USB: Moschip 7840 USB-Serial Driver

Signed-off-by: Paul B Schroeder <pschroeder@uplogix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 2978 insertions, 0 deletions

diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index e4df0ac358fb30..5076b9d97057ae 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -422,6 +422,21 @@ config USB_SERIAL_MCT_U232
 	  To compile this driver as a module, choose M here: the
 	  module will be called mct_u232.
 
+config USB_SERIAL_MOS7840
+	tristate "USB Moschip 7840/7820 USB Serial Driver"
+	depends on USB_SERIAL
+	---help---
+	  Say Y here if you want to use a MCS7840 Quad-Serial or MCS7820
+	  Dual-Serial port device from MosChip Semiconductor.
+
+	  The MCS7840 and MCS7820 have been developed to connect a wide range
+	  of standard serial devices to a USB host.  The MCS7840 has a USB
+	  device controller connected to four (4) individual UARTs while the
+	  MCS7820 controller connects to two (2) individual UARTs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called mos7840.  If unsure, choose N.
+
 config USB_SERIAL_NAVMAN
 	tristate "USB Navman GPS device"
 	depends on USB_SERIAL
diff --git a/drivers/usb/serial/Makefile b/drivers/usb/serial/Makefile
index 029e2a1d7bf687..8dce83340e3109 100644
--- a/drivers/usb/serial/Makefile
+++ b/drivers/usb/serial/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_USB_SERIAL_KEYSPAN_PDA)		+= keyspan_pda.o
 obj-$(CONFIG_USB_SERIAL_KLSI)			+= kl5kusb105.o
 obj-$(CONFIG_USB_SERIAL_KOBIL_SCT)		+= kobil_sct.o
 obj-$(CONFIG_USB_SERIAL_MCT_U232)		+= mct_u232.o
+obj-$(CONFIG_USB_SERIAL_MOS7840)		+= mos7840.o
 obj-$(CONFIG_USB_SERIAL_NAVMAN)			+= navman.o
 obj-$(CONFIG_USB_SERIAL_OMNINET)		+= omninet.o
 obj-$(CONFIG_USB_SERIAL_OPTION)			+= option.o
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
new file mode 100644
index 00000000000000..95bf57166c5920
--- /dev/null
+++ b/drivers/usb/serial/mos7840.c
@@ -0,0 +1,2962 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Clean ups from Moschip version and a few ioctl implementations by:
+ *	Paul B Schroeder <pschroeder "at" uplogix "dot" com>
+ *
+ * Originally based on drivers/usb/serial/io_edgeport.c which is:
+ *      Copyright (C) 2000 Inside Out Networks, All rights reserved.
+ *      Copyright (C) 2001-2002 Greg Kroah-Hartman <greg@kroah.com>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/module.h>
+#include <linux/serial.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <asm/uaccess.h>
+
+/*
+ * Version Information
+ */
+#define DRIVER_VERSION "1.3.1"
+#define DRIVER_DESC "Moschip 7840/7820 USB Serial Driver"
+
+/*
+ * 16C50 UART register defines
+ */
+
+#define LCR_BITS_5             0x00	/* 5 bits/char */
+#define LCR_BITS_6             0x01	/* 6 bits/char */
+#define LCR_BITS_7             0x02	/* 7 bits/char */
+#define LCR_BITS_8             0x03	/* 8 bits/char */
+#define LCR_BITS_MASK          0x03	/* Mask for bits/char field */
+
+#define LCR_STOP_1             0x00	/* 1 stop bit */
+#define LCR_STOP_1_5           0x04	/* 1.5 stop bits (if 5   bits/char) */
+#define LCR_STOP_2             0x04	/* 2 stop bits   (if 6-8 bits/char) */
+#define LCR_STOP_MASK          0x04	/* Mask for stop bits field */
+
+#define LCR_PAR_NONE           0x00	/* No parity */
+#define LCR_PAR_ODD            0x08	/* Odd parity */
+#define LCR_PAR_EVEN           0x18	/* Even parity */
+#define LCR_PAR_MARK           0x28	/* Force parity bit to 1 */
+#define LCR_PAR_SPACE          0x38	/* Force parity bit to 0 */
+#define LCR_PAR_MASK           0x38	/* Mask for parity field */
+
+#define LCR_SET_BREAK          0x40	/* Set Break condition */
+#define LCR_DL_ENABLE          0x80	/* Enable access to divisor latch */
+
+#define MCR_DTR                0x01	/* Assert DTR */
+#define MCR_RTS                0x02	/* Assert RTS */
+#define MCR_OUT1               0x04	/* Loopback only: Sets state of RI */
+#define MCR_MASTER_IE          0x08	/* Enable interrupt outputs */
+#define MCR_LOOPBACK           0x10	/* Set internal (digital) loopback mode */
+#define MCR_XON_ANY            0x20	/* Enable any char to exit XOFF mode */
+
+#define MOS7840_MSR_CTS        0x10	/* Current state of CTS */
+#define MOS7840_MSR_DSR        0x20	/* Current state of DSR */
+#define MOS7840_MSR_RI         0x40	/* Current state of RI */
+#define MOS7840_MSR_CD         0x80	/* Current state of CD */
+
+/*
+ * Defines used for sending commands to port
+ */
+
+#define WAIT_FOR_EVER   (HZ * 0 )	/* timeout urb is wait for ever */
+#define MOS_WDR_TIMEOUT (HZ * 5 )	/* default urb timeout */
+
+#define MOS_PORT1       0x0200
+#define MOS_PORT2       0x0300
+#define MOS_VENREG      0x0000
+#define MOS_MAX_PORT	0x02
+#define MOS_WRITE       0x0E
+#define MOS_READ        0x0D
+
+/* Requests */
+#define MCS_RD_RTYPE    0xC0
+#define MCS_WR_RTYPE    0x40
+#define MCS_RDREQ       0x0D
+#define MCS_WRREQ       0x0E
+#define MCS_CTRL_TIMEOUT        500
+#define VENDOR_READ_LENGTH      (0x01)
+
+#define MAX_NAME_LEN    64
+
+#define ZLP_REG1  0x3A		//Zero_Flag_Reg1    58
+#define ZLP_REG5  0x3E		//Zero_Flag_Reg5    62
+
+/* For higher baud Rates use TIOCEXBAUD */
+#define TIOCEXBAUD     0x5462
+
+/* vendor id and device id defines */
+
+#define USB_VENDOR_ID_MOSCHIP           0x9710
+#define MOSCHIP_DEVICE_ID_7840          0x7840
+#define MOSCHIP_DEVICE_ID_7820          0x7820
+
+/* Interrupt Rotinue Defines    */
+
+#define SERIAL_IIR_RLS      0x06
+#define SERIAL_IIR_MS       0x00
+
+/*
+ *  Emulation of the bit mask on the LINE STATUS REGISTER.
+ */
+#define SERIAL_LSR_DR       0x0001
+#define SERIAL_LSR_OE       0x0002
+#define SERIAL_LSR_PE       0x0004
+#define SERIAL_LSR_FE       0x0008
+#define SERIAL_LSR_BI       0x0010
+
+#define MOS_MSR_DELTA_CTS   0x10
+#define MOS_MSR_DELTA_DSR   0x20
+#define MOS_MSR_DELTA_RI    0x40
+#define MOS_MSR_DELTA_CD    0x80
+
+// Serial Port register Address
+#define INTERRUPT_ENABLE_REGISTER  ((__u16)(0x01))
+#define FIFO_CONTROL_REGISTER      ((__u16)(0x02))
+#define LINE_CONTROL_REGISTER      ((__u16)(0x03))
+#define MODEM_CONTROL_REGISTER     ((__u16)(0x04))
+#define LINE_STATUS_REGISTER       ((__u16)(0x05))
+#define MODEM_STATUS_REGISTER      ((__u16)(0x06))
+#define SCRATCH_PAD_REGISTER       ((__u16)(0x07))
+#define DIVISOR_LATCH_LSB          ((__u16)(0x00))
+#define DIVISOR_LATCH_MSB          ((__u16)(0x01))
+
+#define CLK_MULTI_REGISTER         ((__u16)(0x02))
+#define CLK_START_VALUE_REGISTER   ((__u16)(0x03))
+
+#define SERIAL_LCR_DLAB            ((__u16)(0x0080))
+
+/*
+ * URB POOL related defines
+ */
+#define NUM_URBS                        16	/* URB Count */
+#define URB_TRANSFER_BUFFER_SIZE        32	/* URB Size  */
+
+
+static struct usb_device_id moschip_port_id_table[] = {
+	{USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7840)},
+	{USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7820)},
+	{}			/* terminating entry */
+};
+
+static __devinitdata struct usb_device_id moschip_id_table_combined[] = {
+	{USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7840)},
+	{USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7820)},
+	{}			/* terminating entry */
+};
+
+MODULE_DEVICE_TABLE(usb, moschip_id_table_combined);
+
+/* This structure holds all of the local port information */
+
+struct moschip_port {
+	int port_num;		/*Actual port number in the device(1,2,etc) */
+	struct urb *write_urb;	/* write URB for this port */
+	struct urb *read_urb;	/* read URB for this port */
+	__u8 shadowLCR;		/* last LCR value received */
+	__u8 shadowMCR;		/* last MCR value received */
+	char open;
+	wait_queue_head_t wait_chase;	/* for handling sleeping while waiting for chase to finish */
+	wait_queue_head_t delta_msr_wait;	/* for handling sleeping while waiting for msr change to happen */
+	int delta_msr_cond;
+	struct async_icount icount;
+	struct usb_serial_port *port;	/* loop back to the owner of this object */
+
+	/*Offsets */
+	__u8 SpRegOffset;
+	__u8 ControlRegOffset;
+	__u8 DcrRegOffset;
+	//for processing control URBS in interrupt context
+	struct urb *control_urb;
+	char *ctrl_buf;
+	int MsrLsr;
+
+	struct urb *write_urb_pool[NUM_URBS];
+};
+
+
+static int debug;
+static int mos7840_num_ports;	//this says the number of ports in the device
+static int mos7840_num_open_ports;
+
+
+/*
+ * mos7840_set_reg_sync
+ * 	To set the Control register by calling usb_fill_control_urb function
+ *	by passing usb_sndctrlpipe function as parameter.
+ */
+
+static int mos7840_set_reg_sync(struct usb_serial_port *port, __u16 reg,
+				__u16 val)
+{
+	struct usb_device *dev = port->serial->dev;
+	val = val & 0x00ff;
+	dbg("mos7840_set_reg_sync offset is %x, value %x\n", reg, val);
+
+	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0), MCS_WRREQ,
+			       MCS_WR_RTYPE, val, reg, NULL, 0,
+			       MOS_WDR_TIMEOUT);
+}
+
+/*
+ * mos7840_get_reg_sync
+ * 	To set the Uart register by calling usb_fill_control_urb function by
+ *	passing usb_rcvctrlpipe function as parameter.
+ */
+
+static int mos7840_get_reg_sync(struct usb_serial_port *port, __u16 reg,
+				__u16 * val)
+{
+	struct usb_device *dev = port->serial->dev;
+	int ret = 0;
+
+	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
+			      MCS_RD_RTYPE, 0, reg, val, VENDOR_READ_LENGTH,
+			      MOS_WDR_TIMEOUT);
+	dbg("mos7840_get_reg_sync offset is %x, return val %x\n", reg, *val);
+	*val = (*val) & 0x00ff;
+	return ret;
+}
+
+/*
+ * mos7840_set_uart_reg
+ *	To set the Uart register by calling usb_fill_control_urb function by
+ *	passing usb_sndctrlpipe function as parameter.
+ */
+
+static int mos7840_set_uart_reg(struct usb_serial_port *port, __u16 reg,
+				__u16 val)
+{
+
+	struct usb_device *dev = port->serial->dev;
+	val = val & 0x00ff;
+	// For the UART control registers, the application number need to be Or'ed
+	if (mos7840_num_ports == 4) {
+		val |=
+		    (((__u16) port->number - (__u16) (port->serial->minor)) +
+		     1) << 8;
+		dbg("mos7840_set_uart_reg application number is %x\n", val);
+	} else {
+		if (((__u16) port->number - (__u16) (port->serial->minor)) == 0) {
+			val |=
+			    (((__u16) port->number -
+			      (__u16) (port->serial->minor)) + 1) << 8;
+			dbg("mos7840_set_uart_reg application number is %x\n",
+			    val);
+		} else {
+			val |=
+			    (((__u16) port->number -
+			      (__u16) (port->serial->minor)) + 2) << 8;
+			dbg("mos7840_set_uart_reg application number is %x\n",
+			    val);
+		}
+	}
+	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0), MCS_WRREQ,
+			       MCS_WR_RTYPE, val, reg, NULL, 0,
+			       MOS_WDR_TIMEOUT);
+
+}
+
+/*
+ * mos7840_get_uart_reg
+ *	To set the Control register by calling usb_fill_control_urb function
+ *	by passing usb_rcvctrlpipe function as parameter.
