How does the power telemetry with INA219 even work?

[mich181189]

The Power Telemetry module supports using the INA219 sensor. What I can't see is how it actually works:

In PowerTelemetry.cpp:
m.which_variant = meshtastic_Telemetry_power_metrics_tag;
...
valid = ina219Sensor.getMetrics(m);

Then in INA219Sensor.cpp:
measurement->variant.environment_metrics.has_voltage = true;

As in, the variant tag is set to power_metrics however environment_metrics is being filled in. Only the INA3221 sensor seems ot actually fill in power_metrics.

In the iOS app, the INA219 metrics seem to get attributed to channel 3, and I was wondering why (why not channel 1?) when I spotted this

[viric]

The telemetry.proto file reads in EnvironmentMetrics:

  /*
   * Voltage measured (To be depreciated in favor of PowerMetrics in Meshtastic 3.x)
   */
  optional float voltage = 5;