USB: serial: mos7840: add USB ID to support Moxa UPort 2210

Add USB ID for MOXA UPort 2210. This device contains mos7820 but
it passes GPIO0 check implemented by driver and it's detected as
mos7840. Hence product id check is added to force mos7820 mode.
Signed-off-by: Pavel Löbl <pavel@loebl.cz>
Cc: stable <stable@vger.kernel.org>
[ johan: rename id defines and add vendor-id check ]
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/mos7840.c

@@ -119,11 +119,15 @@
 /* This driver also supports
  * ATEN UC2324 device using Moschip MCS7840
  * ATEN UC2322 device using Moschip MCS7820
+ * MOXA UPort 2210 device using Moschip MCS7820
  */
 #define USB_VENDOR_ID_ATENINTL		0x0557
 #define ATENINTL_DEVICE_ID_UC2324	0x2011
 #define ATENINTL_DEVICE_ID_UC2322	0x7820
 
+#define USB_VENDOR_ID_MOXA		0x110a
+#define MOXA_DEVICE_ID_2210		0x2210
+
 /* Interrupt Routine Defines    */
 
 #define SERIAL_IIR_RLS      0x06
@@ -195,6 +199,7 @@ static const struct usb_device_id id_table[] = {
 	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL2_4)},
 	{USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2324)},
 	{USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2322)},
+	{USB_DEVICE(USB_VENDOR_ID_MOXA, MOXA_DEVICE_ID_2210)},
 	{}			/* terminating entry */
 };
 MODULE_DEVICE_TABLE(usb, id_table);
@@ -2020,6 +2025,7 @@ static int mos7840_probe(struct usb_serial *serial,
 				const struct usb_device_id *id)
 {
 	u16 product = le16_to_cpu(serial->dev->descriptor.idProduct);
+	u16 vid = le16_to_cpu(serial->dev->descriptor.idVendor);
 	u8 *buf;
 	int device_type;
 
@@ -2030,6 +2036,11 @@ static int mos7840_probe(struct usb_serial *serial,
 		goto out;
 	}
 
+	if (vid == USB_VENDOR_ID_MOXA && product == MOXA_DEVICE_ID_2210) {
+		device_type = MOSCHIP_DEVICE_ID_7820;
+		goto out;
+	}
+
 	buf = kzalloc(VENDOR_READ_LENGTH, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;