forked from Qortal/Brooklyn
80 lines
2.4 KiB
Plaintext
80 lines
2.4 KiB
Plaintext
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/*
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* Overlay for the Raspberry Pi GPIO Fan @ BCM GPIO12.
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* References:
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* - https://www.raspberrypi.org/forums/viewtopic.php?f=107&p=1367135#p1365084
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*
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* Optional parameters:
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* - "gpiopin" - BCM number of the pin driving the fan, default 12 (GPIO12);
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* - "temp" - CPU temperature at which fan is started in millicelsius, default 55000;
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*
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* Requires:
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* - kernel configurations: CONFIG_SENSORS_GPIO_FAN=m;
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* - kernel rebuild;
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* - N-MOSFET connected to gpiopin, 2N7002-[https://en.wikipedia.org/wiki/2N7000];
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* - DC Fan connected to N-MOSFET Drain terminal, a 12V fan is working fine and quite silently;
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* [https://www.tme.eu/en/details/ee40101s1-999-a/dc12v-fans/sunon/ee40101s1-1000u-999/]
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*
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* ┌─────────────────────┐
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* │Fan negative terminal│
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* └┬────────────────────┘
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* │D
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* G │──┘
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* [GPIO12]──────┤ │<─┐ 2N7002
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* │──┤
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* │S
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* ─┴─
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* GND
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*
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* Build:
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* - `sudo dtc -W no-unit_address_vs_reg -@ -I dts -O dtb -o /boot/overlays/gpio-fan.dtbo gpio-fan-overlay.dts`
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* Activate:
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* - sudo nano /boot/config.txt add "dtoverlay=gpio-fan" or "dtoverlay=gpio-fan,gpiopin=12,temp=45000"
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* or
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* - sudo sh -c 'printf "\n# Enable PI GPIO-Fan Default\ndtoverlay=gpio-fan\n" >> /boot/config.txt'
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* - sudo sh -c 'printf "\n# Enable PI GPIO-Fan Custom\ndtoverlay=gpio-fan,gpiopin=12,temp=45000\n" >> /boot/config.txt'
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*
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*/
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/dts-v1/;
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/plugin/;
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/ {
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compatible = "brcm,bcm2835";
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fragment@0 {
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target-path = "/";
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__overlay__ {
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fan0: gpio-fan@0 {
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compatible = "gpio-fan";
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gpios = <&gpio 12 0>;
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gpio-fan,speed-map = <0 0>,
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<5000 1>;
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#cooling-cells = <2>;
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};
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};
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};
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fragment@1 {
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target = <&cpu_thermal>;
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polling-delay = <2000>; /* milliseconds */
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__overlay__ {
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trips {
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cpu_hot: trip-point@0 {
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temperature = <55000>; /* (millicelsius) Fan started at 55°C */
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hysteresis = <10000>; /* (millicelsius) Fan stopped at 45°C */
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type = "active";
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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_hot>;
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cooling-device = <&fan0 1 1>;
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};
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};
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};
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};
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__overrides__ {
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gpiopin = <&fan0>,"gpios:4", <&fan0>,"brcm,pins:0";
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temp = <&cpu_hot>,"temperature:0";
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};
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};
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