Documentation/devicetree/bindings/hwmon/pwm-fan.txt

   1 Bindings for a fan connected to the PWM lines
   2
   3 Required properties:
   4 - compatible    : "pwm-fan"
   5 - pwms          : the PWM that is used to control the PWM fan
   6 - cooling-levels      : PWM duty cycle values in a range from 0 to 255
   7                         which correspond to thermal cooling states
   8
   9 Optional properties:
  10 - fan-supply            : phandle to the regulator that provides power to the fan
  11 - interrupts            : This contains a single interrupt specifier which
  12                           describes the tachometer output of the fan as an
  13                           interrupt source. The output signal must generate a
  14                           defined number of interrupts per fan revolution, which
  15                           require that it must be self resetting edge interrupts.
  16                           See interrupt-controller/interrupts.txt for the format.
  17 - pulses-per-revolution : define the tachometer pulses per fan revolution as
  18                           an integer (default is 2 interrupts per revolution).
  19                           The value must be greater than zero.
  20
  21 Example:
  22         fan0: pwm-fan {
  23                 compatible = "pwm-fan";
  24                 #cooling-cells = <2>;
  25                 pwms = <&pwm 0 10000 0>;
  26                 cooling-levels = <0 102 170 230>;
  27         };
  28
  29         thermal-zones {
  30                 cpu_thermal: cpu-thermal {
  31                              thermal-sensors = <&tmu 0>;
  32                              polling-delay-passive = <0>;
  33                              polling-delay = <0>;
  34                              trips {
  35                                         cpu_alert1: cpu-alert1 {
  36                                                     temperature = <100000>; /* millicelsius */
  37                                                     hysteresis = <2000>; /* millicelsius */
  38                                                     type = "passive";
  39                                         };
  40                              };
  41                              cooling-maps {
  42                                         map0 {
  43                                                     trip = <&cpu_alert1>;
  44                                                     cooling-device = <&fan0 0 1>;
  45                                         };
  46                              };
  47                 };
  48
  49 Example 2:
  50         fan0: pwm-fan {
  51                 compatible = "pwm-fan";
  52                 pwms = <&pwm 0 40000 0>;
  53                 fan-supply = <&reg_fan>;
  54                 interrupt-parent = <&gpio5>;
  55                 interrupts = <1 IRQ_TYPE_EDGE_FALLING>;
  56                 pulses-per-revolution = <2>;
  57         };