/*
   * 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/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 <linux/uaccess.h>
  
  #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 MOS_WDR_TIMEOUT		5000	/* 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 */
  
  /* The native mos7840/7820 component */
  #define USB_VENDOR_ID_MOSCHIP           0x9710
  #define MOSCHIP_DEVICE_ID_7840          0x7840
  #define MOSCHIP_DEVICE_ID_7820          0x7820
  #define MOSCHIP_DEVICE_ID_7810          0x7810
  /* The native component can have its vendor/device id's overridden
   * in vendor-specific implementations.  Such devices can be handled
   * by making a change here, in id_table.
   */
  #define USB_VENDOR_ID_BANDB              0x0856
  #define BANDB_DEVICE_ID_USO9ML2_2        0xAC22
  #define BANDB_DEVICE_ID_USO9ML2_2P       0xBC00
  #define BANDB_DEVICE_ID_USO9ML2_4        0xAC24
  #define BANDB_DEVICE_ID_USO9ML2_4P       0xBC01
  #define BANDB_DEVICE_ID_US9ML2_2         0xAC29
  #define BANDB_DEVICE_ID_US9ML2_4         0xAC30
  #define BANDB_DEVICE_ID_USPTL4_2         0xAC31
  #define BANDB_DEVICE_ID_USPTL4_4         0xAC32
  #define BANDB_DEVICE_ID_USOPTL4_2        0xAC42
  #define BANDB_DEVICE_ID_USOPTL4_2P       0xBC02
  #define BANDB_DEVICE_ID_USOPTL4_4        0xAC44
  #define BANDB_DEVICE_ID_USOPTL4_4P       0xBC03
  #define BANDB_DEVICE_ID_USOPTL2_4        0xAC24
  
  /* This driver also supports
   * ATEN UC2324 device using Moschip MCS7840
   * ATEN UC2322 device using Moschip MCS7820
   */
  #define USB_VENDOR_ID_ATENINTL		0x0557
  #define ATENINTL_DEVICE_ID_UC2324	0x2011
  #define ATENINTL_DEVICE_ID_UC2322	0x7820
  
  /* Interrupt Routine 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 GPIO_REGISTER              ((__u16)(0x07))
  
  #define SERIAL_LCR_DLAB            ((__u16)(0x0080))
  
  /*
   * URB POOL related defines
   */
  #define NUM_URBS                        16	/* URB Count */
  #define URB_TRANSFER_BUFFER_SIZE        32	/* URB Size  */
  
  /* LED on/off milliseconds*/
  #define LED_ON_MS	500
  #define LED_OFF_MS	500
  
  enum mos7840_flag {
  	MOS7840_FLAG_CTRL_BUSY,
  	MOS7840_FLAG_LED_BUSY,
  };
  
  static const struct usb_device_id id_table[] = {
  	{USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7840)},
  	{USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7820)},
  	{USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7810)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USO9ML2_2)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USO9ML2_2P)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USO9ML2_4)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USO9ML2_4P)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_US9ML2_2)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_US9ML2_4)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USPTL4_2)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USPTL4_4)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_2)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_2P)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_4)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_4P)},
  	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL2_4)},
  	{USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2324)},
  	{USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2322)},
  	{}			/* terminating entry */
  };
  MODULE_DEVICE_TABLE(usb, id_table);
  
  /* 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;
  	char open_ports;
  	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;
  	struct usb_ctrlrequest *dr;
  	char *ctrl_buf;
  	int MsrLsr;
  
  	spinlock_t pool_lock;
  	struct urb *write_urb_pool[NUM_URBS];
  	char busy[NUM_URBS];
  	bool read_urb_busy;
  
  	/* For device(s) with LED indicator */
  	bool has_led;
  	struct timer_list led_timer1;	/* Timer for LED on */
  	struct timer_list led_timer2;	/* Timer for LED off */
  	struct urb *led_urb;
  	struct usb_ctrlrequest *led_dr;
  
  	unsigned long flags;
  };
  
  /*
   * 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;
  	dev_dbg(&port->dev, "mos7840_set_reg_sync offset is %x, value %x
  ", 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;
  	u8 *buf;
  
  	buf = kmalloc(VENDOR_READ_LENGTH, GFP_KERNEL);
  	if (!buf)
  		return -ENOMEM;
  
  	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
  			      MCS_RD_RTYPE, 0, reg, buf, VENDOR_READ_LENGTH,
  			      MOS_WDR_TIMEOUT);
  	*val = buf[0];
  	dev_dbg(&port->dev, "%s offset is %x, return val %x
  ", __func__, reg, *val);
  
  	kfree(buf);
  	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 (port->serial->num_ports == 4) {
  		val |= ((__u16)port->port_number + 1) << 8;
  	} else {
  		if (port->port_number == 0) {
  			val |= ((__u16)port->port_number + 1) << 8;
  		} else {
  			val |= ((__u16)port->port_number + 2) << 8;
  		}
  	}
  	dev_dbg(&port->dev, "%s application number is %x
  ", __func__, 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;
  	u8 *buf;
  
  	buf = kmalloc(VENDOR_READ_LENGTH, GFP_KERNEL);
  	if (!buf)
  		return -ENOMEM;
  
  	/* Wval  is same as application number */
  	if (port->serial->num_ports == 4) {
  		Wval = ((__u16)port->port_number + 1) << 8;
  	} else {
  		if (port->port_number == 0) {
  			Wval = ((__u16)port->port_number + 1) << 8;
  		} else {
  			Wval = ((__u16)port->port_number + 2) << 8;
  		}
  	}
  	dev_dbg(&port->dev, "%s application number is %x
  ", __func__, Wval);
  	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), MCS_RDREQ,
  			      MCS_RD_RTYPE, Wval, reg, buf, VENDOR_READ_LENGTH,
  			      MOS_WDR_TIMEOUT);
  	*val = buf[0];
  
  	kfree(buf);
  	return ret;
  }
  
  static void mos7840_dump_serial_port(struct usb_serial_port *port,
  				     struct moschip_port *mos7840_port)
  {
  
  	dev_dbg(&port->dev, "SpRegOffset is %2x
  ", mos7840_port->SpRegOffset);
  	dev_dbg(&port->dev, "ControlRegOffset is %2x
  ", mos7840_port->ControlRegOffset);
  	dev_dbg(&port->dev, "DCRRegOffset is %2x
  ", mos7840_port->DcrRegOffset);
  
  }
  
  /************************************************************************/
  /************************************************************************/
  /*             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 void mos7840_handle_new_msr(struct moschip_port *port, __u8 new_msr)
  {
  	struct moschip_port *mos7840_port;
  	struct async_icount *icount;
  	mos7840_port = port;
  	if (new_msr &
  	    (MOS_MSR_DELTA_CTS | MOS_MSR_DELTA_DSR | MOS_MSR_DELTA_RI |
  	     MOS_MSR_DELTA_CD)) {
  		icount = &mos7840_port->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++;
  
  		wake_up_interruptible(&port->port->port.delta_msr_wait);
  	}
  }
  
  static void mos7840_handle_new_lsr(struct moschip_port *port, __u8 new_lsr)
  {
  	struct async_icount *icount;
  
  	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->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++;
  }
  
