Re: [PATCH v6 6/9] dt-bindings: arm: add an interrupt property for Coresight CTCU

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 04/12/2025 02:53, Jie Gan wrote:
> 
> 
> On 12/4/2025 2:14 AM, Suzuki K Poulose wrote:
>> On 08/09/2025 03:01, Jie Gan wrote:
>>> Add an interrupt property to CTCU device. The interrupt will be 
>>> triggered
>>> when the data size in the ETR buffer exceeds the threshold of the
>>> BYTECNTRVAL register. Programming a threshold in the BYTECNTRVAL 
>>> register
>>> of CTCU device will enable the interrupt.
>>>
>>> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>>> Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
>>> ---
>>>   .../devicetree/bindings/arm/qcom,coresight-ctcu.yaml    | 17 ++++++ 
>>> + ++++++++++
>>>   1 file changed, 17 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/arm/qcom,coresight- 
>>> ctcu.yaml b/Documentation/devicetree/bindings/arm/qcom,coresight- 
>>> ctcu.yaml
>>> index 843b52eaf872..ea05ad8f3dd3 100644
>>> --- a/Documentation/devicetree/bindings/arm/qcom,coresight-ctcu.yaml
>>> +++ b/Documentation/devicetree/bindings/arm/qcom,coresight-ctcu.yaml
>>> @@ -39,6 +39,16 @@ properties:
>>>       items:
>>>         - const: apb
>>> +  interrupts:
>>> +    items:
>>> +      - description: Byte cntr interrupt for etr0
>>> +      - description: Byte cntr interrupt for etr1
>>> +
>>> +  interrupt-names:
>>> +    items:
>>> +      - const: etr0
>>> +      - const: etr1
>>
> 
> Hi Suzuki,
> 
>> Why are they named "etr0" "etr1" ? That would be confusing, isn't it, 
>> especially with the Linux driver naming things randomly for the TMC-ETRs.
>>
> 
> Yes, it will cause misunderstandings since the "etr0" here may not the 
> right device we are expecting.
> 
>>
>> What we want is the "port" number corresponding to the "TMC-ETR" being
>> monitored ?
>>
>> Have you explored other options, "port-0", "port-1" ?
>>
> 
> I think it's much better. Will update in next version.

I am not sure if there exists a better scheme for identifying or
numbering the interrupts. Happy to listen to the DT experts.

Rob, Krzysztof, thoughts ?

Suzuki


> 
> Thanks,
> Jie
> 
>> Suzuki
>>
>>> +
>>>     in-ports:
>>>       $ref: /schemas/graph.yaml#/properties/ports
>>> @@ -56,6 +66,8 @@ additionalProperties: false
>>>   examples:
>>>     - |
>>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>>> +
>>>       ctcu@1001000 {
>>>           compatible = "qcom,sa8775p-ctcu";
>>>           reg = <0x1001000 0x1000>;
>>> @@ -63,6 +75,11 @@ examples:
>>>           clocks = <&aoss_qmp>;
>>>           clock-names = "apb";
>>> +        interrupts = <GIC_SPI 270 IRQ_TYPE_EDGE_RISING>,
>>> +                     <GIC_SPI 262 IRQ_TYPE_EDGE_RISING>;
>>> +        interrupt-names = "etr0",
>>> +                          "etr1";
>>> +
>>>           in-ports {
>>>               #address-cells = <1>;
>>>               #size-cells = <0>;
>>>
>>
>>
>