USB: ftdi: support NDI devices

It enhances the driver for FTDI-based USB serial adapters to recognize and
support Northern Digital Inc (NDI) measurement equipment. NDI has been
providing this patch for various kernel flavors for several years and we would
like to see these changes built in to the driver so that our equipement works
without the need for customers to patch the kernel themselves.

The patch makes small modifications to 2 files: ./drivers/usb/serial/ftdi_sio.c
and ./drivers/usb/serial/ftdi_sio.h. It accomplishes 3 things:

1. Define the VID and PIDs to allow the driver to recognize the NDI devices.
2. Map the 19200 baud rate setting to our higher baud rate of 1.2Mb
We would have chosen to map 38400 to the higher rate, similar to what
several other vendors have done, but some of our legacy customers actually
use 38400, therefore we remap 19200 to the higher rate.
3. We set the default transmit latency in the FTDI chip to 1ms for our devices.
Our devices are typically polled at 60Hz and the default ftdi latency
seriously affects turn-around time and results in missed data frames. We
have created a modprobe option that allows this setting to be increased.
This has proven necessary particularly in some virtualized environments.

Signed-off-by: Martin P. Geleynse <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/serial/ftdi_sio.c

···
 
 static int   ftdi_jtag_probe(struct usb_serial *serial);
 static int   ftdi_mtxorb_hack_setup(struct usb_serial *serial);
+static int   ftdi_NDI_device_setup(struct usb_serial *serial);
 static void  ftdi_USB_UIRT_setup(struct ftdi_private *priv);
 static void  ftdi_HE_TIRA1_setup(struct ftdi_private *priv);
 
···
 
 static struct ftdi_sio_quirk ftdi_mtxorb_hack_quirk = {
 	.probe  = ftdi_mtxorb_hack_setup,
+};
+
+static struct ftdi_sio_quirk ftdi_NDI_device_quirk = {
+	.probe	= ftdi_NDI_device_setup,
 };
 
