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authorSteve Glendinning <steve.glendinning@smsc.com>2010-08-14 21:08:54 +0200
committerJean Delvare <khali@linux-fr.org>2010-08-14 21:08:54 +0200
commit9df7305b5a8651eb940e98496bc1d4742379c578 (patch)
treea57f2f4feca16e98da54c9fc39d6f549ce137d1e /Documentation
parent5a9c2cd881f48d4bec627cccde386f8e3a28bb4a (diff)
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hwmon: Add driver for SMSC EMC2103 temperature monitor and fan controller
SMSC's EMC2103 family of temperature/fan controllers have 1 onboard and up to 3 external temperature sensors, and allow closed-loop control of one fan. This patch adds support for them. Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
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diff --git a/Documentation/hwmon/emc2103 b/Documentation/hwmon/emc2103
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+Kernel driver emc2103
+======================
+
+Supported chips:
+ * SMSC EMC2103
+ Addresses scanned: I2C 0x2e
+ Prefix: 'emc2103'
+ Datasheet: Not public
+
+Authors:
+ Steve Glendinning <steve.glendinning@smsc.com>
+
+Description
+-----------
+
+The Standard Microsystems Corporation (SMSC) EMC2103 chips
+contain up to 4 temperature sensors and a single fan controller.
+
+Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
+triggered if the rotation speed has dropped below a programmable limit. Fan
+readings can be divided by a programmable divider (1, 2, 4 or 8) to give
+the readings more range or accuracy. Not all RPM values can accurately be
+represented, so some rounding is done. With a divider of 1, the lowest
+representable value is 480 RPM.
+
+This driver supports RPM based control, to use this a fan target
+should be written to fan1_target and pwm1_enable should be set to 3.
+
+The 2103-2 and 2103-4 variants have a third temperature sensor, which can
+be connected to two anti-parallel diodes. These values can be read
+as temp3 and temp4. If only one diode is attached to this channel, temp4
+will show as "fault". The module parameter "apd=0" can be used to suppress
+this 4th channel when anti-parallel diodes are not fitted.