Re: [PATCH v2 2/5] dt-bindings: mmc: sdhci-msm: constrain reg-names perp variants

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 12/07/2022 16:29, Doug Anderson wrote:
> Hi,
> 
> On Tue, Jul 12, 2022 at 12:02 AM Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org> wrote:
>>
>> On 11/07/2022 17:11, Doug Anderson wrote:
>>> Hi,
>>>
>>> On Mon, Jul 11, 2022 at 7:53 AM Krzysztof Kozlowski
>>> <krzysztof.kozlowski@linaro.org> wrote:
>>>>
>>>> On 11/07/2022 16:52, Doug Anderson wrote:
>>>>> Hi
>>>>>
>>>>> On Mon, Jul 11, 2022 at 1:29 AM Krzysztof Kozlowski
>>>>> <krzysztof.kozlowski@linaro.org> wrote:
>>>>>>
>>>>>> The entries in arrays must have fixed order, so the bindings and Linux
>>>>>> driver expecting various combinations of 'reg' addresses was never
>>>>>> actually conforming to guidelines.
>>>>>>
>>>>>> The 'core' reg entry is valid only for SDCC v4 and lower, so disallow it
>>>>>> in SDCC v5.  SDCC v4 supports CQE and ICE, so allow them, even though
>>>>>> the qcom,sdhci-msm-v4 compatible is used also for earlier SoCs with SDCC
>>>>>> v2 or v3, so it is not entirely accurate.
>>>>>>
>>>>>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>>>>>>
>>>>>> ---
>>>>>>
>>>>>> Changes since v1:
>>>>>> 1. Rework the patch based on Doug's feedback.
>>>>>> ---
>>>>>>  .../devicetree/bindings/mmc/sdhci-msm.yaml    | 61 ++++++++++++-------
>>>>>>  1 file changed, 38 insertions(+), 23 deletions(-)
>>>>>
>>>>> In the ${SUBJECT} I'm not sure what a "perp variant" is. Is that a
>>>>> typo or just a phrase I'm not aware of?
>>>>
>>>> Should be:
>>>> "per variants"
>>>>
>>>>>
>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.yaml b/Documentation/devicetree/bindings/mmc/sdhci-msm.yaml
>>>>>> index fc6e5221985a..2f0fdd65e908 100644
>>>>>> --- a/Documentation/devicetree/bindings/mmc/sdhci-msm.yaml
>>>>>> +++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.yaml
>>>>>> @@ -49,33 +49,11 @@ properties:
>>>>>>
>>>>>>    reg:
>>>>>>      minItems: 1
>>>>>> -    items:
>>>>>> -      - description: Host controller register map
>>>>>> -      - description: SD Core register map
>>>>>> -      - description: CQE register map
>>>>>> -      - description: Inline Crypto Engine register map
>>>>>> +    maxItems: 4
>>>>>>
>>>>>>    reg-names:
>>>>>>      minItems: 1
>>>>>>      maxItems: 4
>>>>>> -    oneOf:
>>>>>> -      - items:
>>>>>> -          - const: hc
>>>>>> -      - items:
>>>>>> -          - const: hc
>>>>>> -          - const: core
>>>>>> -      - items:
>>>>>> -          - const: hc
>>>>>> -          - const: cqhci
>>>>>> -      - items:
>>>>>> -          - const: hc
>>>>>> -          - const: cqhci
>>>>>> -          - const: ice
>>>>>> -      - items:
>>>>>> -          - const: hc
>>>>>> -          - const: core
>>>>>> -          - const: cqhci
>>>>>> -          - const: ice
>>>>>>
>>>>>>    clocks:
>>>>>>      minItems: 3
>>>>>> @@ -177,6 +155,43 @@ required:
>>>>>>  allOf:
>>>>>>    - $ref: mmc-controller.yaml#
>>>>>>
>>>>>> +  - if:
>>>>>> +      properties:
>>>>>> +        compatible:
>>>>>> +          contains:
>>>>>> +            enum:
>>>>>> +              - qcom,sdhci-msm-v4
>>>>>> +    then:
>>>>>> +      properties:
>>>>>> +        reg:
>>>>>> +          minItems: 2
>>>>>> +          items:
>>>>>> +            - description: Host controller register map
>>>>>> +            - description: SD Core register map
>>>>>> +            - description: CQE register map
>>>>>> +            - description: Inline Crypto Engine register map
>>>>>> +        reg-names:
>>>>>> +          minItems: 2
>>>>>> +          items:
>>>>>> +            - const: hc
>>>>>> +            - const: core
>>>>>> +            - const: cqhci
>>>>>> +            - const: ice
>>>>>> +    else:
>>>>>> +      properties:
>>>>>> +        reg:
>>>>>> +          minItems: 1
>>>>>> +          items:
>>>>>> +            - description: Host controller register map
>>>>>> +            - description: CQE register map
>>>>>> +            - description: Inline Crypto Engine register map
>>>>>> +        reg-names:
>>>>>> +          minItems: 1
>>>>>> +          items:
>>>>>> +            - const: hc
>>>>>> +            - const: cqhci
>>>>>> +            - const: ice
>>>>>
>>>>> Do you need to set "maxItems" here? If you don't then will it inherit
>>>>> the maxItems of 4 from above?
>>>>
>>>> No, items determine the size instead.
>>>
>>> Can you just remove the "maxItems" from above then? Does it buy us anything?
>>
>> There is no maxItems directly here...
> 
> Sorry, I mean above in the schema. After your patch the schema is effectively:
> 
> reg:
>   minItems: 1
>   maxItems: 4
> reg-names:
>   minItems: 1
>   maxItems: 4
> 
> ...
> 
> allOf:
>   - if:
>       blah-blah-blah
>     then:
>       properties:
>         reg:
>           minItems: 2
>           items:
>             - description: ...
>             - description: ...
>             - description: ...
>             - description: ...
>         reg-names:
>           blah-blah-blah
>     else:
>       blah-blah-blah
> 
> I'm asking about the maxItems _above_, AKA in the section:
> 
> reg:
>   minItems: 1
>   maxItems: 4
> reg-names:
>   minItems: 1
>   maxItems: 4
> 
> Can we remove the "maxItems: 4" from the above and have it just be:
> 
> reg:
>   minItems: 1
> reg-names:
>   minItems: 1
> 


Yes, we can, but preferred is to have it because it makes the broad
constraints easily visible. You don't need to check each if:else branch
to find upper bounds or check if maxItems are defined at all. This also
matches pattern used in bindings without allOf:if:then - each time you
are expected to see array types constraint in the list of properties.

Best regards,
Krzysztof