/*
 * USB Cypress M8 driver
 *
 *      Copyright (C) 2004
 *          Lonnie Mendez (dignome@gmail.com) 
 *      Copyright (C) 2003,2004
 *          Neil Whelchel (koyama@firstlight.net)
 *
 *      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.
 *
 * See Documentation/usb/usb-serial.txt for more information on using this driver
 *
 * See http://geocities.com/i0xox0i for information on this driver and the
 * earthmate usb device.
 *
 *  Lonnie Mendez <dignome@gmail.com>
 *  4-29-2005
 *      Fixed problem where setting or retreiving the serial config would fail with
 *      EPIPE.  Removed CRTS toggling so the driver behaves more like other usbserial
 *      adapters.  Issued new interval of 1ms instead of the default 10ms.  As a
 *      result, transfer speed has been substantially increased.  From avg. 850bps to
 *      avg. 3300bps.  initial termios has also been modified.  Cleaned up code and
 *      formatting issues so it is more readable.  Replaced the C++ style comments.
 *
 *  Lonnie Mendez <dignome@gmail.com>
 *  12-15-2004
 *      Incorporated write buffering from pl2303 driver.  Fixed bug with line
 *      handling so both lines are raised in cypress_open. (was dropping rts)
 *      Various code cleanups made as well along with other misc bug fixes.
 *
 *  Lonnie Mendez <dignome@gmail.com>
 *  04-10-2004
 *      Driver modified to support dynamic line settings.  Various improvments
 *      and features.
 *
 *  Neil Whelchel
 *  10-2003
 *      Driver first released.
 *
 */

/* Thanks to Neil Whelchel for writing the first cypress m8 implementation for linux. */
/* Thanks to cypress for providing references for the hid reports. */
/* Thanks to Jiang Zhang for providing links and for general help. */
/* Code originates and was built up from ftdi_sio, belkin, pl2303 and others. */


#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/moduleparam.h>
#include <linux/spinlock.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/serial.h>
#include <linux/delay.h>
#include <asm/uaccess.h>

#include "cypress_m8.h"


#ifdef CONFIG_USB_SERIAL_DEBUG
        static int debug = 1;
#else
        static int debug;
#endif
static int stats;
static int interval;

/*
 * Version Information
 */
#define DRIVER_VERSION "v1.09"
#define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
#define DRIVER_DESC "Cypress USB to Serial Driver"

/* write buffer size defines */
#define CYPRESS_BUF_SIZE        1024
#define CYPRESS_CLOSING_WAIT    (30*HZ)

static struct usb_device_id id_table_earthmate [] = {
        { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
        { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
        { }                                             /* Terminating entry */
};

static struct usb_device_id id_table_cyphidcomrs232 [] = {
        { USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
        { }                                             /* Terminating entry */
};

static struct usb_device_id id_table_nokiaca42v2 [] = {
        { USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
        { }                                             /* Terminating entry */
};

static struct usb_device_id id_table_combined [] = {
        { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
        { USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
        { USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
        { USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
        { }                                             /* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, id_table_combined);

static struct usb_driver cypress_driver = {
        .name =         "cypress",
        .probe =        usb_serial_probe,
        .disconnect =   usb_serial_disconnect,
        .id_table =     id_table_combined,
        .no_dynamic_id =        1,
};

struct cypress_private {
        spinlock_t lock;                   /* private lock */
        int chiptype;                      /* identifier of device, for quirks/etc */
        int bytes_in;                      /* used for statistics */
        int bytes_out;                     /* used for statistics */
        int cmd_count;                     /* used for statistics */
        int cmd_ctrl;                      /* always set this to 1 before issuing a command */
        struct cypress_buf *buf;           /* write buffer */
        int write_urb_in_use;              /* write urb in use indicator */
        int write_urb_interval;            /* interval to use for write urb */
        int read_urb_interval;             /* interval to use for read urb */
        int comm_is_ok;                    /* true if communication is (still) ok */
        int termios_initialized;
        __u8 line_control;                 /* holds dtr / rts value */
        __u8 current_status;               /* received from last read - info on dsr,cts,cd,ri,etc */
        __u8 current_config;               /* stores the current configuration byte */
        __u8 rx_flags;                     /* throttling - used from whiteheat/ftdi_sio */
        int baud_rate;                     /* stores current baud rate in integer form */
        int cbr_mask;                      /* stores current baud rate in masked form */
        int isthrottled;                   /* if throttled, discard reads */
        wait_queue_head_t delta_msr_wait;  /* used for TIOCMIWAIT */
        char prev_status, diff_status;     /* used for TIOCMIWAIT */
        /* we pass a pointer to this as the arguement sent to cypress_set_termios old_termios */
        struct ktermios tmp_termios;       /* stores the old termios settings */
};

/* write buffer structure */
struct cypress_buf {
        unsigned int    buf_size;
        char            *buf_buf;
        char            *buf_get;
        char            *buf_put;
};

/* function prototypes for the Cypress USB to serial device */
static int  cypress_earthmate_startup   (struct usb_serial *serial);
static int  cypress_hidcom_startup      (struct usb_serial *serial);
static int  cypress_ca42v2_startup      (struct usb_serial *serial);
static void cypress_shutdown            (struct usb_serial *serial);
static int  cypress_open                (struct usb_serial_port *port, struct file *filp);
static void cypress_close               (struct usb_serial_port *port, struct file *filp);
static int  cypress_write               (struct usb_serial_port *port, const unsigned char *buf, int count);
static void cypress_send                (struct usb_serial_port *port);
static int  cypress_write_room          (struct usb_serial_port *port);
static int  cypress_ioctl               (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg);
static void cypress_set_termios         (struct usb_serial_port *port, struct ktermios * old);
static int  cypress_tiocmget            (struct usb_serial_port *port, struct file *file);
static int  cypress_tiocmset            (struct usb_serial_port *port, struct file *file, unsigned int set, unsigned int clear);
static int  cypress_chars_in_buffer     (struct usb_serial_port *port);
static void cypress_throttle            (struct usb_serial_port *port);
static void cypress_unthrottle          (struct usb_serial_port *port);
static void cypress_set_dead            (struct usb_serial_port *port);
static void cypress_read_int_callback   (struct urb *urb);
static void cypress_write_int_callback  (struct urb *urb);
/* baud helper functions */
static int       mask_to_rate           (unsigned mask);
static unsigned  rate_to_mask           (int rate);
/* write buffer functions */
static struct cypress_buf *cypress_buf_alloc(unsigned int size);
static void               cypress_buf_free(struct cypress_buf *cb);
static void               cypress_buf_clear(struct cypress_buf *cb);
static unsigned int       cypress_buf_data_avail(struct cypress_buf *cb);
static unsigned int       cypress_buf_space_avail(struct cypress_buf *cb);
static unsigned int       cypress_buf_put(struct cypress_buf *cb, const char *buf, unsigned int count);
static unsigned int       cypress_buf_get(struct cypress_buf *cb, char *buf, unsigned int count);