+ */
+static int mos7840_get_uart_reg(struct usb_serial_port *port, __u16 reg,
+				__u16 * val)
+{
+	struct usb_device *dev = port->serial->dev;
+	int ret = 0;
+	__u16 Wval;
+
+	//dbg("application number is %4x \n",(((__u16)port->number - (__u16)(port->serial->minor))+1)<<8);
+	/*Wval  is same as application number */
+	if (mos7840_num_ports == 4) {
+		Wval =
+		    (((__u16) port->number - (__u16) (port->serial->minor)) +
+		     1) << 8;
+		dbg("mos7840_get_uart_reg application number is %x\n", Wval);
+	} else {
+		if (((__u16) port->number - (__u16) (port->serial->minor)) == 0) {
+			Wval =
+			    (((__u16) port->number -
+			      (__u16) (port->serial->minor)) + 1) << 8;
+			dbg("mos7840_get_uart_reg application number is %x\n",
+			    Wval);
+		} else {
+			Wval =
+			    (((__u16) port->number -
+			      (__u16) (port->serial->minor)) + 2) << 8;
+			dbg("mos7840_get_uart_reg application number is %x\n",
+			    Wval);
+		}
+	}
+	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
+			      MCS_RD_RTYPE, Wval, reg, val, VENDOR_READ_LENGTH,
+			      MOS_WDR_TIMEOUT);
+	*val = (*val) & 0x00ff;
+	return ret;
+}
+
+static void mos7840_dump_serial_port(struct moschip_port *mos7840_port)
+{
+
+	dbg("***************************************\n");
+	dbg("SpRegOffset is %2x\n", mos7840_port->SpRegOffset);
+	dbg("ControlRegOffset is %2x \n", mos7840_port->ControlRegOffset);
+	dbg("DCRRegOffset is %2x \n", mos7840_port->DcrRegOffset);
+	dbg("***************************************\n");
+
+}
+
+/************************************************************************/
+/************************************************************************/
+/*             I N T E R F A C E   F U N C T I O N S			*/
+/*             I N T E R F A C E   F U N C T I O N S			*/
+/************************************************************************/
+/************************************************************************/
+
+static inline void mos7840_set_port_private(struct usb_serial_port *port,
+					    struct moschip_port *data)
+{
+	usb_set_serial_port_data(port, (void *)data);
+}
+
+static inline struct moschip_port *mos7840_get_port_private(struct
+							    usb_serial_port
+							    *port)
+{
+	return (struct moschip_port *)usb_get_serial_port_data(port);
+}
+
+static int mos7840_handle_new_msr(struct moschip_port *port, __u8 new_msr)
+{
+	struct moschip_port *mos7840_port;
+	struct async_icount *icount;
+	mos7840_port = port;
+	icount = &mos7840_port->icount;
+	if (new_msr &
+	    (MOS_MSR_DELTA_CTS | MOS_MSR_DELTA_DSR | MOS_MSR_DELTA_RI |
+	     MOS_MSR_DELTA_CD)) {
+		icount = &mos7840_port->icount;
+
+		/* update input line counters */
+		if (new_msr & MOS_MSR_DELTA_CTS) {
+			icount->cts++;
+		}
+		if (new_msr & MOS_MSR_DELTA_DSR) {
+			icount->dsr++;
+		}
+		if (new_msr & MOS_MSR_DELTA_CD) {
+			icount->dcd++;
+		}
+		if (new_msr & MOS_MSR_DELTA_RI) {
+			icount->rng++;
+		}
+	}
+
+	return 0;
+}
+
+static int mos7840_handle_new_lsr(struct moschip_port *port, __u8 new_lsr)
+{
+	struct async_icount *icount;
+
+	dbg("%s - %02x", __FUNCTION__, new_lsr);
+
+	if (new_lsr & SERIAL_LSR_BI) {
+		//
+		// Parity and Framing errors only count if they
+		// occur exclusive of a break being
+		// received.
+		//
+		new_lsr &= (__u8) (SERIAL_LSR_OE | SERIAL_LSR_BI);
+	}
+
+	/* update input line counters */
+	icount = &port->icount;
+	if (new_lsr & SERIAL_LSR_BI) {
+		icount->brk++;
+	}
+	if (new_lsr & SERIAL_LSR_OE) {
+		icount->overrun++;
+	}
+	if (new_lsr & SERIAL_LSR_PE) {
+		icount->parity++;
+	}
+	if (new_lsr & SERIAL_LSR_FE) {
+		icount->frame++;
+	}
+
+	return 0;
+}
+
+/************************************************************************/
+/************************************************************************/
+/*            U S B  C A L L B A C K   F U N C T I O N S                */
+/*            U S B  C A L L B A C K   F U N C T I O N S                */
+/************************************************************************/
+/************************************************************************/
+
+static void mos7840_control_callback(struct urb *urb, struct pt_regs *regs)
+{
+	unsigned char *data;
+	struct moschip_port *mos7840_port;
+	__u8 regval = 0x0;
+
+	if (!urb) {
+		dbg("%s", "Invalid Pointer !!!!:\n");
+		return;
+	}
+
+	switch (urb->status) {
+	case 0:
+		/* success */
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		/* this urb is terminated, clean up */
+		dbg("%s - urb shutting down with status: %d", __FUNCTION__,
+		    urb->status);
+		return;
+	default:
+		dbg("%s - nonzero urb status received: %d", __FUNCTION__,
+		    urb->status);
+		goto exit;
+	}
+
+	mos7840_port = (struct moschip_port *)urb->context;
+
+	dbg("%s urb buffer size is %d\n", __FUNCTION__, urb->actual_length);
+	dbg("%s mos7840_port->MsrLsr is %d port %d\n", __FUNCTION__,
+	    mos7840_port->MsrLsr, mos7840_port->port_num);
+	data = urb->transfer_buffer;
+	regval = (__u8) data[0];
+	dbg("%s data is %x\n", __FUNCTION__, regval);
+	if (mos7840_port->MsrLsr == 0)
+		mos7840_handle_new_msr(mos7840_port, regval);
+	else if (mos7840_port->MsrLsr == 1)
+		mos7840_handle_new_lsr(mos7840_port, regval);
+
+      exit:
+	return;
+}
+
+static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg,
+			   __u16 * val)
+{
+	struct usb_device *dev = mcs->port->serial->dev;
+	struct usb_ctrlrequest *dr = NULL;
+	unsigned char *buffer = NULL;
+	int ret = 0;
+	buffer = (__u8 *) mcs->ctrl_buf;
+
+//      dr=(struct usb_ctrlrequest *)(buffer);
+	dr = (void *)(buffer + 2);
+	dr->bRequestType = MCS_RD_RTYPE;
+	dr->bRequest = MCS_RDREQ;
+	dr->wValue = cpu_to_le16(Wval);	//0;
+	dr->wIndex = cpu_to_le16(reg);
+	dr->wLength = cpu_to_le16(2);
+
+	usb_fill_control_urb(mcs->control_urb, dev, usb_rcvctrlpipe(dev, 0),
+			     (unsigned char *)dr, buffer, 2,
+			     mos7840_control_callback, mcs);
+	mcs->control_urb->transfer_buffer_length = 2;
+	ret = usb_submit_urb(mcs->control_urb, GFP_ATOMIC);
+	return ret;
+}
+
+/*****************************************************************************
+ * mos7840_interrupt_callback
+ *	this is the callback function for when we have received data on the
+ *	interrupt endpoint.
+ *****************************************************************************/
+
+static void mos7840_interrupt_callback(struct urb *urb, struct pt_regs *regs)
+{
+	int result;
+	int length;
+	struct moschip_port *mos7840_port;
+	struct usb_serial *serial;
+	__u16 Data;
+	unsigned char *data;
+	__u8 sp[5], st;
+	int i;
+	__u16 wval;
+
+	dbg("%s", " : Entering\n");
+	if (!urb) {
+		dbg("%s", "Invalid Pointer !!!!:\n");
+		return;
+	}
+
+	switch (urb->status) {
+	case 0:
+		/* success */
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		/* this urb is terminated, clean up */
+		dbg("%s - urb shutting down with status: %d", __FUNCTION__,
+		    urb->status);
+		return;
+	default:
+		dbg("%s - nonzero urb status received: %d", __FUNCTION__,
+		    urb->status);
+		goto exit;
+	}
+
+	length = urb->actual_length;
+	data = urb->transfer_buffer;
+
+	serial = (struct usb_serial *)urb->context;
+
+	/* Moschip get 5 bytes
+	 * Byte 1 IIR Port 1 (port.number is 0)
+	 * Byte 2 IIR Port 2 (port.number is 1)
+	 * Byte 3 IIR Port 3 (port.number is 2)
+	 * Byte 4 IIR Port 4 (port.number is 3)
+	 * Byte 5 FIFO status for both */
+
+	if (length && length > 5) {
+		dbg("%s \n", "Wrong data !!!");
+		return;
+	}
+
+	sp[0] = (__u8) data[0];
+	sp[1] = (__u8) data[1];
+	sp[2] = (__u8) data[2];
+	sp[3] = (__u8) data[3];
+	st = (__u8) data[4];
+
+	for (i = 0; i < serial->num_ports; i++) {
+		mos7840_port = mos7840_get_port_private(serial->port[i]);
+		wval =
+		    (((__u16) serial->port[i]->number -
+		      (__u16) (serial->minor)) + 1) << 8;
+		if (mos7840_port->open) {
+			if (sp[i] & 0x01) {
+				dbg("SP%d No Interrupt !!!\n", i);
+			} else {
+				switch (sp[i] & 0x0f) {
+				case SERIAL_IIR_RLS:
+					dbg("Serial Port %d: Receiver status error or ", i);
+					dbg("address bit detected in 9-bit mode\n");
+					mos7840_port->MsrLsr = 1;
+					mos7840_get_reg(mos7840_port, wval,
+							LINE_STATUS_REGISTER,
+							&Data);
+					break;
+				case SERIAL_IIR_MS:
+					dbg("Serial Port %d: Modem status change\n", i);
+					mos7840_port->MsrLsr = 0;
+					mos7840_get_reg(mos7840_port, wval,
+							MODEM_STATUS_REGISTER,
+							&Data);
+					break;
+				}
+			}
+		}
+	}
+      exit:
+	result = usb_submit_urb(urb, GFP_ATOMIC);
+	if (result) {
+		dev_err(&urb->dev->dev,
+			"%s - Error %d submitting interrupt urb\n",
+			__FUNCTION__, result);
+	}
+
+	return;
+
+}
+
+static int mos7840_port_paranoia_check(struct usb_serial_port *port,
+				       const char *function)
+{
+	if (!port) {
+		dbg("%s - port == NULL", function);
+		return -1;
+	}
+	if (!port->serial) {
+		dbg("%s - port->serial == NULL", function);
+		return -1;
+	}
+
+	return 0;
+}
+
+/* Inline functions to check the sanity of a pointer that is passed to us */
+static int mos7840_serial_paranoia_check(struct usb_serial *serial,
+					 const char *function)
+{
+	if (!serial) {
+		dbg("%s - serial == NULL", function);
+		return -1;
+	}
+	if (!serial->type) {
+		dbg("%s - serial->type == NULL!", function);
+		return -1;
+	}
+
+	return 0;
+}
+
+static struct usb_serial *mos7840_get_usb_serial(struct usb_serial_port *port,
+						 const char *function)
+{
+	/* if no port was specified, or it fails a paranoia check */
+	if (!port ||
+	    mos7840_port_paranoia_check(port, function) ||
+	    mos7840_serial_paranoia_check(port->serial, function)) {
+		/* then say that we don't have a valid usb_serial thing, which will                  * end up genrating -ENODEV return values */
+		return NULL;
+	}
+
+	return port->serial;
+}
+
+/*****************************************************************************
+ * mos7840_bulk_in_callback
+ *	this is the callback function for when we have received data on the
+ *	bulk in endpoint.
