Re: [PATCH 5/5] powerpc: dts: remove label = "cpu" from DSA dt-binding

[Rob Herring]

On Thu, Dec 01, 2022 at 06:39:02PM +0100, Pali Rohár wrote:
> On Thursday 01 December 2022 21:40:03 Michael Ellerman wrote:
> > Arınç ÜNAL <arinc.unal@xxxxxxxxxx> writes:
> > > This is not used by the DSA dt-binding, so remove it from all devicetrees.
> > >
> > > Signed-off-by: Arınç ÜNAL <arinc.unal@xxxxxxxxxx>
> > > ---
> > >  arch/powerpc/boot/dts/turris1x.dts | 2 --
> > >  1 file changed, 2 deletions(-)
> > 
> > Adding Pali to Cc.
> > 
> > These were only recently updated in commit:
> > 
> >   8bf056f57f1d ("powerpc: dts: turris1x.dts: Fix labels in DSA cpu port nodes")
> > 
> > Which said:
> > 
> >   DSA cpu port node has to be marked with "cpu" label.
> > 
> > But if the binding doesn't use them then I'm confused why they needed to
> > be updated.
> > 
> > cheers
> 
> I was told by Marek (CCed) that DSA port connected to CPU should have
> label "cpu" and not "cpu<number>". Modern way for specifying CPU port is
> by defining reference to network device, which there is already (&enet1
> and &enet0). So that change just "fixed" incorrect naming cpu0 and cpu1.
> 
> So probably linux kernel does not need label = "cpu" in DTS anymore. But
> this is not the reason to remove this property. Linux kernel does not
> use lot of other nodes and properties too... Device tree should describe
> hardware and not its usage in Linux. "label" property is valid in device
> tree and it exactly describes what or where is this node connected. And
> it may be used for other systems.
> 
> So I do not see a point in removing "label" properties from turris1x.dts
> file, nor from any other dts file.

Well, it seems like a bit of an abuse of 'label' to me. 'label' should 
be aligned with a sticker or other identifier identifying something to a 
human. Software should never care what the value of 'label' is.

Rob