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diff --git a/Documentation/hwmon/ina2xx.rst b/Documentation/hwmon/ina2xx.rst new file mode 100644 index 000000000..f78a5cd44 --- /dev/null +++ b/Documentation/hwmon/ina2xx.rst @@ -0,0 +1,123 @@ +Kernel driver ina2xx +==================== + +Supported chips: + + * Texas Instruments INA219 + + + Prefix: 'ina219' + Addresses: I2C 0x40 - 0x4f + + Datasheet: Publicly available at the Texas Instruments website + + https://www.ti.com/ + + * Texas Instruments INA220 + + Prefix: 'ina220' + + Addresses: I2C 0x40 - 0x4f + + Datasheet: Publicly available at the Texas Instruments website + + https://www.ti.com/ + + * Texas Instruments INA226 + + Prefix: 'ina226' + + Addresses: I2C 0x40 - 0x4f + + Datasheet: Publicly available at the Texas Instruments website + + https://www.ti.com/ + + * Texas Instruments INA230 + + Prefix: 'ina230' + + Addresses: I2C 0x40 - 0x4f + + Datasheet: Publicly available at the Texas Instruments website + + https://www.ti.com/ + + * Texas Instruments INA231 + + Prefix: 'ina231' + + Addresses: I2C 0x40 - 0x4f + + Datasheet: Publicly available at the Texas Instruments website + + https://www.ti.com/ + +Author: Lothar Felten <lothar.felten@gmail.com> + +Description +----------- + +The INA219 is a high-side current shunt and power monitor with an I2C +interface. The INA219 monitors both shunt drop and supply voltage, with +programmable conversion times and filtering. + +The INA220 is a high or low side current shunt and power monitor with an I2C +interface. The INA220 monitors both shunt drop and supply voltage. + +The INA226 is a current shunt and power monitor with an I2C interface. +The INA226 monitors both a shunt voltage drop and bus supply voltage. + +INA230 and INA231 are high or low side current shunt and power monitors +with an I2C interface. The chips monitor both a shunt voltage drop and +bus supply voltage. + +The shunt value in micro-ohms can be set via platform data or device tree at +compile-time or via the shunt_resistor attribute in sysfs at run-time. Please +refer to the Documentation/devicetree/bindings/hwmon/ina2xx.txt for bindings +if the device tree is used. + +Additionally ina226 supports update_interval attribute as described in +Documentation/hwmon/sysfs-interface.rst. Internally the interval is the sum of +bus and shunt voltage conversion times multiplied by the averaging rate. We +don't touch the conversion times and only modify the number of averages. The +lower limit of the update_interval is 2 ms, the upper limit is 2253 ms. +The actual programmed interval may vary from the desired value. + +General sysfs entries +--------------------- + +======================= =============================== +in0_input Shunt voltage(mV) channel +in1_input Bus voltage(mV) channel +curr1_input Current(mA) measurement channel +power1_input Power(uW) measurement channel +shunt_resistor Shunt resistance(uOhm) channel +======================= =============================== + +Sysfs entries for ina226, ina230 and ina231 only +------------------------------------------------ + +======================= ==================================================== +in0_lcrit Critical low shunt voltage +in0_crit Critical high shunt voltage +in0_lcrit_alarm Shunt voltage critical low alarm +in0_crit_alarm Shunt voltage critical high alarm +in1_lcrit Critical low bus voltage +in1_crit Critical high bus voltage +in1_lcrit_alarm Bus voltage critical low alarm +in1_crit_alarm Bus voltage critical high alarm +power1_crit Critical high power +power1_crit_alarm Power critical high alarm +update_interval data conversion time; affects number of samples used + to average results for shunt and bus voltages. +======================= ==================================================== + +.. note:: + + - Configure `shunt_resistor` before configure `power1_crit`, because power + value is calculated based on `shunt_resistor` set. + - Because of the underlying register implementation, only one `*crit` setting + and its `alarm` can be active. Writing to one `*crit` setting clears other + `*crit` settings and alarms. Writing 0 to any `*crit` setting clears all + `*crit` settings and alarms. |