Thermal: Introduce .get_trend() callback.
authorZhang Rui <rui.zhang@intel.com>
Wed, 27 Jun 2012 01:54:33 +0000 (09:54 +0800)
committerZhang Rui <rui.zhang@intel.com>
Mon, 24 Sep 2012 06:44:36 +0000 (14:44 +0800)
commit601f3d4242be6ed6f72a2aadabc91e8255dad811
tree497f09fcf665c066e4efc5d9542b33f021632ea9
parent9d99842f99d847191ebd0c28469d2c70fcc5bf9e
Thermal: Introduce .get_trend() callback.

According to ACPI spec, tc1 and tc2 are used by OSPM
to anticipate the temperature trends.
We introduced the same concept to the generic thermal layer
for passive cooling, but now it seems that these values
are hard to be used on other platforms.

So We introduce .get_trend() as a more general solution.

For the platform thermal drivers that have their own way to
anticipate the temperature trends, they should provide
their own .get_trend() callback.
Or else, we will calculate the temperature trends by simply
comparing the current temperature and the cached previous
temperature reading.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Valentin, Eduardo <eduardo.valentin@ti.com>
drivers/acpi/thermal.c
drivers/thermal/thermal_sys.c
include/linux/thermal.h