Re: [PATCH v2 01/10] dt-bindings: ptp: Document the TSCSS on Qualcomm SA8775P and QCS8300 SoCs

[Krzysztof Kozlowski <krzk@kernel.org>]

On 12/11/2026 10:31, Imran Shaik wrote:
>>> +allOf:
>>> +  - if:
>>> +      properties:
>>> +        reg-names:
>>> +          contains:
>>> +            const: etu
>>
>> Reason for same devices with different address space details should be
>> provided somewhere, preferrably in description. Assuming in the first
>> place, that this stays because how two devices can be basically
>> identical (same compatible) if they have different programming
>> interface?
>>
> 
> TSCSS is a single hardware device, split into two sub-blocks - TSC and
> ETU, each with its own register address. Every SoC with this compatible
> has both blocks in hardware.

This is not what the binding said.

> 
> What changes is whether the vendor/board actually wires up the ETU's
> external event. The ETU block captures a timestamp from the TSC block
> when an external event fires one of the ETU slices, which are driven
> through board-level GPIO/IRQs. If a board doesn't wire any slice,
> there's nothing in the ETU region for Linux to use.

This is not what the binding said. The binding said there are different
types of devices, one with etu and one without. Look, easy to spot:

+  reg:
+    minItems: 1
+    maxItems: 2


Best regards,
Krzysztof