Re: [PATCH 03/11] dt-bindings: reset: mobileye,eyeq5-reset: add EyeQ6L and EyeQ6H

Krzysztof Kozlowski
2024-04-11T15:05:25Z

On 11/04/2024 16:04, Théo Lebrun wrote:
> Hello,
>
> On Thu Apr 11, 2024 at 8:14 AM CEST, Krzysztof Kozlowski wrote:
>> On 10/04/2024 19:12, Théo Lebrun wrote:
>>> Add bindings for EyeQ6L and EyeQ6H reset controllers.
>>>
>>> Some controllers host a single domain, meaning a single cell is enough.
>>> We do not enforce reg-names for such nodes.
>>>
>>> Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
>>> ---
>>> .../bindings/reset/mobileye,eyeq5-reset.yaml | 88 ++++++++++++++++++----
>>> MAINTAINERS | 1 +
>>> 2 files changed, 74 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/reset/mobileye,eyeq5-reset.yaml b/Documentation/devicetree/bindings/reset/mobileye,eyeq5-reset.yaml
>>> index 062b4518347b..799bcf15bed9 100644
>>> --- a/Documentation/devicetree/bindings/reset/mobileye,eyeq5-reset.yaml
>>> +++ b/Documentation/devicetree/bindings/reset/mobileye,eyeq5-reset.yaml
>>> @@ -4,11 +4,13 @@
>>> $id: http://devicetree.org/schemas/reset/mobileye,eyeq5-reset.yaml#
>>> $schema: http://devicetree.org/meta-schemas/core.yaml#
>>>
>>> -title: Mobileye EyeQ5 reset controller
>>> +title: Mobileye EyeQ reset controller
>>>
>>> description:
>>> - The EyeQ5 reset driver handles three reset domains. Its registers live in a
>>> - shared region called OLB.
>>> + EyeQ reset controller handles one or more reset domains. They live in shared
>>> + regions called OLB. EyeQ5 and EyeQ6L host one OLB each, each with one reset
>>> + instance. EyeQ6H hosts 7 OLB regions; three of those (west, east,
>>> + accelerator) host reset controllers. West and east are duplicates.
>>>
>>> maintainers:
>>> - Grégory Clement <gregory.clement@bootlin.com>
>>> @@ -17,27 +19,83 @@ maintainers:
>>>
>>> properties:
>>> compatible:
>>> - const: mobileye,eyeq5-reset
>>> + enum:
>>> + - mobileye,eyeq5-reset
>>> + - mobileye,eyeq6l-reset
>>> + - mobileye,eyeq6h-we-reset
>>> + - mobileye,eyeq6h-acc-reset
>>>
>>> - reg:
>>> - maxItems: 3
>>> + reg: true
>>
>> Same mistakes. Please open existing bindings with multiple variants,
>> e.g. some Qualcomm, and take a look how it is done there.
>
> Thanks for the pointer to good example, that is useful! So if we take
> one random binding matching
> Documentation/devicetree/bindings/clock/qcom,*.yaml and that contains
> the "reg-names" string, we see:
>
> reg:
> items:
> - description: LPASS qdsp6ss register
> - description: LPASS top-cc register
>
> reg-names:
> items:
> - const: qdsp6ss
> - const: top_cc
>
> I don't understand one thing; this doesn't tell you:
>
> You can provide 2 MMIO blocks, which must be qdsp6ss and top_cc.

No, it tells you exactly this, with difference: s/can/must/

>
> But it tells you:
>
> Block zero must be qdsp6ss.
> Block one must be top_cc.
>
> If we do that I do not get the point of reg-names; we put more
> information in our devicetree that is in any case imposed.

Same old argument. Order is not flexible. Order is fixed.

Why do you need names? I don't need, it's purely your optional choice.
Maybe you find it more readable, up to you.

>
> This is why I went with a different approach looking like:
>
> reg:
> minItems: 2
> maxItems: 2
> reg-names:
> minItems: 2
> maxItems: 2
> items:
> enum: [ d0, d1 ]

No, order is fixed.

>
> I know this is not perfect, but at least you don't enforce an order for
> no reason. If "items: const..." approach should be taken, then I'll
> remove reg-names which bring no benefit.

You can remove it, you can keep it, whatever makes code more readable,
but order is fixed.

Best regards,
Krzysztof