Thermal: Add Hysteresis attributes

The Linux Thermal Framework does not support hysteresis
attributes. Most thermal sensors, today, have a
hysteresis value associated with trip points.

This patch adds hysteresis attributes on a per-trip-point
basis, to the Thermal Framework. These attributes are
optionally writable.

Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
index 4c105934c599..2ba4c9bb790a 100644
--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt
@@ -121,6 +121,7 @@ Thermal zone device sys I/F, created once it's registered:
     |---mode:                   Working mode of the thermal zone
     |---trip_point_[0-*]_temp:  Trip point temperature
     |---trip_point_[0-*]_type:  Trip point type
+    |---trip_point_[0-*]_hyst:  Hysteresis value for this trip point
 
 Thermal cooling device sys I/F, created once it's registered:
 /sys/class/thermal/cooling_device[0-*]:
@@ -190,6 +191,11 @@ trip_point_[0-*]_type
         thermal zone.
         RO, Optional
 
+trip_point_[0-*]_hyst
+        The hysteresis value for a trip point, represented as an integer
+        Unit: Celsius
+        RW, Optional
+
 cdev[0-*]
         Sysfs link to the thermal cooling device node where the sys I/F
         for cooling device throttling control represents.