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- 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 <[email protected]>
- 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/ti,ina2xx.yaml 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.
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