Re: [PATCH 1/4] dt-bindings: memory: additional compatible strings for Broadcom DPFE

Krzysztof Kozlowski
2023-12-06T18:31:09Z

On 06/12/2023 17:32, Florian Fainelli wrote:
>
>
> On 12/6/2023 3:09 AM, Krzysztof Kozlowski wrote:
>> On 05/12/2023 19:47, Markus Mayer wrote:
>>> Add versioned compatible strings for Broadcom DPFE. These take the form
>>> brcm,dpfe-cpu-v<N> where <N> is a number from 1 to 4.
>>>
>>> These API version related compatible strings are more specific than the
>>> catch-all "brcm,dpfe-cpu" and more generic than chip-specific compatible
>>> strings.
>>
>> None of this explains: Why? I don't see any point in this and commit
>> does not explain.
>>
>>>
>>> Signed-off-by: Markus Mayer <mmayer@broadcom.com>
>>> ---
>>> .../bindings/memory-controllers/brcm,dpfe-cpu.yaml | 8 +++++++-
>>> 1 file changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/memory-controllers/brcm,dpfe-cpu.yaml b/Documentation/devicetree/bindings/memory-controllers/brcm,dpfe-cpu.yaml
>>> index 08cbdcddfead..6dffa7b62baf 100644
>>> --- a/Documentation/devicetree/bindings/memory-controllers/brcm,dpfe-cpu.yaml
>>> +++ b/Documentation/devicetree/bindings/memory-controllers/brcm,dpfe-cpu.yaml
>>> @@ -16,6 +16,11 @@ properties:
>>> - enum:
>>> - brcm,bcm7271-dpfe-cpu
>>> - brcm,bcm7268-dpfe-cpu
>>> + - enum:
>>> + - brcm,dpfe-cpu-v1
>>> + - brcm,dpfe-cpu-v2
>>> + - brcm,dpfe-cpu-v3
>>> + - brcm,dpfe-cpu-v4
>>
>> No, that's just wrong. So you want to say bcm7271 is brcm,dpfe-cpu-v4?
>
> No as the example shows it "speaks" API v1.

Example is not a binding. It does not matter except of validating the
binding. This is just incorrect.

>
> I would be inclined to completely remove the chip specific compatible
> strings from the binding because they are not sufficient or descriptive
> enough to determine which API version is being spoken, since the
> firmware is unfortunately allowed to change major APIs (and the
> messaging format, because why not?) at a moments notice.

Then versions do not give you anything more.

Best regards,
Krzysztof