Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mv-sheeva.git] / Documentation / hwmon / ds620

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+Kernel driver ds620
+===================
+
+Supported chips:
+  * Dallas Semiconductor DS620
+    Prefix: 'ds620'
+    Datasheet: Publicly available at the Dallas Semiconductor website
+               http://www.dalsemi.com/
+
+Authors:
+        Roland Stigge <stigge@antcom.de>
+        based on ds1621.c by
+        Christian W. Zuckschwerdt <zany@triq.net>
+
+Description
+-----------
+
+The DS620 is a (one instance) digital thermometer and thermostat. It has both
+high and low temperature limits which can be user defined (i.e.  programmed
+into non-volatile on-chip registers). Temperature range is -55 degree Celsius
+to +125. Between 0 and 70 degree Celsius, accuracy is 0.5 Kelvin. The value
+returned via sysfs displays post decimal positions.
+
+The thermostat function works as follows: When configured via platform_data
+(struct ds620_platform_data) .pomode == 0 (default), the thermostat output pin
+PO is always low. If .pomode == 1, the thermostat is in PO_LOW mode. I.e., the
+output pin PO becomes active when the temperature falls below temp1_min and
+stays active until the temperature goes above temp1_max.
+
+Likewise, with .pomode == 2, the thermostat is in PO_HIGH mode. I.e., the PO
+output pin becomes active when the temperature goes above temp1_max and stays
+active until the temperature falls below temp1_min.
+
+The PO output pin of the DS620 operates active-low.