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 an interrupt specifier for each fan
  12                           tachometer output connected to an interrupt source.
  13                           The output signal must generate a defined number of
  14                           interrupts per fan revolution, which require that
  15                           it must be self resetting edge interrupts. See
  16                           interrupt-controller/interrupts.txt for the format.
  17 - pulses-per-revolution : define the number of pulses per fan revolution for
  18                           each tachometer input as an integer (default is 2
  19                           interrupts per revolution). The value must be
  20                           greater than zero.
  21
  22 Example:
  23         fan0: pwm-fan {
  24                 compatible = "pwm-fan";
  25                 #cooling-cells = <2>;
  26                 pwms = <&pwm 0 10000 0>;
  27                 cooling-levels = <0 102 170 230>;
  28         };
  29
  30         thermal-zones {
  31                 cpu_thermal: cpu-thermal {
  32                              thermal-sensors = <&tmu 0>;
  33                              polling-delay-passive = <0>;
  34                              polling-delay = <0>;
  35                              trips {
  36                                         cpu_alert1: cpu-alert1 {
  37                                                     temperature = <100000>; /* millicelsius */
  38                                                     hysteresis = <2000>; /* millicelsius */
  39                                                     type = "passive";
  40                                         };
  41                              };
  42                              cooling-maps {
  43                                         map0 {
  44                                                     trip = <&cpu_alert1>;
  45                                                     cooling-device = <&fan0 0 1>;
  46                                         };
  47                              };
  48                 };
  49
  50 Example 2:
  51         fan0: pwm-fan {
  52                 compatible = "pwm-fan";
  53                 pwms = <&pwm 0 40000 0>;
  54                 fan-supply = <&reg_fan>;
  55                 interrupt-parent = <&gpio5>;
  56                 interrupts = <1 IRQ_TYPE_EDGE_FALLING>;
  57                 pulses-per-revolution = <2>;
  58         };
  59
  60 Example 3:
  61         fan0: pwm-fan {
  62                 compatible = "pwm-fan";
  63                 pwms = <&pwm1 0 25000 0>;
  64                 interrupts-extended = <&gpio1 1 IRQ_TYPE_EDGE_FALLING>,
  65                         <&gpio2 5 IRQ_TYPE_EDGE_FALLING>;
  66                 pulses-per-revolution = <2>, <1>;
  67         };