Re: [PATCH 1/8] dt-bindings: embedded-controller: qcom,hamoa-crd-ec: Add qcom,tsens

[Anvesh Jain P <anvesh.p@oss.qualcomm.com>]

On 7/29/2026 4:43 PM, Konrad Dybcio wrote:
> On 7/28/26 7:44 PM, Anvesh Jain P wrote:
>> Add the qcom,tsens property so Hamoa-based boards can list the tsens
>> providers, and how many leading sensor IDs on each, whose readings the
>> driver averages to compute the SoC junction temperature reported to
>> the EC for fan control.
>>
>> The generic thermal-sensors property has no standard semantic for
>> selecting a range of sensor IDs from a provider without enumerating
>> each one, so a vendor-specific phandle-array with an explicit sensor
>> count is used instead.
>>
>> Signed-off-by: Anvesh Jain P <anvesh.p@oss.qualcomm.com>
>> ---
>>  .../embedded-controller/qcom,hamoa-crd-ec.yaml     | 31 ++++++++++++++++++++++
>>  1 file changed, 31 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/embedded-controller/qcom,hamoa-crd-ec.yaml b/Documentation/devicetree/bindings/embedded-controller/qcom,hamoa-crd-ec.yaml
>> index c07483aa5937..ec809fcd03ab 100644
>> --- a/Documentation/devicetree/bindings/embedded-controller/qcom,hamoa-crd-ec.yaml
>> +++ b/Documentation/devicetree/bindings/embedded-controller/qcom,hamoa-crd-ec.yaml
>> @@ -33,11 +33,40 @@ properties:
>>    interrupts:
>>      maxItems: 1
>>  
>> +  # A generic "thermal-sensors" phandle only identifies individual sensor
>> +  # IDs, and thermal zones are a Linux-side grouping of those sensors, not
>> +  # a devicetree concept the EC cares about. What the driver actually needs
>> +  # is raw readings from a contiguous range of leading sensor IDs on each
>> +  # tsens provider, averaged together, so qcom,tsens pairs each provider
>> +  # phandle with a count instead of enumerating every sensor cell.
>> +  qcom,tsens:
>> +    description:
>> +      List of tsens providers and, for each, the number of leading sensor
>> +      IDs on that provider whose readings are averaged to compute the SoC
>> +      junction temperature reported to the EC for fan control. Only
>> +      applicable for Hamoa based devices.
>> +    $ref: /schemas/types.yaml#/definitions/phandle-array
>> +    minItems: 1
>> +    maxItems: 2
>> +    items:
>> +      items:
>> +        - description: phandle to a tsens thermal-sensor provider
>> +        - description: number of leading sensor IDs on that provider to average
> 
> Why don't we want to look at all of the TSENS sensors?
> 
> Konrad

Each tsens provider has more physical sensors (16) than the count used
here. The leading N we take exactly matches the number of sensors
already wired to board thermal-zones for other purposes (CPU clusters,
GPU, camera, etc.) on that provider — e.g. on hamoa, tsens2 has 11 such
zones and tsens3 has 15, matching qcom,tsens = <&tsens2 11>, <&tsens3
15>;. The remaining sensor IDs aren't referenced by any thermal-zone on
this platform, so there's no per-purpose reading to include in the SoC
Tj average.

-- 
Best Regards,
Anvesh