+ *****************************************************************************/
+
+static void mos7840_bulk_in_callback(struct urb *urb, struct pt_regs *regs)
+{
+	int status;
+	unsigned char *data;
+	struct usb_serial *serial;
+	struct usb_serial_port *port;
+	struct moschip_port *mos7840_port;
+	struct tty_struct *tty;
+
+	if (!urb) {
+		dbg("%s", "Invalid Pointer !!!!:\n");
+		return;
+	}
+
+	if (urb->status) {
+		dbg("nonzero read bulk status received: %d", urb->status);
+		return;
+	}
+
+	mos7840_port = (struct moschip_port *)urb->context;
+	if (!mos7840_port) {
+		dbg("%s", "NULL mos7840_port pointer \n");
+		return;
+	}
+
+	port = (struct usb_serial_port *)mos7840_port->port;
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Port Paranoia failed \n");
+		return;
+	}
+
+	serial = mos7840_get_usb_serial(port, __FUNCTION__);
+	if (!serial) {
+		dbg("%s\n", "Bad serial pointer ");
+		return;
+	}
+
+	dbg("%s\n", "Entering... \n");
+
+	data = urb->transfer_buffer;
+
+	dbg("%s", "Entering ........... \n");
+
+	if (urb->actual_length) {
+		tty = mos7840_port->port->tty;
+		if (tty) {
+			tty_buffer_request_room(tty, urb->actual_length);
+			tty_insert_flip_string(tty, data, urb->actual_length);
+			dbg(" %s \n", data);
+			tty_flip_buffer_push(tty);
+		}
+		mos7840_port->icount.rx += urb->actual_length;
+		dbg("mos7840_port->icount.rx is %d:\n",
+		    mos7840_port->icount.rx);
+	}
+
+	if (!mos7840_port->read_urb) {
+		dbg("%s", "URB KILLED !!!\n");
+		return;
+	}
+
+	if (mos7840_port->read_urb->status != -EINPROGRESS) {
+		mos7840_port->read_urb->dev = serial->dev;
+
+		status = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
+
+		if (status) {
+			dbg(" usb_submit_urb(read bulk) failed, status = %d",
+			    status);
+		}
+	}
+}
+
+/*****************************************************************************
+ * mos7840_bulk_out_data_callback
+ *	this is the callback function for when we have finished sending serial data
+ *	on the bulk out endpoint.
+ *****************************************************************************/
+
+static void mos7840_bulk_out_data_callback(struct urb *urb,
+					   struct pt_regs *regs)
+{
+	struct moschip_port *mos7840_port;
+	struct tty_struct *tty;
+	if (!urb) {
+		dbg("%s", "Invalid Pointer !!!!:\n");
+		return;
+	}
+
+	if (urb->status) {
+		dbg("nonzero write bulk status received:%d\n", urb->status);
+		return;
+	}
+
+	mos7840_port = (struct moschip_port *)urb->context;
+	if (!mos7840_port) {
+		dbg("%s", "NULL mos7840_port pointer \n");
+		return;
+	}
+
+	if (mos7840_port_paranoia_check(mos7840_port->port, __FUNCTION__)) {
+		dbg("%s", "Port Paranoia failed \n");
+		return;
+	}
+
+	dbg("%s \n", "Entering .........");
+
+	tty = mos7840_port->port->tty;
+
+	if (tty && mos7840_port->open) {
+		/* let the tty driver wakeup if it has a special *
+		 * write_wakeup function                         */
+
+		if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP))
+		    && tty->ldisc.write_wakeup) {
+			(tty->ldisc.write_wakeup) (tty);
+		}
+
+		/* tell the tty driver that something has changed */
+		wake_up_interruptible(&tty->write_wait);
+	}
+
+}
+
+/************************************************************************/
+/*       D R I V E R  T T Y  I N T E R F A C E  F U N C T I O N S       */
+/************************************************************************/
+#ifdef MCSSerialProbe
+static int mos7840_serial_probe(struct usb_serial *serial,
+				const struct usb_device_id *id)
+{
+
+	/*need to implement the mode_reg reading and updating\
+	   structures usb_serial_ device_type\
+	   (i.e num_ports, num_bulkin,bulkout etc) */
+	/* Also we can update the changes  attach */
+	return 1;
+}
+#endif
+
+/*****************************************************************************
+ * mos7840_open
+ *	this function is called by the tty driver when a port is opened
+ *	If successful, we return 0
+ *	Otherwise we return a negative error number.
+ *****************************************************************************/
+
+static int mos7840_open(struct usb_serial_port *port, struct file *filp)
+{
+	int response;
+	int j;
+	struct usb_serial *serial;
+	struct urb *urb;
+	__u16 Data;
+	int status;
+	struct moschip_port *mos7840_port;
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Port Paranoia failed \n");
+		return -ENODEV;
+	}
+
+	mos7840_num_open_ports++;
+	serial = port->serial;
+
+	if (mos7840_serial_paranoia_check(serial, __FUNCTION__)) {
+		dbg("%s", "Serial Paranoia failed \n");
+		return -ENODEV;
+	}
+
+	mos7840_port = mos7840_get_port_private(port);
+
+	if (mos7840_port == NULL)
+		return -ENODEV;
+
+	usb_clear_halt(serial->dev, port->write_urb->pipe);
+	usb_clear_halt(serial->dev, port->read_urb->pipe);
+
+	/* Initialising the write urb pool */
+	for (j = 0; j < NUM_URBS; ++j) {
+		urb = usb_alloc_urb(0, SLAB_ATOMIC);
+		mos7840_port->write_urb_pool[j] = urb;
+
+		if (urb == NULL) {
+			err("No more urbs???");
+			continue;
+		}
+
+		urb->transfer_buffer = NULL;
+		urb->transfer_buffer =
+		    kmalloc(URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);
+		if (!urb->transfer_buffer) {
+			err("%s-out of memory for urb buffers.", __FUNCTION__);
+			continue;
+		}
+	}
+
+/*****************************************************************************
+ * Initialize MCS7840 -- Write Init values to corresponding Registers
+ *
+ * Register Index
+ * 1 : IER
+ * 2 : FCR
+ * 3 : LCR
+ * 4 : MCR
+ *
+ * 0x08 : SP1/2 Control Reg
+ *****************************************************************************/
+
+//NEED to check the following Block
+
+	status = 0;
+	Data = 0x0;
+	status = mos7840_get_reg_sync(port, mos7840_port->SpRegOffset, &Data);
+	if (status < 0) {
+		dbg("Reading Spreg failed\n");
+		return -1;
+	}
+	Data |= 0x80;
+	status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
+	if (status < 0) {
+		dbg("writing Spreg failed\n");
+		return -1;
+	}
+
+	Data &= ~0x80;
+	status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
+	if (status < 0) {
+		dbg("writing Spreg failed\n");
+		return -1;
+	}
+//End of block to be checked
+
+	status = 0;
+	Data = 0x0;
+	status =
+	    mos7840_get_reg_sync(port, mos7840_port->ControlRegOffset, &Data);
+	if (status < 0) {
+		dbg("Reading Controlreg failed\n");
+		return -1;
+	}
+	Data |= 0x08;		//Driver done bit
+	Data |= 0x20;		//rx_disable
+	status = 0;
+	status =
+	    mos7840_set_reg_sync(port, mos7840_port->ControlRegOffset, Data);
+	if (status < 0) {
+		dbg("writing Controlreg failed\n");
+		return -1;
+	}
+	//do register settings here
+	// Set all regs to the device default values.
+	////////////////////////////////////
+	// First Disable all interrupts.
+	////////////////////////////////////
+
+	Data = 0x00;
+	status = 0;
+	status = mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);
+	if (status < 0) {
+		dbg("disableing interrupts failed\n");
+		return -1;
+	}
+	// Set FIFO_CONTROL_REGISTER to the default value
+	Data = 0x00;
+	status = 0;
+	status = mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
+	if (status < 0) {
+		dbg("Writing FIFO_CONTROL_REGISTER  failed\n");
+		return -1;
+	}
+
+	Data = 0xcf;
+	status = 0;
+	status = mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
+	if (status < 0) {
+		dbg("Writing FIFO_CONTROL_REGISTER  failed\n");
+		return -1;
+	}
+
+	Data = 0x03;
+	status = 0;
+	status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
+	mos7840_port->shadowLCR = Data;
+
+	Data = 0x0b;
+	status = 0;
+	status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
+	mos7840_port->shadowMCR = Data;
+
+	Data = 0x00;
+	status = 0;
+	status = mos7840_get_uart_reg(port, LINE_CONTROL_REGISTER, &Data);
+	mos7840_port->shadowLCR = Data;
+
+	Data |= SERIAL_LCR_DLAB;	//data latch enable in LCR 0x80
+	status = 0;
+	status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
+
+	Data = 0x0c;
+	status = 0;
+	status = mos7840_set_uart_reg(port, DIVISOR_LATCH_LSB, Data);
+
+	Data = 0x0;
+	status = 0;
+	status = mos7840_set_uart_reg(port, DIVISOR_LATCH_MSB, Data);
+
+	Data = 0x00;
+	status = 0;
+	status = mos7840_get_uart_reg(port, LINE_CONTROL_REGISTER, &Data);
+
+	Data = Data & ~SERIAL_LCR_DLAB;
+	status = 0;
+	status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
+	mos7840_port->shadowLCR = Data;
+
+	//clearing Bulkin and Bulkout Fifo
+	Data = 0x0;
+	status = 0;
+	status = mos7840_get_reg_sync(port, mos7840_port->SpRegOffset, &Data);
+
+	Data = Data | 0x0c;
+	status = 0;
+	status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
+
+	Data = Data & ~0x0c;
+	status = 0;
+	status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
+	//Finally enable all interrupts
+	Data = 0x0;
+	Data = 0x0c;
+	status = 0;
+	status = mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);
+
+	//clearing rx_disable
+	Data = 0x0;
+	status = 0;
+	status =
+	    mos7840_get_reg_sync(port, mos7840_port->ControlRegOffset, &Data);
+	Data = Data & ~0x20;
+	status = 0;
+	status =
+	    mos7840_set_reg_sync(port, mos7840_port->ControlRegOffset, Data);
+
+	// rx_negate
+	Data = 0x0;
+	status = 0;
+	status =
+	    mos7840_get_reg_sync(port, mos7840_port->ControlRegOffset, &Data);
+	Data = Data | 0x10;
+	status = 0;
+	status =
+	    mos7840_set_reg_sync(port, mos7840_port->ControlRegOffset, Data);
+
+	/* force low_latency on so that our tty_push actually forces *
+	 * the data through,otherwise it is scheduled, and with      *
+	 * high data rates (like with OHCI) data can get lost.       */
+
+	if (port->tty)
+		port->tty->low_latency = 1;
+/* Check to see if we've set up our endpoint info yet    *
+     * (can't set it up in mos7840_startup as the structures *
+     * were not set up at that time.)                        */
+	if (mos7840_num_open_ports == 1) {
+		if (serial->port[0]->interrupt_in_buffer == NULL) {
+
+			/* set up interrupt urb */
+
+			usb_fill_int_urb(serial->port[0]->interrupt_in_urb,
+					 serial->dev,
+					 usb_rcvintpipe(serial->dev,
+							serial->port[0]->
+							interrupt_in_endpointAddress),
+					 serial->port[0]->interrupt_in_buffer,
+					 serial->port[0]->interrupt_in_urb->
+					 transfer_buffer_length,
+					 mos7840_interrupt_callback,
+					 serial,
+					 serial->port[0]->interrupt_in_urb->
+					 interval);
+
+			/* start interrupt read for mos7840               *
+			 * will continue as long as mos7840 is connected  */
+
+			response =
+			    usb_submit_urb(serial->port[0]->interrupt_in_urb,
+					   GFP_KERNEL);
+			if (response) {
+				err("%s - Error %d submitting interrupt urb",
+				    __FUNCTION__, response);
+			}
+
+		}
+
+	}
+
+	/* see if we've set up our endpoint info yet   *
+	 * (can't set it up in mos7840_startup as the  *
+	 * structures were not set up at that time.)   */
+
+	dbg("port number is %d \n", port->number);
+	dbg("serial number is %d \n", port->serial->minor);
+	dbg("Bulkin endpoint is %d \n", port->bulk_in_endpointAddress);
+	dbg("BulkOut endpoint is %d \n", port->bulk_out_endpointAddress);
+	dbg("Interrupt endpoint is %d \n", port->interrupt_in_endpointAddress);
+	dbg("port's number in the device is %d\n", mos7840_port->port_num);
+	mos7840_port->read_urb = port->read_urb;
+
+	/* set up our bulk in urb */
+
+	usb_fill_bulk_urb(mos7840_port->read_urb,
+			  serial->dev,
+			  usb_rcvbulkpipe(serial->dev,
+					  port->bulk_in_endpointAddress),
+			  port->bulk_in_buffer,
+			  mos7840_port->read_urb->transfer_buffer_length,
+			  mos7840_bulk_in_callback, mos7840_port);
+
+	dbg("mos7840_open: bulkin endpoint is %d\n",
+	    port->bulk_in_endpointAddress);
+	response = usb_submit_urb(mos7840_port->read_urb, GFP_KERNEL);
+	if (response) {
+		err("%s - Error %d submitting control urb", __FUNCTION__,
+		    response);
+	}
+
+	/* initialize our wait queues */
+	init_waitqueue_head(&mos7840_port->wait_chase);
+	init_waitqueue_head(&mos7840_port->delta_msr_wait);
+
+	/* initialize our icount structure */
+	memset(&(mos7840_port->icount), 0x00, sizeof(mos7840_port->icount));
+
+	/* initialize our port settings */
+	mos7840_port->shadowMCR = MCR_MASTER_IE;	/* Must set to enable ints! */
+	/* send a open port command */
+	mos7840_port->open = 1;
+	//mos7840_change_port_settings(mos7840_port,old_termios);
+	mos7840_port->icount.tx = 0;
+	mos7840_port->icount.rx = 0;
+
+	dbg("\n\nusb_serial serial:%x       mos7840_port:%x\n      usb_serial_port port:%x\n\n", (unsigned int)serial, (unsigned int)mos7840_port, (unsigned int)port);
+
+	return 0;
+
+}
+
+/*****************************************************************************
+ * mos7840_chars_in_buffer
+ *	this function is called by the tty driver when it wants to know how many
+ *	bytes of data we currently have outstanding in the port (data that has
+ *	been written, but hasn't made it out the port yet)
+ *	If successful, we return the number of bytes left to be written in the
+ *	system,
+ *	Otherwise we return a negative error number.
