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 <mgeleyns@ndigital.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 60 insertions, 1 deletions

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index e9e9c78dceb3..88eb5878914a 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -107,6 +107,7 @@ struct ftdi_sio_quirk {
 
 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);
 
@@ -118,6 +119,10 @@ 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 = {
 	.port_probe = ftdi_USB_UIRT_setup,
 };
@@ -648,6 +653,16 @@ static struct usb_device_id id_table_combined [] = {
 	{ 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) },
@@ -671,7 +686,6 @@ static struct usb_device_id id_table_combined [] = {
 	{ 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) },
@@ -1027,6 +1041,16 @@ static __u32 get_ftdi_divisor(struct tty_struct *tty,
 	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__);
@@ -1558,6 +1582,39 @@ static void ftdi_HE_TIRA1_setup(struct ftdi_private *priv)
 } /* 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
  * Neo1973 Debug Board is reserved for JTAG interface and can be accessed from
  * userspace using openocd.
@@ -2626,3 +2683,5 @@ MODULE_PARM_DESC(vendor, "User specified vendor ID (default="
 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");