#!/bin/sh
# Kookabus-01 through the kernel's ina2xx hwmon driver: no user-space I2C code.
# Run as root once per boot (or put the first two steps in rc.local / a systemd unit):
#   sudo ./kookabus-hwmon.sh [i2c bus number] [address]
# Afterwards any user can read the values; `sensors` (lm-sensors) shows them too.
BUS=${1:-1}
ADDR=${2:-0x40}
DEV=/sys/bus/i2c/devices/$BUS-$(printf %04x "$ADDR")

[ -d "$DEV" ] || echo ina226 "$ADDR" > /sys/bus/i2c/devices/i2c-"$BUS"/new_device
HW=$(echo "$DEV"/hwmon/hwmon*)
echo 5000 > "$HW"/shunt_resistor   # micro-ohm

while :; do
    # in1 = bus voltage (mV), curr1 = mA, power1 = uW
    awk -v v="$(cat "$HW"/in1_input)" -v i="$(cat "$HW"/curr1_input)" -v p="$(cat "$HW"/power1_input)" \
        'BEGIN { printf "%6.2f V  %6.3f A  %6.1f W\n", v/1000, i/1000, p/1e6 }'
    sleep 1
done