xref: /OK3568_Linux_fs/kernel/Documentation/hwmon/emc2103.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593SmuzhiyunKernel driver emc2103
2*4882a593Smuzhiyun======================
3*4882a593Smuzhiyun
4*4882a593SmuzhiyunSupported chips:
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun  * SMSC EMC2103
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun    Addresses scanned: I2C 0x2e
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun    Prefix: 'emc2103'
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun    Datasheet: Not public
13*4882a593Smuzhiyun
14*4882a593SmuzhiyunAuthors:
15*4882a593Smuzhiyun	Steve Glendinning <steve.glendinning@smsc.com>
16*4882a593Smuzhiyun
17*4882a593SmuzhiyunDescription
18*4882a593Smuzhiyun-----------
19*4882a593Smuzhiyun
20*4882a593SmuzhiyunThe Standard Microsystems Corporation (SMSC) EMC2103 chips
21*4882a593Smuzhiyuncontain up to 4 temperature sensors and a single fan controller.
22*4882a593Smuzhiyun
23*4882a593SmuzhiyunFan rotation speeds are reported in RPM (rotations per minute). An alarm is
24*4882a593Smuzhiyuntriggered if the rotation speed has dropped below a programmable limit. Fan
25*4882a593Smuzhiyunreadings can be divided by a programmable divider (1, 2, 4 or 8) to give
26*4882a593Smuzhiyunthe readings more range or accuracy. Not all RPM values can accurately be
27*4882a593Smuzhiyunrepresented, so some rounding is done. With a divider of 1, the lowest
28*4882a593Smuzhiyunrepresentable value is 480 RPM.
29*4882a593Smuzhiyun
30*4882a593SmuzhiyunThis driver supports RPM based control, to use this a fan target
31*4882a593Smuzhiyunshould be written to fan1_target and pwm1_enable should be set to 3.
32*4882a593Smuzhiyun
33*4882a593SmuzhiyunThe 2103-2 and 2103-4 variants have a third temperature sensor, which can
34*4882a593Smuzhiyunbe connected to two anti-parallel diodes.  These values can be read
35*4882a593Smuzhiyunas temp3 and temp4.  If only one diode is attached to this channel, temp4
36*4882a593Smuzhiyunwill show as "fault".  The module parameter "apd=0" can be used to suppress
37*4882a593Smuzhiyunthis 4th channel when anti-parallel diodes are not fitted.
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