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

From: Xiangsheng Hou (侯祥胜)
Date: Mon Nov 28 2022 - 21:50:49 EST


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