linux/Documentation/hwmon/ltc4245
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   1Kernel driver ltc4245
   2=====================
   3
   4Supported chips:
   5  * Linear Technology LTC4245
   6    Prefix: 'ltc4245'
   7    Addresses scanned: 0x20-0x3f
   8    Datasheet:
   9        http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
  10
  11Author: Ira W. Snyder <iws@ovro.caltech.edu>
  12
  13
  14Description
  15-----------
  16
  17The LTC4245 controller allows a board to be safely inserted and removed
  18from a live backplane in multiple supply systems such as CompactPCI and
  19PCI Express.
  20
  21
  22Usage Notes
  23-----------
  24
  25This driver does not probe for LTC4245 devices, due to the fact that some
  26of the possible addresses are unfriendly to probing. You will have to
  27instantiate the devices explicitly.
  28
  29Example: the following will load the driver for an LTC4245 at address 0x23
  30on I2C bus #1:
  31$ modprobe ltc4245
  32$ echo ltc4245 0x23 > /sys/bus/i2c/devices/i2c-1/new_device
  33
  34
  35Sysfs entries
  36-------------
  37
  38The LTC4245 has built-in limits for over and under current warnings. This
  39makes it very likely that the reference circuit will be used.
  40
  41This driver uses the values in the datasheet to change the register values
  42into the values specified in the sysfs-interface document. The current readings
  43rely on the sense resistors listed in Table 2: "Sense Resistor Values".
  44
  45in1_input               12v input voltage (mV)
  46in2_input               5v  input voltage (mV)
  47in3_input               3v  input voltage (mV)
  48in4_input               Vee (-12v) input voltage (mV)
  49
  50in1_min_alarm           12v input undervoltage alarm
  51in2_min_alarm           5v  input undervoltage alarm
  52in3_min_alarm           3v  input undervoltage alarm
  53in4_min_alarm           Vee (-12v) input undervoltage alarm
  54
  55curr1_input             12v current (mA)
  56curr2_input             5v  current (mA)
  57curr3_input             3v  current (mA)
  58curr4_input             Vee (-12v) current (mA)
  59
  60curr1_max_alarm         12v overcurrent alarm
  61curr2_max_alarm         5v  overcurrent alarm
  62curr3_max_alarm         3v  overcurrent alarm
  63curr4_max_alarm         Vee (-12v) overcurrent alarm
  64
  65in5_input               12v output voltage (mV)
  66in6_input               5v  output voltage (mV)
  67in7_input               3v  output voltage (mV)
  68in8_input               Vee (-12v) output voltage (mV)
  69
  70in5_min_alarm           12v output undervoltage alarm
  71in6_min_alarm           5v  output undervoltage alarm
  72in7_min_alarm           3v  output undervoltage alarm
  73in8_min_alarm           Vee (-12v) output undervoltage alarm
  74
  75in9_input               GPIO voltage data (see note 1)
  76in10_input              GPIO voltage data (see note 1)
  77in11_input              GPIO voltage data (see note 1)
  78
  79power1_input            12v power usage (mW)
  80power2_input            5v  power usage (mW)
  81power3_input            3v  power usage (mW)
  82power4_input            Vee (-12v) power usage (mW)
  83
  84
  85Note 1
  86------
  87
  88If you have NOT configured the driver to sample all GPIO pins as analog
  89voltages, then the in10_input and in11_input sysfs attributes will not be
  90created. The driver will sample the GPIO pin that is currently connected to the
  91ADC as an analog voltage, and report the value in in9_input.
  92
  93If you have configured the driver to sample all GPIO pins as analog voltages,
  94then they will be sampled in round-robin fashion. If userspace reads too
  95slowly, -EAGAIN will be returned when you read the sysfs attribute containing
  96the sensor reading.
  97
  98The LTC4245 chip can be configured to sample all GPIO pins with two methods:
  991) platform data -- see include/linux/i2c/ltc4245.h
 1002) OF device tree -- add the "ltc4245,use-extra-gpios" property to each chip
 101
 102The default mode of operation is to sample a single GPIO pin.
 103
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