target/linux/bcm27xx/patches-5.4/950-0486-Reduce-noise-from-rpi-poe-hat-fan.patch

   1 From 863dace20e48954a7e013a2e88e27c692ce165b0 Mon Sep 17 00:00:00 2001
   2 From: Nick B <nick@pelagiris.org>
   3 Date: Mon, 9 Mar 2020 09:05:39 -0400
   4 Subject: [PATCH] Reduce noise from rpi poe hat fan
   5
   6 This adds 2 extra states, at 40c and 45c, with PWM of 31 and 63 (out
   7 of 255) for the rpi poe hat fan.  This significantly improves user
   8 experience by providing a smoother ramp up of the fan, from a pwm 0
   9 to 31 to 63 then finally to 150, and additionally makes it very easy
  10 for users to further tweak the values as needed for their specific
  11 application.
  12
  13 The possible concerns I have are that a hysteresis of 2000 (2c) could
  14 be too narrow, and that running the fan more at a reduced temperature
  15 (40000 - 40c) could cause problems.
  16
  17 Signed-off-by: Nick B <nick@pelagiris.org>
  18 ---
  19  .../arm/boot/dts/overlays/rpi-poe-overlay.dts | 35 ++++++++++++++++---
  20  1 file changed, 30 insertions(+), 5 deletions(-)
  21
  22 --- a/arch/arm/boot/dts/overlays/rpi-poe-overlay.dts
  23 +++ b/arch/arm/boot/dts/overlays/rpi-poe-overlay.dts
  24 @@ -14,9 +14,9 @@
  25                                 compatible = "raspberrypi,rpi-poe-fan";
  26                                 firmware = <&firmware>;
  27                                 cooling-min-state = <0>;
  28 -                               cooling-max-state = <2>;
  29 +                               cooling-max-state = <4>;
  30                                 #cooling-cells = <2>;
  31 -                               cooling-levels = <0 150 255>;
  32 +                               cooling-levels = <0 31 63 150 255>;
  33                                 status = "okay";
  34                         };
  35                 };
  36 @@ -27,12 +27,21 @@
  37                 __overlay__ {
  38                         trips {
  39                                 trip0: trip0 {
  40 -                                       temperature = <50000>;
  41 -                                       hysteresis = <5000>;
  42 +                                       temperature = <40000>;
  43 +                                       hysteresis = <2000>;
  44                                         type = "active";
  45                                 };
  46                                 trip1: trip1 {
  47 -
  48 +                                       temperature = <45000>;
  49 +                                       hysteresis = <2000>;
  50 +                                       type = "active";
  51 +                               };
  52 +                               trip2: trip2 {
  53 +                                       temperature = <50000>;
  54 +                                       hysteresis = <2000>;
  55 +                                       type = "active";
  56 +                               };
  57 +                               trip3: trip3 {
  58                                         temperature = <55000>;
  59                                         hysteresis = <5000>;
  60                                         type = "active";
  61 @@ -47,6 +56,14 @@
  62                                         trip = <&trip1>;
  63                                         cooling-device = <&fan0 1 2>;
  64                                 };
  65 +                               map2 {
  66 +                                       trip = <&trip2>;
  67 +                                       cooling-device = <&fan0 2 3>;
  68 +                               };
  69 +                               map3 {
  70 +                                       trip = <&trip3>;
  71 +                                       cooling-device = <&fan0 3 4>;
  72 +                               };
  73                         };
  74                 };
  75         };
  76 @@ -58,6 +75,10 @@
  77                         poe_fan_temp0_hyst =    <&trip0>,"hysteresis:0";
  78                         poe_fan_temp1 =         <&trip1>,"temperature:0";
  79                         poe_fan_temp1_hyst =    <&trip1>,"hysteresis:0";
  80 +                       poe_fan_temp2 =         <&trip2>,"temperature:0";
  81 +                       poe_fan_temp2_hyst =    <&trip2>,"hysteresis:0";
  82 +                       poe_fan_temp3 =         <&trip3>,"temperature:0";
  83 +                       poe_fan_temp3_hyst =    <&trip3>,"hysteresis:0";
  84                 };
  85         };
  86
  87 @@ -66,5 +87,9 @@
  88                 poe_fan_temp0_hyst =    <&trip0>,"hysteresis:0";
  89                 poe_fan_temp1 =         <&trip1>,"temperature:0";
  90                 poe_fan_temp1_hyst =    <&trip1>,"hysteresis:0";
  91 +               poe_fan_temp2 =         <&trip2>,"temperature:0";
  92 +               poe_fan_temp2_hyst =    <&trip2>,"hysteresis:0";
  93 +               poe_fan_temp3 =         <&trip3>,"temperature:0";
  94 +               poe_fan_temp3_hyst =    <&trip3>,"hysteresis:0";
  95         };
  96  };