Configure golangci-lint and fix warnings

cmd/signer/main.go

@@ -13,12 +13,13 @@ import (
 
 func main() {
 	var (
-		address  string
-		baudRate int
+		address            string
+		baudRate, dataBits int
 	)
 
 	flag.StringVar(&address, "a", "/dev/ttyUSB0", "address")
 	flag.IntVar(&baudRate, "b", 115200, "baud rate")
+	flag.IntVar(&dataBits, "d", 8, "data bits")
 	flag.Parse()
 
 	log.SetFormatter(&log.TextFormatter{
@@ -29,15 +30,18 @@ func main() {
 
 	serialMode := &serial.Mode{
 		BaudRate: baudRate,
-		DataBits: 8,
+		DataBits: dataBits,
 		StopBits: serial.OneStopBit,
 		Parity:   serial.NoParity,
 	}
+
 	log.Infof("connecting to %s using %+v", address, serialMode)
+
 	port, err := serial.Open(address, serialMode)
 	if err != nil {
 		log.Fatalf("could not open serial port: %v", err)
 	}
+
 	log.Info("connected")
 
 	defer func() {
@@ -45,6 +49,7 @@ func main() {
 		if err != nil {
 			log.Fatalf("could not close port: %v", err)
 		}
+
 		log.Info("serial port closed")
 	}()