Re: [EXT] Re: [PATCH v1] arm64: dts: fsl: ls1028a-rdb: Add dts file to choose swp5 as dsa master

Vladimir Oltean
2021-08-13T14:07:58Z

On Fri, Aug 13, 2021 at 01:56:53PM +0000, Hongbo Wang wrote:
> > You will end up with two DT blobs with the same top level compatible. This is
> > going to cause confusion. I suggest you add an additional top level compatible
> > to make it clear this differs from the compatible = "fsl,ls1028a-rdb",
> > "fsl,ls1028a" blob.
> >
> > Andrew
>
> hi Andrew,
>
> thanks for comments.
>
> this "fsl-ls1028a-rdb-dsa-swp5-eno3.dts" is also for fsl-ls1028a-rdb platform,
> the only difference with "fsl-ls1028a-rdb.dts" is that it use swp5 as dsa master, not swp4,
> and it's based on "fsl-ls1028a-rdb.dts", so I choose this manner,
> if "fsl-ls1028a-rdb.dts" has some modification for new version, this file don't need be changed.

I tend to agree with Hongbo. What confusion is it going to cause? It is
fundamentally the same board, just an Ethernet port stopped having
'status = "disabled"' and another changed role, all inside of the SoC
with no externally-visible change. If anything, I think that creating a
new top-level compatible for each small change like this would create a
bloat-fest of its own.

I was going to suggest as an alternative to define a device tree overlay
file with the changes in the CPU port assignment, instead of defining a
wholly new DTS for the LS1028A reference design board. But I am pretty
sure that it is not possible to specify a /delete-property/ inside a
device tree overlay file, so that won't actually work.