static struct usb_serial_driver cypress_earthmate_device = {
        .driver = {
                .owner =                THIS_MODULE,
                .name =                 "earthmate",
        },
        .description =                  "DeLorme Earthmate USB",
        .id_table =                     id_table_earthmate,
        .num_interrupt_in =             1,
        .num_interrupt_out =            1,
        .num_bulk_in =                  NUM_DONT_CARE,
        .num_bulk_out =                 NUM_DONT_CARE,
        .num_ports =                    1,
        .attach =                       cypress_earthmate_startup,
        .shutdown =                     cypress_shutdown,
        .open =                         cypress_open,
        .close =                        cypress_close,
        .write =                        cypress_write,
        .write_room =                   cypress_write_room,
        .ioctl =                        cypress_ioctl,
        .set_termios =                  cypress_set_termios,
        .tiocmget =                     cypress_tiocmget,
        .tiocmset =                     cypress_tiocmset,
        .chars_in_buffer =              cypress_chars_in_buffer,
        .throttle =                     cypress_throttle,
        .unthrottle =                   cypress_unthrottle,
        .read_int_callback =            cypress_read_int_callback,
        .write_int_callback =           cypress_write_int_callback,
};

static struct usb_serial_driver cypress_hidcom_device = {
        .driver = {
                .owner =                THIS_MODULE,
                .name =                 "cyphidcom",
        },
        .description =                  "HID->COM RS232 Adapter",
        .id_table =                     id_table_cyphidcomrs232,
        .num_interrupt_in =             1,
        .num_interrupt_out =            1,
        .num_bulk_in =                  NUM_DONT_CARE,
        .num_bulk_out =                 NUM_DONT_CARE,
        .num_ports =                    1,
        .attach =                       cypress_hidcom_startup,
        .shutdown =                     cypress_shutdown,
        .open =                         cypress_open,
        .close =                        cypress_close,
        .write =                        cypress_write,
        .write_room =                   cypress_write_room,
        .ioctl =                        cypress_ioctl,
        .set_termios =                  cypress_set_termios,
        .tiocmget =                     cypress_tiocmget,
        .tiocmset =                     cypress_tiocmset,
        .chars_in_buffer =              cypress_chars_in_buffer,
        .throttle =                     cypress_throttle,
        .unthrottle =                   cypress_unthrottle,
        .read_int_callback =            cypress_read_int_callback,
        .write_int_callback =           cypress_write_int_callback,
};

static struct usb_serial_driver cypress_ca42v2_device = {
        .driver = {
                .owner =                THIS_MODULE,
                .name =                 "nokiaca42v2",
        },
        .description =                  "Nokia CA-42 V2 Adapter",
        .id_table =                     id_table_nokiaca42v2,
        .num_interrupt_in =             1,
        .num_interrupt_out =            1,
        .num_bulk_in =                  NUM_DONT_CARE,
        .num_bulk_out =                 NUM_DONT_CARE,
        .num_ports =                    1,
        .attach =                       cypress_ca42v2_startup,
        .shutdown =                     cypress_shutdown,
        .open =                         cypress_open,
        .close =                        cypress_close,
        .write =                        cypress_write,
        .write_room =                   cypress_write_room,
        .ioctl =                        cypress_ioctl,
        .set_termios =                  cypress_set_termios,
        .tiocmget =                     cypress_tiocmget,
        .tiocmset =                     cypress_tiocmset,
        .chars_in_buffer =              cypress_chars_in_buffer,
        .throttle =                     cypress_throttle,
        .unthrottle =                   cypress_unthrottle,
        .read_int_callback =            cypress_read_int_callback,
        .write_int_callback =           cypress_write_int_callback,
};

/*****************************************************************************
 * Cypress serial helper functions
 *****************************************************************************/


/* This function can either set or retrieve the current serial line settings */
static int cypress_serial_control (struct usb_serial_port *port, unsigned baud_mask, int data_bits, int stop_bits,
                                   int parity_enable, int parity_type, int reset, int cypress_request_type)
{
        int new_baudrate = 0, retval = 0, tries = 0;
        struct cypress_private *priv;
        __u8 feature_buffer[8];
        unsigned long flags;

        dbg("%s", __FUNCTION__);
        
        priv = usb_get_serial_port_data(port);

        if (!priv->comm_is_ok)
                return -ENODEV;

        switch(cypress_request_type) {
                case CYPRESS_SET_CONFIG:

                        /*
                         * The general purpose firmware for the Cypress M8 allows for a maximum speed
                         * of 57600bps (I have no idea whether DeLorme chose to use the general purpose
                         * firmware or not), if you need to modify this speed setting for your own
                         * project please add your own chiptype and modify the code likewise.  The
                         * Cypress HID->COM device will work successfully up to 115200bps (but the
                         * actual throughput is around 3kBps).
                         */
                        if (baud_mask != priv->cbr_mask) {
                                dbg("%s - baud rate is changing", __FUNCTION__);
                                if ( priv->chiptype == CT_EARTHMATE ) {
                                        /* 300 and 600 baud rates are supported under the generic firmware,
                                         * but are not used with NMEA and SiRF protocols */
                                        
                                        if ( (baud_mask == B300) || (baud_mask == B600) ) {
                                                err("%s - failed setting baud rate, unsupported speed",
                                                    __FUNCTION__);
                                                new_baudrate = priv->baud_rate;
                                        } else if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) {
                                                err("%s - failed setting baud rate, unsupported speed",
                                                    __FUNCTION__);
                                                new_baudrate = priv->baud_rate;
                                        }
                                } else if (priv->chiptype == CT_CYPHIDCOM) {
                                        if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) {
                                                err("%s - failed setting baud rate, unsupported speed",
                                                    __FUNCTION__);
                                                new_baudrate = priv->baud_rate;
                                        }
                                } else if (priv->chiptype == CT_CA42V2) {
                                        if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) {
                                                err("%s - failed setting baud rate, unsupported speed",
                                                    __FUNCTION__);
                                                new_baudrate = priv->baud_rate;
                                        }
                                } else if (priv->chiptype == CT_GENERIC) {
                                        if ( (new_baudrate = mask_to_rate(baud_mask)) == -1) {
                                                err("%s - failed setting baud rate, unsupported speed",
                                                    __FUNCTION__);
                                                new_baudrate = priv->baud_rate;
                                        }
                                } else {
                                        info("%s - please define your chiptype", __FUNCTION__);
                                        new_baudrate = priv->baud_rate;
                                }
                        } else {  /* baud rate not changing, keep the old */
                                new_baudrate = priv->baud_rate;
                        }
                        dbg("%s - baud rate is being sent as %d", __FUNCTION__, new_baudrate);
                        
                        memset(feature_buffer, 0, 8);
                        /* fill the feature_buffer with new configuration */
                        *((u_int32_t *)feature_buffer) = new_baudrate;

