Fix missing return value in getBemf() method of Haptic_Driver.cpp

[ShijiMi-Soup]

Problem

While trying the I2C_mode example using Arduino IDE 2.3.4, I encountered the following error during compilation:

/Users/takahiro/Documents/Arduino/libraries/SparkFun_Qwiic_Haptic_Driver_DA7280_Library/src/Haptic_Driver.cpp: In member function 'float Haptic_Driver::getBemf()':
/Users/takahiro/Documents/Arduino/libraries/SparkFun_Qwiic_Haptic_Driver_DA7280_Library/src/Haptic_Driver.cpp:502:1: error: control reaches end of non-void function [-Werror=return-type]
  502 | }
      | ^
cc1plus: some warnings being treated as errors

exit status 1

Compilation error: exit status 1

It seems the issue is that the getBemf() method not having a default return value, even though it is declared to return a float. The error occurs even when I only import "Haptic_Driver.h" without using the library in my code, which suggests it is an issue with the library's implementation rather than usage.

Fix

I added a return 0.0 at the end of the method as a workaround, and the example compiled successfully.

Concerns

I am unsure whether returning 0.0 is appropriate, as I am not familiar with the intended behavior of the getBemf() method. If another value is more appropriate, I am open to suggestions.

[tyirvine]

Thank you for opening this pull request. Check the comment above the function. It states the default value is 0x01 or 4.9mV. In the switch statement you could insert the following:

default:
  return 4.9;

[edspark]

I agree with you on this.

[tyirvine]

@edspark Some compilers won't compile the library without this fix. Thank you for the library by the way. 🤙

[edspark]

Only going to reject this pull request because I had a number of other warnings to fix as well.