Modbus: add coils (#8385)

provider/modbus.go

@@ -13,7 +13,6 @@ import (
 	"github.com/evcc-io/evcc/util/modbus"
 	gridx "github.com/grid-x/modbus"
 	"github.com/volkszaehler/mbmd/meters"
-	"github.com/volkszaehler/mbmd/meters/rs485"
 	"github.com/volkszaehler/mbmd/meters/sunspec"
 )
 
@@ -140,10 +139,12 @@ func NewModbusFromConfig(other map[string]interface{}) (Provider, error) {
 func (m *Modbus) bytesGetter() ([]byte, error) {
 	if op := m.op.MBMD; op.FuncCode != 0 {
 		switch op.FuncCode {
-		case rs485.ReadHoldingReg:
+		case gridx.FuncCodeReadHoldingRegisters:
 			return m.conn.ReadHoldingRegisters(op.OpCode, op.ReadLen)
-		case rs485.ReadInputReg:
+		case gridx.FuncCodeReadInputRegisters:
 			return m.conn.ReadInputRegisters(op.OpCode, op.ReadLen)
+		case gridx.FuncCodeReadCoils:
+			return m.conn.ReadCoils(op.OpCode, op.ReadLen)
 		default:
 			return nil, fmt.Errorf("unknown function code %d", op.FuncCode)
 		}
@@ -234,6 +235,8 @@ func (m *Modbus) StringGetter() func() (string, error) {
 // UintFromBytes converts byte slice to bigendian uint value
 func UintFromBytes(bytes []byte) (u uint64, err error) {
 	switch l := len(bytes); l {
+	case 1:
+		u = uint64(bytes[0])
 	case 2:
 		u = uint64(binary.BigEndian.Uint16(bytes))
 	case 4:
@@ -272,6 +275,13 @@ func (m *Modbus) IntSetter(param string) func(int64) error {
 			switch op.FuncCode {
 			case gridx.FuncCodeWriteSingleRegister:
 				_, err = m.conn.WriteSingleRegister(op.OpCode, uval)
+			case gridx.FuncCodeWriteSingleCoil:
+				if uval != 0 {
+					// Modbus protocol requires 0xFF00 for ON
+					// and 0x0000 for OFF
+					uval = 0xFF00
+				}
+				_, err = m.conn.WriteSingleCoil(op.OpCode, uval)
 			default:
 				err = fmt.Errorf("unknown function code %d", op.FuncCode)
 			}

util/modbus/functions.go

@@ -39,6 +39,15 @@ func decodeMask(mask string) (uint64, error) {
 	return strconv.ParseUint(mask, 10, 64)
 }
 
+// decodeBool8 converts a masked uint1 to a bool
+func decodeBool8(b []byte) float64 {
+	u := b[0]
+	if u > 0 {
+		return 1
+	}
+	return 0
+}
+
 // decodeBool16 converts a masked uint16 to a bool
 func decodeBool16(mask uint64) func(b []byte) float64 {
 	return func(b []byte) float64 {

util/modbus/modbus.go

@@ -375,14 +375,25 @@ func RegisterOperation(r Register) (rs485.Operation, error) {
 		op.FuncCode = modbus.FuncCodeReadHoldingRegisters
 	case "input":
 		op.FuncCode = modbus.FuncCodeReadInputRegisters
-	case "writesingle":
+	case "coil":
+		op.FuncCode = modbus.FuncCodeReadCoils
+		r.Decode = "bool8"
+	case "writesingle", "writeholding":
 		op.FuncCode = modbus.FuncCodeWriteSingleRegister
+	case "writecoil":
+		op.FuncCode = modbus.FuncCodeWriteSingleCoil
+		r.Decode = "bool8"
 	default:
 		return rs485.Operation{}, fmt.Errorf("invalid register type: %s", r.Type)
 	}
 
 	switch strings.ToLower(r.Decode) {
 
+	// 8 bit (coil)
+	case "bool8":
+		op.Transform = decodeBool8
+		op.ReadLen = 1
+
 	// 16 bit
 	case "int16":
 		op.Transform = asFloat64(encoding.Int16)