tree bdc4f1e2f83ec52a681d6c633614a60d4c6cd90e
parent 825e31e5c2eec64384b78acfe9ab4d2f689020bf
author Brad Bishop <bradleyb@fuzziesquirrel.com> 1497473515 -0400
committer Patrick Williams <patrick@stwcx.xyz> 1501705098 +0000

presence: Add presence sensor interface

Prepare to extend the fan presence model to include
sensors of other types with a presence sensor interface
class.

Presence sensors can be both event driven or polled.  Provide
start and stop for the former and present for the latter.

Change-Id: Ia1b91a5e30e27fbe66c6f075e5e5ce620dac997e
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>