[PATCH 2/9] hwmon: dts: Doc: Add DTS doc to explain how to use PWM FAN as a cooling device

From: Lukasz Majewski
Date: Thu Dec 18 2014 - 05:13:59 EST


Several new properties to allow PWM fan working as a cooling device have been
combined into this single commit.

Signed-off-by: Lukasz Majewski <l.majewski@xxxxxxxxxxx>
---
.../devicetree/bindings/hwmon/pwm-fan.txt | 28 ++++++++++++++++++++++
1 file changed, 28 insertions(+)

diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
index 610757c..3877810 100644
--- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
+++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
@@ -3,10 +3,38 @@ 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-pwm-values : PWM duty cycle values relative to
+ cooling-max-pwm-value correspondig to
+ proper cooling states
+- default-pulse-width : Property specifying default pulse width for FAN
+ at system boot (zero to disable FAN on boot).
+ Allowed range is 0 to 255
+
+Thorough description of the following bindings:
+ cooling-min-state = <0>;
+ cooling-max-state = <3>;
+ #cooling-cells = <2>;
+ thermal-zone {
+ cpu_thermal: cpu-thermal {
+ cooling-maps {
+ map0 {
+ trip = <&cpu_alert1>;
+ cooling-device = <&fan0 0 1>;
+ };
+ };
+ };
+
+for PWM FAN used as cooling device can be found at:
+./Documentation/devicetree/bindings/thermal/thermal.txt

Example:
pwm-fan {
compatible = "pwm-fan";
status = "okay";
pwms = <&pwm 0 10000 0>;
+ cooling-min-state = <0>;
+ cooling-max-state = <3>;
+ #cooling-cells = <2>;
+ cooling-pwm-values = <0 102 170 255>;
+ default-pulse-width = <0>;
};
--
2.0.0.rc2

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