Re: [PATCH 1/3] dt-bindings: spi: add SpacemiT K1 SPI support

[Alex Elder]

On 9/17/25 7:16 PM, Yixun Lan wrote:
> Hi Alex,
>
> On 18:40 Wed 17 Sep     , Alex Elder wrote:
> > On 9/17/25 6:15 PM, Yixun Lan wrote:
> > > Hi Alex,
> > >
> > > On 17:07 Wed 17 Sep     , Alex Elder wrote:
> > > > Add support for the SPI controller implemented by the SpacemiT K1 SoC.
> > > >
> > > > Signed-off-by: Alex Elder <elder@xxxxxxxxxxxx>
> > > > ---
> > > >    .../bindings/spi/spacemit,k1-spi.yaml         | 94 +++++++++++++++++++
> > > >    1 file changed, 94 insertions(+)
> > > >    create mode 100644 Documentation/devicetree/bindings/spi/spacemit,k1-spi.yaml
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/spi/spacemit,k1-spi.yaml b/Documentation/devicetree/bindings/spi/spacemit,k1-spi.yaml
> > > > new file mode 100644
> > > > index 0000000000000..5abd4fe268da9
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/spi/spacemit,k1-spi.yaml
> ..
> > > > +
> > > > +  spacemit,k1-ssp-id:
> > > > +    description: SPI controller number
> > > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > could you explain a little bit why this vendor specific property should
> > > be introduced? I took a look at the code, and didn't get the reason
> > > behind.. or what's the problem of simply using "pdev->id"?
> >
> > This property was carried over from the vendor code.  It is
> inherit from vendor code isn't a valid reason
>
> > optional, and if it isn't specified, the platform device ID (-1)
> > will be used.  It's just intended to provide a well-defined ID
> > for a particular SPI controller.
> while looking at the code, it seems you can use alias to map specific id
> to the spi controller, it even can do non-linear map, something like
> 	spi0 = &spi3;
I've never used this before, but yes, it looks like it's exactly
what I want.  I'll just get rid of the "spacemit,k1-ssp-id" DT
property entirely.  Easy.

> plese check of_alias_get_id()
>
> note, I haven't actually verified on board, just look through the code
>
> > > we should really be careful to introduce vendor specific property..
> >
> > If there were a standard way of doing this I'd love to use it.

Looks like you have told me the standard way of doing this.

Thank you.

					-Alex

> > And if it isn't necessary, please just explain to me why.  I
> > have no problem removing it.
> on the opposite, please have explicit good reason to introduce vendor
> speifici property, and if there is generic way, then we shouldn't do it