Re: [RFC PATCH v2 1/2] dt-bindings: nand: meson: support for 512B ECC step size

Miquel Raynal
2023-07-06T06:06:00Z

Hi Arseniy,

avkrasnov@sberdevices.ru wrote on Thu, 6 Jul 2023 08:57:00 +0300:

> On 05.07.2023 11:22, Miquel Raynal wrote:
> > Hi Arseniy,
> >
> > avkrasnov@sberdevices.ru wrote on Wed, 5 Jul 2023 11:03:30 +0300:
> >
> >> On 05.07.2023 10:37, Miquel Raynal wrote:
> >>> Hi Arseniy,
> >>>
> >>> AVKrasnov@sberdevices.ru wrote on Wed, 5 Jul 2023 09:54:33 +0300:
> >>>
> >>>> Meson NAND supports both 512B and 1024B ECC step size, so replace
> >>>> 'const' for only 1024B step size with enum for both sizes.
> >>>>
> >>>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
> >>>> ---
> >>>> Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml | 4 +++-
> >>>> 1 file changed, 3 insertions(+), 1 deletion(-)
> >>>>
> >>>> diff --git a/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml b/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml
> >>>> index 3bec8af91bbb..81ca8828731a 100644
> >>>> --- a/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml
> >>>> +++ b/Documentation/devicetree/bindings/mtd/amlogic,meson-nand.yaml
> >>>> @@ -49,7 +49,8 @@ patternProperties:
> >>>> const: hw
> >>>>
> >>>> nand-ecc-step-size:
> >>>> - const: 1024
> >>>> + enum: [512, 1024]
> >>>> + default: 1024
> >>>
> >>> I was actually wrong in my previous review, there is no strong default
> >>> here as the existing binding (and code) try to use the closest
> >>> parameters required by the NAND chip: we pick the "optimal"
> >>> configuration. So if you don't provide any value here, we expect
> >>> the strength and step size advertized by the chip to be used. This is a
> >>> common default in the raw NAND subsystem.
> >>>
> >>> Please drop the default line, re-integrate the missing R-by tag from
> >>> Rob and in a separate patch please mark nand-ecc-step-size and
> >>> nand-ecc-strength mandatory if the other is provide. IOW, we expect
> >>> either both, or none of them, but not a single one.
> >>
> >> I see, no problem! "mandatory" means update description of both fields like:
> >>
> >> description:
> >> Mandatory if nand-ecc-step-size is set.
> >
> > Nope :-)
> >
> > Something along:
> >
> > allOf:
> > - if:
> > <nand-chip>:
> > properties:
> > contains:
> > - nand-ecc-step-size
> > then:
> > required:
> > <nand-chip>:
> > properties:
> > - nand-ecc-strength
> >
> > And same with the opposite logic.
>
> I see, thanks! And this should be for all nand chips, not only Amlogic? I mean in
> nand-chip.yaml?

Some drivers can directly manage the user requests in terms of either
step size *or* strength, so I would keep this into the Amlogic file for
now.

> I'll include it as third patch in this patchset.
>
> Thanks, Arseniy

Thanks,
Miquèl