Commit 9a95beb6 authored by Phil Elwell's avatar Phil Elwell
Browse files

BCM270X_DT: Add gpio-fan overlay 



Signed-off-by: default avatarPhil Elwell <phil@raspberrypi.org>
parent 898a5560

arch/arm/boot/dts/overlays/Makefile

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@@ -35,6 +35,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \ 
	fe-pi-audio.dtbo \

	goodix.dtbo \

	googlevoicehat-soundcard.dtbo \

	gpio-fan.dtbo \

	gpio-ir.dtbo \

	gpio-ir-tx.dtbo \

	gpio-key.dtbo \

arch/arm/boot/dts/overlays/README

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@@ -563,6 +563,14 @@ Load: dtoverlay=googlevoicehat-soundcard 
Params: <None>





Name:   gpio-fan

Info:   Configure a GPIO pin to control a cooling fan.

Load:   dtoverlay=gpio-fan,<param>=<val>

Params: gpiopin                 GPIO used to control the fan (default 12)

        temp                    Temperature at which the fan switches on, in

                                millicelcius (default 55000)





Name:   gpio-ir

Info:   Use GPIO pin as rc-core style infrared receiver input. The rc-core-

        based gpio_ir_recv driver maps received keys directly to a

arch/arm/boot/dts/overlays/gpio-fan-overlay.dts

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/*

 * Overlay for the Raspberry Pi GPIO Fan @ BCM GPIO12.

 * Optional parameters:

 *	- "gpiopin"	- default GPIO12

 * 	- "temp"	- 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)

 *

 *                   ┌─────────────────────┐

 *                   │Fan negative terminal│

 *                   └┬────────────────────┘

 *                    │

 *                 │──┘

 * [GPIO12]──────┤ │<─┐  2N7002

 *                 │──┤

 *                    │

 *                   ─┴─

 *                   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"

 *

 */

/dts-v1/;

/plugin/;



/ {

	compatible = "brcm,bcm2708";



	fragment@0 {

		target-path = "/";

		__overlay__ {

			fan0: gpio-fan@0 {

				compatible = "gpio-fan";

				gpios = <&gpio 12 1>;

				gpio-fan,speed-map = <0    0>,

									 <5000 1>;

				#cooling-cells = <2>;

			};

		};

	};



	fragment@1 {

		target = <&cpu_thermal>;

		polling-delay = <2000>;	/* milliseconds */

		__overlay__ {

			trips {

				cpu_hot: trip-point@0 {

					temperature = <55000>;	/* (millicelsius) Fan started at 55°C */

					hysteresis = <5000>;	/* (millicelsius) Fan stopped at 50°C */

					type = "active";

				};

			};

			cooling-maps {

				map0 {

					trip = <&cpu_hot>;

					cooling-device = <&fan0 1 1>;

				};

			};

		};

	};

	__overrides__ {

		gpiopin = <&fan0>,"gpios:4", <&fan0>,"brcm,pins:0";

		temp = <&cpu_hot>,"temperature:0";

	};

};