+ *****************************************************************************/
+
+static int mos7840_chars_in_buffer(struct usb_serial_port *port)
+{
+	int i;
+	int chars = 0;
+	struct moschip_port *mos7840_port;
+
+	dbg("%s \n", " mos7840_chars_in_buffer:entering ...........");
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Invalid port \n");
+		return -1;
+	}
+
+	mos7840_port = mos7840_get_port_private(port);
+	if (mos7840_port == NULL) {
+		dbg("%s \n", "mos7840_break:leaving ...........");
+		return -1;
+	}
+
+	for (i = 0; i < NUM_URBS; ++i) {
+		if (mos7840_port->write_urb_pool[i]->status == -EINPROGRESS) {
+			chars += URB_TRANSFER_BUFFER_SIZE;
+		}
+	}
+	dbg("%s - returns %d", __FUNCTION__, chars);
+	return (chars);
+
+}
+
+/************************************************************************
+ *
+ * mos7840_block_until_tx_empty
+ *
+ *	This function will block the close until one of the following:
+ *		1. TX count are 0
+ *		2. The mos7840 has stopped
+ *		3. A timout of 3 seconds without activity has expired
+ *
+ ************************************************************************/
+static void mos7840_block_until_tx_empty(struct moschip_port *mos7840_port)
+{
+	int timeout = HZ / 10;
+	int wait = 30;
+	int count;
+
+	while (1) {
+
+		count = mos7840_chars_in_buffer(mos7840_port->port);
+
+		/* Check for Buffer status */
+		if (count <= 0) {
+			return;
+		}
+
+		/* Block the thread for a while */
+		interruptible_sleep_on_timeout(&mos7840_port->wait_chase,
+					       timeout);
+
+		/* No activity.. count down section */
+		wait--;
+		if (wait == 0) {
+			dbg("%s - TIMEOUT", __FUNCTION__);
+			return;
+		} else {
+			/* Reset timout value back to seconds */
+			wait = 30;
+		}
+	}
+}
+
+/*****************************************************************************
+ * mos7840_close
+ *	this function is called by the tty driver when a port is closed
+ *****************************************************************************/
+
+static void mos7840_close(struct usb_serial_port *port, struct file *filp)
+{
+	struct usb_serial *serial;
+	struct moschip_port *mos7840_port;
+	int j;
+	__u16 Data;
+
+	dbg("%s\n", "mos7840_close:entering...");
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Port Paranoia failed \n");
+		return;
+	}
+
+	serial = mos7840_get_usb_serial(port, __FUNCTION__);
+	if (!serial) {
+		dbg("%s", "Serial Paranoia failed \n");
+		return;
+	}
+
+	mos7840_port = mos7840_get_port_private(port);
+
+	if (mos7840_port == NULL) {
+		return;
+	}
+
+	for (j = 0; j < NUM_URBS; ++j)
+		usb_kill_urb(mos7840_port->write_urb_pool[j]);
+
+	/* Freeing Write URBs */
+	for (j = 0; j < NUM_URBS; ++j) {
+		if (mos7840_port->write_urb_pool[j]) {
+			if (mos7840_port->write_urb_pool[j]->transfer_buffer)
+				kfree(mos7840_port->write_urb_pool[j]->
+				      transfer_buffer);
+
+			usb_free_urb(mos7840_port->write_urb_pool[j]);
+		}
+	}
+
+	if (serial->dev) {
+		/* flush and block until tx is empty */
+		mos7840_block_until_tx_empty(mos7840_port);
+	}
+
+	/* While closing port, shutdown all bulk read, write  *
+	 * and interrupt read if they exists                  */
+	if (serial->dev) {
+
+		if (mos7840_port->write_urb) {
+			dbg("%s", "Shutdown bulk write\n");
+			usb_kill_urb(mos7840_port->write_urb);
+		}
+
+		if (mos7840_port->read_urb) {
+			dbg("%s", "Shutdown bulk read\n");
+			usb_kill_urb(mos7840_port->read_urb);
+		}
+		if ((&mos7840_port->control_urb)) {
+			dbg("%s", "Shutdown control read\n");
+			//      usb_kill_urb (mos7840_port->control_urb);
+
+		}
+	}
+//              if(mos7840_port->ctrl_buf != NULL)
+//                      kfree(mos7840_port->ctrl_buf);
+	mos7840_num_open_ports--;
+	dbg("mos7840_num_open_ports in close%d:in port%d\n",
+	    mos7840_num_open_ports, port->number);
+	if (mos7840_num_open_ports == 0) {
+		if (serial->port[0]->interrupt_in_urb) {
+			dbg("%s", "Shutdown interrupt_in_urb\n");
+		}
+	}
+
+	if (mos7840_port->write_urb) {
+		/* if this urb had a transfer buffer already (old tx) free it */
+
+		if (mos7840_port->write_urb->transfer_buffer != NULL) {
+			kfree(mos7840_port->write_urb->transfer_buffer);
+		}
+		usb_free_urb(mos7840_port->write_urb);
+	}
+
+	Data = 0x0;
+	mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
+
+	Data = 0x00;
+	mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);
+
+	mos7840_port->open = 0;
+
+	dbg("%s \n", "Leaving ............");
+}
+
+/************************************************************************
+ *
+ * mos7840_block_until_chase_response
+ *
+ *	This function will block the close until one of the following:
+ *		1. Response to our Chase comes from mos7840
+ *		2. A timout of 10 seconds without activity has expired
+ *		   (1K of mos7840 data @ 2400 baud ==> 4 sec to empty)
+ *
+ ************************************************************************/
+
+static void mos7840_block_until_chase_response(struct moschip_port
+					       *mos7840_port)
+{
+	int timeout = 1 * HZ;
+	int wait = 10;
+	int count;
+
+	while (1) {
+		count = mos7840_chars_in_buffer(mos7840_port->port);
+
+		/* Check for Buffer status */
+		if (count <= 0) {
+			return;
+		}
+
+		/* Block the thread for a while */
+		interruptible_sleep_on_timeout(&mos7840_port->wait_chase,
+					       timeout);
+		/* No activity.. count down section */
+		wait--;
+		if (wait == 0) {
+			dbg("%s - TIMEOUT", __FUNCTION__);
+			return;
+		} else {
+			/* Reset timout value back to seconds */
+			wait = 10;
+		}
+	}
+
+}
+
+/*****************************************************************************
+ * mos7840_break
+ *	this function sends a break to the port
+ *****************************************************************************/
+static void mos7840_break(struct usb_serial_port *port, int break_state)
+{
+	unsigned char data;
+	struct usb_serial *serial;
+	struct moschip_port *mos7840_port;
+
+	dbg("%s \n", "Entering ...........");
+	dbg("mos7840_break: Start\n");
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Port Paranoia failed \n");
+		return;
+	}
+
+	serial = mos7840_get_usb_serial(port, __FUNCTION__);
+	if (!serial) {
+		dbg("%s", "Serial Paranoia failed \n");
+		return;
+	}
+
+	mos7840_port = mos7840_get_port_private(port);
+
+	if (mos7840_port == NULL) {
+		return;
+	}
+
+	if (serial->dev) {
+
+		/* flush and block until tx is empty */
+		mos7840_block_until_chase_response(mos7840_port);
+	}
+
+	if (break_state == -1) {
+		data = mos7840_port->shadowLCR | LCR_SET_BREAK;
+	} else {
+		data = mos7840_port->shadowLCR & ~LCR_SET_BREAK;
+	}
+
+	mos7840_port->shadowLCR = data;
+	dbg("mcs7840_break mos7840_port->shadowLCR is %x\n",
+	    mos7840_port->shadowLCR);
+	mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER,
+			     mos7840_port->shadowLCR);
+
+	return;
+}
+
+/*****************************************************************************
+ * mos7840_write_room
+ *	this function is called by the tty driver when it wants to know how many
+ *	bytes of data we can accept for a specific port.
+ *	If successful, we return the amount of room that we have for this port
+ *	Otherwise we return a negative error number.
+ *****************************************************************************/
+
+static int mos7840_write_room(struct usb_serial_port *port)
+{
+	int i;
+	int room = 0;
+	struct moschip_port *mos7840_port;
+
+	dbg("%s \n", " mos7840_write_room:entering ...........");
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Invalid port \n");
+		dbg("%s \n", " mos7840_write_room:leaving ...........");
+		return -1;
+	}
+
+	mos7840_port = mos7840_get_port_private(port);
+	if (mos7840_port == NULL) {
+		dbg("%s \n", "mos7840_break:leaving ...........");
+		return -1;
+	}
+
+	for (i = 0; i < NUM_URBS; ++i) {
+		if (mos7840_port->write_urb_pool[i]->status != -EINPROGRESS) {
+			room += URB_TRANSFER_BUFFER_SIZE;
+		}
+	}
+
+	dbg("%s - returns %d", __FUNCTION__, room);
+	return (room);
+
+}
+
+/*****************************************************************************
+ * mos7840_write
+ *	this function is called by the tty driver when data should be written to
+ *	the port.
+ *	If successful, we return the number of bytes written, otherwise we
+ *      return a negative error number.
