Re: [PATCH V3 2/4] dt-bindings: hwmon: ina3221: Add ti,summation-disable

[Rob Herring <robh@kernel.org>]

On Thu, Sep 21, 2023 at 02:08:16PM +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.

You are adding this feature to the driver, but requiring a new property 
to disable it. So what happens with an existing user (old DT) and a 
kernel with the new feature?

Rob