hwmon_ina219 - Driver for UPS based on INA219

       Andrew Anderson <aander07@gmail.com>

       The required parameter for this driver:

       port=hwmon-dir
           Path to appropriate /sys/hwmon/hwmonX or auto to detect automatically.

       Optional parameters:

       default.battery.charge.low=low-battery-threshold
           Threshold for low battery state (in percent).

       default.battery.voltage.nominal=voltage-value
           Nominal voltage (V) value of utilized batteries, used to derive their low and high watermark settings
           (see below). Default: 3.6.

           Known pre-sets include: 3.6, 3.7, 3.8, 3.85.

       default.battery.voltage.low=voltage-value
           Low voltage (V) value of used batteries. Practically, it denotes depleted batteries. If not given, it
           is derived from the battery.voltage.nominal.

       default.battery.voltage.high=voltage-value
           High voltage (V) value of used batteries. Practically, it denotes fully charged batteries. If not
           given, it is derived from the battery.voltage.nominal.

       This driver is specific to the Linux hwmon API.

       When using with the Waveshare CM4-POE-UPS-BASE baseboard, there are few steps to be done to enable access
       to the INA219 circuit:

        1. edit boot/config.txt:

                 dtparam=i2c_vc=on
                 dtoverlay=i2c-ina219

        2. create a new device tree overlay file i2c-ina219.dts:

               /dts-v1/;
               /plugin/;

               / {
                   compatible = "brcm,bcm2835";

                   fragment@0 {
                       target = <&i2c_csi_dsi>;
                       __overlay__ {
                           #address-cells = (1);
                           #size-cells = (2);

                           ina219@43 {
                               status = "okay";
                               compatible = "ti,ina219";
                               reg = <0x43>;
                               shunt-resistor = (3);  // R100
                           };
                       };
                   };
               };

        3. convert i2c-ina219.dts to dtbo and place it into /boot/overlays:

               $ dtc -@ -I dts -O dtb -o /boot/overlays/i2c-ina219.dtbo i2c-ina219.dts

        4. configure hwmon_ina219 UPS driver for NUT (ups.conf):

               [ina219]
               driver = hwmon_ina219
               port = auto

       The driver shutdown function is not implemented.

       hwmon_ina219 - Driver for UPS based on INA219

Thecoredriver:nutupsdrv(8)

   Internetresources:
       •   Initial pull requests adding this driver:

           •   https://github.com/networkupstools/nut/pull/2430

           •   https://github.com/networkupstools/nut/issues/2378

       •   Baseboard with INA219: https://www.waveshare.com/wiki/CM4-POE-UPS-BASE

       •   TI INA219: https://www.ti.com/lit/ds/symlink/ina219.pdf

       •   The NUT (Network UPS Tools) home page: https://www.networkupstools.org/historic/v2.8.3/

Network UPS Tools 2.8.3                            07/08/2025                                    HWMON_INA219(8)

       The hwmon_ina219 driver is based on setup with Raspberry PI Compute Module 4 and its baseboard Waveshare
       CM4-POE-UPS-BASE.

hwmon_ina219 -h

       hwmon_ina219 -a UPS_NAME [OPTIONS]

           Note

           This man page only documents the specific features of the hwmon_ina219 driver. For information about
           the core driver, see nutupsdrv(8).

       The driver implements reading of current and voltage from INA219 by using hwmon sysfs API of the Linux
       Kernel. There is no other UPS-like logic in there. Based on the measurements of the battery voltage and
       charging current, the driver makes assumptions of the current state of the system.