diff mbox series

[V5,2/4] dt-bindings: hwmon: ina3221: Add ti,summation-disable

Message ID 20230929103650.86074-3-jonathanh@nvidia.com
State Handled Elsewhere
Headers show
Series hwmon: ina3221: Add selective summation support | expand

Commit Message

Jon Hunter Sept. 29, 2023, 10:36 a.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
vendor specific property, 'ti,summation-disable', to allow specific
channels to be excluded from the summation control function if the shunt
resistor is different to other channels or the channel should not be
considered for triggering the critical alert pin.

Note that the ina3221 has always supported summing the various input
channels and summation is enabled by default if the shunt-resistor
values are the same. This change simply provides a way to exclude
inputs from the summation. If this property is not populated, then the
functionality of the driver does not change.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Ninad Malwade <nmalwade@nvidia.com>
---
 .../devicetree/bindings/hwmon/ti,ina3221.yaml | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

Comments

Rob Herring (Arm) Oct. 2, 2023, 5:20 p.m. UTC | #1 
On Fri, 29 Sep 2023 11:36:48 +0100, Jon Hunter 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
> vendor specific property, 'ti,summation-disable', to allow specific
> channels to be excluded from the summation control function if the shunt
> resistor is different to other channels or the channel should not be
> considered for triggering the critical alert pin.
> 
> Note that the ina3221 has always supported summing the various input
> channels and summation is enabled by default if the shunt-resistor
> values are the same. This change simply provides a way to exclude
> inputs from the summation. If this property is not populated, then the
> functionality of the driver does not change.
> 
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> Signed-off-by: Ninad Malwade <nmalwade@nvidia.com>
> ---
>  .../devicetree/bindings/hwmon/ti,ina3221.yaml | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>
Guenter Roeck Oct. 26, 2023, 12:59 a.m. UTC | #2 
On Fri, Sep 29, 2023 at 11:36:48AM +0100, Jon Hunter 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
> vendor specific property, 'ti,summation-disable', to allow specific
> channels to be excluded from the summation control function if the shunt
> resistor is different to other channels or the channel should not be
> considered for triggering the critical alert pin.
> 
> Note that the ina3221 has always supported summing the various input
> channels and summation is enabled by default if the shunt-resistor
> values are the same. This change simply provides a way to exclude
> inputs from the summation. If this property is not populated, then the
> functionality of the driver does not change.
> 
> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> Signed-off-by: Ninad Malwade <nmalwade@nvidia.com>
> Reviewed-by: Rob Herring <robh@kernel.org>

Applied.

Thanks,
Guenter
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
index 0fd8ae5f6a22..5f10f1207d69 100644
--- a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
+++ b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml
@@ -58,6 +58,25 @@  patternProperties:
       shunt-resistor-micro-ohms:
         description: shunt resistor value in micro-Ohm
 
+      ti,summation-disable:
+        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
+          is asserted.
+
+          For the summation limit to have a meaningful value, it is necessary
+          to use the same shunt-resistor value on all enabled channels. If
+          this is not the case or if a channel should not be used for
+          triggering the critical alert pin, then this property can be used
+          exclude specific channels from the summation control function.
+        type: boolean
+
     required:
       - reg