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authorLukasz Majewski <l.majewski@samsung.com>2015-08-17 01:53:47 +0200
committerKukjin Kim <kgene@kernel.org>2015-09-17 00:48:11 +0200
commit41553f267a369f24244867f5d6c8d4df254906b7 (patch)
treed3ae8a1912f17e71746851c7fdfb09ec45b58752 /Documentation
parentARM: dts: add suspend opp to exynos4412 (diff)
downloadlinux-41553f267a369f24244867f5d6c8d4df254906b7.tar.xz
linux-41553f267a369f24244867f5d6c8d4df254906b7.zip
dt-bindings: Documentation entry to explain how to use PWM FAN as a cooling device
Explanation of several properties, which allow PWM fan working as a cooling device, have been embraced in this commit. Signed-off-by: Lukasz Majewski <l.majewski@samsung.com> Acked-by: Eduardo Valentin <edubezval@gmail.com> Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Signed-off-by: Kukjin Kim <kgene@kernel.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/hwmon/pwm-fan.txt29
1 files changed, 27 insertions, 2 deletions
diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
index 610757ce4492..c6d533202d3e 100644
--- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
+++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
@@ -3,10 +3,35 @@ Bindings for a fan connected to the PWM lines
Required properties:
- compatible : "pwm-fan"
- pwms : the PWM that is used to control the PWM fan
+- cooling-levels : PWM duty cycle values in a range from 0 to 255
+ which correspond to thermal cooling states
Example:
- pwm-fan {
+ fan0: pwm-fan {
compatible = "pwm-fan";
- status = "okay";
+ cooling-min-state = <0>;
+ cooling-max-state = <3>;
+ #cooling-cells = <2>;
pwms = <&pwm 0 10000 0>;
+ cooling-levels = <0 102 170 230>;
};
+
+ thermal-zones {
+ cpu_thermal: cpu-thermal {
+ thermal-sensors = <&tmu 0>;
+ polling-delay-passive = <0>;
+ polling-delay = <0>;
+ trips {
+ cpu_alert1: cpu-alert1 {
+ temperature = <100000>; /* millicelsius */
+ hysteresis = <2000>; /* millicelsius */
+ type = "passive";
+ };
+ };
+ cooling-maps {
+ map0 {
+ trip = <&cpu_alert1>;
+ cooling-device = <&fan0 0 1>;
+ };
+ };
+ };