This version (14 Jan 2021 05:43) was approved by Robin Getz.The Previously approved version (20 Aug 2019 17:49) is available.
Table of Contents
Fan Control HDL CORE driver
Supported Devices
Supported boards
Description
This is a Hardware Monitor subsystem driver. The Hwmon subsystem provides a unified framework for drivers doing hardware monitoring. It exposes a set of sysfs files that should follow the sysfs-interface.
Source Code
Status
| Source | Mainlined? |
|---|---|
| drivers/hwmon/axi_fan_control.c | WIP |
Files
| Function | File |
|---|---|
| driver | drivers/hwmon/axi_fan_control.c |
Example platform device initialization
The AXI FAN CONTROL driver is a platform driver and can currently only be instantiated via device tree.
Required devicetree properties:
- compatible: Should always be one of these:
- adi,axi-fan-control-1.00.a
- reg: Base address and register area size. This parameter expects a register range.
- clocks: Reference clock.
- interrupts: Interrupt line.
- adi,pulses-per-revolution: Number of pulses per revolution
&fpga_axi {
axi_fan_control: axi-fan-control@80000000 {
compatible = "adi,axi-fan-control-1.00.a";
reg = <0x0 0x80000000 0x10000>;
clocks = <&clk 71>;
interrupts = <0 110 0>;
adi,pulses-per-revolution = <2>;
};
Enabling Linux driver support
Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”)
Adding Linux driver support
Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”)
Linux Kernel Configuration
Device Drivers --->
<*> Hardware Monitoring support --->
--- Hardware Monitoring support
[--snip--]
<*> Analog Devices FAN Control HDL Core driver
[--snip--]
Hardware configuration
Driver testing
HWMON device files
Each and every HWMON device has a device folder under /sys/class/hwmon/hwmonX, where X is the hwmon device index. Under every of these directory folders there are a set of files, depending on what kind of hardware monitoring is supported (temperature, voltage). In order to determine which hwmon device corresponds to which hardware chip, the user can read the name file under /sys/class/hwmon/hwmonX/name.
This specifies any shell prompt running on the target
root:/> cd /sys/class/hwmon/ root:/sys/class/hwmon> ls hwmon0 hwmon1 root:/sys/class/hwmon> cd hwmon0 root:/sys/class/hwmon/hwmon0> ls -l total 0 drwxr-xr-x 3 root root 0 Nov 16 11:17 . drwxr-xr-x 3 root root 0 Nov 16 11:17 .. lrwxrwxrwx 1 root root 0 Nov 16 11:17 device -> ../../../axi-fan-control@80000000 -r--r--r-- 1 root root 4096 Nov 16 11:17 fan1_fault -r--r--r-- 1 root root 4096 Nov 16 11:17 fan1_input -r--r--r-- 1 root root 4096 Nov 16 11:17 fan1_label -r--r--r-- 1 root root 4096 Nov 16 11:17 name lrwxrwxrwx 1 root root 0 Nov 16 11:17 of_node -> ../../../../../firmware/devicetree/base/axi-fan-control@80000000 drwxr-xr-x 2 root root 0 Nov 16 11:17 power -rw-r--r-- 1 root root 4096 Nov 16 11:17 pwm1 lrwxrwxrwx 1 root root 0 Nov 16 11:17 subsystem -> ../../../../../class/hwmon -r--r--r-- 1 root root 4096 Nov 16 11:17 temp1_input -r--r--r-- 1 root root 4096 Nov 16 11:17 temp1_label -rw-r--r-- 1 root root 4096 Nov 16 11:17 uevent root:/sys/class/hwmon/hwmon0>
For more information on the files format and accepted values, take a look to sysfs-interface.
Show device name
This specifies any shell prompt running on the target
root:/sys/class/hwmon/hwmon0> cat name axi_fan_control
Show FAN input (in RPM)
This specifies any shell prompt running on the target
root:/sys/class/hwmon/hwmon0> cat fan1_input 3600
Show FAN label
This specifies any shell prompt running on the target
root:/sys/class/hwmon/hwmon0> cat fan1_label SOM FAN
Show PWM input
This specifies any shell prompt running on the target
root:/sys/class/hwmon/hwmon0> cat pwm1 200
Show Temperature input (in milliC)
This specifies any shell prompt running on the target
root:/sys/class/hwmon/hwmon0> cat temp1_input 32000
Show Temperature label
This specifies any shell prompt running on the target
root:/sys/class/hwmon/hwmon0> cat temp1_label SYSMON4
Show fault
When reading fan1_fault returns 1, that means that either the FAN is physically not working/broken or the tacho signal fails to stay within its designated frequency interval.
This specifies any shell prompt running on the target
root:/sys/class/hwmon/hwmon0> cat fan1_fault 0
Set PWM value
This specifies any shell prompt running on the target
root:/sys/class/hwmon/hwmon0> echo 250 > pwm1
More Information
HWMON pointers
- HWMON mailing list: linux [dash] hwmon [at] vger [dot] kernel [dot] org
resources/tools-software/linux-drivers/hwmon/axi_fan_control.txt · Last modified: 14 Jan 2021 05:38 by Robin Getz