                        feature_buffer[4] |= data_bits;   /* assign data bits in 2 bit space ( max 3 ) */
                        /* 1 bit gap */
                        feature_buffer[4] |= (stop_bits << 3);   /* assign stop bits in 1 bit space */
                        feature_buffer[4] |= (parity_enable << 4);   /* assign parity flag in 1 bit space */
                        feature_buffer[4] |= (parity_type << 5);   /* assign parity type in 1 bit space */
                        /* 1 bit gap */
                        feature_buffer[4] |= (reset << 7);   /* assign reset at end of byte, 1 bit space */
                                
                        dbg("%s - device is being sent this feature report:", __FUNCTION__);
                        dbg("%s - %02X - %02X - %02X - %02X - %02X", __FUNCTION__, feature_buffer[0], feature_buffer[1],
                            feature_buffer[2], feature_buffer[3], feature_buffer[4]);
                        
                        do {
                        retval = usb_control_msg (port->serial->dev, usb_sndctrlpipe(port->serial->dev, 0),
                                                  HID_REQ_SET_REPORT, USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
                                                          0x0300, 0, feature_buffer, 8, 500);

                                if (tries++ >= 3)
                                        break;

                        } while (retval != 8 && retval != -ENODEV);

                        if (retval != 8) {
                                err("%s - failed sending serial line settings - %d", __FUNCTION__, retval);
                                cypress_set_dead(port);
                        } else {
                                spin_lock_irqsave(&priv->lock, flags);
                                priv->baud_rate = new_baudrate;
                                priv->cbr_mask = baud_mask;
                                priv->current_config = feature_buffer[4];
                                spin_unlock_irqrestore(&priv->lock, flags);
                        }
                break;
                case CYPRESS_GET_CONFIG:
                        dbg("%s - retreiving serial line settings", __FUNCTION__);
                        /* set initial values in feature buffer */
                        memset(feature_buffer, 0, 8);

                        do {
                        retval = usb_control_msg (port->serial->dev, usb_rcvctrlpipe(port->serial->dev, 0),
                                                  HID_REQ_GET_REPORT, USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
                                                          0x0300, 0, feature_buffer, 8, 500);
                                
                                if (tries++ >= 3)
                                        break;

                        } while (retval != 5 && retval != -ENODEV);

                        if (retval != 5) {
                                err("%s - failed to retrieve serial line settings - %d", __FUNCTION__, retval);
                                cypress_set_dead(port);
                                return retval;
                        } else {
                                spin_lock_irqsave(&priv->lock, flags);

                                /* store the config in one byte, and later use bit masks to check values */
                                priv->current_config = feature_buffer[4];
                                priv->baud_rate = *((u_int32_t *)feature_buffer);
                                
                                if ( (priv->cbr_mask = rate_to_mask(priv->baud_rate)) == 0x40)
                                        dbg("%s - failed setting the baud mask (not defined)", __FUNCTION__);
                                spin_unlock_irqrestore(&priv->lock, flags);
                        }
        }
        spin_lock_irqsave(&priv->lock, flags);
        ++priv->cmd_count;
        spin_unlock_irqrestore(&priv->lock, flags);

        return retval;
} /* cypress_serial_control */


static void cypress_set_dead(struct usb_serial_port *port)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;

        spin_lock_irqsave(&priv->lock, flags);
        if (!priv->comm_is_ok) {
                spin_unlock_irqrestore(&priv->lock, flags);
                return;
        }
        priv->comm_is_ok = 0;
        spin_unlock_irqrestore(&priv->lock, flags);

        err("cypress_m8 suspending failing port %d - interval might be too short",
            port->number);
}


/* given a baud mask, it will return integer baud on success */
static int mask_to_rate (unsigned mask)
{
        int rate;

        switch (mask) {
                case B0: rate = 0; break;
                case B300: rate = 300; break;
                case B600: rate = 600; break;
                case B1200: rate = 1200; break;
                case B2400: rate = 2400; break;
                case B4800: rate = 4800; break;
                case B9600: rate = 9600; break;
                case B19200: rate = 19200; break;
                case B38400: rate = 38400; break;
                case B57600: rate = 57600; break;
                case B115200: rate = 115200; break;
                default: rate = -1;
        }

        return rate;
}


static unsigned rate_to_mask (int rate)
{
        unsigned mask;

        switch (rate) {
                case 0: mask = B0; break;
                case 300: mask = B300; break;
                case 600: mask = B600; break;
                case 1200: mask = B1200; break;
                case 2400: mask = B2400; break;
                case 4800: mask = B4800; break;
                case 9600: mask = B9600; break;
                case 19200: mask = B19200; break;
                case 38400: mask = B38400; break;
                case 57600: mask = B57600; break;
                case 115200: mask = B115200; break;
                default: mask = 0x40;
        }

        return mask;
}
/*****************************************************************************
 * Cypress serial driver functions
 *****************************************************************************/


static int generic_startup (struct usb_serial *serial)
{
        struct cypress_private *priv;
        struct usb_serial_port *port = serial->port[0];

        dbg("%s - port %d", __FUNCTION__, port->number);

        priv = kzalloc(sizeof (struct cypress_private), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->comm_is_ok = !0;
        spin_lock_init(&priv->lock);
        priv->buf = cypress_buf_alloc(CYPRESS_BUF_SIZE);
        if (priv->buf == NULL) {
                kfree(priv);
                return -ENOMEM;
        }
        init_waitqueue_head(&priv->delta_msr_wait);
        
        usb_reset_configuration (serial->dev);
        
        priv->cmd_ctrl = 0;
        priv->line_control = 0;
        priv->termios_initialized = 0;
        priv->rx_flags = 0;
        priv->cbr_mask = B300;
        if (interval > 0) {
                priv->write_urb_interval = interval;
                priv->read_urb_interval = interval;
                dbg("%s - port %d read & write intervals forced to %d",
                    __FUNCTION__,port->number,interval);
        } else {
                priv->write_urb_interval = port->interrupt_out_urb->interval;
                priv->read_urb_interval = port->interrupt_in_urb->interval;
                dbg("%s - port %d intervals: read=%d write=%d",
                    __FUNCTION__,port->number,
                    priv->read_urb_interval,priv->write_urb_interval);
        }
        usb_set_serial_port_data(port, priv);
        
        return 0;
}


static int cypress_earthmate_startup (struct usb_serial *serial)
{
        struct cypress_private *priv;

        dbg("%s", __FUNCTION__);

        if (generic_startup(serial)) {
                dbg("%s - Failed setting up port %d", __FUNCTION__,
                                serial->port[0]->number);
                return 1;
        }

        priv = usb_get_serial_port_data(serial->port[0]);
        priv->chiptype = CT_EARTHMATE;

        return 0;
} /* cypress_earthmate_startup */


static int cypress_hidcom_startup (struct usb_serial *serial)
{
        struct cypress_private *priv;

        dbg("%s", __FUNCTION__);

        if (generic_startup(serial)) {
                dbg("%s - Failed setting up port %d", __FUNCTION__,
                                serial->port[0]->number);
                return 1;
        }

        priv = usb_get_serial_port_data(serial->port[0]);
        priv->chiptype = CT_CYPHIDCOM;
        
        return 0;
} /* cypress_hidcom_startup */


static int cypress_ca42v2_startup (struct usb_serial *serial)
{
        struct cypress_private *priv;

        dbg("%s", __FUNCTION__);

        if (generic_startup(serial)) {
                dbg("%s - Failed setting up port %d", __FUNCTION__,
                                serial->port[0]->number);
                return 1;
        }

        priv = usb_get_serial_port_data(serial->port[0]);
        priv->chiptype = CT_CA42V2;

        return 0;
} /* cypress_ca42v2_startup */


static void cypress_shutdown (struct usb_serial *serial)
{
        struct cypress_private *priv;

        dbg ("%s - port %d", __FUNCTION__, serial->port[0]->number);

