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Update gpio-fan-overlay.dts (#2711)

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Add references, links, clear details, some typo correction.
This commit is contained in:
Paul
2018-10-11 12:17:20 +03:00
committed by popcornmix
parent c71a6c3589
commit 334a1cedd3
1 changed files with 22 additions and 14 deletions
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36
arch/arm/boot/dts/overlays/gpio-fan-overlay.dts
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@@ -1,29 +1,37 @@
/*
* Overlay for the Raspberry Pi GPIO Fan @ BCM GPIO12.
* References:
* - https://www.raspberrypi.org/forums/viewtopic.php?f=107&p=1367135#p1365084
*
* Optional parameters:
* - "gpiopin" - default GPIO12
* - "temp" - default 55000
* - "gpiopin" - BCM number of the pin driving the fan, default 12 (GPIO12);
* - "temp" - CPU temperature at which fan is started in millicelsius, default 55000;
*
* Requires:
* - kernel configurations: CONFIG_SENSORS_GPIO_FAN=m and CONFIG_SENSORS_PWM_FAN=m;
* - kernel rebuid;
* - DC Fan connected to GPIO via a N-MOSFET (2N7002)
* - kernel configurations: CONFIG_SENSORS_GPIO_FAN=m;
* - kernel rebuild;
* - N-MOSFET connected to gpiopin, 2N7002-[https://en.wikipedia.org/wiki/2N7000];
* - DC Fan connected to N-MOSFET Drain terminal, a 12V fan is working fine and quite silently;
* [https://www.tme.eu/en/details/ee40101s1-999-a/dc12v-fans/sunon/ee40101s1-1000u-999/]
*
* ┌─────────────────────┐
* │Fan negative terminal│
* └┬────────────────────┘
* │
* │──┘
* │D
* G │──┘
* [GPIO12]──────┤ │<─┐ 2N7002
* │──┤
* │
* │S
* ─┴─
* GND
*
* sudo dtc -W no-unit_address_vs_reg -@ -I dts -O dtb -o /boot/overlays/gpio-fan.dtbo gpio-fan.dts
* sudo nano /boot/config.txt add "dtoverlay=gpio-fan" or "dtoverlay=gpio-fan,gpiopin=12,temp=45000"
* or
* sudo sh -c "echo '\n# Enable PI GPIO-Fan\ndtoverlay=gpio-fan\n' >> /boot/config.txt"
* sudo sh -c "echo '\n# Enable PI GPIO-Fan\ndtoverlay=gpio-fan,gpiopin=12\n' >> /boot/config.txt"
* Build:
* - `sudo dtc -W no-unit_address_vs_reg -@ -I dts -O dtb -o /boot/overlays/gpio-fan.dtbo gpio-fan-overlay.dts`
* Activate:
* - sudo nano /boot/config.txt add "dtoverlay=gpio-fan" or "dtoverlay=gpio-fan,gpiopin=12,temp=45000"
* or
* - sudo sh -c 'printf "\n# Enable PI GPIO-Fan Default\ndtoverlay=gpio-fan\n" >> /boot/config.txt'
* - sudo sh -c 'printf "\n# Enable PI GPIO-Fan Custom\ntoverlay=gpio-fan,gpiopin=12,temp=45000\n" >> /boot/config.txt'
*
*/
/dts-v1/;
@@ -52,7 +60,7 @@
trips {
cpu_hot: trip-point@0 {
temperature = <55000>; /* (millicelsius) Fan started at 55°C */
hysteresis = <5000>; /* (millicelsius) Fan stopped at 50°C */
hysteresis = <10000>; /* (millicelsius) Fan stopped at 45°C */
type = "active";
};
};