Re: [PATCH v2 5/5] dt-bindings: perf: Add compatible for Arm DSU-110

[Robin Murphy <robin.murphy@arm.com>]

On 2021-12-14 14:42, Suzuki K Poulose wrote:
> On 14/12/2021 14:16, Robin Murphy wrote:
>> DSU-110 is the newest and shiniest for Armv9. Its programmer's model is
>> largely identical to the previous generation of DSUs, so we can treat it
>> as compatible, but it does have a a handful of extra IMP-DEF PMU events
>> to call its own. Thanks to the new notion of core complexes, the maximum
>> number of supported CPUs goes up as well.
>>
>> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
>> ---
>>
>> v2: Also make it complete and valid
>>
>>   Documentation/devicetree/bindings/perf/arm,dsu-pmu.yaml | 8 ++++++--
>>   1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/perf/arm,dsu-pmu.yaml 
>> b/Documentation/devicetree/bindings/perf/arm,dsu-pmu.yaml
>> index 09ddeb6a3ccc..7f31bcecedb5 100644
>> --- a/Documentation/devicetree/bindings/perf/arm,dsu-pmu.yaml
>> +++ b/Documentation/devicetree/bindings/perf/arm,dsu-pmu.yaml
>> @@ -21,7 +21,11 @@ description:
>>   properties:
>>     compatible:
>> -    const: arm,dsu-pmu
>> +    oneOf:
>> +      - const: arm,dsu-pmu
>> +      - items:
>> +          - const: arm,dsu-110-pmu
>> +          - const: arm,dsu-pmu
> 
> Couldn't this be :
> 
>      compatible:
>        oneOf:
>          - const: arm,dsu-110-pmu
>          - const: arm,dsu-pmu
> 
> Otherwise, looks good to me.

My intent here was for the new case to use both strings and thus still 
permit a less-specific match to the original one (hence why there's no 
change to the actual driver included here). It's a true "compatible" in 
the sense that you can run the thing with the existing driver as if it's 
a 1st-gen DSU and get the expected results - at least that's the 
conclusion I drew from a side-by-side comparison of the TRMs, and the 
folks testing FPGAs haven't complained since I told them to try it 
months ago :)

Thanks,
Robin.