1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
From 4a2be174938ac115beac4f07fa8b7ee33406cde8 Mon Sep 17 00:00:00 2001
From: Paul <paulenuta@users.noreply.github.com>
Date: Thu, 11 Oct 2018 12:17:20 +0300
Subject: [PATCH] Update gpio-fan-overlay.dts (#2711)
Add references, links, clear details, some typo correction.
---
.../boot/dts/overlays/gpio-fan-overlay.dts | 36 +++++++++++--------
1 file changed, 22 insertions(+), 14 deletions(-)
--- a/arch/arm/boot/dts/overlays/gpio-fan-overlay.dts
+++ b/arch/arm/boot/dts/overlays/gpio-fan-overlay.dts
@@ -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";
};
};
|