  /************************************************************************/
  /************************************************************************/
  /*            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)
  {
  	unsigned char *data;
  	struct moschip_port *mos7840_port;
  	struct device *dev = &urb->dev->dev;
  	__u8 regval = 0x0;
  	int status = urb->status;
  
  	mos7840_port = urb->context;
  
  	switch (status) {
  	case 0:
  		/* success */
  		break;
  	case -ECONNRESET:
  	case -ENOENT:
  	case -ESHUTDOWN:
  		/* this urb is terminated, clean up */
  		dev_dbg(dev, "%s - urb shutting down with status: %d
  ", __func__, status);
  		goto out;
  	default:
  		dev_dbg(dev, "%s - nonzero urb status received: %d
  ", __func__, status);
  		goto out;
  	}
  
  	dev_dbg(dev, "%s urb buffer size is %d
  ", __func__, urb->actual_length);
  	dev_dbg(dev, "%s mos7840_port->MsrLsr is %d port %d
  ", __func__,
  		mos7840_port->MsrLsr, mos7840_port->port_num);
  	data = urb->transfer_buffer;
  	regval = (__u8) data[0];
  	dev_dbg(dev, "%s data is %x
  ", __func__, 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);
  out:
  	clear_bit_unlock(MOS7840_FLAG_CTRL_BUSY, &mos7840_port->flags);
  }
  
  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 = mcs->dr;
  	unsigned char *buffer = mcs->ctrl_buf;
  	int ret;
  
  	if (test_and_set_bit_lock(MOS7840_FLAG_CTRL_BUSY, &mcs->flags))
  		return -EBUSY;
  
  	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);
  	if (ret)
  		clear_bit_unlock(MOS7840_FLAG_CTRL_BUSY, &mcs->flags);
  
  	return ret;
  }
  
  static void mos7840_set_led_callback(struct urb *urb)
  {
  	switch (urb->status) {
  	case 0:
  		/* Success */
  		break;
  	case -ECONNRESET:
  	case -ENOENT:
  	case -ESHUTDOWN:
  		/* This urb is terminated, clean up */
  		dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d",
  			__func__, urb->status);
  		break;
  	default:
  		dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d",
  			__func__, urb->status);
  	}
  }
  
  static void mos7840_set_led_async(struct moschip_port *mcs, __u16 wval,
  				__u16 reg)
  {
  	struct usb_device *dev = mcs->port->serial->dev;
  	struct usb_ctrlrequest *dr = mcs->led_dr;
  
  	dr->bRequestType = MCS_WR_RTYPE;
  	dr->bRequest = MCS_WRREQ;
  	dr->wValue = cpu_to_le16(wval);
  	dr->wIndex = cpu_to_le16(reg);
  	dr->wLength = cpu_to_le16(0);
  
  	usb_fill_control_urb(mcs->led_urb, dev, usb_sndctrlpipe(dev, 0),
  		(unsigned char *)dr, NULL, 0, mos7840_set_led_callback, NULL);
  
  	usb_submit_urb(mcs->led_urb, GFP_ATOMIC);
  }
  
  static void mos7840_set_led_sync(struct usb_serial_port *port, __u16 reg,
  				__u16 val)
  {
  	struct usb_device *dev = port->serial->dev;
  
  	usb_control_msg(dev, usb_sndctrlpipe(dev, 0), MCS_WRREQ, MCS_WR_RTYPE,
  			val, reg, NULL, 0, MOS_WDR_TIMEOUT);
  }
  
  static void mos7840_led_off(unsigned long arg)
  {
  	struct moschip_port *mcs = (struct moschip_port *) arg;
  
  	/* Turn off LED */
  	mos7840_set_led_async(mcs, 0x0300, MODEM_CONTROL_REGISTER);
  	mod_timer(&mcs->led_timer2,
  				jiffies + msecs_to_jiffies(LED_OFF_MS));
  }
  
  static void mos7840_led_flag_off(unsigned long arg)
  {
  	struct moschip_port *mcs = (struct moschip_port *) arg;
  
  	clear_bit_unlock(MOS7840_FLAG_LED_BUSY, &mcs->flags);
  }
  
  static void mos7840_led_activity(struct usb_serial_port *port)
  {
  	struct moschip_port *mos7840_port = usb_get_serial_port_data(port);
  
  	if (test_and_set_bit_lock(MOS7840_FLAG_LED_BUSY, &mos7840_port->flags))
  		return;
  
  	mos7840_set_led_async(mos7840_port, 0x0301, MODEM_CONTROL_REGISTER);
  	mod_timer(&mos7840_port->led_timer1,
  				jiffies + msecs_to_jiffies(LED_ON_MS));
  }
  
  /*****************************************************************************
   * 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)
  {
  	int result;
  	int length;
  	struct moschip_port *mos7840_port;
  	struct usb_serial *serial;
  	__u16 Data;
  	unsigned char *data;
  	__u8 sp[5], st;
  	int i, rv = 0;
  	__u16 wval, wreg = 0;
  	int status = urb->status;
  
  	switch (status) {
  	case 0:
  		/* success */
  		break;
  	case -ECONNRESET:
  	case -ENOENT:
  	case -ESHUTDOWN:
  		/* this urb is terminated, clean up */
  		dev_dbg(&urb->dev->dev, "%s - urb shutting down with status: %d
  ",
  			__func__, status);
  		return;
  	default:
  		dev_dbg(&urb->dev->dev, "%s - nonzero urb status received: %d
  ",
  			__func__, status);
  		goto exit;
  	}
  
  	length = urb->actual_length;
  	data = urb->transfer_buffer;
  
  	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) {
  		dev_dbg(&urb->dev->dev, "%s", "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]->port_number + 1) << 8;
  		if (mos7840_port->open) {
  			if (sp[i] & 0x01) {
  				dev_dbg(&urb->dev->dev, "SP%d No Interrupt !!!
  ", i);
  			} else {
  				switch (sp[i] & 0x0f) {
  				case SERIAL_IIR_RLS:
  					dev_dbg(&urb->dev->dev, "Serial Port %d: Receiver status error or 
  ", i);
  					dev_dbg(&urb->dev->dev, "address bit detected in 9-bit mode
  ");
  					mos7840_port->MsrLsr = 1;
  					wreg = LINE_STATUS_REGISTER;
  					break;
  				case SERIAL_IIR_MS:
  					dev_dbg(&urb->dev->dev, "Serial Port %d: Modem status change
  ", i);
  					mos7840_port->MsrLsr = 0;
  					wreg = MODEM_STATUS_REGISTER;
  					break;
  				}
  				rv = mos7840_get_reg(mos7840_port, wval, wreg, &Data);
  			}
  		}
  	}
  	if (!(rv < 0))
  		/* the completion handler for the control urb will resubmit */
  		return;
  exit:
  	result = usb_submit_urb(urb, GFP_ATOMIC);
  	if (result) {
  		dev_err(&urb->dev->dev,
  			"%s - Error %d submitting interrupt urb
  ",
  			__func__, result);
  	}
  }
  
  static int mos7840_port_paranoia_check(struct usb_serial_port *port,
  				       const char *function)
  {
  	if (!port) {
  		pr_debug("%s - port == NULL
  ", function);
  		return -1;
  	}
  	if (!port->serial) {
  		pr_debug("%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) {
  		pr_debug("%s - serial == NULL
  ", function);
  		return -1;
  	}
  	if (!serial->type) {
  		pr_debug("%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)
  {
  	int retval;
  	unsigned char *data;
  	struct usb_serial *serial;
  	struct usb_serial_port *port;
  	struct moschip_port *mos7840_port;
  	int status = urb->status;
  
