Move analogReference enum to ArduinoCore-API

[rubenstar]

Currently, the header for analogReference(...) is in ArduinoCore-API and takes uint8_t as argument type.

The implementation of that function is in ArduinoCore-samd (here), but takes eAnalogReference enum as argument type. The enum is defined in Arduino.h

Compiling ArduinoCore-samd/cores/arduino/wiring_analog.c will give a warning:

[ 31%] Building C object .../ArduinoCore-samd/cores/arduino/wiring_analog.c.obj
/home/.../ArduinoCore-samd/cores/arduino/wiring_analog.c:94:6: warning: conflicting types for 'analogReference' due to enum/integer mismatch; have 'void(eAnalogReference)' {aka 'void(enum _eAnalogReference)'} [-Wenum-int-mismatch]
   94 | void analogReference(eAnalogReference mode)
      |      ^~~~~~~~~~~~~~~
In file included from /home/.../ArduinoCore-API/api/ArduinoAPI.h:50,
                 from /home/.../ArduinoCore-samd/cores/arduino/Arduino.h:23,
                 from /home/.../ArduinoCore-samd/cores/arduino/wiring_analog.c:19:
/home/.../ArduinoCore-API/api/Common.h:100:6: note: previous declaration of 'analogReference' with type 'void(uint8_t)' {aka 'void(unsigned char)'}
  100 | void analogReference(uint8_t mode);
      |      ^~~~~~~~~~~~~~~

My proposal is to move that enum from Arduino.h in ArduinoCore-samd fully into ArduinoCore-API. Seems cleaner to me.

I filed a corresponding PR in ArduinoCore-samd too:
arduino/ArduinoCore-samd#718

[CLAassistant]

All committers have signed the CLA.

[bmourit]

These values seem very specific. How can other platforms use them? Does it benefit any platform besides SAMD? Just curious as to if this is generic enough for other platforms following the API.

[facchinm]

Hi @rubenstar, as @bmourit already explained, the analogReference parameters are architecture specific, so they cannot be generalized and added to the API repo.
The warning arises from the SAMD port being stricter than usual on the parameter type, but the fix for the warning should just be applied in that core.

[rubenstar]

@facchinm @bmourit Thanks for your input, that makes perfect sense. Sorry for raising the PR before really thinking it through.

[bmourit]

No need to be sorry!!!