pwm-fan.yaml

  1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
  2%YAML 1.2
  3---
  4$id: http://devicetree.org/schemas/hwmon/pwm-fan.yaml#
  5$schema: http://devicetree.org/meta-schemas/core.yaml#
  6
  7title: Fan connected to PWM lines
  8
  9maintainers:
 10  - Jean Delvare <jdelvare@suse.com>
 11  - Guenter Roeck <linux@roeck-us.net>
 12
 13properties:
 14  compatible:
 15    const: pwm-fan
 16
 17  cooling-levels:
 18    description: PWM duty cycle values corresponding to thermal cooling states.
 19    $ref: /schemas/types.yaml#/definitions/uint32-array
 20    items:
 21      maximum: 255
 22
 23  fan-supply:
 24    description: Phandle to the regulator that provides power to the fan.
 25
 26  interrupts:
 27    description:
 28      This contains an interrupt specifier for each fan tachometer output
 29      connected to an interrupt source. The output signal must generate a
 30      defined number of interrupts per fan revolution, which require that
 31      it must be self resetting edge interrupts.
 32    maxItems: 1
 33
 34  fan-shutdown-percent:
 35    description:
 36      Fan RPM in percent set during shutdown. This is used to keep the fan
 37      running at fixed RPM after the kernel shut down, which is useful on
 38      hardware that does keep heating itself even after the kernel did shut
 39      down, for example from some sort of management core.
 40    minimum: 0
 41    maximum: 100
 42
 43  fan-stop-to-start-percent:
 44    description:
 45      Minimum fan RPM in percent to start when stopped.
 46    minimum: 0
 47    maximum: 100
 48
 49  fan-stop-to-start-us:
 50    description:
 51      Time to wait in microseconds after start when stopped.
 52
 53  pulses-per-revolution:
 54    description:
 55      Define the number of pulses per fan revolution for each tachometer
 56      input as an integer.
 57    $ref: /schemas/types.yaml#/definitions/uint32
 58    minimum: 1
 59    maximum: 4
 60    default: 2
 61
 62  pwms:
 63    description: The PWM that is used to control the fan.
 64    maxItems: 1
 65
 66  "#cooling-cells": true
 67
 68required:
 69  - compatible
 70  - pwms
 71
 72additionalProperties: false
 73
 74examples:
 75  - |
 76    pwm-fan {
 77      compatible = "pwm-fan";
 78      cooling-levels = <0 102 170 230>;
 79      pwms = <&pwm 0 10000 0>;
 80      #cooling-cells = <2>;
 81    };
 82
 83    thermal-zones {
 84      cpu_thermal: cpu-thermal {
 85        thermal-sensors = <&tmu 0>;
 86        polling-delay-passive = <0>;
 87        polling-delay = <0>;
 88
 89        trips {
 90          cpu_alert1: cpu-alert1 {
 91            temperature = <100000>; /* millicelsius */
 92            hysteresis = <2000>; /* millicelsius */
 93            type = "passive";
 94          };
 95        };
 96
 97        cooling-maps {
 98          map0 {
 99            trip = <&cpu_alert1>;
100            cooling-device = <&fan0 0 1>;
101          };
102        };
103      };
104    };
105
106  - |
107    #include <dt-bindings/interrupt-controller/irq.h>
108
109    pwm-fan {
110      compatible = "pwm-fan";
111      pwms = <&pwm 0 40000 0>;
112      fan-supply = <&reg_fan>;
113      interrupt-parent = <&gpio5>;
114      interrupts = <1 IRQ_TYPE_EDGE_FALLING>;
115      pulses-per-revolution = <2>;
116    };