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[V2,2/4] dt-bindings: hwmon: ina3221: Add summation-bypass

Message ID 20230825164249.22860-3-nmalwade@nvidia.com
State Changes Requested, archived
Headers show
Series hwmon: ina3221: Add selective summation support | expand

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Commit Message

Ninad Malwade Aug. 25, 2023, 4:42 p.m. UTC
The INA3221 has a critical alert pin that can be controlled by the
summation control function. This function adds the single
shunt-voltage conversions for the desired channels in order to
compare the combined sum to the programmed limit. The Shunt-Voltage
Sum Limit register contains the programmed value that is compared
to the value in the Shunt-Voltage Sum register in order to
determine if the total summed limit is exceeded. If the
shunt-voltage sum limit value is exceeded, the critical alert pin
pulls low.

For the summation limit to have a meaningful value, it is necessary
to use the same shunt-resistor value on all included channels. Add a
new property, 'summation-bypass', to allow specific channels to be
excluded from the summation control function if the shunt resistor
is different to other channels.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ninad Malwade <nmalwade@nvidia.com>
---
 .../devicetree/bindings/hwmon/ti,ina3221.yaml  | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

Comments

Krzysztof Kozlowski Aug. 26, 2023, 8:56 a.m. UTC | #1
On 25/08/2023 18:42, Ninad Malwade wrote:
> The INA3221 has a critical alert pin that can be controlled by the
> summation control function. This function adds the single
> shunt-voltage conversions for the desired channels in order to
> compare the combined sum to the programmed limit. The Shunt-Voltage
> Sum Limit register contains the programmed value that is compared
> to the value in the Shunt-Voltage Sum register in order to
> determine if the total summed limit is exceeded. If the
> shunt-voltage sum limit value is exceeded, the critical alert pin
> pulls low.
> 
> For the summation limit to have a meaningful value, it is necessary
> to use the same shunt-resistor value on all included channels. Add a
> new property, 'summation-bypass', to allow specific channels to be
> excluded from the summation control function if the shunt resistor
> is different to other channels.
> 
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> Signed-off-by: Ninad Malwade <nmalwade@nvidia.com>
> ---
>  .../devicetree/bindings/hwmon/ti,ina3221.yaml  | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
> index 0c6d41423d8c..20c23febf575 100644
> --- a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
> +++ b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
> @@ -55,6 +55,24 @@ patternProperties:
>        shunt-resistor-micro-ohms:
>          description: shunt resistor value in micro-Ohm
>  
> +      summation-bypass:

What is the type? There is no vendor prefix here, so you added it as a
generic property. Which other devices use or can use it?

> +        description: |
> +          The INA3221 has a critical alert pin that can be controlled by the
> +          summation control function. This function adds the single
> +          shunt-voltage conversions for the desired channels in order to
> +          compare the combined sum to the programmed limit. The Shunt-Voltage
> +          Sum Limit register contains the programmed value that is compared
> +          to the value in the Shunt-Voltage Sum register in order to
> +          determine if the total summed limit is exceeded. If the
> +          shunt-voltage sum limit value is exceeded, the critical alert pin
> +          pulls low.
> +
> +          For the summation limit to have a meaningful value, it is necessary
> +          to use the same shunt-resistor value on all included channels. If
> +          this is not the case for specific channels, then the
> +          'summation-bypass' can be populated for a specific channel to
> +          exclude from the summation control function.

I don't understand what this property does. You described feature in the
device, that's good, but how does it map to the property? Bypass means
disable?

> +
>      additionalProperties: false
>  
>      required:

Best regards,
Krzysztof
Jon Hunter Aug. 29, 2023, 12:48 p.m. UTC | #2
On 26/08/2023 09:56, Krzysztof Kozlowski wrote:
> On 25/08/2023 18:42, Ninad Malwade wrote:
>> The INA3221 has a critical alert pin that can be controlled by the
>> summation control function. This function adds the single
>> shunt-voltage conversions for the desired channels in order to
>> compare the combined sum to the programmed limit. The Shunt-Voltage
>> Sum Limit register contains the programmed value that is compared
>> to the value in the Shunt-Voltage Sum register in order to
>> determine if the total summed limit is exceeded. If the
>> shunt-voltage sum limit value is exceeded, the critical alert pin
>> pulls low.
>>
>> For the summation limit to have a meaningful value, it is necessary
>> to use the same shunt-resistor value on all included channels. Add a
>> new property, 'summation-bypass', to allow specific channels to be
>> excluded from the summation control function if the shunt resistor
>> is different to other channels.
>>
>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>> Signed-off-by: Ninad Malwade <nmalwade@nvidia.com>
>> ---
>>   .../devicetree/bindings/hwmon/ti,ina3221.yaml  | 18 ++++++++++++++++++
>>   1 file changed, 18 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
>> index 0c6d41423d8c..20c23febf575 100644
>> --- a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
>> +++ b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
>> @@ -55,6 +55,24 @@ patternProperties:
>>         shunt-resistor-micro-ohms:
>>           description: shunt resistor value in micro-Ohm
>>   
>> +      summation-bypass:
> 
> What is the type? There is no vendor prefix here, so you added it as a
> generic property. Which other devices use or can use it?
> 
>> +        description: |
>> +          The INA3221 has a critical alert pin that can be controlled by the
>> +          summation control function. This function adds the single
>> +          shunt-voltage conversions for the desired channels in order to
>> +          compare the combined sum to the programmed limit. The Shunt-Voltage
>> +          Sum Limit register contains the programmed value that is compared
>> +          to the value in the Shunt-Voltage Sum register in order to
>> +          determine if the total summed limit is exceeded. If the
>> +          shunt-voltage sum limit value is exceeded, the critical alert pin
>> +          pulls low.
>> +
>> +          For the summation limit to have a meaningful value, it is necessary
>> +          to use the same shunt-resistor value on all included channels. If
>> +          this is not the case for specific channels, then the
>> +          'summation-bypass' can be populated for a specific channel to
>> +          exclude from the summation control function.
> 
> I don't understand what this property does. You described feature in the
> device, that's good, but how does it map to the property? Bypass means
> disable?