  	mos7840_port = urb->context;
  	if (!mos7840_port)
  		return;
  
  	if (status) {
  		dev_dbg(&urb->dev->dev, "nonzero read bulk status received: %d
  ", status);
  		mos7840_port->read_urb_busy = false;
  		return;
  	}
  
  	port = mos7840_port->port;
  	if (mos7840_port_paranoia_check(port, __func__)) {
  		mos7840_port->read_urb_busy = false;
  		return;
  	}
  
  	serial = mos7840_get_usb_serial(port, __func__);
  	if (!serial) {
  		mos7840_port->read_urb_busy = false;
  		return;
  	}
  
  	data = urb->transfer_buffer;
  	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
  
  	if (urb->actual_length) {
  		struct tty_port *tport = &mos7840_port->port->port;
  		tty_insert_flip_string(tport, data, urb->actual_length);
  		tty_flip_buffer_push(tport);
  		port->icount.rx += urb->actual_length;
  		dev_dbg(&port->dev, "icount.rx is %d:
  ", port->icount.rx);
  	}
  
  	if (!mos7840_port->read_urb) {
  		dev_dbg(&port->dev, "%s", "URB KILLED !!!
  ");
  		mos7840_port->read_urb_busy = false;
  		return;
  	}
  
  	if (mos7840_port->has_led)
  		mos7840_led_activity(port);
  
  	mos7840_port->read_urb_busy = true;
  	retval = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
  
  	if (retval) {
  		dev_dbg(&port->dev, "usb_submit_urb(read bulk) failed, retval = %d
  ", retval);
  		mos7840_port->read_urb_busy = false;
  	}
  }
  
  /*****************************************************************************
   * 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 moschip_port *mos7840_port;
  	struct usb_serial_port *port;
  	int status = urb->status;
  	int i;
  
  	mos7840_port = urb->context;
  	port = mos7840_port->port;
  	spin_lock(&mos7840_port->pool_lock);
  	for (i = 0; i < NUM_URBS; i++) {
  		if (urb == mos7840_port->write_urb_pool[i]) {
  			mos7840_port->busy[i] = 0;
  			break;
  		}
  	}
  	spin_unlock(&mos7840_port->pool_lock);
  
  	if (status) {
  		dev_dbg(&port->dev, "nonzero write bulk status received:%d
  ", status);
  		return;
  	}
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return;
  
  	if (mos7840_port->open)
  		tty_port_tty_wakeup(&port->port);
  
  }
  
  /************************************************************************/
  /*       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       */
  /************************************************************************/
  
  /*****************************************************************************
   * 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 tty_struct *tty, struct usb_serial_port *port)
  {
  	int response;
  	int j;
  	struct usb_serial *serial;
  	struct urb *urb;
  	__u16 Data;
  	int status;
  	struct moschip_port *mos7840_port;
  	struct moschip_port *port0;
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return -ENODEV;
  
  	serial = port->serial;
  
  	if (mos7840_serial_paranoia_check(serial, __func__))
  		return -ENODEV;
  
  	mos7840_port = mos7840_get_port_private(port);
  	port0 = mos7840_get_port_private(serial->port[0]);
  
  	if (mos7840_port == NULL || port0 == NULL)
  		return -ENODEV;
  
  	usb_clear_halt(serial->dev, port->write_urb->pipe);
  	usb_clear_halt(serial->dev, port->read_urb->pipe);
  	port0->open_ports++;
  
  	/* Initialising the write urb pool */
  	for (j = 0; j < NUM_URBS; ++j) {
  		urb = usb_alloc_urb(0, GFP_KERNEL);
  		mos7840_port->write_urb_pool[j] = urb;
  		if (!urb)
  			continue;
  
  		urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
  								GFP_KERNEL);
  		if (!urb->transfer_buffer) {
  			usb_free_urb(urb);
  			mos7840_port->write_urb_pool[j] = NULL;
  			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 */
  
  	Data = 0x0;
  	status = mos7840_get_reg_sync(port, mos7840_port->SpRegOffset, &Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Reading Spreg failed
  ");
  		goto err;
  	}
  	Data |= 0x80;
  	status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "writing Spreg failed
  ");
  		goto err;
  	}
  
  	Data &= ~0x80;
  	status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "writing Spreg failed
  ");
  		goto err;
  	}
  	/* End of block to be checked */
  
  	Data = 0x0;
  	status = mos7840_get_reg_sync(port, mos7840_port->ControlRegOffset,
  									&Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Reading Controlreg failed
  ");
  		goto err;
  	}
  	Data |= 0x08;		/* Driver done bit */
  	Data |= 0x20;		/* rx_disable */
  	status = mos7840_set_reg_sync(port,
  				mos7840_port->ControlRegOffset, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "writing Controlreg failed
  ");
  		goto err;
  	}
  	/* do register settings here */
  	/* Set all regs to the device default values. */
  	/***********************************
  	 * First Disable all interrupts.
  	 ***********************************/
  	Data = 0x00;
  	status = mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "disabling interrupts failed
  ");
  		goto err;
  	}
  	/* Set FIFO_CONTROL_REGISTER to the default value */
  	Data = 0x00;
  	status = mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Writing FIFO_CONTROL_REGISTER  failed
  ");
  		goto err;
  	}
  
  	Data = 0xcf;
  	status = mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Writing FIFO_CONTROL_REGISTER  failed
  ");
  		goto err;
  	}
  
  	Data = 0x03;
  	status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
  	mos7840_port->shadowLCR = Data;
  
  	Data = 0x0b;
  	status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, Data);
  	mos7840_port->shadowMCR = Data;
  
  	Data = 0x00;
  	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 = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
  
  	Data = 0x0c;
  	status = mos7840_set_uart_reg(port, DIVISOR_LATCH_LSB, Data);
  
  	Data = 0x0;
  	status = mos7840_set_uart_reg(port, DIVISOR_LATCH_MSB, Data);
  
  	Data = 0x00;
  	status = mos7840_get_uart_reg(port, LINE_CONTROL_REGISTER, &Data);
  
  	Data = Data & ~SERIAL_LCR_DLAB;
  	status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
  	mos7840_port->shadowLCR = Data;
  
  	/* clearing Bulkin and Bulkout Fifo */
  	Data = 0x0;
  	status = mos7840_get_reg_sync(port, mos7840_port->SpRegOffset, &Data);
  
  	Data = Data | 0x0c;
  	status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
  
  	Data = Data & ~0x0c;
  	status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
  	/* Finally enable all interrupts */
  	Data = 0x0c;
  	status = mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);
  
  	/* clearing rx_disable */
  	Data = 0x0;
  	status = mos7840_get_reg_sync(port, mos7840_port->ControlRegOffset,
  									&Data);
  	Data = Data & ~0x20;
  	status = mos7840_set_reg_sync(port, mos7840_port->ControlRegOffset,
  									Data);
  
  	/* rx_negate */
  	Data = 0x0;
  	status = mos7840_get_reg_sync(port, mos7840_port->ControlRegOffset,
  									&Data);
  	Data = Data | 0x10;
  	status = mos7840_set_reg_sync(port, mos7840_port->ControlRegOffset,
  									Data);
  
