From 2e6a3be1004044561064b0549ee5cae6bd36980e Mon Sep 17 00:00:00 2001
From: hmelder <service@hugomelder.com>
Date: Sun, 10 Nov 2024 01:47:01 +0100
Subject: [PATCH] Add modbus integration

---
 succbone/succd/go.mod     |   3 ++
 succbone/succd/go.sum     |   4 ++
 succbone/succd/main.go    |   9 ++++
 succbone/succd/modbus.go  | 101 ++++++++++++++++++++++++++++++++++++++
 succbone/succd/process.go |   2 +
 5 files changed, 119 insertions(+)
 create mode 100644 succbone/succd/modbus.go

diff --git a/succbone/succd/go.mod b/succbone/succd/go.mod
index 574985d..d35e107 100644
--- a/succbone/succd/go.mod
+++ b/succbone/succd/go.mod
@@ -4,5 +4,8 @@ go 1.22.3
 
 require (
 	github.com/coder/websocket v1.8.12
+	github.com/simonvetter/modbus v1.6.3
 	k8s.io/klog v1.0.0
 )
+
+require github.com/goburrow/serial v0.1.0 // indirect
diff --git a/succbone/succd/go.sum b/succbone/succd/go.sum
index c8b5195..ab9ca54 100644
--- a/succbone/succd/go.sum
+++ b/succbone/succd/go.sum
@@ -1,5 +1,9 @@
 github.com/coder/websocket v1.8.12 h1:5bUXkEPPIbewrnkU8LTCLVaxi4N4J8ahufH2vlo4NAo=
 github.com/coder/websocket v1.8.12/go.mod h1:LNVeNrXQZfe5qhS9ALED3uA+l5pPqvwXg3CKoDBB2gs=
 github.com/go-logr/logr v0.1.0/go.mod h1:ixOQHD9gLJUVQQ2ZOR7zLEifBX6tGkNJF4QyIY7sIas=
+github.com/goburrow/serial v0.1.0 h1:v2T1SQa/dlUqQiYIT8+Cu7YolfqAi3K96UmhwYyuSrA=
+github.com/goburrow/serial v0.1.0/go.mod h1:sAiqG0nRVswsm1C97xsttiYCzSLBmUZ/VSlVLZJ8haA=
+github.com/simonvetter/modbus v1.6.3 h1:kDzwVfIPczsM4Iz09il/Dij/bqlT4XiJVa0GYaOVA9w=
+github.com/simonvetter/modbus v1.6.3/go.mod h1:hh90ZaTaPLcK2REj6/fpTbiV0J6S7GWmd8q+GVRObPw=
 k8s.io/klog v1.0.0 h1:Pt+yjF5aB1xDSVbau4VsWe+dQNzA0qv1LlXdC2dF6Q8=
 k8s.io/klog v1.0.0/go.mod h1:4Bi6QPql/J/LkTDqv7R/cd3hPo4k2DG6Ptcz060Ez5I=
diff --git a/succbone/succd/main.go b/succbone/succd/main.go
index a56f2cc..cfd93a9 100644
--- a/succbone/succd/main.go
+++ b/succbone/succd/main.go
@@ -61,6 +61,11 @@ func main() {
 		}
 		d.adcPirani = adc
 
+		err = d.modbusConnect()
+		if err != nil {
+			klog.Exitf("Failed to connect to modbus %v", err)
+		}
+
 		for _, c := range []struct {
 			out *gpio
 			num int
@@ -92,5 +97,9 @@ func main() {
 	}()
 
 	go d.process(ctx)
+	if !flagFake {
+		go d.modbusProcess(ctx)
+	}
+
 	<-ctx.Done()
 }
diff --git a/succbone/succd/modbus.go b/succbone/succd/modbus.go
new file mode 100644
index 0000000..15c3697
--- /dev/null
+++ b/succbone/succd/modbus.go
@@ -0,0 +1,101 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/simonvetter/modbus"
+)
+
+func modbusValuesToFloat(v uint16) float32 {
+	return float32(v) / 10.0
+}
+
+func (d *daemon) modbusConnect() error {
+	var err error
+
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	// Setup modbus client
+	d.modbusClient, err = modbus.NewClient(&modbus.ClientConfiguration{
+		URL:     "tcp://10.250.241.20:8887",
+		Timeout: 5 * time.Second,
+	})
+	if err != nil {
+		return err
+	}
+	// Connect to modbus client
+	err = d.modbusClient.Open()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// There are currently two devices connected to the modbus.
+// The first one (slave 1) is a temperature/humidity sensor.
+// The second one (slave 2) is a PTA8D08 transmitter
+func (d *daemon) modbusUpdate() error {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	var err error
+	var registers []uint16 // temperature, humidity
+
+	// Switch to slave 1
+	d.modbusClient.SetUnitId(1)
+
+	// Read temperature and humidity
+	registers, err = d.modbusClient.ReadRegisters(1, 2, modbus.INPUT_REGISTER)
+	if err != nil {
+		return err
+	}
+
+	if len(registers) != 2 {
+		msg := fmt.Sprintf("Expected two registers from modbus slave 1, but got %d", len(registers))
+		return errors.New(msg)
+	}
+
+	d.daemonState.tempSEM = modbusValuesToFloat(registers[0])
+	d.daemonState.humiditySEM = modbusValuesToFloat(registers[1])
+
+	// Switch to slave 2
+	d.modbusClient.SetUnitId(2)
+
+	// PT100 mapping
+	// Channel 0: Cable -WGA6, Sensor "dp bottom"
+	// Channel 1: Cable -WGA8, Sensor "dp inlet"
+	// Channel 2: Cable WGA7, Sensor "dp top"
+	registers, err = d.modbusClient.ReadRegisters(0, 3, modbus.HOLDING_REGISTER)
+	if err != nil {
+		return err
+	}
+
+	if len(registers) != 3 {
+		msg := fmt.Sprintf("Expected three registers from modbus slave 2, but got %d", len(registers))
+		return errors.New(msg)
+	}
+
+	d.daemonState.tempDPBottom = modbusValuesToFloat(registers[0])
+	d.daemonState.tempDPInlet = modbusValuesToFloat(registers[1])
+	d.daemonState.tempDPTop = modbusValuesToFloat(registers[2])
+
+	return nil
+}
+
+// Call modbusUpdate every second
+func (d *daemon) modbusProcess(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+			d.modbusUpdate()
+			time.Sleep(time.Second * 1)
+		}
+	}
+}
diff --git a/succbone/succd/process.go b/succbone/succd/process.go
index c886260..7ade055 100644
--- a/succbone/succd/process.go
+++ b/succbone/succd/process.go
@@ -8,11 +8,13 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/simonvetter/modbus"
 	"k8s.io/klog"
 )
 
 // daemon is the main service of the succdaemon.
 type daemon struct {
+	modbusClient *modbus.ModbusClient
 	// adcPirani is the adc implementation returning the voltage of the Pfeiffer
 	// Pirani gauge.
 	adcPirani adc