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authorSteve Glendinning <steve.glendinning@smsc.com>2010-07-13 10:32:39 +1000
committerStephen Rothwell <sfr@canb.auug.org.au>2010-07-13 10:32:39 +1000
commitceb19c4db182e83f8cb850dd9cc74d572c9cb345 (patch)
tree95ae4f030ea45fb5cb611423b2e171ba6e33a698 /Documentation
parented9d6bb6b65a8f215c394ec254363dfabd89434f (diff)
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.