tree 92a7a40aff62481b8bef2949827287932cb9d1cc
parent 04974df8049fc4240d22759a91e035082ccd18b4
author Michele Di Giorgio <michele.digiorgio@arm.com> 1462960147 +0100
committer Zhang Rui <rui.zhang@intel.com> 1463376071 +0800

thermal: check validity get_trip_hyst function pointer in bang-bang governor

Bang-bang thermal governor uses trip point hysteresis to make decisions.
Hysteresis is a required property in the device tree for trip points, but it is
an optional thermal zone device operation. Hence, we need to check whether the
function pointer is valid or not.

If it is not available, we assume the hysteresis to be zero. Consequently, a
highly varying temperature will make the governor continuosly switch a cooling
device ON and OFF.

CC: Zhang Rui <rui.zhang@intel.com>
CC: Eduardo Valentin <edubezval@gmail.com>
CC: Peter Feuerer <peter@piie.net>
Signed-off-by: Michele Di Giorgio <michele.digiorgio@arm.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>