Yes it means 'disable'. I kept as 'bypass' to align with the original 
patch [0], but if it is clearer, we could change this to be 
'summation-disable'.

Jon

[0] https://lore.kernel.org/lkml/20221108045243.24143-1-nmalwade@nvidia.com/
Krzysztof Kozlowski Aug. 29, 2023, 5:19 p.m. UTC | #3
On 29/08/2023 14:48, Jon Hunter wrote:
> 
> 
> On 26/08/2023 09:56, Krzysztof Kozlowski wrote:
>> On 25/08/2023 18:42, Ninad Malwade wrote:
>>> The INA3221 has a critical alert pin that can be controlled by the
>>> summation control function. This function adds the single
>>> shunt-voltage conversions for the desired channels in order to
>>> compare the combined sum to the programmed limit. The Shunt-Voltage
>>> Sum Limit register contains the programmed value that is compared
>>> to the value in the Shunt-Voltage Sum register in order to
>>> determine if the total summed limit is exceeded. If the
>>> shunt-voltage sum limit value is exceeded, the critical alert pin
>>> pulls low.
>>>
>>> For the summation limit to have a meaningful value, it is necessary
>>> to use the same shunt-resistor value on all included channels. Add a
>>> new property, 'summation-bypass', to allow specific channels to be
>>> excluded from the summation control function if the shunt resistor
>>> is different to other channels.
>>>
>>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
>>> Signed-off-by: Ninad Malwade <nmalwade@nvidia.com>
>>> ---
>>>   .../devicetree/bindings/hwmon/ti,ina3221.yaml  | 18 ++++++++++++++++++
>>>   1 file changed, 18 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
>>> index 0c6d41423d8c..20c23febf575 100644
>>> --- a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
>>> +++ b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
>>> @@ -55,6 +55,24 @@ patternProperties:
>>>         shunt-resistor-micro-ohms:
>>>           description: shunt resistor value in micro-Ohm
>>>   
>>> +      summation-bypass:
>>
>> What is the type? There is no vendor prefix here, so you added it as a
>> generic property. Which other devices use or can use it?
>>
>>> +        description: |
>>> +          The INA3221 has a critical alert pin that can be controlled by the
>>> +          summation control function. This function adds the single
>>> +          shunt-voltage conversions for the desired channels in order to
>>> +          compare the combined sum to the programmed limit. The Shunt-Voltage
>>> +          Sum Limit register contains the programmed value that is compared
>>> +          to the value in the Shunt-Voltage Sum register in order to
>>> +          determine if the total summed limit is exceeded. If the
>>> +          shunt-voltage sum limit value is exceeded, the critical alert pin
>>> +          pulls low.
>>> +
>>> +          For the summation limit to have a meaningful value, it is necessary
>>> +          to use the same shunt-resistor value on all included channels. If
>>> +          this is not the case for specific channels, then the
>>> +          'summation-bypass' can be populated for a specific channel to

"populated" is confusing here. I guess you wanted "can be used"?

>>> +          exclude from the summation control function.
>>
>> I don't understand what this property does. You described feature in the
>> device, that's good, but how does it map to the property? Bypass means
>> disable?
> 
> 
> Yes it means 'disable'. I kept as 'bypass' to align with the original 
> patch [0], but if it is clearer, we could change this to be 
> 'summation-disable'.

Sounds better, but the description could also start with it, e.g.
"Disable the summation on specific channel. .... "

Best regards,
Krzysztof
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
index 0c6d41423d8c..20c23febf575 100644
--- a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
+++ b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
@@ -55,6 +55,24 @@  patternProperties:
       shunt-resistor-micro-ohms:
         description: shunt resistor value in micro-Ohm
 
+      summation-bypass:
+        description: |
+          The INA3221 has a critical alert pin that can be controlled by the
+          summation control function. This function adds the single
+          shunt-voltage conversions for the desired channels in order to
+          compare the combined sum to the programmed limit. The Shunt-Voltage
+          Sum Limit register contains the programmed value that is compared
+          to the value in the Shunt-Voltage Sum register in order to
+          determine if the total summed limit is exceeded. If the
+          shunt-voltage sum limit value is exceeded, the critical alert pin
+          pulls low.
+
+          For the summation limit to have a meaningful value, it is necessary
+          to use the same shunt-resistor value on all included channels. If
+          this is not the case for specific channels, then the
+          'summation-bypass' can be populated for a specific channel to
+          exclude from the summation control function.
+
     additionalProperties: false
 
     required: