commit 124e954d3a3dd0c7ae4d041ad90b444332ac1723
Author: Thomas Klaehn <thomas.klaehn@perinet.io>
Date:   Sun Aug 20 07:57:49 2023 +0200

    Initial commit

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..5c9ca26
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,11 @@
+module git.blackfinn.de/solar/ina3221
+
+go 1.20
+
+require (
+	gotest.tools/v3 v3.5.0
+	periph.io/x/conn/v3 v3.7.0
+	periph.io/x/host/v3 v3.8.2
+)
+
+require github.com/google/go-cmp v0.5.9 // indirect
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..095c2bd
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,9 @@
+github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/jonboulle/clockwork v0.3.0 h1:9BSCMi8C+0qdApAp4auwX0RkLGUjs956h0EkuQymUhg=
+gotest.tools/v3 v3.5.0 h1:Ljk6PdHdOhAb5aDMWXjDLMMhph+BpztA4v1QdqEW2eY=
+gotest.tools/v3 v3.5.0/go.mod h1:isy3WKz7GK6uNw/sbHzfKBLvlvXwUyV06n6brMxxopU=
+periph.io/x/conn/v3 v3.7.0 h1:f1EXLn4pkf7AEWwkol2gilCNZ0ElY+bxS4WE2PQXfrA=
+periph.io/x/conn/v3 v3.7.0/go.mod h1:ypY7UVxgDbP9PJGwFSVelRRagxyXYfttVh7hJZUHEhg=
+periph.io/x/host/v3 v3.8.2 h1:ayKUDzgUCN0g8+/xM9GTkWaOBhSLVcVHGTfjAOi8OsQ=
+periph.io/x/host/v3 v3.8.2/go.mod h1:yFL76AesNHR68PboofSWYaQTKmvPXsQH2Apvp/ls/K4=
diff --git a/ina3221.go b/ina3221.go
new file mode 100644
index 0000000..5ba5cc3
--- /dev/null
+++ b/ina3221.go
@@ -0,0 +1,105 @@
+package ina3221
+
+import (
+	"encoding/binary"
+	"log"
+
+	"periph.io/x/conn/v3/i2c"
+	"periph.io/x/conn/v3/i2c/i2creg"
+	"periph.io/x/conn/v3/mmr"
+	"periph.io/x/host/v3"
+)
+
+type Channel uint8
+
+const (
+	Channel_1 Channel = 1
+	Channel_2 Channel = 3
+	Channel_3 Channel = 5
+
+	current_factor float64 = 40e-6
+	voltage_factor float64 = 8e-3
+)
+
+var (
+	logger log.Logger = *log.Default()
+
+	mem_dev mmr.Dev8
+	bus     i2c.BusCloser
+	i2c_dev i2c.Dev
+)
+
+func start(slave_addr uint16) error {
+	logger.SetPrefix("ina3112: ")
+	logger.Println("Starting")
+
+	var err error
+	_, err = host.Init()
+	if err != nil {
+		logger.Println(err)
+	}
+	bus, err = i2creg.Open("")
+	if err != nil {
+		logger.Println(err)
+	}
+	i2c_dev = i2c.Dev{
+		Bus:  bus,
+		Addr: slave_addr,
+	}
+	mem_dev = mmr.Dev8{
+		Conn:  &i2c_dev,
+		Order: binary.BigEndian,
+	}
+	return err
+}
+
+func stop() error {
+	return bus.Close()
+}
+
+func read_register(address uint8) (uint16, error) {
+	return mem_dev.ReadUint16(address)
+}
+
+func shunt_voltage(channel Channel) (float64, error) {
+	res, err := read_register(uint8(channel))
+	if err != nil {
+		logger.Println(err)
+		return 0.0, err
+	}
+	res >>= 3
+	return float64(res), err
+}
+
+func bus_voltage(channel Channel) (float64, error) {
+	res, err := read_register(uint8(channel) + 1)
+	if err != nil {
+		logger.Println(err)
+		return 0.0, err
+	}
+	res >>= 3
+	return float64(res), err
+}
+
+func Current(channel Channel) (float64, error) {
+	res, err := shunt_voltage(channel)
+	if err != nil {
+		logger.Println(err)
+		return 0.0, err
+	}
+
+	return res * current_factor, err
+}
+
+func Voltage(channel Channel) (float64, error) {
+	res, err := bus_voltage(channel)
+	if err != nil {
+		logger.Println(err)
+		return 0.0, err
+	}
+	return res * voltage_factor, err
+}
+
+func ManufacturerID() (uint16, error) {
+	return read_register(0xfe)
+}
diff --git a/ina3221_test.go b/ina3221_test.go
new file mode 100644
index 0000000..b626118
--- /dev/null
+++ b/ina3221_test.go
@@ -0,0 +1,32 @@
+package ina3221
+
+import (
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+const (
+	i2c_slave_addr  uint16 = 0x40
+	manufacturer_id uint16 = 0x5449
+)
+
+func TestMain(t *testing.T) {
+	err := start(i2c_slave_addr)
+	assert.NilError(t, err)
+
+	var id uint16
+	id, err = ManufacturerID()
+	assert.NilError(t, err)
+	assert.Assert(t, id == manufacturer_id)
+
+	for i := 1; i < 4; i++ {
+		_, err = Current(Channel(i))
+		assert.NilError(t, err)
+		_, err = Voltage(Channel(i))
+		assert.NilError(t, err)
+	}
+
+	err = stop()
+	assert.NilError(t, err)
+}