This CL,

https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/231402/

Should have enabled the ability to select which USBC charger to use in the event there were multiple or disable them altogether by writing -1 to charge_control_limit_max sysfs parameter as mentioned here:

https://chromium.googlesource.com/chromiumos/platform2/+/master/power_manager/docs/power_supplies.md#Multiple-sources

Lets fix this so we can perform these operations programmatically.  In particular it would be useful to disable charging via,

dbus-send --type=method_call --system --print-reply --dest=org.chromium.PowerManager /org/chromium/PowerManager org.chromium.PowerManager.SetPowerSource string:'-1'

or

for f in `find /sys/devices -name "charge_control_limit_max"` ; do echo -1 > $f ; done