  	/* 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 (port0->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) {
  				dev_err(&port->dev, "%s - Error %d submitting "
  					"interrupt urb
  ", __func__, 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.)   */
  
  	dev_dbg(&port->dev, "port number is %d
  ", port->port_number);
  	dev_dbg(&port->dev, "minor number is %d
  ", port->minor);
  	dev_dbg(&port->dev, "Bulkin endpoint is %d
  ", port->bulk_in_endpointAddress);
  	dev_dbg(&port->dev, "BulkOut endpoint is %d
  ", port->bulk_out_endpointAddress);
  	dev_dbg(&port->dev, "Interrupt endpoint is %d
  ", port->interrupt_in_endpointAddress);
  	dev_dbg(&port->dev, "port's number in the device is %d
  ", mos7840_port->port_num);
  	mos7840_port->read_urb = port->read_urb;
  
  	/* set up our bulk in urb */
  	if ((serial->num_ports == 2) && (((__u16)port->port_number % 2) != 0)) {
  		usb_fill_bulk_urb(mos7840_port->read_urb,
  			serial->dev,
  			usb_rcvbulkpipe(serial->dev,
  				(port->bulk_in_endpointAddress) + 2),
  			port->bulk_in_buffer,
  			mos7840_port->read_urb->transfer_buffer_length,
  			mos7840_bulk_in_callback, mos7840_port);
  	} else {
  		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);
  	}
  
  	dev_dbg(&port->dev, "%s: bulkin endpoint is %d
  ", __func__, port->bulk_in_endpointAddress);
  	mos7840_port->read_urb_busy = true;
  	response = usb_submit_urb(mos7840_port->read_urb, GFP_KERNEL);
  	if (response) {
  		dev_err(&port->dev, "%s - Error %d submitting control urb
  ",
  			__func__, response);
  		mos7840_port->read_urb_busy = false;
  	}
  
  	/* initialize our port settings */
  	/* Must set to enable ints! */
  	mos7840_port->shadowMCR = MCR_MASTER_IE;
  	/* send a open port command */
  	mos7840_port->open = 1;
  	/* mos7840_change_port_settings(mos7840_port,old_termios); */
  
  	return 0;
  err:
  	for (j = 0; j < NUM_URBS; ++j) {
  		urb = mos7840_port->write_urb_pool[j];
  		if (!urb)
  			continue;
  		kfree(urb->transfer_buffer);
  		usb_free_urb(urb);
  	}
  	return status;
  }
  
  /*****************************************************************************
   * 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 zero.
   *****************************************************************************/
  
  static int mos7840_chars_in_buffer(struct tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	int i;
  	int chars = 0;
  	unsigned long flags;
  	struct moschip_port *mos7840_port;
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return 0;
  
  	mos7840_port = mos7840_get_port_private(port);
  	if (mos7840_port == NULL)
  		return 0;
  
  	spin_lock_irqsave(&mos7840_port->pool_lock, flags);
  	for (i = 0; i < NUM_URBS; ++i) {
  		if (mos7840_port->busy[i]) {
  			struct urb *urb = mos7840_port->write_urb_pool[i];
  			chars += urb->transfer_buffer_length;
  		}
  	}
  	spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
  	dev_dbg(&port->dev, "%s - returns %d
  ", __func__, chars);
  	return chars;
  
  }
  
  /*****************************************************************************
   * 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 usb_serial *serial;
  	struct moschip_port *mos7840_port;
  	struct moschip_port *port0;
  	int j;
  	__u16 Data;
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return;
  
  	serial = mos7840_get_usb_serial(port, __func__);
  	if (!serial)
  		return;
  
  	mos7840_port = mos7840_get_port_private(port);
  	port0 = mos7840_get_port_private(serial->port[0]);
  
  	if (mos7840_port == NULL || port0 == 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]);
  		}
  	}
  
  	usb_kill_urb(mos7840_port->write_urb);
  	usb_kill_urb(mos7840_port->read_urb);
  	mos7840_port->read_urb_busy = false;
  
  	port0->open_ports--;
  	dev_dbg(&port->dev, "%s in close%d
  ", __func__, port0->open_ports);
  	if (port0->open_ports == 0) {
  		if (serial->port[0]->interrupt_in_urb) {
  			dev_dbg(&port->dev, "Shutdown interrupt_in_urb
  ");
  			usb_kill_urb(serial->port[0]->interrupt_in_urb);
  		}
  	}
  
  	if (mos7840_port->write_urb) {
  		/* if this urb had a transfer buffer already (old tx) free it */
  		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;
  }
  
  /*****************************************************************************
   * mos7840_break
   *	this function sends a break to the port
   *****************************************************************************/
  static void mos7840_break(struct tty_struct *tty, int break_state)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	unsigned char data;
  	struct usb_serial *serial;
  	struct moschip_port *mos7840_port;
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return;
  
  	serial = mos7840_get_usb_serial(port, __func__);
  	if (!serial)
  		return;
  
  	mos7840_port = mos7840_get_port_private(port);
  
  	if (mos7840_port == NULL)
  		return;
  
  	if (break_state == -1)
  		data = mos7840_port->shadowLCR | LCR_SET_BREAK;
  	else
  		data = mos7840_port->shadowLCR & ~LCR_SET_BREAK;
  
  	/* FIXME: no locking on shadowLCR anywhere in driver */
  	mos7840_port->shadowLCR = data;
  	dev_dbg(&port->dev, "%s mos7840_port->shadowLCR is %x
  ", __func__, mos7840_port->shadowLCR);
  	mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER,
  			     mos7840_port->shadowLCR);
  }
  
  /*****************************************************************************
   * 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 tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	int i;
  	int room = 0;
  	unsigned long flags;
  	struct moschip_port *mos7840_port;
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return -1;
  
  	mos7840_port = mos7840_get_port_private(port);
  	if (mos7840_port == NULL)
  		return -1;
  
  	spin_lock_irqsave(&mos7840_port->pool_lock, flags);
  	for (i = 0; i < NUM_URBS; ++i) {
  		if (!mos7840_port->busy[i])
  			room += URB_TRANSFER_BUFFER_SIZE;
  	}
  	spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
  
  	room = (room == 0) ? 0 : room - URB_TRANSFER_BUFFER_SIZE + 1;
  	dev_dbg(&mos7840_port->port->dev, "%s - returns %d
  ", __func__, 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 tty_struct *tty, struct usb_serial_port *port,
  			 const unsigned char *data, int count)
  {
  	int status;
  	int i;
  	int bytes_sent = 0;
  	int transfer_size;
  	unsigned long flags;
  
  	struct moschip_port *mos7840_port;
  	struct usb_serial *serial;
  	struct urb *urb;
  	/* __u16 Data; */
  	const unsigned char *current_position = data;
  	unsigned char *data1;
  
  #ifdef NOTMOS7840
  	Data = 0x00;
  	status = mos7840_get_uart_reg(port, LINE_CONTROL_REGISTER, &Data);
  	mos7840_port->shadowLCR = Data;
  	dev_dbg(&port->dev, "%s: LINE_CONTROL_REGISTER is %x
  ", __func__, Data);
  	dev_dbg(&port->dev, "%s: mos7840_port->shadowLCR is %x
  ", __func__, 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 = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
  
