Re: [PATCH v5 10/14] dt-bindings: PCI: Add CIX Sky1 PCIe Root Complex bindings

[Hans Zhang <hans.zhang@cixtech.com>]

On 2025/7/15 14:40, Krzysztof Kozlowski wrote:
> EXTERNAL EMAIL
> 
> On 14/07/2025 10:03, Hans Zhang wrote:
>>
>>
>> On 2025/7/14 15:43, Krzysztof Kozlowski wrote:
>>> EXTERNAL EMAIL
>>>
>>> On 03/07/2025 03:47, Hans Zhang wrote:
>>>>>>
>>>>>> We initially used the logic of Cadence common driver as follows:
>>>>>> drivers/pci/controller/cadence/pcie-cadence-host.c
>>>>>> of_property_read_u32(np, "vendor-id", &rc->vendor_id);
>>>>>>
>>>>>> of_property_read_u32(np, "device-id", &rc->device_id);
>>>>>>
>>>>>> So, can the code in Cadence be deleted?
>>>>>
>>>>> Don't know. If this is ABI, then not.
>>>>>
>>>>
>>>> According to my understanding, this is not ABI.
>>>
>>> Huh? Then what is ABI, by your understanding?
>>>
>>
>> Dear Krzysztof,
>>
>> I understand kernel ABI primarily refers to the stable binary contract
>> between the kernel and userspace (e.g., syscalls, /sys/proc interfaces).
>> Device tree properties are part of the boot-time hardware description
>> consumed by drivers during initialization. They are not directly exposed
>> to userspace as ABI interfaces.
>>
>> If I understand wrongly, please correct me.
> 
> 
> Then that's wrong understanding.
> 
> The DT interface, documented explicitly and one implied by kernel
> drivers in case it differs, is the ABI, as explained in docs in the
> kernel and what we said on the lists thousands of times.
> 

Dear Krzysztof,

Thank you very much for your reply and explanation. Now I understand 
that I have been discussing issues in the linux community for about half 
a year. I didn't pay attention to it before. Thank you again.

Best regards,
Hans