target/linux/brcm2708/patches-4.19/950-0152-Update-gpio-fan-overlay.dts-2711.patch

   1 From 4a2be174938ac115beac4f07fa8b7ee33406cde8 Mon Sep 17 00:00:00 2001
   2 From: Paul <paulenuta@users.noreply.github.com>
   3 Date: Thu, 11 Oct 2018 12:17:20 +0300
   4 Subject: [PATCH] Update gpio-fan-overlay.dts (#2711)
   5
   6 Add references, links, clear details, some typo correction.
   7 ---
   8  .../boot/dts/overlays/gpio-fan-overlay.dts    | 36 +++++++++++--------
   9  1 file changed, 22 insertions(+), 14 deletions(-)
  10
  11 --- a/arch/arm/boot/dts/overlays/gpio-fan-overlay.dts
  12 +++ b/arch/arm/boot/dts/overlays/gpio-fan-overlay.dts
  13 @@ -1,29 +1,37 @@
  14  /*
  15   * Overlay for the Raspberry Pi GPIO Fan @ BCM GPIO12.
  16 + * References:
  17 + *     - https://www.raspberrypi.org/forums/viewtopic.php?f=107&p=1367135#p1365084
  18 + *
  19   * Optional parameters:
  20 - *     - "gpiopin"     - default GPIO12
  21 - *     - "temp"        - default 55000
  22 + *     - "gpiopin"     - BCM number of the pin driving the fan, default 12 (GPIO12);
  23 + *     - "temp"        - CPU temperature at which fan is started in millicelsius, default 55000;
  24 + *
  25   * Requires:
  26 - *     - kernel configurations: CONFIG_SENSORS_GPIO_FAN=m and CONFIG_SENSORS_PWM_FAN=m;
  27 - *     - kernel rebuid;
  28 - *     - DC Fan connected to GPIO via a N-MOSFET (2N7002)
  29 + *     - kernel configurations: CONFIG_SENSORS_GPIO_FAN=m;
  30 + *     - kernel rebuild;
  31 + *     - N-MOSFET connected to gpiopin, 2N7002-[https://en.wikipedia.org/wiki/2N7000];
  32 + *     - DC Fan connected to N-MOSFET Drain terminal, a 12V fan is working fine and quite silently;
  33 + *       [https://www.tme.eu/en/details/ee40101s1-999-a/dc12v-fans/sunon/ee40101s1-1000u-999/]
  34   *
  35   *                   ┌─────────────────────┐
  36   *                   │Fan negative terminal│
  37   *                   └┬────────────────────┘
  38 - *                    │
  39 - *                 │──┘
  40 + *                    │D
  41 + *             G   │──┘
  42   * [GPIO12]──────┤ │<─┐  2N7002
  43   *                 │──┤
  44 - *                    │
  45 + *                    │S
  46   *                   ─┴─
  47   *                   GND
  48   *
  49 - * sudo dtc -W no-unit_address_vs_reg -@ -I dts -O dtb -o /boot/overlays/gpio-fan.dtbo gpio-fan.dts
  50 - * sudo nano /boot/config.txt add "dtoverlay=gpio-fan" or "dtoverlay=gpio-fan,gpiopin=12,temp=45000"
  51 - * or
  52 - * sudo sh -c "echo '\n# Enable PI GPIO-Fan\ndtoverlay=gpio-fan\n' >> /boot/config.txt"
  53 - * sudo sh -c "echo '\n# Enable PI GPIO-Fan\ndtoverlay=gpio-fan,gpiopin=12\n' >> /boot/config.txt"
  54 + * Build:
  55 + *     - `sudo dtc -W no-unit_address_vs_reg -@ -I dts -O dtb -o /boot/overlays/gpio-fan.dtbo gpio-fan-overlay.dts`
  56 + * Activate:
  57 + *     - sudo nano /boot/config.txt add "dtoverlay=gpio-fan" or "dtoverlay=gpio-fan,gpiopin=12,temp=45000"
  58 + *      or
  59 + *     - sudo sh -c 'printf "\n# Enable PI GPIO-Fan Default\ndtoverlay=gpio-fan\n" >> /boot/config.txt'
  60 + *     - sudo sh -c 'printf "\n# Enable PI GPIO-Fan Custom\ntoverlay=gpio-fan,gpiopin=12,temp=45000\n" >> /boot/config.txt'
  61   *
  62   */
  63  /dts-v1/;
  64 @@ -52,7 +60,7 @@
  65                         trips {
  66                                 cpu_hot: trip-point@0 {
  67                                         temperature = <55000>;  /* (millicelsius) Fan started at 55°C */
  68 -                                       hysteresis = <5000>;    /* (millicelsius) Fan stopped at 50°C */
  69 +                                       hysteresis = <10000>;   /* (millicelsius) Fan stopped at 45°C */
  70                                         type = "active";
  71                                 };
  72                         };