+ *****************************************************************************/
+
+static int mos7840_write(struct usb_serial_port *port,
+			 const unsigned char *data, int count)
+{
+	int status;
+	int i;
+	int bytes_sent = 0;
+	int transfer_size;
+	int from_user = 0;
+
+	struct moschip_port *mos7840_port;
+	struct usb_serial *serial;
+	struct urb *urb;
+	//__u16 Data;
+	const unsigned char *current_position = data;
+	unsigned char *data1;
+	dbg("%s \n", "entering ...........");
+	//dbg("mos7840_write: mos7840_port->shadowLCR is %x\n",mos7840_port->shadowLCR);
+
+#ifdef NOTMOS7840
+	Data = 0x00;
+	status = 0;
+	status = mos7840_get_uart_reg(port, LINE_CONTROL_REGISTER, &Data);
+	mos7840_port->shadowLCR = Data;
+	dbg("mos7840_write: LINE_CONTROL_REGISTER is %x\n", Data);
+	dbg("mos7840_write: mos7840_port->shadowLCR is %x\n",
+	    mos7840_port->shadowLCR);
+
+	//Data = 0x03;
+	//status = mos7840_set_uart_reg(port,LINE_CONTROL_REGISTER,Data);
+	//mos7840_port->shadowLCR=Data;//Need to add later
+
+	Data |= SERIAL_LCR_DLAB;	//data latch enable in LCR 0x80
+	status = 0;
+	status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
+
+	//Data = 0x0c;
+	//status = mos7840_set_uart_reg(port,DIVISOR_LATCH_LSB,Data);
+	Data = 0x00;
+	status = 0;
+	status = mos7840_get_uart_reg(port, DIVISOR_LATCH_LSB, &Data);
+	dbg("mos7840_write:DLL value is %x\n", Data);
+
+	Data = 0x0;
+	status = 0;
+	status = mos7840_get_uart_reg(port, DIVISOR_LATCH_MSB, &Data);
+	dbg("mos7840_write:DLM value is %x\n", Data);
+
+	Data = Data & ~SERIAL_LCR_DLAB;
+	dbg("mos7840_write: mos7840_port->shadowLCR is %x\n",
+	    mos7840_port->shadowLCR);
+	status = 0;
+	status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
+#endif
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Port Paranoia failed \n");
+		return -1;
+	}
+
+	serial = port->serial;
+	if (mos7840_serial_paranoia_check(serial, __FUNCTION__)) {
+		dbg("%s", "Serial Paranoia failed \n");
+		return -1;
+	}
+
+	mos7840_port = mos7840_get_port_private(port);
+	if (mos7840_port == NULL) {
+		dbg("%s", "mos7840_port is NULL\n");
+		return -1;
+	}
+
+	/* try to find a free urb in the list */
+	urb = NULL;
+
+	for (i = 0; i < NUM_URBS; ++i) {
+		if (mos7840_port->write_urb_pool[i]->status != -EINPROGRESS) {
+			urb = mos7840_port->write_urb_pool[i];
+			dbg("\nURB:%d", i);
+			break;
+		}
+	}
+
+	if (urb == NULL) {
+		dbg("%s - no more free urbs", __FUNCTION__);
+		goto exit;
+	}
+
+	if (urb->transfer_buffer == NULL) {
+		urb->transfer_buffer =
+		    kmalloc(URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);
+
+		if (urb->transfer_buffer == NULL) {
+			err("%s no more kernel memory...", __FUNCTION__);
+			goto exit;
+		}
+	}
+	transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);
+
+	if (from_user) {
+		if (copy_from_user
+		    (urb->transfer_buffer, current_position, transfer_size)) {
+			bytes_sent = -EFAULT;
+			goto exit;
+		}
+	} else {
+		memcpy(urb->transfer_buffer, current_position, transfer_size);
+	}
+
+	/* fill urb with data and submit  */
+	usb_fill_bulk_urb(urb,
+			  serial->dev,
+			  usb_sndbulkpipe(serial->dev,
+					  port->bulk_out_endpointAddress),
+			  urb->transfer_buffer,
+			  transfer_size,
+			  mos7840_bulk_out_data_callback, mos7840_port);
+
+	data1 = urb->transfer_buffer;
+	dbg("\nbulkout endpoint is %d", port->bulk_out_endpointAddress);
+
+	/* send it down the pipe */
+	status = usb_submit_urb(urb, GFP_ATOMIC);
+
+	if (status) {
+		err("%s - usb_submit_urb(write bulk) failed with status = %d",
+		    __FUNCTION__, status);
+		bytes_sent = status;
+		goto exit;
+	}
+	bytes_sent = transfer_size;
+	mos7840_port->icount.tx += transfer_size;
+	dbg("mos7840_port->icount.tx is %d:\n", mos7840_port->icount.tx);
+      exit:
+
+	return bytes_sent;
+
+}
+
+/*****************************************************************************
+ * mos7840_throttle
+ *	this function is called by the tty driver when it wants to stop the data
+ *	being read from the port.
+ *****************************************************************************/
+
+static void mos7840_throttle(struct usb_serial_port *port)
+{
+	struct moschip_port *mos7840_port;
+	struct tty_struct *tty;
+	int status;
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Invalid port \n");
+		return;
+	}
+
+	dbg("- port %d\n", port->number);
+
+	mos7840_port = mos7840_get_port_private(port);
+
+	if (mos7840_port == NULL)
+		return;
+
+	if (!mos7840_port->open) {
+		dbg("%s\n", "port not opened");
+		return;
+	}
+
+	dbg("%s", "Entering .......... \n");
+
+	tty = port->tty;
+	if (!tty) {
+		dbg("%s - no tty available", __FUNCTION__);
+		return;
+	}
+
+	/* if we are implementing XON/XOFF, send the stop character */
+	if (I_IXOFF(tty)) {
+		unsigned char stop_char = STOP_CHAR(tty);
+		status = mos7840_write(port, &stop_char, 1);
+		if (status <= 0) {
+			return;
+		}
+	}
+
+	/* if we are implementing RTS/CTS, toggle that line */
+	if (tty->termios->c_cflag & CRTSCTS) {
+		mos7840_port->shadowMCR &= ~MCR_RTS;
+		status = 0;
+		status =
+		    mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
+					 mos7840_port->shadowMCR);
+
+		if (status < 0) {
+			return;
+		}
+	}
+
+	return;
+}
+
+/*****************************************************************************
+ * mos7840_unthrottle
+ *	this function is called by the tty driver when it wants to resume the data
+ *	being read from the port (called after SerialThrottle is called)
+ *****************************************************************************/
+static void mos7840_unthrottle(struct usb_serial_port *port)
+{
+	struct tty_struct *tty;
+	int status;
+	struct moschip_port *mos7840_port = mos7840_get_port_private(port);
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Invalid port \n");
+		return;
+	}
+
+	if (mos7840_port == NULL)
+		return;
+
+	if (!mos7840_port->open) {
+		dbg("%s - port not opened", __FUNCTION__);
+		return;
+	}
+
+	dbg("%s", "Entering .......... \n");
+
+	tty = port->tty;
+	if (!tty) {
+		dbg("%s - no tty available", __FUNCTION__);
+		return;
+	}
+
+	/* if we are implementing XON/XOFF, send the start character */
+	if (I_IXOFF(tty)) {
+		unsigned char start_char = START_CHAR(tty);
+		status = mos7840_write(port, &start_char, 1);
+		if (status <= 0) {
+			return;
+		}
+	}
+
+	/* if we are implementing RTS/CTS, toggle that line */
+	if (tty->termios->c_cflag & CRTSCTS) {
+		mos7840_port->shadowMCR |= MCR_RTS;
+		status = 0;
+		status =
+		    mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
+					 mos7840_port->shadowMCR);
+		if (status < 0) {
+			return;
+		}
+	}
+
+	return;
+}
+
+static int mos7840_tiocmget(struct usb_serial_port *port, struct file *file)
+{
+	struct moschip_port *mos7840_port;
+	unsigned int result;
+	__u16 msr;
+	__u16 mcr;
+	int status = 0;
+	mos7840_port = mos7840_get_port_private(port);
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	if (mos7840_port == NULL)
+		return -ENODEV;
+
+	status = mos7840_get_uart_reg(port, MODEM_STATUS_REGISTER, &msr);
+	status = mos7840_get_uart_reg(port, MODEM_CONTROL_REGISTER, &mcr);
+	result = ((mcr & MCR_DTR) ? TIOCM_DTR : 0)
+	    | ((mcr & MCR_RTS) ? TIOCM_RTS : 0)
+	    | ((mcr & MCR_LOOPBACK) ? TIOCM_LOOP : 0)
+	    | ((msr & MOS7840_MSR_CTS) ? TIOCM_CTS : 0)
+	    | ((msr & MOS7840_MSR_CD) ? TIOCM_CAR : 0)
+	    | ((msr & MOS7840_MSR_RI) ? TIOCM_RI : 0)
+	    | ((msr & MOS7840_MSR_DSR) ? TIOCM_DSR : 0);
+
+	dbg("%s - 0x%04X", __FUNCTION__, result);
+
+	return result;
+}
+
+static int mos7840_tiocmset(struct usb_serial_port *port, struct file *file,
+			    unsigned int set, unsigned int clear)
+{
+	struct moschip_port *mos7840_port;
+	unsigned int mcr;
+	unsigned int status;
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	mos7840_port = mos7840_get_port_private(port);
+
+	if (mos7840_port == NULL)
+		return -ENODEV;
+
+	mcr = mos7840_port->shadowMCR;
+	if (clear & TIOCM_RTS)
+		mcr &= ~MCR_RTS;
+	if (clear & TIOCM_DTR)
+		mcr &= ~MCR_DTR;
+	if (clear & TIOCM_LOOP)
+		mcr &= ~MCR_LOOPBACK;
+
+	if (set & TIOCM_RTS)
+		mcr |= MCR_RTS;
+	if (set & TIOCM_DTR)
+		mcr |= MCR_DTR;
+	if (set & TIOCM_LOOP)
+		mcr |= MCR_LOOPBACK;
+
+	mos7840_port->shadowMCR = mcr;
+
+	status = 0;
+	status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, mcr);
+	if (status < 0) {
+		dbg("setting MODEM_CONTROL_REGISTER Failed\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+/*****************************************************************************
+ * mos7840_calc_baud_rate_divisor
+ *	this function calculates the proper baud rate divisor for the specified
+ *	baud rate.
+ *****************************************************************************/
+static int mos7840_calc_baud_rate_divisor(int baudRate, int *divisor,
+					  __u16 * clk_sel_val)
+{
+
+	dbg("%s - %d", __FUNCTION__, baudRate);
+
+	if (baudRate <= 115200) {
+		*divisor = 115200 / baudRate;
+		*clk_sel_val = 0x0;
+	}
+	if ((baudRate > 115200) && (baudRate <= 230400)) {
+		*divisor = 230400 / baudRate;
+		*clk_sel_val = 0x10;
+	} else if ((baudRate > 230400) && (baudRate <= 403200)) {
+		*divisor = 403200 / baudRate;
+		*clk_sel_val = 0x20;
+	} else if ((baudRate > 403200) && (baudRate <= 460800)) {
+		*divisor = 460800 / baudRate;
+		*clk_sel_val = 0x30;
+	} else if ((baudRate > 460800) && (baudRate <= 806400)) {
+		*divisor = 806400 / baudRate;
+		*clk_sel_val = 0x40;
+	} else if ((baudRate > 806400) && (baudRate <= 921600)) {
+		*divisor = 921600 / baudRate;
+		*clk_sel_val = 0x50;
+	} else if ((baudRate > 921600) && (baudRate <= 1572864)) {
+		*divisor = 1572864 / baudRate;
+		*clk_sel_val = 0x60;
+	} else if ((baudRate > 1572864) && (baudRate <= 3145728)) {
+		*divisor = 3145728 / baudRate;
+		*clk_sel_val = 0x70;
+	}
+	return 0;
+
+#ifdef NOTMCS7840
+
+	for (i = 0; i < ARRAY_SIZE(mos7840_divisor_table); i++) {
+		if (mos7840_divisor_table[i].BaudRate == baudrate) {
+			*divisor = mos7840_divisor_table[i].Divisor;
+			return 0;
+		}
+	}
+
+	/* After trying for all the standard baud rates    *
+	 * Try calculating the divisor for this baud rate  */
+
+	if (baudrate > 75 && baudrate < 230400) {
+		/* get the divisor */
+		custom = (__u16) (230400L / baudrate);
+
+		/* Check for round off */
+		round1 = (__u16) (2304000L / baudrate);
+		round = (__u16) (round1 - (custom * 10));
+		if (round > 4) {
+			custom++;
+		}
+		*divisor = custom;
+
+		dbg(" Baud %d = %d\n", baudrate, custom);
+		return 0;
+	}
+
+	dbg("%s\n", " Baud calculation Failed...");
+	return -1;
+#endif
+}
+
+/*****************************************************************************
+ * mos7840_send_cmd_write_baud_rate
+ *	this function sends the proper command to change the baud rate of the
+ *	specified port.
