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[linux-2.6.git] / Documentation / hwmon / adm1021

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+Kernel driver adm1021
+=====================
+
+Supported chips:
+  * Analog Devices ADM1021
+    Prefix: 'adm1021'
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet: Publicly available at the Analog Devices website
+  * Analog Devices ADM1021A/ADM1023
+    Prefix: 'adm1023'
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet: Publicly available at the Analog Devices website
+  * Genesys Logic GL523SM
+    Prefix: 'gl523sm'
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet:
+  * Intel Xeon Processor
+    Prefix: - any other - may require 'force_adm1021' parameter
+    Addresses scanned: none
+    Datasheet: Publicly available at Intel website
+  * Maxim MAX1617
+    Prefix: 'max1617'
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet: Publicly available at the Maxim website
+  * Maxim MAX1617A
+    Prefix: 'max1617a'
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet: Publicly available at the Maxim website
+  * National Semiconductor LM84
+    Prefix: 'lm84'
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet: Publicly available at the National Semiconductor website
+  * Philips NE1617
+    Prefix: 'max1617' (probably detected as a max1617)
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet: Publicly available at the Philips website
+  * Philips NE1617A
+    Prefix: 'max1617' (probably detected as a max1617)
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet: Publicly available at the Philips website
+  * TI THMC10
+    Prefix: 'thmc10'
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet: Publicly available at the TI website
+  * Onsemi MC1066
+    Prefix: 'mc1066'
+    Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e
+    Datasheet: Publicly available at the Onsemi website
+
+
+Authors:
+        Frodo Looijaard <frodol@dds.nl>,
+        Philip Edelbrock <phil@netroedge.com>
+
+Module Parameters
+-----------------
+
+* read_only: int
+  Don't set any values, read only mode
+
+
+Description
+-----------
+
+The chips supported by this driver are very similar. The Maxim MAX1617 is
+the oldest; it has the problem that it is not very well detectable. The
+MAX1617A solves that. The ADM1021 is a straight clone of the MAX1617A.
+Ditto for the THMC10. From here on, we will refer to all these chips as
+ADM1021-clones.
+
+The ADM1021 and MAX1617A reports a die code, which is a sort of revision
+code. This can help us pinpoint problems; it is not very useful
+otherwise.
+
+ADM1021-clones implement two temperature sensors. One of them is internal,
+and measures the temperature of the chip itself; the other is external and
+is realised in the form of a transistor-like device. A special alarm
+indicates whether the remote sensor is connected.
+
+Each sensor has its own low and high limits. When they are crossed, the
+corresponding alarm is set and remains on as long as the temperature stays
+out of range. Temperatures are measured in degrees Celsius. Measurements
+are possible between -65 and +127 degrees, with a resolution of one degree.
+
+If an alarm triggers, it will remain triggered until the hardware register
+is read at least once. This means that the cause for the alarm may already
+have disappeared!
+
+This driver only updates its values each 1.5 seconds; reading it more often
+will do no harm, but will return 'old' values. It is possible to make
+ADM1021-clones do faster measurements, but there is really no good reason
+for that.
+
+Xeon support
+------------
+
+Some Xeon processors have real max1617, adm1021, or compatible chips
+within them, with two temperature sensors.
+
+Other Xeons have chips with only one sensor.
+
+If you have a Xeon, and the adm1021 module loads, and both temperatures
+appear valid, then things are good.
+
+If the adm1021 module doesn't load, you should try this:
+       modprobe adm1021 force_adm1021=BUS,ADDRESS
+       ADDRESS can only be 0x18, 0x1a, 0x29, 0x2b, 0x4c, or 0x4e.
+
+If you have dual Xeons you may have appear to have two separate
+adm1021-compatible chips, or two single-temperature sensors, at distinct
+addresses.