Re: [PATCH 7/9] dt-bindings: spi: mtk-snfi: add two timing delay property

[Xiangsheng Hou (侯祥胜) <Xiangsheng.Hou@xxxxxxxxxxxx>]

Hi Krzysztof,

On Mon, 2022-11-28 at 10:04 +0100, Krzysztof Kozlowski wrote:
> On 28/11/2022 03:06, Xiangsheng Hou wrote:
> > add rx-sample-delay and rx-latch-latency property.
> 
> Start sentences with capital letter.
> 
> Here and in commit subject: property->properties
Will be fixed in next series.

> > 
> > --- a/Documentation/devicetree/bindings/spi/mediatek,spi-mtk-
> > snfi.yaml
> > +++ b/Documentation/devicetree/bindings/spi/mediatek,spi-mtk-
> > snfi.yaml
> > @@ -55,6 +55,22 @@ properties:
> >      description: device-tree node of the accompanying ECC engine.
> >      $ref: /schemas/types.yaml#/definitions/phandle
> >  
> > +  rx-sample-delay:
> 
> No, use existing property, don't invent your own stuff - missing unit
> suffix. See spi-peripheral-props.yaml.
Will change to other private property. The read sample delay with
MediaTek SPI NAND controller can be set with values from 0 to 47.
However, it`s difficult to say the unit of each vaule, because the unit
value will be difference with different chip process or different
corner IC.

> > +    description: Rx delay to sample data with this value, the
> > valid
> > +                 values are from 0 to 47. The delay is smaller
> > than
> > +                 the rx-latch-latency.
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> 
> Drop $ref.
Will do.

> 
> > +    minItems: 0
> > +    maxItems: 47
> > +    default: 0
> > +
> > +  rx-latch-latency:
> 
> Same problems. Did you check spi-peripheral-props.yaml or other SPI
> controller schemas for such property?
> 
> > +    description: Rx delay to sample data with this value, the
> > value
> > +                 unit is clock cycle.
> 
> I think the unit should be rather time (e.g. us).
> 
Yes, I checked the spi-peripheral-props.yaml and the delay values are
described exactly unit with ns or us. However the unit of MediaTek read
latch latency is clock cycle and it`s difference with different clock
frequency.

> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    enum: [0, 1, 2, 3]
> > +    default: 0
> > +
> >  required:
> >    - compatible
> >    - reg
> 
Best regards,
Xiangsheng Hou