73 lines
2.2 KiB
Plaintext
73 lines
2.2 KiB
Plaintext
Bindings for a fan connected to the PWM lines
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Required properties:
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- compatible : "pwm-fan"
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- pwms : the PWM that is used to control the PWM fan
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- cooling-levels : PWM duty cycle values in a range from 0 to 255
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which correspond to thermal cooling states
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Optional properties:
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- fan-supply : phandle to the regulator that provides power to the fan
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- interrupts : This contains an interrupt specifier for each fan
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tachometer output connected to an interrupt source.
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The output signal must generate a defined number of
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interrupts per fan revolution, which require that
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it must be self resetting edge interrupts. See
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interrupt-controller/interrupts.txt for the format.
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- pulses-per-revolution : define the number of pulses per fan revolution for
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each tachometer input as an integer (default is 2
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interrupts per revolution). The value must be
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greater than zero.
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- rockchip,temp-trips : The property is an array of 2-tuples items, and
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each item consists of temperature in millicelsius and
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pwm cooling state. This depends on CONFIG_ROCKCHIP_SYSTEM_MONITOR.
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If add the property the fan cooling state will be changed
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by system monitor. Otherwise, use the default thermal governor.
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Example:
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fan0: pwm-fan {
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compatible = "pwm-fan";
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#cooling-cells = <2>;
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pwms = <&pwm 0 10000 0>;
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cooling-levels = <0 102 170 230>;
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};
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thermal-zones {
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cpu_thermal: cpu-thermal {
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thermal-sensors = <&tmu 0>;
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polling-delay-passive = <0>;
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polling-delay = <0>;
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trips {
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cpu_alert1: cpu-alert1 {
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temperature = <100000>; /* millicelsius */
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hysteresis = <2000>; /* millicelsius */
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type = "passive";
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};
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};
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cooling-maps {
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map0 {
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trip = <&cpu_alert1>;
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cooling-device = <&fan0 0 1>;
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};
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};
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};
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Example 2:
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fan0: pwm-fan {
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compatible = "pwm-fan";
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pwms = <&pwm 0 40000 0>;
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fan-supply = <®_fan>;
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interrupt-parent = <&gpio5>;
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interrupts = <1 IRQ_TYPE_EDGE_FALLING>;
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pulses-per-revolution = <2>;
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};
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Example 3:
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fan0: pwm-fan {
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compatible = "pwm-fan";
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pwms = <&pwm1 0 25000 0>;
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interrupts-extended = <&gpio1 1 IRQ_TYPE_EDGE_FALLING>,
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<&gpio2 5 IRQ_TYPE_EDGE_FALLING>;
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pulses-per-revolution = <2>, <1>;
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};
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