Re: [Patch v4 6/6] dt-bindings: thermal: Add dt binding for QCOM LMh

[Thara Gopinath <thara.gopinath@linaro.org>]

Hi Rob,

Thanks for the reviews.

On 7/28/21 12:10 PM, Rob Herring wrote:
> On Tue, Jul 27, 2021 at 11:25:12AM -0400, Thara Gopinath wrote:
>> Add dt binding documentation to describe Qualcomm
>> Limits Management Hardware node.
>>
>> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
>> ---
>>
>> v3->v4:
>> 	- Changed dt property qcom,lmh-cpu-id to qcom,lmh-cpu and made it
>> 	  a phandle pointing to the cpu node instead of a number as per
>> 	  Rob Herring's review comments.
>> 	- Added suffix -millicelsius to all temperature properties as per
>> 	  Rob Herring's review comments.
>> 	- Dropped unnecessary #includes in the example as pointed out by Bjorn.
>> 	- Other minor fixes.
>>
>>   .../devicetree/bindings/thermal/qcom-lmh.yaml | 100 ++++++++++++++++++
>>   1 file changed, 100 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/thermal/qcom-lmh.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/thermal/qcom-lmh.yaml b/Documentation/devicetree/bindings/thermal/qcom-lmh.yaml
>> new file mode 100644
>> index 000000000000..0978f458b9ec
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/thermal/qcom-lmh.yaml
>> @@ -0,0 +1,100 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +# Copyright 2021 Linaro Ltd.
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/thermal/qcom-lmh.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Qualcomm Limits Management Hardware(LMh)
>> +
>> +maintainers:
>> +  - Thara Gopinath <thara.gopinath@linaro.org>
>> +
>> +description:
>> +  Limits Management Hardware(LMh) is a hardware infrastructure on some
>> +  Qualcomm SoCs that can enforce temperature and current limits as
>> +  programmed by software for certain IPs like CPU.
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - qcom,sdm845-lmh
>> +
>> +  reg:
>> +    items:
>> +      - description: core registers
>> +
>> +  interrupts:
>> +    maxItems: 1
>> +
>> +  '#interrupt-cells':
>> +    const: 1
>> +
>> +  interrupt-controller: true
>> +
>> +  qcom,lmh-cpu:
>> +    description:
>> +      phandle of the first cpu in the LMh cluster
>> +    $ref: /schemas/types.yaml#/definitions/phandle
> 
> 'cpus' property is the somewhat standard way to reference a cpu.

So are you suggesting renaming qcom,lmh-cpu to cpus ? I need the cpu-id 
here to identify the LMh cluster. Depending on the LMh cluster, I have 
different node ids which is a parameter in the LMh smc call.

> 
> But you should already have cpu topology information, why do you need
> this?
> 
>> +
>> +  qcom,lmh-temp-arm-millicelsius:
>> +    description:
>> +      An integer expressing temperature threshold at which the LMh thermal
>> +      FSM is engaged.
>> +    $ref: /schemas/types.yaml#/definitions/int32
> 
> Standard unit-suffixes already have a type.

yep.. I will remove this

> 
>> +
>> +  qcom,lmh-temp-low-millicelsius:
>> +    description:
>> +      An integer expressing temperature threshold at which the state machine
>> +      will attempt to remove frequency throttling.
>> +    $ref: /schemas/types.yaml#/definitions/int32
>> +
>> +  qcom,lmh-temp-high-millicelsius:
>> +    description:
>> +      An integer expressing temperature threshold at which the state machine
>> +      will attempt to throttle the frequency.
>> +    $ref: /schemas/types.yaml#/definitions/int32
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - interrupts
>> +  - #interrupt-cells
>> +  - interrupt-controller
>> +  - qcom,lmh-cpu
>> +  - qcom,lmh-temp-arm-millicelsius
>> +  - qcom,lmh-temp-low-millicelsius
>> +  - qcom,lmh-temp-high-millicelsius
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +
>> +    lmh_cluster1: lmh@17d70800 {
> 
> Drop unused labels.

sure.

> 
>> +      compatible = "qcom,sdm845-lmh";
>> +      reg = <0x17d70800 0x401>;
> 
> 0x401 is an odd size...

I double checked the spec and this is the size. But also there is no 
register specified around this address. So I will make the size to 0x400 
so that it looks sane.


> 
>> +      interrupts = <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>;
>> +      qcom,lmh-cpu = <&CPU4>;
>> +      qcom,lmh-temp-arm-millicelsius = <65000>;
>> +      qcom,lmh-temp-low-millicelsius = <94500>;
>> +      qcom,lmh-temp-high-millicelsius = <95000>;
>> +      interrupt-controller;
>> +      #interrupt-cells = <1>;
>> +    };
>> +  - |
> 
> Seems like this is 1 example, not 2.

Will fix it.

> 
>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +
>> +    lmh_cluster0: lmh@17d78800 {
>> +      compatible = "qcom,sdm845-lmh";
>> +      reg = <0x17d78800 0x401>;
>> +      interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>;
>> +      qcom,lmh-cpu = <&CPU0>;
>> +      qcom,lmh-temp-arm-millicelsius = <65000>;
>> +      qcom,lmh-temp-low-millicelsius = <94500>;
>> +      qcom,lmh-temp-high-millicelsius = <95000>;
>> +      interrupt-controller;
>> +      #interrupt-cells = <1>;
>> +    };
>> +  - |
>> -- 
>> 2.25.1
>>
>>

-- 
Warm Regards
Thara (She/Her/Hers)