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>

diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
index 610757ce449213aa03765b1c476785433c1afa24..c6d533202d3e3a1a12eee650fe17125d48e5963f 100644 (file)
--- 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>;
+                                       };
+                            };
+               };