xref: /linux/Documentation/hwmon/kfan.rst (revision ab93e0dd72c37d378dd936f031ffb83ff2bd87ce)
1*9b96f82cSGerhard Engleder.. SPDX-License-Identifier: GPL-2.0
2*9b96f82cSGerhard Engleder
3*9b96f82cSGerhard EnglederKernel driver kfan
4*9b96f82cSGerhard Engleder==================
5*9b96f82cSGerhard Engleder
6*9b96f82cSGerhard EnglederSupported chips:
7*9b96f82cSGerhard Engleder
8*9b96f82cSGerhard Engleder  * KEBA fan controller (IP core in FPGA)
9*9b96f82cSGerhard Engleder
10*9b96f82cSGerhard Engleder    Prefix: 'kfan'
11*9b96f82cSGerhard Engleder
12*9b96f82cSGerhard EnglederAuthors:
13*9b96f82cSGerhard Engleder
14*9b96f82cSGerhard Engleder	Gerhard Engleder <eg@keba.com>
15*9b96f82cSGerhard Engleder	Petar Bojanic <boja@keba.com>
16*9b96f82cSGerhard Engleder
17*9b96f82cSGerhard EnglederDescription
18*9b96f82cSGerhard Engleder-----------
19*9b96f82cSGerhard Engleder
20*9b96f82cSGerhard EnglederThe KEBA fan controller is an IP core for FPGAs, which monitors the health
21*9b96f82cSGerhard Englederand controls the speed of a fan. The fan is typically used to cool the CPU
22*9b96f82cSGerhard Englederand the whole device. E.g., the CP500 FPGA includes this IP core to monitor
23*9b96f82cSGerhard Englederand control the fan of PLCs and the corresponding cp500 driver creates an
24*9b96f82cSGerhard Englederauxiliary device for the kfan driver.
25*9b96f82cSGerhard Engleder
26*9b96f82cSGerhard EnglederThis driver provides information about the fan health to user space.
27*9b96f82cSGerhard EnglederThe user space shall be informed if the fan is removed or blocked.
28*9b96f82cSGerhard EnglederAdditionally, the speed in RPM is reported for fans with tacho signal.
29*9b96f82cSGerhard Engleder
30*9b96f82cSGerhard EnglederFor fan control PWM is supported. For PWM 255 equals 100%. None-regulable
31*9b96f82cSGerhard Englederfans can be turned on with PWM 255 and turned off with PWM 0.
32*9b96f82cSGerhard Engleder
33*9b96f82cSGerhard Engleder====================== ==== ===================================================
34*9b96f82cSGerhard EnglederAttribute              R/W  Contents
35*9b96f82cSGerhard Engleder====================== ==== ===================================================
36*9b96f82cSGerhard Englederfan1_fault             R    Fan fault
37*9b96f82cSGerhard Englederfan1_input             R    Fan tachometer input (in RPM)
38*9b96f82cSGerhard Englederpwm1                   RW   Fan target duty cycle (0..255)
39*9b96f82cSGerhard Engleder====================== ==== ===================================================
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