Thread (117 messages) 117 messages, 9 authors, 2015-09-16
STALE3927d

[PATCH v5 1/6] Documentation: dts: Documentation entry to explain how to use PWM FAN as a cooling device

From: Lukasz Majewski <hidden>
Date: 2015-02-25 15:34:49
Also in: linux-pm, linux-samsung-soc, lkml
Subsystem: hardware monitoring, open firmware and flattened device tree bindings, the rest · Maintainers: Guenter Roeck, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds

Explanation of several properties, which allow PWM fan working as a cooling
device, have been embraced in this commit.

Signed-off-by: Lukasz Majewski <redacted>
---
Changes for v2:
- Rename cooling-pwm-values to cooling-levels
- Remove default-pulse-width property and stick to default hwmon policy
Changes for v3:
- Changing commit title from "hwmon: dts: Doc:" to "Documentation: dts"
- Remove unnecessary properties
- Set maximal cooling level to 230 instead of 255
Changes for v4:
- None
Changes for v5:
- Move thermal-zones description to example section
- Extending example section

---
 .../devicetree/bindings/hwmon/pwm-fan.txt          | 25 +++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
index 610757c..645251b 100644
--- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
+++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
@@ -3,10 +3,33 @@ 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";
 		pwms = <&pwm 0 10000 0>;
+		cooling-levels = <0 102 170 230>;
+	};
+
+	thermal-zones {
+		cpu_thermal: cpu-thermal {
+		cooling-min-state = <0>;
+		cooling-max-state = <3>;
+		#cooling-cells = <2>;
+		trips {
+			cpu_alert1: cpu-alert1 {
+				temperature = <100000>; /* millicelsius */
+				hysteresis = <2000>; /* millicelsius */
+				type = "passive";
+			};
+		};
+		cooling-maps {
+			map0 {
+			     trip = <&cpu_alert1>;
+			     cooling-device = <&fan0 0 1>;
+			};
+		};
 	};
-- 
2.0.0.rc2
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