  	/* Data = 0x0c; */
  	/* status = mos7840_set_uart_reg(port,DIVISOR_LATCH_LSB,Data); */
  	Data = 0x00;
  	status = mos7840_get_uart_reg(port, DIVISOR_LATCH_LSB, &Data);
  	dev_dbg(&port->dev, "%s: DLL value is %x
  ", __func__, Data);
  
  	Data = 0x0;
  	status = mos7840_get_uart_reg(port, DIVISOR_LATCH_MSB, &Data);
  	dev_dbg(&port->dev, "%s: DLM value is %x
  ", __func__, Data);
  
  	Data = Data & ~SERIAL_LCR_DLAB;
  	dev_dbg(&port->dev, "%s: mos7840_port->shadowLCR is %x
  ", __func__, mos7840_port->shadowLCR);
  	status = mos7840_set_uart_reg(port, LINE_CONTROL_REGISTER, Data);
  #endif
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return -1;
  
  	serial = port->serial;
  	if (mos7840_serial_paranoia_check(serial, __func__))
  		return -1;
  
  	mos7840_port = mos7840_get_port_private(port);
  	if (mos7840_port == NULL)
  		return -1;
  
  	/* try to find a free urb in the list */
  	urb = NULL;
  
  	spin_lock_irqsave(&mos7840_port->pool_lock, flags);
  	for (i = 0; i < NUM_URBS; ++i) {
  		if (!mos7840_port->busy[i]) {
  			mos7840_port->busy[i] = 1;
  			urb = mos7840_port->write_urb_pool[i];
  			dev_dbg(&port->dev, "URB:%d
  ", i);
  			break;
  		}
  	}
  	spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
  
  	if (urb == NULL) {
  		dev_dbg(&port->dev, "%s - no more free urbs
  ", __func__);
  		goto exit;
  	}
  
  	if (urb->transfer_buffer == NULL) {
  		urb->transfer_buffer =
  		    kmalloc(URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);
  		if (!urb->transfer_buffer)
  			goto exit;
  	}
  	transfer_size = min(count, URB_TRANSFER_BUFFER_SIZE);
  
  	memcpy(urb->transfer_buffer, current_position, transfer_size);
  
  	/* fill urb with data and submit  */
  	if ((serial->num_ports == 2) && (((__u16)port->port_number % 2) != 0)) {
  		usb_fill_bulk_urb(urb,
  			serial->dev,
  			usb_sndbulkpipe(serial->dev,
  				(port->bulk_out_endpointAddress) + 2),
  			urb->transfer_buffer,
  			transfer_size,
  			mos7840_bulk_out_data_callback, mos7840_port);
  	} else {
  		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;
  	dev_dbg(&port->dev, "bulkout endpoint is %d
  ", port->bulk_out_endpointAddress);
  
  	if (mos7840_port->has_led)
  		mos7840_led_activity(port);
  
  	/* send it down the pipe */
  	status = usb_submit_urb(urb, GFP_ATOMIC);
  
  	if (status) {
  		mos7840_port->busy[i] = 0;
  		dev_err_console(port, "%s - usb_submit_urb(write bulk) failed "
  			"with status = %d
  ", __func__, status);
  		bytes_sent = status;
  		goto exit;
  	}
  	bytes_sent = transfer_size;
  	port->icount.tx += transfer_size;
  	dev_dbg(&port->dev, "icount.tx is %d:
  ", 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 tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct moschip_port *mos7840_port;
  	int status;
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return;
  
  	mos7840_port = mos7840_get_port_private(port);
  
  	if (mos7840_port == NULL)
  		return;
  
  	if (!mos7840_port->open) {
  		dev_dbg(&port->dev, "%s", "port not opened
  ");
  		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(tty, 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 = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
  					 mos7840_port->shadowMCR);
  		if (status < 0)
  			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 mos7840_throttle is
   *	called)
   *****************************************************************************/
  static void mos7840_unthrottle(struct tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	int status;
  	struct moschip_port *mos7840_port = mos7840_get_port_private(port);
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return;
  
  	if (mos7840_port == NULL)
  		return;
  
  	if (!mos7840_port->open) {
  		dev_dbg(&port->dev, "%s - port not opened
  ", __func__);
  		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(tty, 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 = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
  					 mos7840_port->shadowMCR);
  		if (status < 0)
  			return;
  	}
  }
  
  static int mos7840_tiocmget(struct tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct moschip_port *mos7840_port;
  	unsigned int result;
  	__u16 msr;
  	__u16 mcr;
  	int status;
  	mos7840_port = mos7840_get_port_private(port);
  
  	if (mos7840_port == NULL)
  		return -ENODEV;
  
  	status = mos7840_get_uart_reg(port, MODEM_STATUS_REGISTER, &msr);
  	if (status != 1)
  		return -EIO;
  	status = mos7840_get_uart_reg(port, MODEM_CONTROL_REGISTER, &mcr);
  	if (status != 1)
  		return -EIO;
  	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);
  
  	dev_dbg(&port->dev, "%s - 0x%04X
  ", __func__, result);
  
  	return result;
  }
  
  static int mos7840_tiocmset(struct tty_struct *tty,
  			    unsigned int set, unsigned int clear)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct moschip_port *mos7840_port;
  	unsigned int mcr;
  	int status;
  
  	mos7840_port = mos7840_get_port_private(port);
  
  	if (mos7840_port == NULL)
  		return -ENODEV;
  
  	/* FIXME: What locks the port registers ? */
  	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 = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER, mcr);
  	if (status < 0) {
  		dev_dbg(&port->dev, "setting MODEM_CONTROL_REGISTER Failed
  ");
  		return status;
  	}
  
  	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(struct usb_serial_port *port,
  					  int baudRate, int *divisor,
  					  __u16 *clk_sel_val)
  {
  	dev_dbg(&port->dev, "%s - %d
  ", __func__, 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;
  
  		dev_dbg(&port->dev, " Baud %d = %d
  ", baudrate, custom);
  		return 0;
  	}
  
  	dev_dbg(&port->dev, "%s", " 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 = mos7840_port->port;
  	if (mos7840_port_paranoia_check(port, __func__))
  		return -1;
  
  	if (mos7840_serial_paranoia_check(port->serial, __func__))
  		return -1;
  
  	number = mos7840_port->port->port_number;
  
  	dev_dbg(&port->dev, "%s - baud = %d
  ", __func__, 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 */
  		Data = 0x2b;
  		mos7840_port->shadowMCR = Data;
  		status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
  									Data);
  		if (status < 0) {
  			dev_dbg(&port->dev, "Writing spreg failed in set_serial_baud
  ");
  			return -1;
  		}
  #endif
  
  	} else {
  #ifdef HW_flow_control
  		/* setting h/w flow control bit to 0 */
  		Data = 0xb;
  		mos7840_port->shadowMCR = Data;
  		status = mos7840_set_uart_reg(port, MODEM_CONTROL_REGISTER,
  									Data);
  		if (status < 0) {
  			dev_dbg(&port->dev, "Writing spreg failed in set_serial_baud
  ");
  			return -1;
  		}
  #endif
  
