| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame] | 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 = <®_fan>; |
| 54 | interrupt-parent = <&gpio5>; |
| 55 | interrupts = <1 IRQ_TYPE_EDGE_FALLING>; |
| 56 | pulses-per-revolution = <2>; |
| 57 | }; |