        /* all open ports are closed at this point */

        priv = usb_get_serial_port_data(serial->port[0]);

        if (priv) {
                cypress_buf_free(priv->buf);
                kfree(priv);
                usb_set_serial_port_data(serial->port[0], NULL);
        }
}


static int cypress_open (struct usb_serial_port *port, struct file *filp)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        struct usb_serial *serial = port->serial;
        unsigned long flags;
        int result = 0;

        dbg("%s - port %d", __FUNCTION__, port->number);

        if (!priv->comm_is_ok)
                return -EIO;

        /* clear halts before open */
        usb_clear_halt(serial->dev, 0x81);
        usb_clear_halt(serial->dev, 0x02);

        spin_lock_irqsave(&priv->lock, flags);
        /* reset read/write statistics */
        priv->bytes_in = 0;
        priv->bytes_out = 0;
        priv->cmd_count = 0;
        priv->rx_flags = 0;
        spin_unlock_irqrestore(&priv->lock, flags);

        /* setting to zero could cause data loss */
        port->tty->low_latency = 1;

        /* raise both lines and set termios */
        spin_lock_irqsave(&priv->lock, flags);
        priv->line_control = CONTROL_DTR | CONTROL_RTS;
        priv->cmd_ctrl = 1;
        spin_unlock_irqrestore(&priv->lock, flags);
        result = cypress_write(port, NULL, 0);

        if (result) {
                dev_err(&port->dev, "%s - failed setting the control lines - error %d\n", __FUNCTION__, result);
                return result;
        } else
                dbg("%s - success setting the control lines", __FUNCTION__);    

        cypress_set_termios(port, &priv->tmp_termios);

        /* setup the port and start reading from the device */
        if(!port->interrupt_in_urb){
                err("%s - interrupt_in_urb is empty!", __FUNCTION__);
                return(-1);
        }

        usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
                usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
                port->interrupt_in_urb->transfer_buffer, port->interrupt_in_urb->transfer_buffer_length,
                cypress_read_int_callback, port, priv->read_urb_interval);
        result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);

        if (result){
                dev_err(&port->dev, "%s - failed submitting read urb, error %d\n", __FUNCTION__, result);
                cypress_set_dead(port);
        }

        return result;
} /* cypress_open */


static void cypress_close(struct usb_serial_port *port, struct file * filp)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        unsigned int c_cflag;
        unsigned long flags;
        int bps;
        long timeout;
        wait_queue_t wait;

        dbg("%s - port %d", __FUNCTION__, port->number);

        /* wait for data to drain from buffer */
        spin_lock_irqsave(&priv->lock, flags);
        timeout = CYPRESS_CLOSING_WAIT;
        init_waitqueue_entry(&wait, current);
        add_wait_queue(&port->tty->write_wait, &wait);
        for (;;) {
                set_current_state(TASK_INTERRUPTIBLE);
                if (cypress_buf_data_avail(priv->buf) == 0
                || timeout == 0 || signal_pending(current)
                || !usb_get_intfdata(port->serial->interface))
                        break;
                spin_unlock_irqrestore(&priv->lock, flags);
                timeout = schedule_timeout(timeout);
                spin_lock_irqsave(&priv->lock, flags);
        }
        set_current_state(TASK_RUNNING);
        remove_wait_queue(&port->tty->write_wait, &wait);
        /* clear out any remaining data in the buffer */
        cypress_buf_clear(priv->buf);
        spin_unlock_irqrestore(&priv->lock, flags);
        
        /* wait for characters to drain from device */
        bps = tty_get_baud_rate(port->tty);
        if (bps > 1200)
                timeout = max((HZ*2560)/bps,HZ/10);
        else
                timeout = 2*HZ;
        schedule_timeout_interruptible(timeout);

        dbg("%s - stopping urbs", __FUNCTION__);
        usb_kill_urb (port->interrupt_in_urb);
        usb_kill_urb (port->interrupt_out_urb);

        if (port->tty) {
                c_cflag = port->tty->termios->c_cflag;
                if (c_cflag & HUPCL) {
                        /* drop dtr and rts */
                        priv = usb_get_serial_port_data(port);
                        spin_lock_irqsave(&priv->lock, flags);
                        priv->line_control = 0;
                        priv->cmd_ctrl = 1;
                        spin_unlock_irqrestore(&priv->lock, flags);
                        cypress_write(port, NULL, 0);
                }
        }

        if (stats)
                dev_info (&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
                          priv->bytes_in, priv->bytes_out, priv->cmd_count);
} /* cypress_close */


static int cypress_write(struct usb_serial_port *port, const unsigned char *buf, int count)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        
        dbg("%s - port %d, %d bytes", __FUNCTION__, port->number, count);

        /* line control commands, which need to be executed immediately,
           are not put into the buffer for obvious reasons.
         */
        if (priv->cmd_ctrl) {
                count = 0;
                goto finish;
        }
        
        if (!count)
                return count;
        
        spin_lock_irqsave(&priv->lock, flags);
        count = cypress_buf_put(priv->buf, buf, count);
        spin_unlock_irqrestore(&priv->lock, flags);

finish:
        cypress_send(port);

        return count;
} /* cypress_write */


static void cypress_send(struct usb_serial_port *port)
{
        int count = 0, result, offset, actual_size;
        struct cypress_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        
        if (!priv->comm_is_ok)
                return;

        dbg("%s - port %d", __FUNCTION__, port->number);
        dbg("%s - interrupt out size is %d", __FUNCTION__, port->interrupt_out_size);
        
        spin_lock_irqsave(&priv->lock, flags);
        if (priv->write_urb_in_use) {
                dbg("%s - can't write, urb in use", __FUNCTION__);
                spin_unlock_irqrestore(&priv->lock, flags);
                return;
        }
        spin_unlock_irqrestore(&priv->lock, flags);

