target/linux/brcm2708/patches-4.19/950-0149-BCM270X_DT-Add-gpio-fan-overlay.patch

   1 From 9762b3a015886c42941f535e688ffac1f56e35aa Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Tue, 18 Sep 2018 11:08:07 +0100
   4 Subject: [PATCH] BCM270X_DT: Add gpio-fan overlay
   5
   6 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
   7 ---
   8  arch/arm/boot/dts/overlays/Makefile           |  1 +
   9  arch/arm/boot/dts/overlays/README             |  8 +++
  10  .../boot/dts/overlays/gpio-fan-overlay.dts    | 71 +++++++++++++++++++
  11  3 files changed, 80 insertions(+)
  12  create mode 100644 arch/arm/boot/dts/overlays/gpio-fan-overlay.dts
  13
  14 --- a/arch/arm/boot/dts/overlays/Makefile
  15 +++ b/arch/arm/boot/dts/overlays/Makefile
  16 @@ -33,6 +33,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
  17         fe-pi-audio.dtbo \
  18         goodix.dtbo \
  19         googlevoicehat-soundcard.dtbo \
  20 +       gpio-fan.dtbo \
  21         gpio-ir.dtbo \
  22         gpio-ir-tx.dtbo \
  23         gpio-key.dtbo \
  24 --- a/arch/arm/boot/dts/overlays/README
  25 +++ b/arch/arm/boot/dts/overlays/README
  26 @@ -541,6 +541,14 @@ Load:   dtoverlay=googlevoicehat-soundca
  27  Params: <None>
  28
  29
  30 +Name:   gpio-fan
  31 +Info:   Configure a GPIO pin to control a cooling fan.
  32 +Load:   dtoverlay=gpio-fan,<param>=<val>
  33 +Params: gpiopin                 GPIO used to control the fan (default 12)
  34 +        temp                    Temperature at which the fan switches on, in
  35 +                                millicelcius (default 55000)
  36 +
  37 +
  38  Name:   gpio-ir
  39  Info:   Use GPIO pin as rc-core style infrared receiver input. The rc-core-
  40          based gpio_ir_recv driver maps received keys directly to a
  41 --- /dev/null
  42 +++ b/arch/arm/boot/dts/overlays/gpio-fan-overlay.dts
  43 @@ -0,0 +1,71 @@
  44 +/*
  45 + * Overlay for the Raspberry Pi GPIO Fan @ BCM GPIO12.
  46 + * Optional parameters:
  47 + *     - "gpiopin"     - default GPIO12
  48 + *     - "temp"        - default 55000
  49 + * Requires:
  50 + *     - kernel configurations: CONFIG_SENSORS_GPIO_FAN=m and CONFIG_SENSORS_PWM_FAN=m;
  51 + *     - kernel rebuid;
  52 + *     - DC Fan connected to GPIO via a N-MOSFET (2N7002)
  53 + *
  54 + *                   ┌─────────────────────┐
  55 + *                   │Fan negative terminal│
  56 + *                   └┬────────────────────┘
  57 + *                    │
  58 + *                 │──┘
  59 + * [GPIO12]──────┤ │<─┐  2N7002
  60 + *                 │──┤
  61 + *                    │
  62 + *                   ─┴─
  63 + *                   GND
  64 + *
  65 + * sudo dtc -W no-unit_address_vs_reg -@ -I dts -O dtb -o /boot/overlays/gpio-fan.dtbo gpio-fan.dts
  66 + * sudo nano /boot/config.txt add "dtoverlay=gpio-fan" or "dtoverlay=gpio-fan,gpiopin=12,temp=45000"
  67 + * or
  68 + * sudo sh -c "echo '\n# Enable PI GPIO-Fan\ndtoverlay=gpio-fan\n' >> /boot/config.txt"
  69 + * sudo sh -c "echo '\n# Enable PI GPIO-Fan\ndtoverlay=gpio-fan,gpiopin=12\n' >> /boot/config.txt"
  70 + *
  71 + */
  72 +/dts-v1/;
  73 +/plugin/;
  74 +
  75 +/ {
  76 +       compatible = "brcm,bcm2708";
  77 +
  78 +       fragment@0 {
  79 +               target-path = "/";
  80 +               __overlay__ {
  81 +                       fan0: gpio-fan@0 {
  82 +                               compatible = "gpio-fan";
  83 +                               gpios = <&gpio 12 1>;
  84 +                               gpio-fan,speed-map = <0    0>,
  85 +                                                                        <5000 1>;
  86 +                               #cooling-cells = <2>;
  87 +                       };
  88 +               };
  89 +       };
  90 +
  91 +       fragment@1 {
  92 +               target = <&cpu_thermal>;
  93 +               polling-delay = <2000>; /* milliseconds */
  94 +               __overlay__ {
  95 +                       trips {
  96 +                               cpu_hot: trip-point@0 {
  97 +                                       temperature = <55000>;  /* (millicelsius) Fan started at 55°C */
  98 +                                       hysteresis = <5000>;    /* (millicelsius) Fan stopped at 50°C */
  99 +                                       type = "active";
 100 +                               };
 101 +                       };
 102 +                       cooling-maps {
 103 +                               map0 {
 104 +                                       trip = <&cpu_hot>;
 105 +                                       cooling-device = <&fan0 1 1>;
 106 +                               };
 107 +                       };
 108 +               };
 109 +       };
 110 +       __overrides__ {
 111 +               gpiopin = <&fan0>,"gpios:4", <&fan0>,"brcm,pins:0";
 112 +               temp = <&cpu_hot>,"temperature:0";
 113 +       };
 114 +};