  	}
  
  	if (1) {		/* baudRate <= 115200) */
  		clk_sel_val = 0x0;
  		Data = 0x0;
  		status = mos7840_calc_baud_rate_divisor(port, baudRate, &divisor,
  						   &clk_sel_val);
  		status = mos7840_get_reg_sync(port, mos7840_port->SpRegOffset,
  								 &Data);
  		if (status < 0) {
  			dev_dbg(&port->dev, "reading spreg failed in set_serial_baud
  ");
  			return -1;
  		}
  		Data = (Data & 0x8f) | clk_sel_val;
  		status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset,
  								Data);
  		if (status < 0) {
  			dev_dbg(&port->dev, "Writing spreg failed in set_serial_baud
  ");
  			return -1;
  		}
  		/* Calculate the Divisor */
  
  		if (status) {
  			dev_err(&port->dev, "%s - bad baud rate
  ", __func__);
  			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);
  		dev_dbg(&port->dev, "set_serial_baud Value to write DLL is %x
  ", Data);
  		mos7840_set_uart_reg(port, DIVISOR_LATCH_LSB, Data);
  
  		Data = (unsigned char)((divisor & 0xff00) >> 8);
  		dev_dbg(&port->dev, "set_serial_baud Value to write DLM is %x
  ", 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 tty_struct *tty,
  	struct moschip_port *mos7840_port, struct ktermios *old_termios)
  {
  	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 = mos7840_port->port;
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return;
  
  	if (mos7840_serial_paranoia_check(port->serial, __func__))
  		return;
  
  	serial = port->serial;
  
  	if (!mos7840_port->open) {
  		dev_dbg(&port->dev, "%s - port not opened
  ", __func__);
  		return;
  	}
  
  	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 */
  	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;
  			dev_dbg(&port->dev, "%s - parity = odd
  ", __func__);
  		} else {
  			lParity = LCR_PAR_EVEN;
  			dev_dbg(&port->dev, "%s - parity = even
  ", __func__);
  		}
  
  	} else {
  		dev_dbg(&port->dev, "%s - parity = none
  ", __func__);
  	}
  
  	if (cflag & CMSPAR)
  		lParity = lParity | 0x20;
  
  	/* Change the Stop bit */
  	if (cflag & CSTOPB) {
  		lStop = LCR_STOP_2;
  		dev_dbg(&port->dev, "%s - stop bits = 2
  ", __func__);
  	} else {
  		lStop = LCR_STOP_1;
  		dev_dbg(&port->dev, "%s - stop bits = 1
  ", __func__);
  	}
  
  	/* 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);
  
  	dev_dbg(&port->dev, "%s - mos7840_port->shadowLCR is %x
  ", __func__,
  		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... */
  		dev_dbg(&port->dev, "%s", "Picked default baud...
  ");
  		baud = 9600;
  	}
  
  	dev_dbg(&port->dev, "%s - baud rate = %d
  ", __func__, 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_busy == false) {
  		mos7840_port->read_urb_busy = true;
  		status = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
  		if (status) {
  			dev_dbg(&port->dev, "usb_submit_urb(read bulk) failed, status = %d
  ",
  			    status);
  			mos7840_port->read_urb_busy = false;
  		}
  	}
  	dev_dbg(&port->dev, "%s - mos7840_port->shadowLCR is End %x
  ", __func__,
  		mos7840_port->shadowLCR);
  }
  
  /*****************************************************************************
   * 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 tty_struct *tty,
  				struct usb_serial_port *port,
  				struct ktermios *old_termios)
  {
  	int status;
  	unsigned int cflag;
  	struct usb_serial *serial;
  	struct moschip_port *mos7840_port;
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return;
  
  	serial = port->serial;
  
  	if (mos7840_serial_paranoia_check(serial, __func__))
  		return;
  
  	mos7840_port = mos7840_get_port_private(port);
  
  	if (mos7840_port == NULL)
  		return;
  
  	if (!mos7840_port->open) {
  		dev_dbg(&port->dev, "%s - port not opened
  ", __func__);
  		return;
  	}
  
  	dev_dbg(&port->dev, "%s", "setting termios - 
  ");
  
  	cflag = tty->termios.c_cflag;
  
  	dev_dbg(&port->dev, "%s - clfag %08x iflag %08x
  ", __func__,
  		tty->termios.c_cflag, RELEVANT_IFLAG(tty->termios.c_iflag));
  	dev_dbg(&port->dev, "%s - old clfag %08x old iflag %08x
  ", __func__,
  		old_termios->c_cflag, RELEVANT_IFLAG(old_termios->c_iflag));
  
  	/* change the port settings to the new ones specified */
  
  	mos7840_change_port_settings(tty, mos7840_port, old_termios);
  
  	if (!mos7840_port->read_urb) {
  		dev_dbg(&port->dev, "%s", "URB KILLED !!!!!
  ");
  		return;
  	}
  
  	if (mos7840_port->read_urb_busy == false) {
  		mos7840_port->read_urb_busy = true;
  		status = usb_submit_urb(mos7840_port->read_urb, GFP_ATOMIC);
  		if (status) {
  			dev_dbg(&port->dev, "usb_submit_urb(read bulk) failed, status = %d
  ",
  			    status);
  			mos7840_port->read_urb_busy = false;
  		}
  	}
  }
  
  /*****************************************************************************
   * 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 tty_struct *tty,
  				unsigned int __user *value)
  {
  	int count;
  	unsigned int result = 0;
  
  	count = mos7840_chars_in_buffer(tty);
  	if (count == 0)
  		result = TIOCSER_TEMT;
  
  	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 __user *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->minor;
  	tmp.port = mos7840_port->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 tty_struct *tty,
  			 unsigned int cmd, unsigned long arg)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	void __user *argp = (void __user *)arg;
  	struct moschip_port *mos7840_port;
  
  	if (mos7840_port_paranoia_check(port, __func__))
  		return -1;
  
  	mos7840_port = mos7840_get_port_private(port);
  
  	if (mos7840_port == NULL)
  		return -1;
  
  	switch (cmd) {
  		/* return number of bytes available */
  
  	case TIOCSERGETLSR:
  		dev_dbg(&port->dev, "%s TIOCSERGETLSR
  ", __func__);
  		return mos7840_get_lsr_info(tty, argp);
  
  	case TIOCGSERIAL:
  		dev_dbg(&port->dev, "%s TIOCGSERIAL
  ", __func__);
  		return mos7840_get_serial_info(mos7840_port, argp);
  
  	case TIOCSSERIAL:
  		dev_dbg(&port->dev, "%s TIOCSSERIAL
  ", __func__);
  		break;
  	default:
  		break;
  	}
  	return -ENOIOCTLCMD;
  }
  
  static int mos7810_check(struct usb_serial *serial)
  {
  	int i, pass_count = 0;
  	u8 *buf;
  	__u16 data = 0, mcr_data = 0;
  	__u16 test_pattern = 0x55AA;
  	int res;
  
  	buf = kmalloc(VENDOR_READ_LENGTH, GFP_KERNEL);
  	if (!buf)
  		return 0;	/* failed to identify 7810 */
  
  	/* Store MCR setting */
  	res = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
  		MCS_RDREQ, MCS_RD_RTYPE, 0x0300, MODEM_CONTROL_REGISTER,
  		buf, VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT);
  	if (res == VENDOR_READ_LENGTH)
  		mcr_data = *buf;
  
  	for (i = 0; i < 16; i++) {
  		/* Send the 1-bit test pattern out to MCS7810 test pin */
  		usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
  			MCS_WRREQ, MCS_WR_RTYPE,
  			(0x0300 | (((test_pattern >> i) & 0x0001) << 1)),
  			MODEM_CONTROL_REGISTER, NULL, 0, MOS_WDR_TIMEOUT);
  
