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.