jhd1313m1_driver: fix '\n' processing

platforms/i2c/i2c.go

@@ -7,9 +7,10 @@ import (
 )
 
 var (
-	ErrEncryptedBytes = errors.New("Encrypted bytes")
-	ErrNotEnoughBytes = errors.New("Not enough bytes read")
-	ErrNotReady       = errors.New("Device is not ready")
+	ErrEncryptedBytes  = errors.New("Encrypted bytes")
+	ErrNotEnoughBytes  = errors.New("Not enough bytes read")
+	ErrNotReady        = errors.New("Device is not ready")
+	ErrInvalidPosition = errors.New("Invalid position value")
 )
 
 const (

platforms/i2c/jhd1313m1_driver.go

@@ -34,6 +34,8 @@ const (
 	LCD_MOVERIGHT           = 0x04
 	LCD_MOVELEFT            = 0x00
 	LCD_2LINE               = 0x08
+
+	LCD_2NDLINEOFFSET = 0x40
 )
 
 var _ gobot.Driver = (*JHD1313M1Driver)(nil)
@@ -145,13 +147,36 @@ func (h *JHD1313M1Driver) Home() (err error) {
 
 func (h *JHD1313M1Driver) Write(message string) (err error) {
 	for _, val := range message {
+		if val == '\n' {
+			if err = h.SetPosition(16); err != nil {
+				return
+			}
+			continue
+		}
 		if err = h.connection.I2cWrite(h.lcdAddress, []byte{0x40, byte(val)}); err != nil {
 			break
 		}
 	}
 	return
 }
 
+// SetPosition sets the cursor and the data display to pos.
+// 0..15 are the positions in the first display line.
+// 16..32 are the positions in the second display line.
+func (h *JHD1313M1Driver) SetPosition(pos int) (err error) {
+	if pos < 0 || pos > 31 {
+		err = ErrInvalidPosition
+		return
+	}
+	offset := byte(pos)
+	if pos >= 16 {
+		offset -= 16
+		offset |= LCD_2NDLINEOFFSET
+	}
+	err = h.command([]byte{LCD_SETDDRAMADDR | offset})
+	return
+}
+
 func (h *JHD1313M1Driver) Halt() (errs []error) { return }
 
 func (h *JHD1313M1Driver) command(buf []byte) (err error) {