Re: [PATCH v4 3/8] Documentation: dts: Documentation entry to explain how to use PWM FAN as a cooling device

Eduardo Valentin
2015-02-24T19:25:21Z

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On Wed, Feb 18, 2015 at 11:07:31AM +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
> ---
> Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
> index 610757c..d53fe0c 100644
> --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
> +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
> @@ -3,10 +3,30 @@ 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
> +
> +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>;
> + };
> + };
> + };

I am fine if you leave the reference to thermal.txt biding description,
but I would prefer if you move the above lines to a proper example section.

> +
> +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-levels = <0 102 170 230>;
> };
> --
> 2.0.0.rc2
>

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