hwmon: Add LTC4245 driver

Add Linux support for the Linear Technology LTC4245 Multiple Supply Hot
Swap controller I2C monitoring interface.

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 81 insertions, 0 deletions

diff --git a/Documentation/hwmon/ltc4245 b/Documentation/hwmon/ltc4245
new file mode 100644
index 000000000000..bae7a3adc5d8
--- /dev/null
+++ b/Documentation/hwmon/ltc4245
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+Kernel driver ltc4245
+=====================
+
+Supported chips:
+  * Linear Technology LTC4245
+    Prefix: 'ltc4245'
+    Addresses scanned: 0x20-0x3f
+    Datasheet:
+        http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
+
+Author: Ira W. Snyder <iws@ovro.caltech.edu>
+
+
+Description
+-----------
+
+The LTC4245 controller allows a board to be safely inserted and removed
+from a live backplane in multiple supply systems such as CompactPCI and
+PCI Express.
+
+
+Usage Notes
+-----------
+
+This driver does not probe for LTC4245 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 LTC4245 at address 0x23
+on I2C bus #1:
+$ modprobe ltc4245 force=1,0x23
+
+
+Sysfs entries
+-------------
+
+The LTC4245 has built-in limits for over and under current warnings. This
+makes it very likely that the reference circuit will be used.
+
+This driver uses the values in the datasheet to change the register values
+into the values specified in the sysfs-interface document. The current readings
+rely on the sense resistors listed in Table 2: "Sense Resistor Values".
+
+in1_input               12v input voltage (mV)
+in2_input               5v  input voltage (mV)
+in3_input               3v  input voltage (mV)
+in4_input               Vee (-12v) input voltage (mV)
+
+in1_min_alarm           12v input undervoltage alarm
+in2_min_alarm           5v  input undervoltage alarm
+in3_min_alarm           3v  input undervoltage alarm
+in4_min_alarm           Vee (-12v) input undervoltage alarm
+
+curr1_input             12v current (mA)
+curr2_input             5v  current (mA)
+curr3_input             3v  current (mA)
+curr4_input             Vee (-12v) current (mA)
+
+curr1_max_alarm         12v overcurrent alarm
+curr2_max_alarm         5v  overcurrent alarm
+curr3_max_alarm         3v  overcurrent alarm
+curr4_max_alarm         Vee (-12v) overcurrent alarm
+
+in5_input               12v output voltage (mV)
+in6_input               5v  output voltage (mV)
+in7_input               3v  output voltage (mV)
+in8_input               Vee (-12v) output voltage (mV)
+
+in5_min_alarm           12v output undervoltage alarm
+in6_min_alarm           5v  output undervoltage alarm
+in7_min_alarm           3v  output undervoltage alarm
+in8_min_alarm           Vee (-12v) output undervoltage alarm
+
+in9_input               GPIO #1 voltage data
+in10_input              GPIO #2 voltage data
+in11_input              GPIO #3 voltage data
+
+power1_input            12v power usage (mW)
+power2_input            5v  power usage (mW)
+power3_input            3v  power usage (mW)
+power4_input            Vee (-12v) power usage (mW)