Re: [PATCH v5 02/10] dt-bindings: clock: Add required "interconnect-cells" property

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 9/12/25 11:27 AM, Krzysztof Kozlowski wrote:
> On 12/09/2025 11:21, Konrad Dybcio wrote:
>> On 9/12/25 11:17 AM, Krzysztof Kozlowski wrote:
>>> On 12/09/2025 11:13, Konrad Dybcio wrote:
>>>> On 9/12/25 11:13 AM, Konrad Dybcio wrote:
>>>>> On 9/12/25 9:04 AM, Krzysztof Kozlowski wrote:
>>>>>> On Tue, Sep 09, 2025 at 09:39:11PM +0800, Luo Jie wrote:
>>>>>>> The Networking Subsystem (NSS) clock controller acts as both a clock
>>>>>>> provider and an interconnect provider. The #interconnect-cells property
>>>>>>> is mandatory in the Device Tree Source (DTS) to ensure that client
>>>>>>> drivers, such as the PPE driver, can correctly acquire ICC clocks from
>>>>>>> the NSS ICC provider.
>>>>>>>
>>>>>>> Although this property is already present in the NSS CC node of the DTS
>>>>>>> for CMN PLL for IPQ9574 SoC which is currently supported, it was previously
>>>>>>> omitted from the list of required properties in the bindings documentation.
>>>>>>> Adding this as a required property is not expected to break the ABI for
>>>>>>> currently supported SoC.
>>>>>>>
>>>>>>> Marking #interconnect-cells as required to comply with Device Tree (DT)
>>>>>>> binding requirements for interconnect providers.
>>>>>>
>>>>>> DT bindings do not require interconnect-cells, so that's not a correct
>>>>>> reason. Drop them from required properties.
>>>>>
>>>>> "Mark #interconnect-cells as required to allow consuming the provided
>>>>> interconnect endpoints"?
>>>>
>>>> "which are in turn necessary for the SoC to function"
>>>
>>> If this never worked and code was buggy, never booted, was sent
>>> incomplete and in junk state, then sure. Say like that. :)
>>>
>>> But I have a feeling code was working okayish...
>>
>> If Linux is unaware of resources, it can't turn them off/on, so it was
>> only working courtesy of the previous boot stages messing with them.
> 
> 
> Which is fine and present in all other cases/drivers/devices. Entire
> Linux in many places relies on bootloader and that is not a "work by
> coincidence".
> 
> Another thing is if you keep backwards compatibility in the driver but
> want to enforce DTS to care about these resources, but that is not
> explained here, I think.

I don't feel like arguing axiology today ;) But I see your point and I
won't object to either outcome, so long as the property is *allowed*

As a sidenote the IPQ SoCs have a rather thin layer of fw

Konrad