 static struct ftdi_sio_quirk ftdi_USB_UIRT_quirk = {
···
 	{ USB_DEVICE(FTDI_VID, FTDI_TACTRIX_OPENPORT_13S_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_TACTRIX_OPENPORT_13U_PID) },
 	{ USB_DEVICE(ELEKTOR_VID, ELEKTOR_FT323R_PID) },
+	{ USB_DEVICE(FTDI_VID, FTDI_NDI_HUC_PID),
+		.driver_info = (kernel_ulong_t)&ftdi_NDI_device_quirk },
+	{ USB_DEVICE(FTDI_VID, FTDI_NDI_SPECTRA_SCU_PID),
+		.driver_info = (kernel_ulong_t)&ftdi_NDI_device_quirk },
+	{ USB_DEVICE(FTDI_VID, FTDI_NDI_FUTURE_2_PID),
+		.driver_info = (kernel_ulong_t)&ftdi_NDI_device_quirk },
+	{ USB_DEVICE(FTDI_VID, FTDI_NDI_FUTURE_3_PID),
+		.driver_info = (kernel_ulong_t)&ftdi_NDI_device_quirk },
+	{ USB_DEVICE(FTDI_VID, FTDI_NDI_AURORA_SCU_PID),
+		.driver_info = (kernel_ulong_t)&ftdi_NDI_device_quirk },
 	{ USB_DEVICE(TELLDUS_VID, TELLDUS_TELLSTICK_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_MAXSTREAM_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_PHI_FISCO_PID) },
···
 	{ USB_DEVICE(FTDI_VID, FTDI_DOMINTELL_DUSB_PID) },
 	{ USB_DEVICE(ALTI2_VID, ALTI2_N3_PID) },
 	{ USB_DEVICE(FTDI_VID, DIEBOLD_BCS_SE923_PID) },
-	{ USB_DEVICE(FTDI_VID, FTDI_NDI_HUC_PID) },
 	{ USB_DEVICE(ATMEL_VID, STK541_PID) },
 	{ USB_DEVICE(DE_VID, STB_PID) },
 	{ USB_DEVICE(DE_VID, WHT_PID) },
···
 	case FT2232C: /* FT2232C chip */
 	case FT232RL:
 		if (baud <= 3000000) {
+			__u16 product_id = le16_to_cpu(
+				port->serial->dev->descriptor.idProduct);
+			if (((FTDI_NDI_HUC_PID == product_id) ||
+			     (FTDI_NDI_SPECTRA_SCU_PID == product_id) ||
+			     (FTDI_NDI_FUTURE_2_PID == product_id) ||
+			     (FTDI_NDI_FUTURE_3_PID == product_id) ||
+			     (FTDI_NDI_AURORA_SCU_PID == product_id)) &&
+			    (baud == 19200)) {
+				baud = 1200000;
+			}
 			div_value = ftdi_232bm_baud_to_divisor(baud);
 		} else {
 			dbg("%s - Baud rate too high!", __func__);
···
 	priv->force_baud = 38400;
 	priv->force_rtscts = 1;
 } /* ftdi_HE_TIRA1_setup */
+
+/*
+ * Module parameter to control latency timer for NDI FTDI-based USB devices.
+ * If this value is not set in modprobe.conf.local its value will be set to 1ms.
+ */
+static int ndi_latency_timer = 1;
+
+/* Setup for the NDI FTDI-based USB devices, which requires hardwired
+ * baudrate (19200 gets mapped to 1200000).
+ *
+ * Called from usbserial:serial_probe.
+ */
+static int ftdi_NDI_device_setup(struct usb_serial *serial)
+{
+	struct usb_device *udev = serial->dev;
+	int latency = ndi_latency_timer;
+	int rv = 0;
+	char buf[1];
+
+	if (latency == 0)
+		latency = 1;
+	if (latency > 99)
+		latency = 99;
+
+	dbg("%s setting NDI device latency to %d", __func__, latency);
+	dev_info(&udev->dev, "NDI device with a latency value of %d", latency);
+
+	rv = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				FTDI_SIO_SET_LATENCY_TIMER_REQUEST,
+				FTDI_SIO_SET_LATENCY_TIMER_REQUEST_TYPE,
+				latency, 0, buf, 0, WDR_TIMEOUT);
+	return 0;
+}
 
 /*
  * First port on JTAG adaptors such as Olimex arm-usb-ocd or the FIC/OpenMoko
···
 module_param(product, ushort, 0);
 MODULE_PARM_DESC(product, "User specified product ID");
 
+module_param(ndi_latency_timer, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(ndi_latency_timer, "NDI device latency timer override");

drivers/usb/serial/ftdi_sio.h

···
 #define FTDI_PYRAMID_PID	0xE6C8	/* Pyramid Appliance Display */
 
 /*
+ * NDI (www.ndigital.com) product ids
+ */
+#define FTDI_NDI_HUC_PID		0xDA70	/* NDI Host USB Converter */
+#define FTDI_NDI_SPECTRA_SCU_PID	0xDA71	/* NDI Spectra SCU */
+#define FTDI_NDI_FUTURE_2_PID		0xDA72	/* NDI future device #2 */
+#define FTDI_NDI_FUTURE_3_PID		0xDA73	/* NDI future device #3 */
+#define FTDI_NDI_AURORA_SCU_PID		0xDA74	/* NDI Aurora SCU */
+
+/*
  * Posiflex inc retail equipment (http://www.posiflex.com.tw)
  */
 #define POSIFLEX_VID		0x0d3a  /* Vendor ID */
···
  */
 #define TML_VID			0x1B91	/* Vendor ID */
 #define TML_USB_SERIAL_PID	0x0064	/* USB - Serial Converter */
-
-/* NDI Polaris System */
-#define FTDI_NDI_HUC_PID        0xDA70
 
 /* Propox devices */
 #define FTDI_PROPOX_JTAGCABLEII_PID	0xD738