        /* clear buffer */
        memset(port->interrupt_out_urb->transfer_buffer, 0, port->interrupt_out_size);

        spin_lock_irqsave(&priv->lock, flags);
        switch (port->interrupt_out_size) {
                case 32:
                        /* this is for the CY7C64013... */
                        offset = 2;
                        port->interrupt_out_buffer[0] = priv->line_control;
                        break;
                case 8:
                        /* this is for the CY7C63743... */
                        offset = 1;
                        port->interrupt_out_buffer[0] = priv->line_control;
                        break;
                default:
                        dbg("%s - wrong packet size", __FUNCTION__);
                        spin_unlock_irqrestore(&priv->lock, flags);
                        return;
        }

        if (priv->line_control & CONTROL_RESET)
                priv->line_control &= ~CONTROL_RESET;

        if (priv->cmd_ctrl) {
                priv->cmd_count++;
                dbg("%s - line control command being issued", __FUNCTION__);
                spin_unlock_irqrestore(&priv->lock, flags);
                goto send;
        } else
                spin_unlock_irqrestore(&priv->lock, flags);

        count = cypress_buf_get(priv->buf, &port->interrupt_out_buffer[offset],
                                port->interrupt_out_size-offset);

        if (count == 0) {
                return;
        }

        switch (port->interrupt_out_size) {
                case 32:
                        port->interrupt_out_buffer[1] = count;
                        break;
                case 8:
                        port->interrupt_out_buffer[0] |= count;
        }

        dbg("%s - count is %d", __FUNCTION__, count);

send:
        spin_lock_irqsave(&priv->lock, flags);
        priv->write_urb_in_use = 1;
        spin_unlock_irqrestore(&priv->lock, flags);

        if (priv->cmd_ctrl)
                actual_size = 1;
        else
                actual_size = count + (port->interrupt_out_size == 32 ? 2 : 1);
        
        usb_serial_debug_data(debug, &port->dev, __FUNCTION__, port->interrupt_out_size,
                              port->interrupt_out_urb->transfer_buffer);

        usb_fill_int_urb(port->interrupt_out_urb, port->serial->dev,
                usb_sndintpipe(port->serial->dev, port->interrupt_out_endpointAddress),
                port->interrupt_out_buffer, port->interrupt_out_size,
                cypress_write_int_callback, port, priv->write_urb_interval);
        result = usb_submit_urb (port->interrupt_out_urb, GFP_ATOMIC);
        if (result) {
                dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __FUNCTION__,
                        result);
                priv->write_urb_in_use = 0;
                cypress_set_dead(port);
        }

        spin_lock_irqsave(&priv->lock, flags);
        if (priv->cmd_ctrl) {
                priv->cmd_ctrl = 0;
        }
        priv->bytes_out += count; /* do not count the line control and size bytes */
        spin_unlock_irqrestore(&priv->lock, flags);

        usb_serial_port_softint(port);
} /* cypress_send */


/* returns how much space is available in the soft buffer */
static int cypress_write_room(struct usb_serial_port *port)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        int room = 0;
        unsigned long flags;

        dbg("%s - port %d", __FUNCTION__, port->number);

        spin_lock_irqsave(&priv->lock, flags);
        room = cypress_buf_space_avail(priv->buf);
        spin_unlock_irqrestore(&priv->lock, flags);

        dbg("%s - returns %d", __FUNCTION__, room);
        return room;
}


static int cypress_tiocmget (struct usb_serial_port *port, struct file *file)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        __u8 status, control;
        unsigned int result = 0;
        unsigned long flags;
        
        dbg("%s - port %d", __FUNCTION__, port->number);

        spin_lock_irqsave(&priv->lock, flags);
        control = priv->line_control;
        status = priv->current_status;
        spin_unlock_irqrestore(&priv->lock, flags);

        result = ((control & CONTROL_DTR)        ? TIOCM_DTR : 0)
                | ((control & CONTROL_RTS)       ? TIOCM_RTS : 0)
                | ((status & UART_CTS)        ? TIOCM_CTS : 0)
                | ((status & UART_DSR)        ? TIOCM_DSR : 0)
                | ((status & UART_RI)         ? TIOCM_RI  : 0)
                | ((status & UART_CD)         ? TIOCM_CD  : 0);

        dbg("%s - result = %x", __FUNCTION__, result);

        return result;
}


static int cypress_tiocmset (struct usb_serial_port *port, struct file *file,
                               unsigned int set, unsigned int clear)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;
        
        dbg("%s - port %d", __FUNCTION__, port->number);

        spin_lock_irqsave(&priv->lock, flags);
        if (set & TIOCM_RTS)
                priv->line_control |= CONTROL_RTS;
        if (set & TIOCM_DTR)
                priv->line_control |= CONTROL_DTR;
        if (clear & TIOCM_RTS)
                priv->line_control &= ~CONTROL_RTS;
        if (clear & TIOCM_DTR)
                priv->line_control &= ~CONTROL_DTR;
        spin_unlock_irqrestore(&priv->lock, flags);

        priv->cmd_ctrl = 1;
        return cypress_write(port, NULL, 0);
}


static int cypress_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);

        dbg("%s - port %d, cmd 0x%.4x", __FUNCTION__, port->number, cmd);

        switch (cmd) {
                case TIOCGSERIAL:
                        if (copy_to_user((void __user *)arg, port->tty->termios, sizeof(struct ktermios))) {
                                return -EFAULT;
                        }
                        return (0);
                        break;
                case TIOCSSERIAL:
                        if (copy_from_user(port->tty->termios, (void __user *)arg, sizeof(struct ktermios))) {
                                return -EFAULT;
                        }
                        /* here we need to call cypress_set_termios to invoke the new settings */
                        cypress_set_termios(port, &priv->tmp_termios);
                        return (0);
                        break;
                /* This code comes from drivers/char/serial.c and ftdi_sio.c */
                case TIOCMIWAIT:
                        while (priv != NULL) {
                                interruptible_sleep_on(&priv->delta_msr_wait);
                                /* see if a signal did it */
                                if (signal_pending(current))
                                        return -ERESTARTSYS;
                                else {
                                        char diff = priv->diff_status;

                                        if (diff == 0) {
                                                return -EIO; /* no change => error */
                                        }
                                        
                                        /* consume all events */
                                        priv->diff_status = 0;

