0001 Kernel driver ina2xx
0002 ====================
0003
0004 Supported chips:
0005
0006 * Texas Instruments INA219
0007
0008
0009 Prefix: 'ina219'
0010 Addresses: I2C 0x40 - 0x4f
0011
0012 Datasheet: Publicly available at the Texas Instruments website
0013
0014 https://www.ti.com/
0015
0016 * Texas Instruments INA220
0017
0018 Prefix: 'ina220'
0019
0020 Addresses: I2C 0x40 - 0x4f
0021
0022 Datasheet: Publicly available at the Texas Instruments website
0023
0024 https://www.ti.com/
0025
0026 * Texas Instruments INA226
0027
0028 Prefix: 'ina226'
0029
0030 Addresses: I2C 0x40 - 0x4f
0031
0032 Datasheet: Publicly available at the Texas Instruments website
0033
0034 https://www.ti.com/
0035
0036 * Texas Instruments INA230
0037
0038 Prefix: 'ina230'
0039
0040 Addresses: I2C 0x40 - 0x4f
0041
0042 Datasheet: Publicly available at the Texas Instruments website
0043
0044 https://www.ti.com/
0045
0046 * Texas Instruments INA231
0047
0048 Prefix: 'ina231'
0049
0050 Addresses: I2C 0x40 - 0x4f
0051
0052 Datasheet: Publicly available at the Texas Instruments website
0053
0054 https://www.ti.com/
0055
0056 Author: Lothar Felten <lothar.felten@gmail.com>
0057
0058 Description
0059 -----------
0060
0061 The INA219 is a high-side current shunt and power monitor with an I2C
0062 interface. The INA219 monitors both shunt drop and supply voltage, with
0063 programmable conversion times and filtering.
0064
0065 The INA220 is a high or low side current shunt and power monitor with an I2C
0066 interface. The INA220 monitors both shunt drop and supply voltage.
0067
0068 The INA226 is a current shunt and power monitor with an I2C interface.
0069 The INA226 monitors both a shunt voltage drop and bus supply voltage.
0070
0071 INA230 and INA231 are high or low side current shunt and power monitors
0072 with an I2C interface. The chips monitor both a shunt voltage drop and
0073 bus supply voltage.
0074
0075 The shunt value in micro-ohms can be set via platform data or device tree at
0076 compile-time or via the shunt_resistor attribute in sysfs at run-time. Please
0077 refer to the Documentation/devicetree/bindings/hwmon/ti,ina2xx.yaml for bindings
0078 if the device tree is used.
0079
0080 Additionally ina226 supports update_interval attribute as described in
0081 Documentation/hwmon/sysfs-interface.rst. Internally the interval is the sum of
0082 bus and shunt voltage conversion times multiplied by the averaging rate. We
0083 don't touch the conversion times and only modify the number of averages. The
0084 lower limit of the update_interval is 2 ms, the upper limit is 2253 ms.
0085 The actual programmed interval may vary from the desired value.
0086
0087 General sysfs entries
0088 ---------------------
0089
0090 ======================= ===============================
0091 in0_input Shunt voltage(mV) channel
0092 in1_input Bus voltage(mV) channel
0093 curr1_input Current(mA) measurement channel
0094 power1_input Power(uW) measurement channel
0095 shunt_resistor Shunt resistance(uOhm) channel
0096 ======================= ===============================
0097
0098 Sysfs entries for ina226, ina230 and ina231 only
0099 ------------------------------------------------
0100
0101 ======================= ====================================================
0102 in0_lcrit Critical low shunt voltage
0103 in0_crit Critical high shunt voltage
0104 in0_lcrit_alarm Shunt voltage critical low alarm
0105 in0_crit_alarm Shunt voltage critical high alarm
0106 in1_lcrit Critical low bus voltage
0107 in1_crit Critical high bus voltage
0108 in1_lcrit_alarm Bus voltage critical low alarm
0109 in1_crit_alarm Bus voltage critical high alarm
0110 power1_crit Critical high power
0111 power1_crit_alarm Power critical high alarm
0112 update_interval data conversion time; affects number of samples used
0113 to average results for shunt and bus voltages.
0114 ======================= ====================================================
0115
0116 .. note::
0117
0118 - Configure `shunt_resistor` before configure `power1_crit`, because power
0119 value is calculated based on `shunt_resistor` set.
0120 - Because of the underlying register implementation, only one `*crit` setting
0121 and its `alarm` can be active. Writing to one `*crit` setting clears other
0122 `*crit` settings and alarms. Writing 0 to any `*crit` setting clears all
0123 `*crit` settings and alarms.