+ *****************************************************************************/
+
+static int mos7840_send_cmd_write_baud_rate(struct moschip_port *mos7840_port,
+					    int baudRate)
+{
+	int divisor = 0;
+	int status;
+	__u16 Data;
+	unsigned char number;
+	__u16 clk_sel_val;
+	struct usb_serial_port *port;
+
+	if (mos7840_port == NULL)
+		return -1;
+
+	port = (struct usb_serial_port *)mos7840_port->port;
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Invalid port \n");
+		return -1;
+	}
+
+	if (mos7840_serial_paranoia_check(port->serial, __FUNCTION__)) {
+		dbg("%s", "Invalid Serial \n");
+		return -1;
+	}
+
+	dbg("%s", "Entering .......... \n");
+
+	number = mos7840_port->port->number - mos7840_port->port->serial->minor;
+
+	dbg("%s - port = %d, baud = %d", __FUNCTION__,
+	    mos7840_port->port->number, baudRate);
+	//reset clk_uart_sel in spregOffset
+	if (baudRate > 115200) {
+#ifdef HW_flow_control
+		//NOTE: need to see the pther register to modify
+		//setting h/w flow control bit to 1;
+		status = 0;
+		Data = 0x2b;
+		mos7840_port->shadowMCR = Data;
+		status =
+		    mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
+		if (status < 0) {
+			dbg("Writing spreg failed in set_serial_baud\n");
+			return -1;
+		}
+#endif
+
+	} else {
+#ifdef HW_flow_control
+		//setting h/w flow control bit to 0;
+		status = 0;
+		Data = 0xb;
+		mos7840_port->shadowMCR = Data;
+		status =
+		    mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
+		if (status < 0) {
+			dbg("Writing spreg failed in set_serial_baud\n");
+			return -1;
+		}
+#endif
+
+	}
+
+	if (1)			//baudRate <= 115200)
+	{
+		clk_sel_val = 0x0;
+		Data = 0x0;
+		status = 0;
+		status =
+		    mos7840_calc_baud_rate_divisor(baudRate, &divisor,
+						   &clk_sel_val);
+		status =
+		    mos7840_get_reg_sync(port, mos7840_port->SpRegOffset,
+					 &Data);
+		if (status < 0) {
+			dbg("reading spreg failed in set_serial_baud\n");
+			return -1;
+		}
+		Data = (Data & 0x8f) | clk_sel_val;
+		status = 0;
+		status =
+		    mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
+		if (status < 0) {
+			dbg("Writing spreg failed in set_serial_baud\n");
+			return -1;
+		}
+		/* Calculate the Divisor */
+
+		if (status) {
+			err("%s - bad baud rate", __FUNCTION__);
+			dbg("%s\n", "bad baud rate");
+			return status;
+		}
+		/* Enable access to divisor latch */
+		Data = mos7840_port->shadowLCR | SERIAL_LCR_DLAB;
+		mos7840_port->shadowLCR = Data;
+		mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
+
+		/* Write the divisor */
+		Data = (unsigned char)(divisor & 0xff);
+		dbg("set_serial_baud Value to write DLL is %x\n", Data);
+		mos7840_set_uart_reg(port, DIVISOR_LATCH_LSB, Data);
+
+		Data = (unsigned char)((divisor & 0xff00) >> 8);
+		dbg("set_serial_baud Value to write DLM is %x\n", Data);
+		mos7840_set_uart_reg(port, DIVISOR_LATCH_MSB, Data);
+
+		/* Disable access to divisor latch */
+		Data = mos7840_port->shadowLCR & ~SERIAL_LCR_DLAB;
+		mos7840_port->shadowLCR = Data;
+		mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
+
+	}
+
+	return status;
+}
+
+/*****************************************************************************
+ * mos7840_change_port_settings
+ *	This routine is called to set the UART on the device to match
+ *      the specified new settings.
+ *****************************************************************************/
+
+static void mos7840_change_port_settings(struct moschip_port *mos7840_port,
+					 struct termios *old_termios)
+{
+	struct tty_struct *tty;
+	int baud;
+	unsigned cflag;
+	unsigned iflag;
+	__u8 lData;
+	__u8 lParity;
+	__u8 lStop;
+	int status;
+	__u16 Data;
+	struct usb_serial_port *port;
+	struct usb_serial *serial;
+
+	if (mos7840_port == NULL)
+		return;
+
+	port = (struct usb_serial_port *)mos7840_port->port;
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Invalid port \n");
+		return;
+	}
+
+	if (mos7840_serial_paranoia_check(port->serial, __FUNCTION__)) {
+		dbg("%s", "Invalid Serial \n");
+		return;
+	}
+
+	serial = port->serial;
+
+	dbg("%s - port %d", __FUNCTION__, mos7840_port->port->number);
+
+	if (!mos7840_port->open) {
+		dbg("%s - port not opened", __FUNCTION__);
+		return;
+	}
+
+	tty = mos7840_port->port->tty;
+
+	if ((!tty) || (!tty->termios)) {
+		dbg("%s - no tty structures", __FUNCTION__);
+		return;
+	}
+
+	dbg("%s", "Entering .......... \n");
+
+	lData = LCR_BITS_8;
+	lStop = LCR_STOP_1;
+	lParity = LCR_PAR_NONE;
+
+	cflag = tty->termios->c_cflag;
+	iflag = tty->termios->c_iflag;
+
+	/* Change the number of bits */
+	if (cflag & CSIZE) {
+		switch (cflag & CSIZE) {
+		case CS5:
+			lData = LCR_BITS_5;
+			break;
+
+		case CS6:
+			lData = LCR_BITS_6;
+			break;
+
+		case CS7:
+			lData = LCR_BITS_7;
+			break;
+		default:
+		case CS8:
+			lData = LCR_BITS_8;
+			break;
+		}
+	}
+	/* Change the Parity bit */
+	if (cflag & PARENB) {
+		if (cflag & PARODD) {
+			lParity = LCR_PAR_ODD;
+			dbg("%s - parity = odd", __FUNCTION__);
+		} else {
+			lParity = LCR_PAR_EVEN;
+			dbg("%s - parity = even", __FUNCTION__);
+		}
+
+	} else {
+		dbg("%s - parity = none", __FUNCTION__);
+	}
+
+	if (cflag & CMSPAR) {
+		lParity = lParity | 0x20;
+	}
+
+	/* Change the Stop bit */
+	if (cflag & CSTOPB) {
+		lStop = LCR_STOP_2;
+		dbg("%s - stop bits = 2", __FUNCTION__);
+	} else {
+		lStop = LCR_STOP_1;
+		dbg("%s - stop bits = 1", __FUNCTION__);
+	}
+
+	/* Update the LCR with the correct value */
+	mos7840_port->shadowLCR &=
+	    ~(LCR_BITS_MASK | LCR_STOP_MASK | LCR_PAR_MASK);
+	mos7840_port->shadowLCR |= (lData | lParity | lStop);
+
+	dbg("mos7840_change_port_settings mos7840_port->shadowLCR is %x\n",
+	    mos7840_port->shadowLCR);
+	/* Disable Interrupts */
+	Data = 0x00;
+	mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);
+
+	Data = 0x00;
+	mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
+
+	Data = 0xcf;
+	mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
+
+	/* Send the updated LCR value to the mos7840 */
+	Data = mos7840_port->shadowLCR;
+
+	mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
+
+	Data = 0x00b;
+	mos7840_port->shadowMCR = Data;
+	mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
+	Data = 0x00b;
+	mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
+
+	/* set up the MCR register and send it to the mos7840 */
+
+	mos7840_port->shadowMCR = MCR_MASTER_IE;
+	if (cflag & CBAUD) {
+		mos7840_port->shadowMCR |= (MCR_DTR | MCR_RTS);
+	}
+
+	if (cflag & CRTSCTS) {
+		mos7840_port->shadowMCR |= (MCR_XON_ANY);
+
+	} else {
+		mos7840_port->shadowMCR &= ~(MCR_XON_ANY);
+	}
+
+	Data = mos7840_port->shadowMCR;
+	mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
+
+	/* Determine divisor based on baud rate */
+	baud = tty_get_baud_rate(tty);
+
+	if (!baud) {
+		/* pick a default, any default... */
+		dbg("%s\n", "Picked default baud...");
+		baud = 9600;
+	}
+
+	dbg("%s - baud rate = %d", __FUNCTION__, baud);
+	status = mos7840_send_cmd_write_baud_rate(mos7840_port, baud);
+
+	/* Enable Interrupts */
+	Data = 0x0c;
+	mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);
+
+	if (mos7840_port->read_urb->status != -EINPROGRESS) {
+		mos7840_port->read_urb->dev = serial->dev;
+
+		status = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
+
+		if (status) {
+			dbg(" usb_submit_urb(read bulk) failed, status = %d",
+			    status);
+		}
+	}
+	wake_up(&mos7840_port->delta_msr_wait);
+	mos7840_port->delta_msr_cond = 1;
+	dbg("mos7840_change_port_settings mos7840_port->shadowLCR is End %x\n",
+	    mos7840_port->shadowLCR);
+
+	return;
+}
+
+/*****************************************************************************
+ * mos7840_set_termios
+ *	this function is called by the tty driver when it wants to change
+ *	the termios structure
+ *****************************************************************************/
+
+static void mos7840_set_termios(struct usb_serial_port *port,
+				struct termios *old_termios)
+{
+	int status;
+	unsigned int cflag;
+	struct usb_serial *serial;
+	struct moschip_port *mos7840_port;
+	struct tty_struct *tty;
+	dbg("mos7840_set_termios: START\n");
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Invalid port \n");
+		return;
+	}
+
+	serial = port->serial;
+
+	if (mos7840_serial_paranoia_check(serial, __FUNCTION__)) {
+		dbg("%s", "Invalid Serial \n");
+		return;
+	}
+
+	mos7840_port = mos7840_get_port_private(port);
+
+	if (mos7840_port == NULL)
+		return;
+
+	tty = port->tty;
+
+	if (!port->tty || !port->tty->termios) {
+		dbg("%s - no tty or termios", __FUNCTION__);
+		return;
+	}
+
+	if (!mos7840_port->open) {
+		dbg("%s - port not opened", __FUNCTION__);
+		return;
+	}
+
+	dbg("%s\n", "setting termios - ");
+
+	cflag = tty->termios->c_cflag;
+
+	if (!cflag) {
+		dbg("%s %s\n", __FUNCTION__, "cflag is NULL");
+		return;
+	}
+
+	/* check that they really want us to change something */
+	if (old_termios) {
+		if ((cflag == old_termios->c_cflag) &&
+		    (RELEVANT_IFLAG(tty->termios->c_iflag) ==
+		     RELEVANT_IFLAG(old_termios->c_iflag))) {
+			dbg("%s\n", "Nothing to change");
+			return;
+		}
+	}
+
+	dbg("%s - clfag %08x iflag %08x", __FUNCTION__,
+	    tty->termios->c_cflag, RELEVANT_IFLAG(tty->termios->c_iflag));
+
+	if (old_termios) {
+		dbg("%s - old clfag %08x old iflag %08x", __FUNCTION__,
+		    old_termios->c_cflag, RELEVANT_IFLAG(old_termios->c_iflag));
+	}
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	/* change the port settings to the new ones specified */
+
+	mos7840_change_port_settings(mos7840_port, old_termios);
+
+	if (!mos7840_port->read_urb) {
+		dbg("%s", "URB KILLED !!!!!\n");
+		return;
+	}
+
+	if (mos7840_port->read_urb->status != -EINPROGRESS) {
+		mos7840_port->read_urb->dev = serial->dev;
+		status = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
+		if (status) {
+			dbg(" usb_submit_urb(read bulk) failed, status = %d",
+			    status);
+		}
+	}
+	return;
+}
+
+/*****************************************************************************
+ * mos7840_get_lsr_info - get line status register info
+ *
+ * Purpose: Let user call ioctl() to get info when the UART physically
+ * 	    is emptied.  On bus types like RS485, the transmitter must
+ * 	    release the bus after transmitting. This must be done when
+ * 	    the transmit shift register is empty, not be done when the
+ * 	    transmit holding register is empty.  This functionality
+ * 	    allows an RS485 driver to be written in user space.
+ *****************************************************************************/
+
+static int mos7840_get_lsr_info(struct moschip_port *mos7840_port,
+				unsigned int *value)
+{
+	int count;
+	unsigned int result = 0;
+
+	count = mos7840_chars_in_buffer(mos7840_port->port);
+	if (count == 0) {
+		dbg("%s -- Empty", __FUNCTION__);
+		result = TIOCSER_TEMT;
+	}
+
+	if (copy_to_user(value, &result, sizeof(int)))
+		return -EFAULT;
+	return 0;
+}
+
+/*****************************************************************************
+ * mos7840_get_bytes_avail - get number of bytes available
+ *
+ * Purpose: Let user call ioctl to get the count of number of bytes available.
