v2.3.0

This is a larger than usual feature update. While it is unexpected to be
backwards incompatible, please review the compatibility notes below just in
case.

• New features

  • Added Circuits.GPIO.subscribe/2 as an alternative to set_interrupts/3.
    This function simplifies matching of GPIO change notifications and is
    extensible. It is required for listening to changes for multi-GPIO handles.
  • Support opening multiple GPIOs using one handle. This allows backends to
    read and write a set of GPIOs atomically. It's supported on Linux for GPIOs
    in the same hardware bank.
  • Support passing GPIO handles to Circuits.GPIO.status/1
  • Added Circuits.GPIO.force_close/1 to close open handles without knowing
    the handle. This is especially useful when working at the IEx prompt or
    Livebook and you've lost the handle. If the handle is used, it will raise
    an exception.
  • Added an on_busy: :take_over option to Circuits.GPIO.open/3 to
    automatically close any other open handles for the specified GPIO or GPIOs.
    This is not the default. It can be used in GenServer :init callbacks
    to avoid a race with the Erlang GC for cleaning up handles from a previous
    failure.

• Backwards incompatible changes

  • Circuits.GPIO.write/2 no longer treats all non-zero values as 1. Even
    though the typespec for write/2 restricted values to 0 and 1, the
    implementation was forgiving. This is no longer the case.
  • Previously unknown errno values were reported as {:errno, n}. They're now
    reported as their lowercase errno names using Erlang's built-in errno
    conversion.