AXP192 is a small and simple power management IC featuring different
LDOs, DCDCs, AINs and also GPIOs. It also offers functionaltiy for
battery management.
This change includes the basic regulator driver functionaltiy for
LDO2-3 and DCDC1-3 as well as the mfd driver layer. Further drivers
for GPIO and ADC will follow.
Drivers have been developed and tested on M5StackCore2, an ESP32-based
board. Support for M5StackCore2 is still in progress.
Signed-off-by: Martin Kiepfer <mrmarteng@teleschirm.org>