Kernel driver ltc2978

Supported chips:

Author: Guenter Roeck <linux@roeck-us.net>

Description

  • LTC2974 and LTC2975 are quad digital power supply managers.
  • LTC2978 is an octal power supply monitor.
  • LTC2977 is a pin compatible replacement for LTC2978.
  • LTC2980 is a 16-channel Power System Manager, consisting of two LTC2977
  • in a single die. The chip is instantiated and reported as two separate chips
  • on two different I2C bus addresses.
  • LTC3880, LTC3882, LTC3886, and LTC3887 are dual output poly-phase step-down
  • DC/DC controllers.
  • LTC3883 is a single phase step-down DC/DC controller.
  • LTM2987 is a 16-channel Power System Manager with two LTC2977 plus
  • additional components on a single die. The chip is instantiated and reported
  • as two separate chips on two different I2C bus addresses.
  • LTM4675 is a dual 9A or single 18A μModule regulator
  • LTM4676 is a dual 13A or single 26A uModule regulator.
  • LTM4686 is a dual 10A or single 20A uModule regulator.

Usage Notes

This driver does not probe for PMBus devices. You will have to instantiate devices explicitly.

Example: the following commands will load the driver for an LTC2978 at address 0x60 on I2C bus #1:

# modprobe ltc2978
# echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device

Sysfs attributes

in1_label “vin”
in1_input Measured input voltage.
in1_min Minimum input voltage.
in1_max

Maximum input voltage.

LTC2974, LTC2975, LTC2977, LTC2980, LTC2978, and LTM2987 only.
in1_lcrit

Critical minimum input voltage.

LTC2974, LTC2975, LTC2977, LTC2980, LTC2978, and LTM2987 only.
in1_crit Critical maximum input voltage.
in1_min_alarm Input voltage low alarm.
in1_max_alarm

Input voltage high alarm.

LTC2974, LTC2975, LTC2977, LTC2980, LTC2978, and LTM2987 only.
in1_lcrit_alarm

Input voltage critical low alarm.

LTC2974, LTC2975, LTC2977, LTC2980, LTC2978, and LTM2987 only.
in1_crit_alarm Input voltage critical high alarm.
in1_lowest

Lowest input voltage.

LTC2974, LTC2975, LTC2977, LTC2980, LTC2978, and LTM2987 only.
in1_highest Highest input voltage.
in1_reset_history Reset input voltage history.
in[N]_label

“vout[1-8]”.

  • LTC2974, LTC2975: N=2-5
  • LTC2977, LTC2980, LTM2987: N=2-9
  • LTC2978: N=2-9
  • LTC3880, LTC3882, LTC23886 LTC3887, LTM4675, LTM4676: N=2-3
  • LTC3883: N=2
in[N]_input Measured output voltage.
in[N]_min Minimum output voltage.
in[N]_max Maximum output voltage.
in[N]_lcrit Critical minimum output voltage.
in[N]_crit Critical maximum output voltage.
in[N]_min_alarm Output voltage low alarm.
in[N]_max_alarm Output voltage high alarm.
in[N]_lcrit_alarm Output voltage critical low alarm.
in[N]_crit_alarm Output voltage critical high alarm.
in[N]_lowest

Lowest output voltage.

LTC2974, LTC2975,and LTC2978 only.
in[N]_highest Highest output voltage.
in[N]_reset_history Reset output voltage history.
temp[N]_input

Measured temperature.

  • On LTC2974 and LTC2975, temp[1-4] report external temperatures, and temp5 reports the chip temperature.
  • On LTC2977, LTC2980, LTC2978, and LTM2987, only one temperature measurement is supported and reports the chip temperature.
  • On LTC3880, LTC3882, LTC3887, LTM4675, and LTM4676, temp1 and temp2 report external temperatures, and temp3 reports the chip temperature.
  • On LTC3883, temp1 reports an external temperature, and temp2 reports the chip temperature.
temp[N]_min

Mimimum temperature.

LTC2974, LCT2977, LTM2980, LTC2978, and LTM2987 only.
temp[N]_max Maximum temperature.
temp[N]_lcrit Critical low temperature.
temp[N]_crit Critical high temperature.
temp[N]_min_alarm

Temperature low alarm.

LTC2974, LTC2975, LTC2977, LTM2980, LTC2978, and LTM2987 only.
temp[N]_max_alarm Temperature high alarm.
temp[N]_lcrit_alarm Temperature critical low alarm.
temp[N]_crit_alarm Temperature critical high alarm.
temp[N]_lowest

Lowest measured temperature.

  • LTC2974, LTC2975, LTC2977, LTM2980, LTC2978, and LTM2987 only.
  • Not supported for chip temperature sensor on LTC2974 and LTC2975.
temp[N]_highest

Highest measured temperature.

Not supported for chip temperature sensor on LTC2974 and LTC2975.
temp[N]_reset_history

Reset temperature history.

Not supported for chip temperature sensor on LTC2974 and LTC2975.
power1_label “pin”. LTC3883 and LTC3886 only.
power1_input Measured input power.
power[N]_label

“pout[1-4]”.

  • LTC2974, LTC2975: N=1-4
  • LTC2977, LTC2980, LTM2987: Not supported
  • LTC2978: Not supported
  • LTC3880, LTC3882, LTC3886, LTC3887, LTM4675, LTM4676: N=1-2
  • LTC3883: N=2
power[N]_input Measured output power.
curr1_label

“iin”.

LTC3880, LTC3883, LTC3886, LTC3887, LTM4675, and LTM4676 only.
curr1_input Measured input current.
curr1_max Maximum input current.
curr1_max_alarm Input current high alarm.
curr1_highest

Highest input current.

LTC3883 and LTC3886 only.
curr1_reset_history

Reset input current history.

LTC3883 and LTC3886 only.
curr[N]_label

“iout[1-4]”.

  • LTC2974, LTC2975: N=1-4
  • LTC2977, LTC2980, LTM2987: not supported
  • LTC2978: not supported
  • LTC3880, LTC3882, LTC3886, LTC3887, LTM4675, LTM4676: N=2-3
  • LTC3883: N=2
curr[N]_input Measured output current.
curr[N]_max Maximum output current.
curr[N]_crit Critical high output current.
curr[N]_lcrit

Critical low output current.

LTC2974 and LTC2975 only.
curr[N]_max_alarm Output current high alarm.
curr[N]_crit_alarm Output current critical high alarm.
curr[N]_lcrit_alarm

Output current critical low alarm.

LTC2974 and LTC2975 only.
curr[N]_lowest

Lowest output current.

LTC2974 and LTC2975 only.
curr[N]_highest Highest output current.
curr[N]_reset_history Reset output current history.