Re: [PATCH 1/2] dt-bindings: memory-controller: Document rev c.1.5 compatible

[Florian Fainelli]

On 12/18/24 03:37, Krzysztof Kozlowski wrote:
> On Tue, Dec 17, 2024 at 11:44:38AM -0800, Florian Fainelli wrote:
> > Document the revision c.1.5 compatible string that is present on newer
> > Broadcom STB memory controllers (74165 and onwards).
> >
> > Signed-off-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
> > ---
> >   .../bindings/memory-controllers/brcm,brcmstb-memc-ddr.yaml       | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/Documentation/devicetree/bindings/memory-controllers/brcm,brcmstb-memc-ddr.yaml b/Documentation/devicetree/bindings/memory-controllers/brcm,brcmstb-memc-ddr.yaml
> > index 4b072c879b02..99d79ccd1036 100644
> > --- a/Documentation/devicetree/bindings/memory-controllers/brcm,brcmstb-memc-ddr.yaml
> > +++ b/Documentation/devicetree/bindings/memory-controllers/brcm,brcmstb-memc-ddr.yaml
> > @@ -29,6 +29,7 @@ properties:
> >             - brcm,brcmstb-memc-ddr-rev-c.1.2
> >             - brcm,brcmstb-memc-ddr-rev-c.1.3
> >             - brcm,brcmstb-memc-ddr-rev-c.1.4
> > +          - brcm,brcmstb-memc-ddr-rev-c.1.5
>
> You should use v2.1 fallback and drop driver patch. Or explain in
> commit briefly why different approach is suitable.

Are you suggesting that we should have fallback compatible strings, such 
that we have something like this:

compatible = "brcm,brcmstb-memc-ddr-rev-c.1.5", 
"brcm,brcmstb-memc-ddr-rev-c", "brcm,brcmstb-memc-ddr"

and the driver only needs to match on "brcm,brcmstb-memc-ddr-rev-c" and 
apply the adequate register offset table?

If so, that is not how the current binding, and therefore DTBs are being 
deployed, so that will introduce a breakage until we update all DTBs in 
the field...
--
Florian