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

[Arseniy Krasnov]

On 05.07.2023 11:22, Miquel Raynal wrote:
> Hi Arseniy,
> 
> avkrasnov@xxxxxxxxxxxxxx wrote on Wed, 5 Jul 2023 11:03:30 +0300:
> 
>> On 05.07.2023 10:37, Miquel Raynal wrote:
>>> Hi Arseniy,
>>>
>>> AVKrasnov@xxxxxxxxxxxxxx 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@xxxxxxxxxxxxxx>
>>>> ---
>>>>  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? 

I'll include it as third patch in this patchset.

Thanks, Arseniy

> 
>>
>> etc.
>>
>> ?
>>
>>>   
>>>>  
>>>>        nand-ecc-strength:
>>>>          enum: [8, 16, 24, 30, 40, 50, 60]
>>>> @@ -93,6 +94,7 @@ examples:
>>>>        nand@0 {
>>>>          reg = <0>;
>>>>          nand-rb = <0>;
>>>> +        nand-ecc-step-size = <1024>;  
>>>
>>> So in the end this line is wrong and once you get the description right
>>> as I mentioned it above, this will fail to pass
>>> `make DT_SCHEMA_FILES=Documentation/devicetree/bindings/mtd/ dt_binidng_check`
>>> Please drop it from the example, don't add the second property here,
>>> it's best to show a clean example where people stop tampering for no
>>> reason with the optimal values.  
>>
>> Ok!
>>
>> Thanks, Arseniy
>>
>>>   
>>>>        };
>>>>      };
>>>>    
>>>
>>>
>>> Thanks,
>>> Miquèl  
> 
> 
> Thanks,
> Miquèl