Re: [PATCH v2 1/2] spi: dt-bindings: add SPI IPM v59 compatible for mt7987 and mt7989

[Tim Kuo (郭廷笙)]

On Wed, 2026-09-30 at 12:36 +0200, Krzysztof Kozlowski wrote:
> On Tue, Sep 29, 2026 at 02:25:15PM +0800, Tim Kuo wrote:
> > MTK mt7987 and mt7989 SPI hardware has been updated to IPM v59 SPI
> > IP and
> > it differs from earlier IPM designs, most visibly in the tick delay
> > field
> > of SPI_CMD_REG, so it needs its own fallback compatible rather than
> > reusing
> > "mediatek,spi-ipm".
> > 
> > Signed-off-by: Tim Kuo <Tim.Kuo@xxxxxxxxxxxx>
> > ---
> > v2: Add mt7987 and mt7989 real device compatible
> > 
> >  .../devicetree/bindings/spi/mediatek,spi-mt65xx.yaml         | 5
> > +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/spi/mediatek,spi-
> > mt65xx.yaml b/Documentation/devicetree/bindings/spi/mediatek,spi-
> > mt65xx.yaml
> > index 3bf3eb1f8728..d2c740572d85 100644
> > --- a/Documentation/devicetree/bindings/spi/mediatek,spi-
> > mt65xx.yaml
> > +++ b/Documentation/devicetree/bindings/spi/mediatek,spi-
> > mt65xx.yaml
> > @@ -39,6 +39,11 @@ properties:
> >                - mediatek,mt7988-spi-single
> >                - mediatek,mt8188-spi-ipm
> >            - const: mediatek,spi-ipm
> > +      - items:
> > +          - enum:
> > +              - mediatek,mt7987-spi
> > +              - mediatek,mt7989-spi
> > +          - const: mediatek,spi-ipm-v59
> 
> No, look at the binding and recent commits. This should be a specific
> compatible. Git history easily tells you that.
> 
> Best regards,
> Krzysztof
> 

Thanks for the review. I went back through the binding and the history;
let me confirm I took the right lesson from it before I send v3, and
ask one thing about the DTS.

1) My reading now is that the problem is the SoC-less, version-numbered
"mediatek,spi-ipm-v59" string: an internal IP revision is not something
anyone can read off a board, and the binding otherwise never invents a
new generic compatible for a new variant.

So for v3 I dropped "mediatek,spi-ipm-v59" entirely and added MT7987 to
the existing IPM group:

       - items:
          - enum:
               - mediatek,mt7981-spi-ipm
	       - mediatek,mt7986-spi-ipm
+	       - mediatek,mt7987-spi-ipm
	       - mediatek,mt7988-spi-quad
	       - mediatek,mt7988-spi-single
+	       - mediatek,mt7989-spi-ipm
	       - mediatek,mt8188-spi-ipm
          - const: mediatek,spi-ipm


"mediatek,spi-ipm" stays a valid fallback for MT7987: a driver that
only knows the generic string programs bits: 24:22, which are the low 3
bits of the widened field, so it still works. On the driver side
mtk_ipm_v59_compat will become mt7987_compat and matches
"mediatek,mt7987-spi" which outranks the "mediatek,spi-ipm" entry.

Does that what you had in mind? or please let me know if that is still
not what you meant.

2) The mt7987 DTS is not upstream yet. It currently only lives in
OpenWrt's tree, and they will be prepared to upstream separately in the
future. So this patch would add a compatible that no in-tree DTS uses
yet.

https://github.com/openwrt/openwrt/commit/9de7189ed43bb7524fe8bcb3e9f57
a6516d0990d

Is that acceptable, or do you prefer the binding to land together with
(or after) the mt7987 DTS?

BRs,
Tim