The AXP2101 chip is a multi functional power chip offering a regulator,
charge controller and a fuel gauge (battery percentage and voltage).
Hereby, the fuel gauge provides much more reliable data compared to using
an ADC.
We implement minimal support for this chip (connected state, voltage and
gauge) and bind it to the fuel gauge subsystem.
Closes: #89158
Signed-off-by: Felix Moessbauer <felix.moessbauer@gmail.com>
Add a sample sbs gauge driver with feature parity and basic tests
comparison to its sensor counter-part. Includes a simple stub test that is
extended upon.
Signed-off-by: Aaron Massey <aaronmassey@google.com>
