xref: /linux/Documentation/hwmon/emc2103.rst (revision d2912cb15bdda8ba4a5dd73396ad62641af2f520)
1Kernel driver emc2103
2======================
3
4Supported chips:
5
6  * SMSC EMC2103
7
8    Addresses scanned: I2C 0x2e
9
10    Prefix: 'emc2103'
11
12    Datasheet: Not public
13
14Authors:
15	Steve Glendinning <steve.glendinning@smsc.com>
16
17Description
18-----------
19
20The Standard Microsystems Corporation (SMSC) EMC2103 chips
21contain up to 4 temperature sensors and a single fan controller.
22
23Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
24triggered if the rotation speed has dropped below a programmable limit. Fan
25readings can be divided by a programmable divider (1, 2, 4 or 8) to give
26the readings more range or accuracy. Not all RPM values can accurately be
27represented, so some rounding is done. With a divider of 1, the lowest
28representable value is 480 RPM.
29
30This driver supports RPM based control, to use this a fan target
31should be written to fan1_target and pwm1_enable should be set to 3.
32
33The 2103-2 and 2103-4 variants have a third temperature sensor, which can
34be connected to two anti-parallel diodes.  These values can be read
35as temp3 and temp4.  If only one diode is attached to this channel, temp4
36will show as "fault".  The module parameter "apd=0" can be used to suppress
37this 4th channel when anti-parallel diodes are not fitted.
38