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Document fan-shutdown-percent property, used to describe fan RPM in percent set during shutdown. This is used to keep the fan running at fixed RPM after the kernel shut down, which is useful on hardware that does keep heating itself even after the kernel did shut down, for example from some sort of management core. Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org> Acked-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20250904202157.170600-1-marek.vasut+renesas@mailbox.org Signed-off-by: Guenter Roeck <linux@roeck-us.net>
117 lines
2.9 KiB
YAML
117 lines
2.9 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/hwmon/pwm-fan.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Fan connected to PWM lines
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maintainers:
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- Jean Delvare <jdelvare@suse.com>
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- Guenter Roeck <linux@roeck-us.net>
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properties:
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compatible:
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const: pwm-fan
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cooling-levels:
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description: PWM duty cycle values corresponding to thermal cooling states.
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$ref: /schemas/types.yaml#/definitions/uint32-array
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items:
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maximum: 255
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fan-supply:
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description: Phandle to the regulator that provides power to the fan.
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interrupts:
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description:
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This contains an interrupt specifier for each fan tachometer output
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connected to an interrupt source. The output signal must generate a
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defined number of interrupts per fan revolution, which require that
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it must be self resetting edge interrupts.
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maxItems: 1
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fan-shutdown-percent:
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description:
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Fan RPM in percent set during shutdown. This is used to keep the fan
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running at fixed RPM after the kernel shut down, which is useful on
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hardware that does keep heating itself even after the kernel did shut
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down, for example from some sort of management core.
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minimum: 0
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maximum: 100
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fan-stop-to-start-percent:
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description:
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Minimum fan RPM in percent to start when stopped.
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minimum: 0
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maximum: 100
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fan-stop-to-start-us:
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description:
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Time to wait in microseconds after start when stopped.
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pulses-per-revolution:
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description:
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Define the number of pulses per fan revolution for each tachometer
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input as an integer.
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$ref: /schemas/types.yaml#/definitions/uint32
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minimum: 1
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maximum: 4
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default: 2
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pwms:
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description: The PWM that is used to control the fan.
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maxItems: 1
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"#cooling-cells": true
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required:
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- compatible
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- pwms
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additionalProperties: false
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examples:
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- |
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pwm-fan {
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compatible = "pwm-fan";
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cooling-levels = <0 102 170 230>;
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pwms = <&pwm 0 10000 0>;
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#cooling-cells = <2>;
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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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};
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- |
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#include <dt-bindings/interrupt-controller/irq.h>
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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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