On Tue, Jun 21, 2022 at 09:00:36AM +0200, Krzysztof Kozlowski wrote: > On 20/06/2022 22:04, Serge Semin wrote: > > On Mon, Jun 20, 2022 at 09:46:25PM +0200, Krzysztof Kozlowski wrote: > >> On 20/06/2022 21:30, Serge Semin wrote: > >>> On Mon, Jun 13, 2022 at 12:56:47PM -0700, Brad Larson wrote: > >>>> From: Brad Larson <blarson@xxxxxxx> > >>>> > >>>> The AMD Pensando Elba SoC has integrated the DW APB SPI Controller > >>>> > >>>> Signed-off-by: Brad Larson <blarson@xxxxxxx> > >>>> --- > >>>> Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml | 2 ++ > >>>> 1 file changed, 2 insertions(+) > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml > >>>> index e25d44c218f2..2a55b947cffc 100644 > >>>> --- a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml > >>>> +++ b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml > >>>> @@ -73,6 +73,8 @@ properties: > >>>> - renesas,r9a06g032-spi # RZ/N1D > >>>> - renesas,r9a06g033-spi # RZ/N1S > >>>> - const: renesas,rzn1-spi # RZ/N1 > >>> > >>>> + - description: AMD Pensando Elba SoC SPI Controller > >>>> + const: amd,pensando-elba-spi > >>> > >>> Not enough. The driver requires to have a phandle reference to the > >>> Pensando System Controller. So the property like > >>> "amd,pensando-elba-syscon" is also needed to be added to the DT schema > >>> otherwise should the dt-schema tool correctly handle the > >>> "unevaluatedProperties: false" setting (Rob says it isn't fully > >>> supported at the moment), the dtbs_check procedure will fail on your > >>> dts evaluation. > >> > > > >> The property was here before, now removed, so I assume it was also > >> removed from the driver and DTS. Isn't that the case? > > > > Ah, the property has been indeed removed. The driver now searches for > > the system controller by the next compatible string: > > "amd,pensando-elba-syscon" using the > > syscon_regmap_lookup_by_compatible() method. My mistake. Sorry for the > > noise. > > > > * Though personally I'd prefer to have a property with the phandle > > reference in order to signify the connection between the system controller > > and the SPI-controller. Otherwise the implicit DT bindings like having > > the "amd,pensando-elba-syscon"-compatible syscon gets to be > > hidden behind the DT scene. But seeing we have already got the Microsemi > > platform with such semantic, I can't insist on fixing this. > > I agree entirely, this should be explicit syscon-type property. Looking > up for compatibles: > - creates hidden (not expressed via bindings) dependency between nodes, > - is not portable and several people struggled with it later and needed > backward-compatible code (many examples, let's just give recent one: [1]) > > > [1] > https://lore.kernel.org/all/20220619151225.209029-10-tmaimon77@xxxxxxxxx/ Seems even more reasonable now. Thanks for providing a bright example justifying the property-based approach. @Brad, could you get back the property with a phandle to the syscon DT-node? (No need in adding the CS CSR address as the phandle argument, just a phandle.) -Sergey > > > Best regards, > Krzysztof
