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

Eduardo Valentin
2015-02-25T19:11:32Z

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On Wed, Feb 25, 2015 at 04:34:17PM +0100, Lukasz Majewski wrote:
> 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>
> ---
> 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>;
> + };
> + };

The above example has two issues:
(1) it is wrong, as the cooling device properties are in the thermal
zone node.
(2) has a misalignment / tabulation

Can you please fix that in your next version too?

> };
> --
> 2.0.0.rc2
>

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