Re: [PATCH v3 3/3] ARM: dts: stm32: fix several DT warnings on stm32mp15

[Marek Vasut]

On 5/29/23 10:07, Raphael Gallais-Pou wrote:

Hi,

> > > > I think if you retain the stm32mp151.dtsi &ltdc { port { #address-cells = <1>;
> > > > #size-cells = <0>; }; }; part, then you wouldn't be getting any warnings
> > > > regarding LTDC , and you wouldn't have to remove the unit-address from
> > > > endpoint@0 .
> > > >
> > > > btw. I do use both endpoint@0/endpoint@1 in Avenger96 DTOs, but those are not
> > > > submitted yet, I have to clean them up a bit more first.
> > > >
> > > > > One way to do it would be to make the endpoint@0 go down in the device-tree
> > > > > with
> > > > > its dependencies, so that both endpoints are the same level without generating
> > > > > noise.
> > > >
> > > > I'm afraid I really don't quite understand which warning you're referring to.
> > > > Can you please share that warning and ideally how to trigger it (the
> > > > command-line incantation) ?
> > >
> > > Using '$ make dtbs W=1', you can observe several of the followings:
> > >
> > > arch/arm/boot/dts/stm32mp151.dtsi:1533.9-1536.6: Warning
> > > (avoid_unnecessary_addr_size): /soc/display-controller@5a001000/port:
> > > unnecessary #address-cells/#size-cells without "ranges" or child "reg" property
> > > arch/arm/boot/dts/stm32mp151.dtsi:1533.9-1536.6: Warning (graph_child_address):
> > > /soc/display-controller@5a001000/port: graph node has single child node
> > > 'endpoint@0', #address-cells/#size-cells are not necessary
> > >
> > > This &ltdc { port { #address-cells = <1>; #size-cells = <0>; }; }; part is
> > > actually annoying. This is because there is several device-trees that only got
> > > one endpoint, and some other that includes two.
> > >
> > > For instance: stm32mp15xx-dhcor-avenger96.dtsi vs stm32mp157c-dk2.dts.
> > >
> > > I would like to remove to root part of address/size field and let only the lower
> > > device-trees with with multiple endpoints handle their own fields. I hope this
> > > explains a bit better my process.
> >
> > After thinking about this some more, and digging through LTDC driver, and
> > testing on EV1, I think dropping the LTDC node endpoint@N and reg=<N>
> > altogether and just using port/endpoint (singular) is fine.
> >
> > You might want to split the DSI node specific changes and the LTDC node
> > specific changes into separate patches (LTDC specific change like you did in
> > 1/3).
>
> Yes, I prepared a new serie with that split, to that it is better to read and
> review.

Thank you !