  		/* Read the test pattern back */
  		res = usb_control_msg(serial->dev,
  				usb_rcvctrlpipe(serial->dev, 0), MCS_RDREQ,
  				MCS_RD_RTYPE, 0, GPIO_REGISTER, buf,
  				VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT);
  		if (res == VENDOR_READ_LENGTH)
  			data = *buf;
  
  		/* If this is a MCS7810 device, both test patterns must match */
  		if (((test_pattern >> i) ^ (~data >> 1)) & 0x0001)
  			break;
  
  		pass_count++;
  	}
  
  	/* Restore MCR setting */
  	usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0), MCS_WRREQ,
  		MCS_WR_RTYPE, 0x0300 | mcr_data, MODEM_CONTROL_REGISTER, NULL,
  		0, MOS_WDR_TIMEOUT);
  
  	kfree(buf);
  
  	if (pass_count == 16)
  		return 1;
  
  	return 0;
  }
  
  static int mos7840_probe(struct usb_serial *serial,
  				const struct usb_device_id *id)
  {
  	u16 product = le16_to_cpu(serial->dev->descriptor.idProduct);
  	u8 *buf;
  	int device_type;
  
  	if (product == MOSCHIP_DEVICE_ID_7810 ||
  		product == MOSCHIP_DEVICE_ID_7820) {
  		device_type = product;
  		goto out;
  	}
  
  	buf = kzalloc(VENDOR_READ_LENGTH, GFP_KERNEL);
  	if (!buf)
  		return -ENOMEM;
  
  	usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
  			MCS_RDREQ, MCS_RD_RTYPE, 0, GPIO_REGISTER, buf,
  			VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT);
  
  	/* For a MCS7840 device GPIO0 must be set to 1 */
  	if (buf[0] & 0x01)
  		device_type = MOSCHIP_DEVICE_ID_7840;
  	else if (mos7810_check(serial))
  		device_type = MOSCHIP_DEVICE_ID_7810;
  	else
  		device_type = MOSCHIP_DEVICE_ID_7820;
  
  	kfree(buf);
  out:
  	usb_set_serial_data(serial, (void *)(unsigned long)device_type);
  
  	return 0;
  }
  
  static int mos7840_calc_num_ports(struct usb_serial *serial)
  {
  	int device_type = (unsigned long)usb_get_serial_data(serial);
  	int mos7840_num_ports;
  
  	mos7840_num_ports = (device_type >> 4) & 0x000F;
  
  	return mos7840_num_ports;
  }
  
  static int mos7840_port_probe(struct usb_serial_port *port)
  {
  	struct usb_serial *serial = port->serial;
  	int device_type = (unsigned long)usb_get_serial_data(serial);
  	struct moschip_port *mos7840_port;
  	int status;
  	int pnum;
  	__u16 Data;
  
  	/* we set up the pointers to the endpoints in the mos7840_open *
  	 * function, as the structures aren't created yet.             */
  
  	pnum = port->port_number;
  
  	dev_dbg(&port->dev, "mos7840_startup: configuring port %d
  ", pnum);
  	mos7840_port = kzalloc(sizeof(struct moschip_port), GFP_KERNEL);
  	if (!mos7840_port)
  		return -ENOMEM;
  
  	/* Initialize all port interrupt end point to port 0 int
  	 * endpoint. Our device has only one interrupt end point
  	 * common to all port */
  
  	mos7840_port->port = port;
  	mos7840_set_port_private(port, mos7840_port);
  	spin_lock_init(&mos7840_port->pool_lock);
  
  	/* minor is not initialised until later by
  	 * usb-serial.c:get_free_serial() and cannot therefore be used
  	 * to index device instances */
  	mos7840_port->port_num = pnum + 1;
  	dev_dbg(&port->dev, "port->minor = %d
  ", port->minor);
  	dev_dbg(&port->dev, "mos7840_port->port_num = %d
  ", mos7840_port->port_num);
  
  	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) && (serial->num_ports == 4)) {
  		mos7840_port->SpRegOffset = 0x8;
  		mos7840_port->ControlRegOffset = 0x9;
  		mos7840_port->DcrRegOffset = 0x16;
  	} else if ((mos7840_port->port_num == 2) && (serial->num_ports == 2)) {
  		mos7840_port->SpRegOffset = 0xa;
  		mos7840_port->ControlRegOffset = 0xb;
  		mos7840_port->DcrRegOffset = 0x19;
  	} else if ((mos7840_port->port_num == 3) && (serial->num_ports == 4)) {
  		mos7840_port->SpRegOffset = 0xa;
  		mos7840_port->ControlRegOffset = 0xb;
  		mos7840_port->DcrRegOffset = 0x19;
  	} else if ((mos7840_port->port_num == 4) && (serial->num_ports == 4)) {
  		mos7840_port->SpRegOffset = 0xc;
  		mos7840_port->ControlRegOffset = 0xd;
  		mos7840_port->DcrRegOffset = 0x1c;
  	}
  	mos7840_dump_serial_port(port, mos7840_port);
  	mos7840_set_port_private(port, mos7840_port);
  
  	/* enable rx_disable bit in control register */
  	status = mos7840_get_reg_sync(port,
  			mos7840_port->ControlRegOffset, &Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Reading ControlReg failed status-0x%x
  ", status);
  		goto out;
  	} else
  		dev_dbg(&port->dev, "ControlReg Reading success val is %x, status%d
  ", 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 = mos7840_set_reg_sync(port,
  			mos7840_port->ControlRegOffset, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Writing ControlReg failed(rx_disable) status-0x%x
  ", status);
  		goto out;
  	} else
  		dev_dbg(&port->dev, "ControlReg Writing success(rx_disable) status%d
  ", status);
  
  	/* Write default values in DCR (i.e 0x01 in DCR0, 0x05 in DCR2
  	   and 0x24 in DCR3 */
  	Data = 0x01;
  	status = mos7840_set_reg_sync(port,
  			(__u16) (mos7840_port->DcrRegOffset + 0), Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Writing DCR0 failed status-0x%x
  ", status);
  		goto out;
  	} else
  		dev_dbg(&port->dev, "DCR0 Writing success status%d
  ", status);
  
  	Data = 0x05;
  	status = mos7840_set_reg_sync(port,
  			(__u16) (mos7840_port->DcrRegOffset + 1), Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Writing DCR1 failed status-0x%x
  ", status);
  		goto out;
  	} else
  		dev_dbg(&port->dev, "DCR1 Writing success status%d
  ", status);
  
  	Data = 0x24;
  	status = mos7840_set_reg_sync(port,
  			(__u16) (mos7840_port->DcrRegOffset + 2), Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Writing DCR2 failed status-0x%x
  ", status);
  		goto out;
  	} else
  		dev_dbg(&port->dev, "DCR2 Writing success status%d
  ", status);
  
  	/* write values in clkstart0x0 and clkmulti 0x20 */
  	Data = 0x0;
  	status = mos7840_set_reg_sync(port, CLK_START_VALUE_REGISTER, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Writing CLK_START_VALUE_REGISTER failed status-0x%x
  ", status);
  		goto out;
  	} else
  		dev_dbg(&port->dev, "CLK_START_VALUE_REGISTER Writing success status%d
  ", status);
  
