe? Correct, it will be messy. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