+ *****************************************************************************/
+
+static int mos7840_get_bytes_avail(struct moschip_port *mos7840_port,
+				   unsigned int *value)
+{
+	unsigned int result = 0;
+	struct tty_struct *tty = mos7840_port->port->tty;
+
+	if (!tty)
+		return -ENOIOCTLCMD;
+
+	result = tty->read_cnt;
+
+	dbg("%s(%d) = %d", __FUNCTION__, mos7840_port->port->number, result);
+	if (copy_to_user(value, &result, sizeof(int)))
+		return -EFAULT;
+
+	return -ENOIOCTLCMD;
+}
+
+/*****************************************************************************
+ * mos7840_set_modem_info
+ *      function to set modem info
+ *****************************************************************************/
+
+static int mos7840_set_modem_info(struct moschip_port *mos7840_port,
+				  unsigned int cmd, unsigned int *value)
+{
+	unsigned int mcr;
+	unsigned int arg;
+	__u16 Data;
+	int status;
+	struct usb_serial_port *port;
+
+	if (mos7840_port == NULL)
+		return -1;
+
+	port = (struct usb_serial_port *)mos7840_port->port;
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Invalid port \n");
+		return -1;
+	}
+
+	mcr = mos7840_port->shadowMCR;
+
+	if (copy_from_user(&arg, value, sizeof(int)))
+		return -EFAULT;
+
+	switch (cmd) {
+	case TIOCMBIS:
+		if (arg & TIOCM_RTS)
+			mcr |= MCR_RTS;
+		if (arg & TIOCM_DTR)
+			mcr |= MCR_RTS;
+		if (arg & TIOCM_LOOP)
+			mcr |= MCR_LOOPBACK;
+		break;
+
+	case TIOCMBIC:
+		if (arg & TIOCM_RTS)
+			mcr &= ~MCR_RTS;
+		if (arg & TIOCM_DTR)
+			mcr &= ~MCR_RTS;
+		if (arg & TIOCM_LOOP)
+			mcr &= ~MCR_LOOPBACK;
+		break;
+
+	case TIOCMSET:
+		/* turn off the RTS and DTR and LOOPBACK
+		 * and then only turn on what was asked to */
+		mcr &= ~(MCR_RTS | MCR_DTR | MCR_LOOPBACK);
+		mcr |= ((arg & TIOCM_RTS) ? MCR_RTS : 0);
+		mcr |= ((arg & TIOCM_DTR) ? MCR_DTR : 0);
+		mcr |= ((arg & TIOCM_LOOP) ? MCR_LOOPBACK : 0);
+		break;
+	}
+
+	mos7840_port->shadowMCR = mcr;
+
+	Data = mos7840_port->shadowMCR;
+	status = 0;
+	status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
+	if (status < 0) {
+		dbg("setting MODEM_CONTROL_REGISTER Failed\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+/*****************************************************************************
+ * mos7840_get_modem_info
+ *      function to get modem info
+ *****************************************************************************/
+
+static int mos7840_get_modem_info(struct moschip_port *mos7840_port,
+				  unsigned int *value)
+{
+	unsigned int result = 0;
+	__u16 msr;
+	unsigned int mcr = mos7840_port->shadowMCR;
+	int status = 0;
+	status =
+	    mos7840_get_uart_reg(mos7840_port->port, MODEM_STATUS_REGISTER,
+				 &msr);
+	result = ((mcr & MCR_DTR) ? TIOCM_DTR : 0)	/* 0x002 */
+	    |((mcr & MCR_RTS) ? TIOCM_RTS : 0)	/* 0x004 */
+	    |((msr & MOS7840_MSR_CTS) ? TIOCM_CTS : 0)	/* 0x020 */
+	    |((msr & MOS7840_MSR_CD) ? TIOCM_CAR : 0)	/* 0x040 */
+	    |((msr & MOS7840_MSR_RI) ? TIOCM_RI : 0)	/* 0x080 */
+	    |((msr & MOS7840_MSR_DSR) ? TIOCM_DSR : 0);	/* 0x100 */
+
+	dbg("%s -- %x", __FUNCTION__, result);
+
+	if (copy_to_user(value, &result, sizeof(int)))
+		return -EFAULT;
+	return 0;
+}
+
+/*****************************************************************************
+ * mos7840_get_serial_info
+ *      function to get information about serial port
+ *****************************************************************************/
+
+static int mos7840_get_serial_info(struct moschip_port *mos7840_port,
+				   struct serial_struct *retinfo)
+{
+	struct serial_struct tmp;
+
+	if (mos7840_port == NULL)
+		return -1;
+
+	if (!retinfo)
+		return -EFAULT;
+
+	memset(&tmp, 0, sizeof(tmp));
+
+	tmp.type = PORT_16550A;
+	tmp.line = mos7840_port->port->serial->minor;
+	tmp.port = mos7840_port->port->number;
+	tmp.irq = 0;
+	tmp.flags = ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
+	tmp.xmit_fifo_size = NUM_URBS * URB_TRANSFER_BUFFER_SIZE;
+	tmp.baud_base = 9600;
+	tmp.close_delay = 5 * HZ;
+	tmp.closing_wait = 30 * HZ;
+
+	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
+		return -EFAULT;
+	return 0;
+}
+
+/*****************************************************************************
+ * SerialIoctl
+ *	this function handles any ioctl calls to the driver
+ *****************************************************************************/
+
+static int mos7840_ioctl(struct usb_serial_port *port, struct file *file,
+			 unsigned int cmd, unsigned long arg)
+{
+	struct moschip_port *mos7840_port;
+	struct tty_struct *tty;
+
+	struct async_icount cnow;
+	struct async_icount cprev;
+	struct serial_icounter_struct icount;
+	int mosret = 0;
+	int retval;
+	struct tty_ldisc *ld;
+
+	if (mos7840_port_paranoia_check(port, __FUNCTION__)) {
+		dbg("%s", "Invalid port \n");
+		return -1;
+	}
+
+	mos7840_port = mos7840_get_port_private(port);
+	tty = mos7840_port->port->tty;
+
+	if (mos7840_port == NULL)
+		return -1;
+
+	dbg("%s - port %d, cmd = 0x%x", __FUNCTION__, port->number, cmd);
+
+	switch (cmd) {
+		/* return number of bytes available */
+
+	case TIOCINQ:
+		dbg("%s (%d) TIOCINQ", __FUNCTION__, port->number);
+		return mos7840_get_bytes_avail(mos7840_port,
+					       (unsigned int *)arg);
+		break;
+
+	case TIOCOUTQ:
+		dbg("%s (%d) TIOCOUTQ", __FUNCTION__, port->number);
+		return put_user(tty->driver->chars_in_buffer ?
+				tty->driver->chars_in_buffer(tty) : 0,
+				(int __user *)arg);
+		break;
+
+	case TCFLSH:
+		retval = tty_check_change(tty);
+		if (retval)
+			return retval;
+
+		ld = tty_ldisc_ref(tty);
+		switch (arg) {
+		case TCIFLUSH:
+			if (ld && ld->flush_buffer)
+				ld->flush_buffer(tty);
+			break;
+		case TCIOFLUSH:
+			if (ld && ld->flush_buffer)
+				ld->flush_buffer(tty);
+			/* fall through */
+		case TCOFLUSH:
+			if (tty->driver->flush_buffer)
+				tty->driver->flush_buffer(tty);
+			break;
+		default:
+			tty_ldisc_deref(ld);
+			return -EINVAL;
+		}
+		tty_ldisc_deref(ld);
+		return 0;
+
+	case TCGETS:
+		if (kernel_termios_to_user_termios
+		    ((struct termios __user *)arg, tty->termios))
+			return -EFAULT;
+		return 0;
+
+	case TIOCSERGETLSR:
+		dbg("%s (%d) TIOCSERGETLSR", __FUNCTION__, port->number);
+		return mos7840_get_lsr_info(mos7840_port, (unsigned int *)arg);
+		return 0;
+
+	case TIOCMBIS:
+	case TIOCMBIC:
+	case TIOCMSET:
+		dbg("%s (%d) TIOCMSET/TIOCMBIC/TIOCMSET", __FUNCTION__,
+		    port->number);
+		mosret =
+		    mos7840_set_modem_info(mos7840_port, cmd,
+					   (unsigned int *)arg);
+		return mosret;
+
+	case TIOCMGET:
+		dbg("%s (%d) TIOCMGET", __FUNCTION__, port->number);
+		return mos7840_get_modem_info(mos7840_port,
+					      (unsigned int *)arg);
+
+	case TIOCGSERIAL:
+		dbg("%s (%d) TIOCGSERIAL", __FUNCTION__, port->number);
+		return mos7840_get_serial_info(mos7840_port,
+					       (struct serial_struct *)arg);
+
+	case TIOCSSERIAL:
+		dbg("%s (%d) TIOCSSERIAL", __FUNCTION__, port->number);
+		break;
+
+	case TIOCMIWAIT:
+		dbg("%s (%d) TIOCMIWAIT", __FUNCTION__, port->number);
+		cprev = mos7840_port->icount;
+		while (1) {
+			//interruptible_sleep_on(&mos7840_port->delta_msr_wait);
+			mos7840_port->delta_msr_cond = 0;
+			wait_event_interruptible(mos7840_port->delta_msr_wait,
+						 (mos7840_port->
+						  delta_msr_cond == 1));
+
+			/* see if a signal did it */
+			if (signal_pending(current))
+				return -ERESTARTSYS;
+			cnow = mos7840_port->icount;
+			if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
+			    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
+				return -EIO;	/* no change => error */
+			if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
+			    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
+			    ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
+			    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
+				return 0;
+			}
+			cprev = cnow;
+		}
+		/* NOTREACHED */
+		break;
+
+	case TIOCGICOUNT:
+		cnow = mos7840_port->icount;
+		icount.cts = cnow.cts;
+		icount.dsr = cnow.dsr;
+		icount.rng = cnow.rng;
+		icount.dcd = cnow.dcd;
+		icount.rx = cnow.rx;
+		icount.tx = cnow.tx;
+		icount.frame = cnow.frame;
+		icount.overrun = cnow.overrun;
+		icount.parity = cnow.parity;
+		icount.brk = cnow.brk;
+		icount.buf_overrun = cnow.buf_overrun;
+
+		dbg("%s (%d) TIOCGICOUNT RX=%d, TX=%d", __FUNCTION__,
+		    port->number, icount.rx, icount.tx);
+		if (copy_to_user((void *)arg, &icount, sizeof(icount)))
+			return -EFAULT;
+		return 0;
+
+	case TIOCEXBAUD:
+		return 0;
+	default:
+		break;
+	}
+
+	return -ENOIOCTLCMD;
+}
+
+static int mos7840_calc_num_ports(struct usb_serial *serial)
+{
+
+	dbg("numberofendpoints: %d \n",
+	    (int)serial->interface->cur_altsetting->desc.bNumEndpoints);
+	dbg("numberofendpoints: %d \n",
+	    (int)serial->interface->altsetting->desc.bNumEndpoints);
+	if (serial->interface->cur_altsetting->desc.bNumEndpoints == 5) {
+		mos7840_num_ports = 2;
+		serial->type->num_ports = 2;
+	} else if (serial->interface->cur_altsetting->desc.bNumEndpoints == 9) {
+		mos7840_num_ports = 4;
+		serial->type->num_bulk_in = 4;
+		serial->type->num_bulk_out = 4;
+		serial->type->num_ports = 4;
+	}
+
+	return mos7840_num_ports;
+}
+
+/****************************************************************************
+ * mos7840_startup
+ ****************************************************************************/
+
+static int mos7840_startup(struct usb_serial *serial)
+{
+	struct moschip_port *mos7840_port;
+	struct usb_device *dev;
+	int i, status;
+
+	__u16 Data;
+	dbg("%s \n", " mos7840_startup :entering..........");
+
+	if (!serial) {
+		dbg("%s\n", "Invalid Handler");
+		return -1;
+	}
+
+	dev = serial->dev;
+
+	dbg("%s\n", "Entering...");
+
+	/* we set up the pointers to the endpoints in the mos7840_open *
+	 * function, as the structures aren't created yet.             */
+
+	/* set up port private structures */
+	for (i = 0; i < serial->num_ports; ++i) {
+		mos7840_port = kmalloc(sizeof(struct moschip_port), GFP_KERNEL);
