Hi
I had the same problem, but the suggested (uint16_t) correction in M5EPD.cpp lead to another problem: in the files adc.h, the statement
#include "soc/adc_channel.h" must be inserted after tge firts #include statement.
Chris

I got the same compiler errors after inserting (uint...) the firs error disappears - thanks for your hint! But then, I receive a bunch of errors because ADC1_GPI35_CHANNEL 'was not declared in this scope'. Since M5EPD.cpp includes various *.h files, which again inclut files that include... it is hard to find out where ADC _... is declared. I would be grateful if you could tell me. Maybe, something went wrong in my installation.
Icidentally, compilation takes extremely long, probably because I have very many paths to *.h files under ...ArduinoData\packages\m5Stack
Thanks for any hint.
Chris