  	Data = 0x20;
  	status = mos7840_set_reg_sync(port, CLK_MULTI_REGISTER, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Writing CLK_MULTI_REGISTER failed status-0x%x
  ", status);
  		goto error;
  	} else
  		dev_dbg(&port->dev, "CLK_MULTI_REGISTER Writing success status%d
  ", status);
  
  	/* write value 0x0 to scratchpad register */
  	Data = 0x00;
  	status = mos7840_set_uart_reg(port, SCRATCH_PAD_REGISTER, Data);
  	if (status < 0) {
  		dev_dbg(&port->dev, "Writing SCRATCH_PAD_REGISTER failed status-0x%x
  ", status);
  		goto out;
  	} else
  		dev_dbg(&port->dev, "SCRATCH_PAD_REGISTER Writing success status%d
  ", status);
  
  	/* Zero Length flag register */
  	if ((mos7840_port->port_num != 1) && (serial->num_ports == 2)) {
  		Data = 0xff;
  		status = mos7840_set_reg_sync(port,
  				(__u16) (ZLP_REG1 +
  					((__u16)mos7840_port->port_num)), Data);
  		dev_dbg(&port->dev, "ZLIP offset %x
  ",
  				(__u16)(ZLP_REG1 + ((__u16) mos7840_port->port_num)));
  		if (status < 0) {
  			dev_dbg(&port->dev, "Writing ZLP_REG%d failed status-0x%x
  ", pnum + 2, status);
  			goto out;
  		} else
  			dev_dbg(&port->dev, "ZLP_REG%d Writing success status%d
  ", pnum + 2, status);
  	} else {
  		Data = 0xff;
  		status = mos7840_set_reg_sync(port,
  				(__u16) (ZLP_REG1 +
  					((__u16)mos7840_port->port_num) - 0x1), Data);
  		dev_dbg(&port->dev, "ZLIP offset %x
  ",
  				(__u16)(ZLP_REG1 + ((__u16) mos7840_port->port_num) - 0x1));
  		if (status < 0) {
  			dev_dbg(&port->dev, "Writing ZLP_REG%d failed status-0x%x
  ", pnum + 1, status);
  			goto out;
  		} else
  			dev_dbg(&port->dev, "ZLP_REG%d Writing success status%d
  ", pnum + 1, status);
  
  	}
  	mos7840_port->control_urb = usb_alloc_urb(0, GFP_KERNEL);
  	mos7840_port->ctrl_buf = kmalloc(16, GFP_KERNEL);
  	mos7840_port->dr = kmalloc(sizeof(struct usb_ctrlrequest),
  			GFP_KERNEL);
  	if (!mos7840_port->control_urb || !mos7840_port->ctrl_buf ||
  			!mos7840_port->dr) {
  		status = -ENOMEM;
  		goto error;
  	}
  
  	mos7840_port->has_led = false;
  
  	/* Initialize LED timers */
  	if (device_type == MOSCHIP_DEVICE_ID_7810) {
  		mos7840_port->has_led = true;
  
  		mos7840_port->led_urb = usb_alloc_urb(0, GFP_KERNEL);
  		mos7840_port->led_dr = kmalloc(sizeof(*mos7840_port->led_dr),
  								GFP_KERNEL);
  		if (!mos7840_port->led_urb || !mos7840_port->led_dr) {
  			status = -ENOMEM;
  			goto error;
  		}
  
  		init_timer(&mos7840_port->led_timer1);
  		mos7840_port->led_timer1.function = mos7840_led_off;
  		mos7840_port->led_timer1.expires =
  			jiffies + msecs_to_jiffies(LED_ON_MS);
  		mos7840_port->led_timer1.data = (unsigned long)mos7840_port;
  
  		init_timer(&mos7840_port->led_timer2);
  		mos7840_port->led_timer2.function = mos7840_led_flag_off;
  		mos7840_port->led_timer2.expires =
  			jiffies + msecs_to_jiffies(LED_OFF_MS);
  		mos7840_port->led_timer2.data = (unsigned long)mos7840_port;
  
  		/* Turn off LED */
  		mos7840_set_led_sync(port, MODEM_CONTROL_REGISTER, 0x0300);
  	}
  out:
  	if (pnum == serial->num_ports - 1) {
  		/* Zero Length flag enable */
  		Data = 0x0f;
  		status = mos7840_set_reg_sync(serial->port[0], ZLP_REG5, Data);
  		if (status < 0) {
  			dev_dbg(&port->dev, "Writing ZLP_REG5 failed status-0x%x
  ", status);
  			goto error;
  		} else
  			dev_dbg(&port->dev, "ZLP_REG5 Writing success status%d
  ", status);
  
  		/* setting configuration feature to one */
  		usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
  				0x03, 0x00, 0x01, 0x00, NULL, 0x00,
  				MOS_WDR_TIMEOUT);
  	}
  	return 0;
  error:
  	kfree(mos7840_port->led_dr);
  	usb_free_urb(mos7840_port->led_urb);
  	kfree(mos7840_port->dr);
  	kfree(mos7840_port->ctrl_buf);
  	usb_free_urb(mos7840_port->control_urb);
  	kfree(mos7840_port);
  
  	return status;
  }
  
  static int mos7840_port_remove(struct usb_serial_port *port)
  {
  	struct moschip_port *mos7840_port;
  
  	mos7840_port = mos7840_get_port_private(port);
  
  	if (mos7840_port->has_led) {
  		/* Turn off LED */
  		mos7840_set_led_sync(port, MODEM_CONTROL_REGISTER, 0x0300);
  
  		del_timer_sync(&mos7840_port->led_timer1);
  		del_timer_sync(&mos7840_port->led_timer2);
  
  		usb_kill_urb(mos7840_port->led_urb);
  		usb_free_urb(mos7840_port->led_urb);
  		kfree(mos7840_port->led_dr);
  	}
  	usb_kill_urb(mos7840_port->control_urb);
  	usb_free_urb(mos7840_port->control_urb);
  	kfree(mos7840_port->ctrl_buf);
  	kfree(mos7840_port->dr);
  	kfree(mos7840_port);
  
  	return 0;
  }
  
  static struct usb_serial_driver moschip7840_4port_device = {
  	.driver = {
  		   .owner = THIS_MODULE,
  		   .name = "mos7840",
  		   },
  	.description = DRIVER_DESC,
  	.id_table = id_table,
  	.num_ports = 4,
  	.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,
  	.probe = mos7840_probe,
  	.ioctl = mos7840_ioctl,
  	.set_termios = mos7840_set_termios,
  	.break_ctl = mos7840_break,
  	.tiocmget = mos7840_tiocmget,
  	.tiocmset = mos7840_tiocmset,
  	.tiocmiwait = usb_serial_generic_tiocmiwait,
  	.get_icount = usb_serial_generic_get_icount,
  	.port_probe = mos7840_port_probe,
  	.port_remove = mos7840_port_remove,
  	.read_bulk_callback = mos7840_bulk_in_callback,
  	.read_int_callback = mos7840_interrupt_callback,
  };
  
  static struct usb_serial_driver * const serial_drivers[] = {
  	&moschip7840_4port_device, NULL
  };
  
  module_usb_serial_driver(serial_drivers, id_table);
  
  MODULE_DESCRIPTION(DRIVER_DESC);
  MODULE_LICENSE("GPL");