pl2303: improve the chip type information output on startup

The chip type distinction is getting more and more relevant and
complicating, so always print the chip type.
Printing a name string is also much better than just printing an
internal index number.
Signed-off-by: NFrank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/pl2303.c

@@ -177,6 +177,7 @@ static int pl2303_startup(struct usb_serial *serial)
 {
 	struct pl2303_serial_private *spriv;
 	enum pl2303_type type = type_0;
+	char *type_str = "unknown (treating as type_0)";
 	unsigned char *buf;
 
 	spriv = kzalloc(sizeof(*spriv), GFP_KERNEL);
@@ -189,14 +190,18 @@ static int pl2303_startup(struct usb_serial *serial)
 		return -ENOMEM;
 	}
 
-	if (serial->dev->descriptor.bDeviceClass == 0x02)
+	if (serial->dev->descriptor.bDeviceClass == 0x02) {
 		type = type_0;
-	else if (serial->dev->descriptor.bMaxPacketSize0 == 0x40)
+		type_str = "type_0";
+	} else if (serial->dev->descriptor.bMaxPacketSize0 == 0x40) {
 		type = HX;
-	else if (serial->dev->descriptor.bDeviceClass == 0x00
-		 || serial->dev->descriptor.bDeviceClass == 0xFF)
+		type_str = "X/HX";
+	} else if (serial->dev->descriptor.bDeviceClass == 0x00
+		   || serial->dev->descriptor.bDeviceClass == 0xFF) {
 		type = type_1;
-	dev_dbg(&serial->interface->dev, "device type: %d\n", type);
+		type_str = "type_1";
+	}
+	dev_dbg(&serial->interface->dev, "device type: %s\n", type_str);
 
 	spriv->type = type;
 	usb_set_serial_data(serial, spriv);