                                        /* return 0 if caller wanted to know about these bits */
                                        if ( ((arg & TIOCM_RNG) && (diff & UART_RI)) ||
                                             ((arg & TIOCM_DSR) && (diff & UART_DSR)) ||
                                             ((arg & TIOCM_CD) && (diff & UART_CD)) ||
                                             ((arg & TIOCM_CTS) && (diff & UART_CTS)) ) {
                                                return 0;
                                        }
                                        /* otherwise caller can't care less about what happened,
                                         * and so we continue to wait for more events.
                                         */
                                }
                        }
                        return 0;
                        break;
                default:
                        break;
        }

        dbg("%s - arg not supported - it was 0x%04x - check include/asm/ioctls.h", __FUNCTION__, cmd);

        return -ENOIOCTLCMD;
} /* cypress_ioctl */


static void cypress_set_termios (struct usb_serial_port *port,
                struct ktermios *old_termios)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        struct tty_struct *tty;
        int data_bits, stop_bits, parity_type, parity_enable;
        unsigned cflag, iflag, baud_mask;
        unsigned long flags;
        __u8 oldlines;
        int linechange = 0;

        dbg("%s - port %d", __FUNCTION__, port->number);

        tty = port->tty;
        if ((!tty) || (!tty->termios)) {
                dbg("%s - no tty structures", __FUNCTION__);
                return;
        }

        spin_lock_irqsave(&priv->lock, flags);
        if (!priv->termios_initialized) {
                if (priv->chiptype == CT_EARTHMATE) {
                        *(tty->termios) = tty_std_termios;
                        tty->termios->c_cflag = B4800 | CS8 | CREAD | HUPCL |
                                CLOCAL;
                } else if (priv->chiptype == CT_CYPHIDCOM) {
                        *(tty->termios) = tty_std_termios;
                        tty->termios->c_cflag = B9600 | CS8 | CREAD | HUPCL |
                                CLOCAL;
                } else if (priv->chiptype == CT_CA42V2) {
                        *(tty->termios) = tty_std_termios;
                        tty->termios->c_cflag = B9600 | CS8 | CREAD | HUPCL |
                                CLOCAL;
                }
                priv->termios_initialized = 1;
        }
        spin_unlock_irqrestore(&priv->lock, flags);

        cflag = tty->termios->c_cflag;
        iflag = tty->termios->c_iflag;

        /* check if there are new settings */
        if (old_termios) {
                if ((cflag != old_termios->c_cflag) ||
                        (RELEVANT_IFLAG(iflag) !=
                         RELEVANT_IFLAG(old_termios->c_iflag))) {
                        dbg("%s - attempting to set new termios settings",
                                        __FUNCTION__);
                        /* should make a copy of this in case something goes
                         * wrong in the function, we can restore it */
                        spin_lock_irqsave(&priv->lock, flags);
                        priv->tmp_termios = *(tty->termios);
                        spin_unlock_irqrestore(&priv->lock, flags);
                } else {
                        dbg("%s - nothing to do, exiting", __FUNCTION__);
                        return;
                }
        } else
                return;

        /* set number of data bits, parity, stop bits */
        /* when parity is disabled the parity type bit is ignored */

        /* 1 means 2 stop bits, 0 means 1 stop bit */
        stop_bits = cflag & CSTOPB ? 1 : 0;

        if (cflag & PARENB) {
                parity_enable = 1;
                /* 1 means odd parity, 0 means even parity */
                parity_type = cflag & PARODD ? 1 : 0;
        } else
                parity_enable = parity_type = 0;

        if (cflag & CSIZE) {
                switch (cflag & CSIZE) {
                        case CS5:
                                data_bits = 0;
                                break;
                        case CS6:
                                data_bits = 1;
                                break;
                        case CS7:
                                data_bits = 2;
                                break;
                        case CS8:
                                data_bits = 3;
                                break;
                        default:
                                err("%s - CSIZE was set, but not CS5-CS8",
                                                __FUNCTION__);
                                data_bits = 3;
                }
        } else
                data_bits = 3;

        spin_lock_irqsave(&priv->lock, flags);
        oldlines = priv->line_control;
        if ((cflag & CBAUD) == B0) {
                /* drop dtr and rts */
                dbg("%s - dropping the lines, baud rate 0bps", __FUNCTION__);
                baud_mask = B0;
                priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
        } else {
                baud_mask = (cflag & CBAUD);
                switch(baud_mask) {
                        case B300:
                                dbg("%s - setting baud 300bps", __FUNCTION__);
                                break;
                        case B600:
                                dbg("%s - setting baud 600bps", __FUNCTION__);
                                break;
                        case B1200:
                                dbg("%s - setting baud 1200bps", __FUNCTION__);
                                break;
                        case B2400:
                                dbg("%s - setting baud 2400bps", __FUNCTION__);
                                break;
                        case B4800:
                                dbg("%s - setting baud 4800bps", __FUNCTION__);
                                break;
                        case B9600:
                                dbg("%s - setting baud 9600bps", __FUNCTION__);
                                break;
                        case B19200:
                                dbg("%s - setting baud 19200bps", __FUNCTION__);
                                break;
                        case B38400:
                                dbg("%s - setting baud 38400bps", __FUNCTION__);
                                break;
                        case B57600:
                                dbg("%s - setting baud 57600bps", __FUNCTION__);
                                break;
                        case B115200:
                                dbg("%s - setting baud 115200bps", __FUNCTION__);
                                break;
                        default:
                                dbg("%s - unknown masked baud rate", __FUNCTION__);
                }
                priv->line_control = (CONTROL_DTR | CONTROL_RTS);
        }
        spin_unlock_irqrestore(&priv->lock, flags);

        dbg("%s - sending %d stop_bits, %d parity_enable, %d parity_type, "
                        "%d data_bits (+5)", __FUNCTION__, stop_bits,
                        parity_enable, parity_type, data_bits);

        cypress_serial_control(port, baud_mask, data_bits, stop_bits,
                        parity_enable, parity_type, 0, CYPRESS_SET_CONFIG);

        /* we perform a CYPRESS_GET_CONFIG so that the current settings are
         * filled into the private structure this should confirm that all is
         * working if it returns what we just set */
        cypress_serial_control(port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);

        /* Here we can define custom tty settings for devices; the main tty
         * termios flag base comes from empeg.c */

        spin_lock_irqsave(&priv->lock, flags);
        if ( (priv->chiptype == CT_EARTHMATE) && (priv->baud_rate == 4800) ) {
                dbg("Using custom termios settings for a baud rate of "
                                "4800bps.");
                /* define custom termios settings for NMEA protocol */

                tty->termios->c_iflag /* input modes - */
                        &= ~(IGNBRK  /* disable ignore break */
                        | BRKINT     /* disable break causes interrupt */
                        | PARMRK     /* disable mark parity errors */
                        | ISTRIP     /* disable clear high bit of input char */
                        | INLCR      /* disable translate NL to CR */
                        | IGNCR      /* disable ignore CR */
                        | ICRNL      /* disable translate CR to NL */
                        | IXON);     /* disable enable XON/XOFF flow control */

                tty->termios->c_oflag /* output modes */
                        &= ~OPOST;    /* disable postprocess output char */

                tty->termios->c_lflag /* line discipline modes */
                        &= ~(ECHO     /* disable echo input characters */
                        | ECHONL      /* disable echo new line */
                        | ICANON      /* disable erase, kill, werase, and rprnt
                                         special characters */
                        | ISIG        /* disable interrupt, quit, and suspend
                                         special characters */
                        | IEXTEN);    /* disable non-POSIX special characters */
        } /* CT_CYPHIDCOM: Application should handle this for device */

        linechange = (priv->line_control != oldlines);
        spin_unlock_irqrestore(&priv->lock, flags);

