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authorIra Snyder <iws@ovro.caltech.edu>2009-03-31 15:24:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-01 08:59:21 -0700
commit72f5de92e199f96cfcea125aefc76c138d8c553c (patch)
treeef24990f791801283f520b5f96a4ea1e592bf37b /Documentation/hwmon/ltc4215
parent061603275814544842e7df77d1157eff18565997 (diff)
downloadlinux-72f5de92e199f96cfcea125aefc76c138d8c553c.tar.bz2
hwmon: Add LTC4215 driver
Add Linux support for the Linear Technology LTC4215 Hot Swap controller I2C monitoring interface. I have tested the driver with my board, and it appears to work fine. With the power supplies disabled, it reads 11.93V input, 1.93V output, no current and no power. With the supplies enabled, it reads 11.93V input, 11.98V output, no current, no power. I'm not drawing any current at the moment, so this is reasonable. The value in the sense register never reads anything except 0, so I expect to get zero from the current and power calculations. I didn't attempt to support changing any of the chip's settings or enabling the FET. I'm not sure even how to do that and still fit within the hwmon framework. :) Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Cc: Jean Delvare <khali@linux-fr.org> Cc: "Mark M. Hoffman" <mhoffman@lightlink.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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+Kernel driver ltc4215
+=====================
+
+Supported chips:
+ * Linear Technology LTC4215
+ Prefix: 'ltc4215'
+ Addresses scanned: 0x44
+ Datasheet:
+ http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1163,P17572,D12697
+
+Author: Ira W. Snyder <iws@ovro.caltech.edu>
+
+
+Description
+-----------
+
+The LTC4215 controller allows a board to be safely inserted and removed
+from a live backplane.
+
+
+Usage Notes
+-----------
+
+This driver does not probe for LTC4215 devices, due to the fact that some
+of the possible addresses are unfriendly to probing. You will need to use
+the "force" parameter to tell the driver where to find the device.
+
+Example: the following will load the driver for an LTC4215 at address 0x44
+on I2C bus #0:
+$ modprobe ltc4215 force=0,0x44
+
+
+Sysfs entries
+-------------
+
+The LTC4215 has built-in limits for overvoltage, undervoltage, and
+undercurrent warnings. This makes it very likely that the reference
+circuit will be used.
+
+in1_input input voltage
+in2_input output voltage
+
+in1_min_alarm input undervoltage alarm
+in1_max_alarm input overvoltage alarm
+
+curr1_input current
+curr1_max_alarm overcurrent alarm
+
+power1_input power usage
+power1_alarm power bad alarm