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

[Ninad Malwade <nmalwade@nvidia.com>]

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:
+        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:
-- 
2.17.1