        /* if necessary, set lines */
        if (linechange) {
                priv->cmd_ctrl = 1;
                cypress_write(port, NULL, 0);
        }
} /* cypress_set_termios */


/* returns amount of data still left in soft buffer */
static int cypress_chars_in_buffer(struct usb_serial_port *port)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        int chars = 0;
        unsigned long flags;

        dbg("%s - port %d", __FUNCTION__, port->number);
        
        spin_lock_irqsave(&priv->lock, flags);
        chars = cypress_buf_data_avail(priv->buf);
        spin_unlock_irqrestore(&priv->lock, flags);

        dbg("%s - returns %d", __FUNCTION__, chars);
        return chars;
}


static void cypress_throttle (struct usb_serial_port *port)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        unsigned long flags;

        dbg("%s - port %d", __FUNCTION__, port->number);

        spin_lock_irqsave(&priv->lock, flags);
        priv->rx_flags = THROTTLED;
        spin_unlock_irqrestore(&priv->lock, flags);
}


static void cypress_unthrottle (struct usb_serial_port *port)
{
        struct cypress_private *priv = usb_get_serial_port_data(port);
        int actually_throttled, result;
        unsigned long flags;

        dbg("%s - port %d", __FUNCTION__, port->number);

        spin_lock_irqsave(&priv->lock, flags);
        actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
        priv->rx_flags = 0;
        spin_unlock_irqrestore(&priv->lock, flags);

        if (!priv->comm_is_ok)
                return;

        if (actually_throttled) {
                port->interrupt_in_urb->dev = port->serial->dev;

                result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
                if (result) {
                        dev_err(&port->dev, "%s - failed submitting read urb, "
                                        "error %d\n", __FUNCTION__, result);
                        cypress_set_dead(port);
                }
        }
}


static void cypress_read_int_callback(struct urb *urb)
{
        struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
        struct cypress_private *priv = usb_get_serial_port_data(port);
        struct tty_struct *tty;
        unsigned char *data = urb->transfer_buffer;
        unsigned long flags;
        char tty_flag = TTY_NORMAL;
        int havedata = 0;
        int bytes = 0;
        int result;
        int i = 0;

        dbg("%s - port %d", __FUNCTION__, port->number);

        switch (urb->status) {
        case 0: /* success */
                break;
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                /* precursor to disconnect so just go away */
                return;
        case -EPIPE:
                usb_clear_halt(port->serial->dev,0x81);
                break;
        default:
                /* something ugly is going on... */
                dev_err(&urb->dev->dev,"%s - unexpected nonzero read status received: %d\n",
                        __FUNCTION__,urb->status);
                cypress_set_dead(port);
                return;
        }

        spin_lock_irqsave(&priv->lock, flags);
        if (priv->rx_flags & THROTTLED) {
                dbg("%s - now throttling", __FUNCTION__);
                priv->rx_flags |= ACTUALLY_THROTTLED;
                spin_unlock_irqrestore(&priv->lock, flags);
                return;
        }
        spin_unlock_irqrestore(&priv->lock, flags);

        tty = port->tty;
        if (!tty) {
                dbg("%s - bad tty pointer - exiting", __FUNCTION__);
                return;
        }

        spin_lock_irqsave(&priv->lock, flags);
        switch(urb->actual_length) {
                case 32:
                        /* This is for the CY7C64013... */
                        priv->current_status = data[0] & 0xF8;
                        bytes = data[1] + 2;
                        i = 2;
                        if (bytes > 2)
                                havedata = 1;
                        break;
                case 8:
                        /* This is for the CY7C63743... */
                        priv->current_status = data[0] & 0xF8;
                        bytes = (data[0] & 0x07) + 1;
                        i = 1;
                        if (bytes > 1)
                                havedata = 1;
                        break;
                default:
                        dbg("%s - wrong packet size - received %d bytes",
                                        __FUNCTION__, urb->actual_length);
                        spin_unlock_irqrestore(&priv->lock, flags);
                        goto continue_read;
        }
        spin_unlock_irqrestore(&priv->lock, flags);

        usb_serial_debug_data (debug, &port->dev, __FUNCTION__,
                        urb->actual_length, data);

        spin_lock_irqsave(&priv->lock, flags);
        /* check to see if status has changed */
        if (priv != NULL) {
                if (priv->current_status != priv->prev_status) {
                        priv->diff_status |= priv->current_status ^
                                priv->prev_status;
                        wake_up_interruptible(&priv->delta_msr_wait);
                        priv->prev_status = priv->current_status;
                }
        }
        spin_unlock_irqrestore(&priv->lock, flags);

        /* hangup, as defined in acm.c... this might be a bad place for it
         * though */
        if (tty && !(tty->termios->c_cflag & CLOCAL) &&
                        !(priv->current_status & UART_CD)) {
                dbg("%s - calling hangup", __FUNCTION__);
                tty_hangup(tty);
                goto continue_read;
        }

        /* There is one error bit... I'm assuming it is a parity error
         * indicator as the generic firmware will set this bit to 1 if a
         * parity error occurs.
         * I can not find reference to any other error events. */
        spin_lock_irqsave(&priv->lock, flags);
        if (priv->current_status & CYP_ERROR) {
                spin_unlock_irqrestore(&priv->lock, flags);
                tty_flag = TTY_PARITY;
                dbg("%s - Parity Error detected", __FUNCTION__);
        } else
                spin_unlock_irqrestore(&priv->lock, flags);

        /* process read if there is data other than line status */
        if (tty && (bytes > i)) {
                bytes = tty_buffer_request_room(tty, bytes);
                for (; i < bytes ; ++i) {
                        dbg("pushing byte number %d - %d - %c", i, data[i],
                                        data[i]);
                        tty_insert_flip_char(tty, data[i], tty_flag);
                }
                tty_flip_buffer_push(port->tty);
        }

        spin_lock_irqsave(&priv->lock, flags);
        /* control and status byte(s) are also counted */
        priv->bytes_in += bytes;
        spin_unlock_irqrestore(&priv->lock, flags);

continue_read:

        /* Continue trying to always read... unless the port has closed. */

        if (port->open_count > 0 && priv->comm_is_ok) {
                usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
                                usb_rcvintpipe(port->serial->dev,
                                        port->interrupt_in_endpointAddress),
                                port->interrupt_in_urb->transfer_buffer,
                                port->interrupt_in_urb->transfer_buffer_length,
                                cypress_read_int_callback, port, priv->read_urb_interval);
                result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
                if (result) {
                        dev_err(&urb->dev->dev, "%s - failed resubmitting "
                                        "read urb, error %d\n", __FUNCTION__,
                                        result);
                        cypress_set_dead(port);
                }
        }

        return;
} /* cypress_read_int_callback */


static void cypress_write_int_callback(struct urb *urb)
{
        struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
        struct cypress_private *priv = usb_get_serial_port_data(port);
        int result;

        dbg("%s - port %d", __FUNCTION__, port->number);
        
