Re: [PATCH v21 2/4] dt-bindings: i2c: ast2600-i2c.yaml: Add global-regs and transfer-mode properties

Krzysztof Kozlowski
2025-10-28T07:48:01Z

On Mon, Oct 27, 2025 at 08:14:45PM +0100, Krzysztof Kozlowski wrote:
> On 27/10/2025 07:12, Ryan Chen wrote:
> > The AST2600 I2C controller supports three transfer modes: byte,
> > buffer, and DMA. To allow board designers and firmware to
> > explicitly select the preferred transfer mode for each controller
> > instance. "aspeed,transfer-mode" to allow device tree to specify
> > the desired transfer method used by each I2C controller instance.
> >
> > And AST2600 i2c controller have two register mode, one is legacy
> > register layout which is mix controller/target register control
> > together, another is new mode which is separate controller/target
> > register control.
> >
>
> This implies your "reg" properties have now completely different meaning
> and this would be quite an ABI break. We discussed this probably 15
> revisions ago. Where did you document the resolution of that discussion?
>
> >
> > unevaluatedProperties: false
> >
> > @@ -57,10 +85,12 @@ examples:
> > #address-cells = <1>;
> > #size-cells = <0>;
> > compatible = "aspeed,ast2600-i2c-bus";
> > - reg = <0x40 0x40>;
> > + reg = <0x80 0x80>, <0xc00 0x20>;
>
> Not relevant to this patch. You just added this line in patch #1, so did
> you add incorrect code just to fix it right away?
>
> No, fix your example when creating it.

Heh, and this was not even tested... you have warnings here (see
maintainer soc profiles).

Best regards,
Krzysztof