USB: ftdi_sio: add support for FT-X series devices

Add PID 0x6015, corresponding to the new series of FT-X chips
(FT220XD, FT201X, FT220X, FT221X, FT230X, FT231X, FT240X). They all
appear as serial devices, and seem indistinguishable except for the
default product string stored in their EEPROM. The baudrate
generation matches FT232RL devices.

Tested with a FT201X and FT230X at various baudrates (100 - 3000000).

Sample dmesg:
ftdi_sio: v1.6.0:USB FTDI Serial Converters Driver
usb 2-1: new full-speed USB device number 6 using ohci_hcd
usb 2-1: New USB device found, idVendor=0403, idProduct=6015
usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 2-1: Product: FT230X USB Half UART
usb 2-1: Manufacturer: FTDI
usb 2-1: SerialNumber: DC001WI6
ftdi_sio 2-1:1.0: FTDI USB Serial Device converter detected
drivers/usb/serial/ftdi_sio.c: ftdi_sio_port_probe
drivers/usb/serial/ftdi_sio.c: ftdi_determine_type: bcdDevice = 0x1000, bNumInterfaces = 1
usb 2-1: Detected FT-X
usb 2-1: Number of endpoints 2
usb 2-1: Endpoint 1 MaxPacketSize 64
usb 2-1: Endpoint 2 MaxPacketSize 64
usb 2-1: Setting MaxPacketSize 64
drivers/usb/serial/ftdi_sio.c: read_latency_timer
drivers/usb/serial/ftdi_sio.c: write_latency_timer: setting latency timer = 1
drivers/usb/serial/ftdi_sio.c: create_sysfs_attrs
drivers/usb/serial/ftdi_sio.c: sysfs attributes for FT-X
usb 2-1: FTDI USB Serial Device converter now attached to ttyUSB0

Signed-off-by: Jim Paris <[e-mail]>
Cc: stable <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/serial/ftdi_sio.c

···
 		.driver_info = (kernel_ulong_t)&ftdi_8u2232c_quirk },
 	{ USB_DEVICE(FTDI_VID, FTDI_4232H_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_232H_PID) },
+	{ USB_DEVICE(FTDI_VID, FTDI_FTX_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_MICRO_CHAMELEON_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_RELAIS_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_OPENDCC_PID) },
···
 	[FT232RL] = "FT232RL",
 	[FT2232H] = "FT2232H",
 	[FT4232H] = "FT4232H",
-	[FT232H]  = "FT232H"
+	[FT232H]  = "FT232H",
+	[FTX]     = "FT-X"
 };
 
 
···
 		break;
 	case FT232BM: /* FT232BM chip */
 	case FT2232C: /* FT2232C chip */
-	case FT232RL:
+	case FT232RL: /* FT232RL chip */
+	case FTX:     /* FT-X series */
 		if (baud <= 3000000) {
 			__u16 product_id = le16_to_cpu(
 				port->serial->dev->descriptor.idProduct);
···
 	} else if (version < 0x900) {
 		/* Assume it's an FT232RL */
 		priv->chip_type = FT232RL;
-	} else {
+	} else if (version < 0x1000) {
 		/* Assume it's an FT232H */
 		priv->chip_type = FT232H;
+	} else {
+		/* Assume it's an FT-X series device */
+		priv->chip_type = FTX;
 	}
+
 	dev_info(&udev->dev, "Detected %s\n", ftdi_chip_name[priv->chip_type]);
 }
 
···
 		     priv->chip_type == FT232RL ||
 		     priv->chip_type == FT2232H ||
 		     priv->chip_type == FT4232H ||
-		     priv->chip_type == FT232H)) {
+		     priv->chip_type == FT232H ||
+		     priv->chip_type == FTX)) {
 			retval = device_create_file(&port->dev,
 						    &dev_attr_latency_timer);
 		}
···
 		    priv->chip_type == FT232RL ||
 		    priv->chip_type == FT2232H ||
 		    priv->chip_type == FT4232H ||
-                    priv->chip_type == FT232H) {
+		    priv->chip_type == FT232H ||
+		    priv->chip_type == FTX) {
 			device_remove_file(&port->dev, &dev_attr_latency_timer);
 		}
 	}
···
 	case FT2232H:
 	case FT4232H:
 	case FT232H:
+	case FTX:
 		len = 2;
 		break;
 	default:

drivers/usb/serial/ftdi_sio.h

···
 	FT232RL = 5,
 	FT2232H = 6,
 	FT4232H = 7,
-	FT232H  = 8
+	FT232H  = 8,
+	FTX     = 9,
 };
 
 enum ftdi_sio_baudrate {

drivers/usb/serial/ftdi_sio_ids.h

···
 #define FTDI_8U2232C_PID 0x6010 /* Dual channel device */
 #define FTDI_4232H_PID 0x6011 /* Quad channel hi-speed device */
 #define FTDI_232H_PID  0x6014 /* Single channel hi-speed device */
+#define FTDI_FTX_PID   0x6015 /* FT-X series (FT201X, FT230X, FT231X, etc) */
 #define FTDI_SIO_PID	0x8372	/* Product Id SIO application of 8U100AX */
 #define FTDI_232RL_PID  0xFBFA  /* Product ID for FT232RL */