        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);
                        priv->write_urb_in_use = 0;
                        return;
                case -EPIPE: /* no break needed; clear halt and resubmit */
                        if (!priv->comm_is_ok)
                                break;
                        usb_clear_halt(port->serial->dev, 0x02);
                        /* error in the urb, so we have to resubmit it */
                        dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
                        port->interrupt_out_urb->transfer_buffer_length = 1;
                        port->interrupt_out_urb->dev = port->serial->dev;
                        result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
                        if (!result)
                                return;
                        dev_err(&urb->dev->dev, "%s - failed resubmitting write urb, error %d\n",
                                __FUNCTION__, result);
                        cypress_set_dead(port);
                        break;
                default:
                        dev_err(&urb->dev->dev,"%s - unexpected nonzero write status received: %d\n",
                                __FUNCTION__,urb->status);
                        cypress_set_dead(port);
                        break;
        }
        
        priv->write_urb_in_use = 0;
        
        /* send any buffered data */
        cypress_send(port);
}


/*****************************************************************************
 * Write buffer functions - buffering code from pl2303 used
 *****************************************************************************/

/*
 * cypress_buf_alloc
 *
 * Allocate a circular buffer and all associated memory.
 */

static struct cypress_buf *cypress_buf_alloc(unsigned int size)
{

        struct cypress_buf *cb;


        if (size == 0)
                return NULL;

        cb = kmalloc(sizeof(struct cypress_buf), GFP_KERNEL);
        if (cb == NULL)
                return NULL;

        cb->buf_buf = kmalloc(size, GFP_KERNEL);
        if (cb->buf_buf == NULL) {
                kfree(cb);
                return NULL;
        }

        cb->buf_size = size;
        cb->buf_get = cb->buf_put = cb->buf_buf;

        return cb;

}


/*
 * cypress_buf_free
 *
 * Free the buffer and all associated memory.
 */

static void cypress_buf_free(struct cypress_buf *cb)
{
        if (cb) {
                kfree(cb->buf_buf);
                kfree(cb);
        }
}


/*
 * cypress_buf_clear
 *
 * Clear out all data in the circular buffer.
 */

static void cypress_buf_clear(struct cypress_buf *cb)
{
        if (cb != NULL)
                cb->buf_get = cb->buf_put;
                /* equivalent to a get of all data available */
}


/*
 * cypress_buf_data_avail
 *
 * Return the number of bytes of data available in the circular
 * buffer.
 */

static unsigned int cypress_buf_data_avail(struct cypress_buf *cb)
{
        if (cb != NULL)
                return ((cb->buf_size + cb->buf_put - cb->buf_get) % cb->buf_size);
        else
                return 0;
}


/*
 * cypress_buf_space_avail
 *
 * Return the number of bytes of space available in the circular
 * buffer.
 */

static unsigned int cypress_buf_space_avail(struct cypress_buf *cb)
{
        if (cb != NULL)
                return ((cb->buf_size + cb->buf_get - cb->buf_put - 1) % cb->buf_size);
        else
                return 0;
}


/*
 * cypress_buf_put
 *
 * Copy data data from a user buffer and put it into the circular buffer.
 * Restrict to the amount of space available.
 *
 * Return the number of bytes copied.
 */

static unsigned int cypress_buf_put(struct cypress_buf *cb, const char *buf,
        unsigned int count)
{

        unsigned int len;


        if (cb == NULL)
                return 0;

        len  = cypress_buf_space_avail(cb);
        if (count > len)
                count = len;

        if (count == 0)
                return 0;

        len = cb->buf_buf + cb->buf_size - cb->buf_put;
        if (count > len) {
                memcpy(cb->buf_put, buf, len);
                memcpy(cb->buf_buf, buf+len, count - len);
                cb->buf_put = cb->buf_buf + count - len;
        } else {
                memcpy(cb->buf_put, buf, count);
                if (count < len)
                        cb->buf_put += count;
                else /* count == len */
                        cb->buf_put = cb->buf_buf;
        }

        return count;

}


/*
 * cypress_buf_get
 *
 * Get data from the circular buffer and copy to the given buffer.
 * Restrict to the amount of data available.
 *
 * Return the number of bytes copied.
 */

static unsigned int cypress_buf_get(struct cypress_buf *cb, char *buf,
        unsigned int count)
{

        unsigned int len;


        if (cb == NULL)
                return 0;

        len = cypress_buf_data_avail(cb);
        if (count > len)
                count = len;

        if (count == 0)
                return 0;

        len = cb->buf_buf + cb->buf_size - cb->buf_get;
        if (count > len) {
                memcpy(buf, cb->buf_get, len);
                memcpy(buf+len, cb->buf_buf, count - len);
                cb->buf_get = cb->buf_buf + count - len;
        } else {
                memcpy(buf, cb->buf_get, count);
                if (count < len)
                        cb->buf_get += count;
                else /* count == len */
                        cb->buf_get = cb->buf_buf;
        }

        return count;

}

/*****************************************************************************
 * Module functions
 *****************************************************************************/

static int __init cypress_init(void)
{
        int retval;
        
        dbg("%s", __FUNCTION__);
        
        retval = usb_serial_register(&cypress_earthmate_device);
        if (retval)
                goto failed_em_register;
        retval = usb_serial_register(&cypress_hidcom_device);
        if (retval)
                goto failed_hidcom_register;
        retval = usb_serial_register(&cypress_ca42v2_device);
        if (retval)
                goto failed_ca42v2_register;
        retval = usb_register(&cypress_driver);
        if (retval)
                goto failed_usb_register;

        info(DRIVER_DESC " " DRIVER_VERSION);
        return 0;

failed_usb_register:
        usb_serial_deregister(&cypress_ca42v2_device);
failed_ca42v2_register:
        usb_serial_deregister(&cypress_hidcom_device);
failed_hidcom_register:
        usb_serial_deregister(&cypress_earthmate_device);
failed_em_register:
        return retval;
}


static void __exit cypress_exit (void)
{
        dbg("%s", __FUNCTION__);

        usb_deregister (&cypress_driver);
        usb_serial_deregister (&cypress_earthmate_device);
        usb_serial_deregister (&cypress_hidcom_device);
        usb_serial_deregister (&cypress_ca42v2_device);
}


module_init(cypress_init);
module_exit(cypress_exit);

MODULE_AUTHOR( DRIVER_AUTHOR );
MODULE_DESCRIPTION( DRIVER_DESC );
MODULE_VERSION( DRIVER_VERSION );
MODULE_LICENSE("GPL");

module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
module_param(stats, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(stats, "Enable statistics or not");
module_param(interval, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(interval, "Overrides interrupt interval");