On 29/09/2023 11:27, 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@xxxxxxxxxx> Signed-off-by: Ninad Malwade <nmalwade@xxxxxxxxxx> --- .../devicetree/bindings/hwmon/ti,ina3221.yaml | 23 +++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml b/Documentation/devicetree/bindings/hwmon/ti,ina3221.yaml index d0e64a72af5b..d69f50d0e4ab 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@@ -81,6 +100,10 @@ examples: input@0 {reg = <0x0>; + /* + * Input channels are enabled by default in the device and so + * to disable, must be explicitly disabled in device-tree. + */ status = "disabled"; };
Ugh, I added this to the wrong patch. Let me correct this and send this again.
Jon -- nvpublic