+		if (mos7840_port == NULL) {
+			err("%s - Out of memory", __FUNCTION__);
+			return -ENOMEM;
+		}
+		memset(mos7840_port, 0, sizeof(struct moschip_port));
+
+		/* Initialize all port interrupt end point to port 0 int endpoint *
+		 * Our device has only one interrupt end point comman to all port */
+
+		mos7840_port->port = serial->port[i];
+		mos7840_set_port_private(serial->port[i], mos7840_port);
+
+		mos7840_port->port_num = ((serial->port[i]->number -
+					   (serial->port[i]->serial->minor)) +
+					  1);
+
+		if (mos7840_port->port_num == 1) {
+			mos7840_port->SpRegOffset = 0x0;
+			mos7840_port->ControlRegOffset = 0x1;
+			mos7840_port->DcrRegOffset = 0x4;
+		} else if ((mos7840_port->port_num == 2)
+			   && (mos7840_num_ports == 4)) {
+			mos7840_port->SpRegOffset = 0x8;
+			mos7840_port->ControlRegOffset = 0x9;
+			mos7840_port->DcrRegOffset = 0x16;
+		} else if ((mos7840_port->port_num == 2)
+			   && (mos7840_num_ports == 2)) {
+			mos7840_port->SpRegOffset = 0xa;
+			mos7840_port->ControlRegOffset = 0xb;
+			mos7840_port->DcrRegOffset = 0x19;
+		} else if ((mos7840_port->port_num == 3)
+			   && (mos7840_num_ports == 4)) {
+			mos7840_port->SpRegOffset = 0xa;
+			mos7840_port->ControlRegOffset = 0xb;
+			mos7840_port->DcrRegOffset = 0x19;
+		} else if ((mos7840_port->port_num == 4)
+			   && (mos7840_num_ports == 4)) {
+			mos7840_port->SpRegOffset = 0xc;
+			mos7840_port->ControlRegOffset = 0xd;
+			mos7840_port->DcrRegOffset = 0x1c;
+		}
+		mos7840_dump_serial_port(mos7840_port);
+
+		mos7840_set_port_private(serial->port[i], mos7840_port);
+
+		//enable rx_disable bit in control register
+
+		status =
+		    mos7840_get_reg_sync(serial->port[i],
+					 mos7840_port->ControlRegOffset, &Data);
+		if (status < 0) {
+			dbg("Reading ControlReg failed status-0x%x\n", status);
+			break;
+		} else
+			dbg("ControlReg Reading success val is %x, status%d\n",
+			    Data, status);
+		Data |= 0x08;	//setting driver done bit
+		Data |= 0x04;	//sp1_bit to have cts change reflect in modem status reg
+
+		//Data |= 0x20; //rx_disable bit
+		status = 0;
+		status =
+		    mos7840_set_reg_sync(serial->port[i],
+					 mos7840_port->ControlRegOffset, Data);
+		if (status < 0) {
+			dbg("Writing ControlReg failed(rx_disable) status-0x%x\n", status);
+			break;
+		} else
+			dbg("ControlReg Writing success(rx_disable) status%d\n",
+			    status);
+
+		//Write default values in DCR (i.e 0x01 in DCR0, 0x05 in DCR2 and 0x24 in DCR3
+		Data = 0x01;
+		status = 0;
+		status =
+		    mos7840_set_reg_sync(serial->port[i],
+					 (__u16) (mos7840_port->DcrRegOffset +
+						  0), Data);
+		if (status < 0) {
+			dbg("Writing DCR0 failed status-0x%x\n", status);
+			break;
+		} else
+			dbg("DCR0 Writing success status%d\n", status);
+
+		Data = 0x05;
+		status = 0;
+		status =
+		    mos7840_set_reg_sync(serial->port[i],
+					 (__u16) (mos7840_port->DcrRegOffset +
+						  1), Data);
+		if (status < 0) {
+			dbg("Writing DCR1 failed status-0x%x\n", status);
+			break;
+		} else
+			dbg("DCR1 Writing success status%d\n", status);
+
+		Data = 0x24;
+		status = 0;
+		status =
+		    mos7840_set_reg_sync(serial->port[i],
+					 (__u16) (mos7840_port->DcrRegOffset +
+						  2), Data);
+		if (status < 0) {
+			dbg("Writing DCR2 failed status-0x%x\n", status);
+			break;
+		} else
+			dbg("DCR2 Writing success status%d\n", status);
+
+		// write values in clkstart0x0 and clkmulti 0x20
+		Data = 0x0;
+		status = 0;
+		status =
+		    mos7840_set_reg_sync(serial->port[i],
+					 CLK_START_VALUE_REGISTER, Data);
+		if (status < 0) {
+			dbg("Writing CLK_START_VALUE_REGISTER failed status-0x%x\n", status);
+			break;
+		} else
+			dbg("CLK_START_VALUE_REGISTER Writing success status%d\n", status);
+
+		Data = 0x20;
+		status = 0;
+		status =
+		    mos7840_set_reg_sync(serial->port[i], CLK_MULTI_REGISTER,
+					 Data);
+		if (status < 0) {
+			dbg("Writing CLK_MULTI_REGISTER failed status-0x%x\n",
+			    status);
+			break;
+		} else
+			dbg("CLK_MULTI_REGISTER Writing success status%d\n",
+			    status);
+
+		//write value 0x0 to scratchpad register
+		Data = 0x00;
+		status = 0;
+		status =
+		    mos7840_set_uart_reg(serial->port[i], SCRATCH_PAD_REGISTER,
+					 Data);
+		if (status < 0) {
+			dbg("Writing SCRATCH_PAD_REGISTER failed status-0x%x\n",
+			    status);
+			break;
+		} else
+			dbg("SCRATCH_PAD_REGISTER Writing success status%d\n",
+			    status);
+
+		//Zero Length flag register
+		if ((mos7840_port->port_num != 1)
+		    && (mos7840_num_ports == 2)) {
+
+			Data = 0xff;
+			status = 0;
+			status = mos7840_set_reg_sync(serial->port[i],
+						      (__u16) (ZLP_REG1 +
+							       ((__u16)
+								mos7840_port->
+								port_num)),
+						      Data);
+			dbg("ZLIP offset%x\n",
+			    (__u16) (ZLP_REG1 +
+				     ((__u16) mos7840_port->port_num)));
+			if (status < 0) {
+				dbg("Writing ZLP_REG%d failed status-0x%x\n",
+				    i + 2, status);
+				break;
+			} else
+				dbg("ZLP_REG%d Writing success status%d\n",
+				    i + 2, status);
+		} else {
+			Data = 0xff;
+			status = 0;
+			status = mos7840_set_reg_sync(serial->port[i],
+						      (__u16) (ZLP_REG1 +
+							       ((__u16)
+								mos7840_port->
+								port_num) -
+							       0x1), Data);
+			dbg("ZLIP offset%x\n",
+			    (__u16) (ZLP_REG1 +
+				     ((__u16) mos7840_port->port_num) - 0x1));
+			if (status < 0) {
+				dbg("Writing ZLP_REG%d failed status-0x%x\n",
+				    i + 1, status);
+				break;
+			} else
+				dbg("ZLP_REG%d Writing success status%d\n",
+				    i + 1, status);
+
+		}
+		mos7840_port->control_urb = usb_alloc_urb(0, SLAB_ATOMIC);
+		mos7840_port->ctrl_buf = kmalloc(16, GFP_KERNEL);
+
+	}
+
+	//Zero Length flag enable
+	Data = 0x0f;
+	status = 0;
+	status = mos7840_set_reg_sync(serial->port[0], ZLP_REG5, Data);
+	if (status < 0) {
+		dbg("Writing ZLP_REG5 failed status-0x%x\n", status);
+		return -1;
+	} else
+		dbg("ZLP_REG5 Writing success status%d\n", status);
+
+	/* setting configuration feature to one */
+	usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
+			(__u8) 0x03, 0x00, 0x01, 0x00, 0x00, 0x00, 5 * HZ);
+	return 0;
+}
+
+/****************************************************************************
+ * mos7840_shutdown
+ *	This function is called whenever the device is removed from the usb bus.
+ ****************************************************************************/
+
+static void mos7840_shutdown(struct usb_serial *serial)
+{
+	int i;
+	struct moschip_port *mos7840_port;
+	dbg("%s \n", " shutdown :entering..........");
+
+	if (!serial) {
+		dbg("%s", "Invalid Handler \n");
+		return;
+	}
+
+	/*      check for the ports to be closed,close the ports and disconnect         */
+
+	/* free private structure allocated for serial port  *
+	 * stop reads and writes on all ports                */
+
+	for (i = 0; i < serial->num_ports; ++i) {
+		mos7840_port = mos7840_get_port_private(serial->port[i]);
+		kfree(mos7840_port->ctrl_buf);
+		usb_kill_urb(mos7840_port->control_urb);
+		kfree(mos7840_port);
+		mos7840_set_port_private(serial->port[i], NULL);
+	}
+
+	dbg("%s\n", "Thank u :: ");
+
+}
+
+static struct usb_serial_driver moschip7840_4port_device = {
+	.driver = {
+		   .owner = THIS_MODULE,
+		   .name = "mos7840",
+		   },
+	.description = DRIVER_DESC,
+	.id_table = moschip_port_id_table,
+	.num_interrupt_in = 1,	//NUM_DONT_CARE,//1,
+#ifdef check
+	.num_bulk_in = 4,
+	.num_bulk_out = 4,
+	.num_ports = 4,
+#endif
+	.open = mos7840_open,
+	.close = mos7840_close,
+	.write = mos7840_write,
+	.write_room = mos7840_write_room,
+	.chars_in_buffer = mos7840_chars_in_buffer,
+	.throttle = mos7840_throttle,
+	.unthrottle = mos7840_unthrottle,
+	.calc_num_ports = mos7840_calc_num_ports,
+#ifdef MCSSerialProbe
+	.probe = mos7840_serial_probe,
+#endif
+	.ioctl = mos7840_ioctl,
+	.set_termios = mos7840_set_termios,
+	.break_ctl = mos7840_break,
+	.tiocmget = mos7840_tiocmget,
+	.tiocmset = mos7840_tiocmset,
+	.attach = mos7840_startup,
+	.shutdown = mos7840_shutdown,
+	.read_bulk_callback = mos7840_bulk_in_callback,
+	.read_int_callback = mos7840_interrupt_callback,
+};
+
+static struct usb_driver io_driver = {
+	.name = "mos7840",
+	.probe = usb_serial_probe,
+	.disconnect = usb_serial_disconnect,
+	.id_table = moschip_id_table_combined,
+};
+
+/****************************************************************************
+ * moschip7840_init
+ *	This is called by the module subsystem, or on startup to initialize us
+ ****************************************************************************/
+static int __init moschip7840_init(void)
+{
+	int retval;
+
+	dbg("%s \n", " mos7840_init :entering..........");
+
+	/* Register with the usb serial */
+	retval = usb_serial_register(&moschip7840_4port_device);
+
+	if (retval)
+		goto failed_port_device_register;
+
+	dbg("%s\n", "Entring...");
+	info(DRIVER_DESC " " DRIVER_VERSION);
+
+	/* Register with the usb */
+	retval = usb_register(&io_driver);
+
+	if (retval)
+		goto failed_usb_register;
+
+	if (retval == 0) {
+		dbg("%s\n", "Leaving...");
+		return 0;
+	}
+
+      failed_usb_register:
+	usb_serial_deregister(&moschip7840_4port_device);
+
+      failed_port_device_register:
+
+	return retval;
+}
+
+/****************************************************************************
+ * moschip7840_exit
+ *	Called when the driver is about to be unloaded.
+ ****************************************************************************/
+static void __exit moschip7840_exit(void)
+{
+
+	dbg("%s \n", " mos7840_exit :entering..........");
+
+	usb_deregister(&io_driver);
+
+	usb_serial_deregister(&moschip7840_4port_device);
+
+	dbg("%s\n", "Entring...");
+}
+
+module_init(moschip7840_init);
+module_exit(moschip7840_exit);
+
+/* Module information */
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+module_param(debug, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Debug enabled or not");