text: /*
   * 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.
   */
  
  /* 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/kfifo.h>
  #include <linux/delay.h>
  #include <linux/uaccess.h>
  #include <asm/unaligned.h>
  
  #include "cypress_m8.h"
  
  
  static bool debug;
  static bool stats;
  static int interval;
  static bool unstable_bauds;
  
  /*
   * Version Information
   */
  #define DRIVER_VERSION "v1.10"
  #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
  
  static const 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 const struct usb_device_id id_table_cyphidcomrs232[] = {
  	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
  	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
  	{ }						/* Terminating entry */
  };
  
  static const struct usb_device_id id_table_nokiaca42v2[] = {
  	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
  	{ }						/* Terminating entry */
  };
  
  static const 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_POWERCOM, PRODUCT_ID_UPS) },
  	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
  	{ }						/* Terminating entry */
  };
  
  MODULE_DEVICE_TABLE(usb, id_table_combined);
  
  enum packet_format {
  	packet_format_1,  /* b0:status, b1:payload count */
  	packet_format_2   /* b0[7:3]:status, b0[2:0]:payload count */
  };
  
  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 kfifo write_fifo;	   /* write fifo */
  	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 */
  	enum packet_format pkt_fmt;	   /* format to use for packet send / receive */
  	int get_cfg_unsafe;		   /* If true, the CYPRESS_GET_CONFIG is unsafe */
  	int baud_rate;			   /* stores current baud rate in
  					      integer 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 argument sent to
  	   cypress_set_termios old_termios */
  	struct ktermios tmp_termios; 	   /* stores the old termios settings */
  };
  
  /* 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_release(struct usb_serial *serial);
  static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
  static void cypress_close(struct usb_serial_port *port);
  static void cypress_dtr_rts(struct usb_serial_port *port, int on);
  static int  cypress_write(struct tty_struct *tty, 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 tty_struct *tty);
  static int  cypress_ioctl(struct tty_struct *tty,
  			unsigned int cmd, unsigned long arg);
  static void cypress_set_termios(struct tty_struct *tty,
  			struct usb_serial_port *port, struct ktermios *old);
  static int  cypress_tiocmget(struct tty_struct *tty);
  static int  cypress_tiocmset(struct tty_struct *tty,
  			unsigned int set, unsigned int clear);
  static int  cypress_chars_in_buffer(struct tty_struct *tty);
  static void cypress_throttle(struct tty_struct *tty);
  static void cypress_unthrottle(struct tty_struct *tty);
  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);
  
  static struct usb_serial_driver cypress_earthmate_device = {
  	.driver = {
  		.owner =		THIS_MODULE,
  		.name =			"earthmate",
  	},
  	.description =			"DeLorme Earthmate USB",
  	.id_table =			id_table_earthmate,
  	.num_ports =			1,
  	.attach =			cypress_earthmate_startup,
  	.release =			cypress_release,
  	.open =				cypress_open,
  	.close =			cypress_close,
  	.dtr_rts =			cypress_dtr_rts,
  	.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_ports =			1,
  	.attach =			cypress_hidcom_startup,
  	.release =			cypress_release,
  	.open =				cypress_open,
  	.close =			cypress_close,
  	.dtr_rts =			cypress_dtr_rts,
  	.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_ports =			1,
  	.attach =			cypress_ca42v2_startup,
  	.release =			cypress_release,
  	.open =				cypress_open,
  	.close =			cypress_close,
  	.dtr_rts =			cypress_dtr_rts,
  	.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 * const serial_drivers[] = {
  	&cypress_earthmate_device, &cypress_hidcom_device,
  	&cypress_ca42v2_device, NULL
  };
  
  /*****************************************************************************
   * Cypress serial helper functions
   *****************************************************************************/
  
  
  static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
  {
  	struct cypress_private *priv;
  	priv = usb_get_serial_port_data(port);
  
  	if (unstable_bauds)
  		return new_rate;
  
  	/*
  	 * 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 (port->serial->dev->speed == USB_SPEED_LOW) {
  		/*
  		 * Mike Isely <isely@pobox.com> 2-Feb-2008: The
  		 * Cypress app note that describes this mechanism
  		 * states the the low-speed part can't handle more
  		 * than 800 bytes/sec, in which case 4800 baud is the
  		 * safest speed for a part like that.
  		 */
  		if (new_rate > 4800) {
  			dbg("%s - failed setting baud rate, device incapable "
  			    "speed %d", __func__, new_rate);
  			return -1;
  		}
  	}
  	switch (priv->chiptype) {
  	case CT_EARTHMATE:
  		if (new_rate <= 600) {
  			/* 300 and 600 baud rates are supported under
  			 * the generic firmware, but are not used with
  			 * NMEA and SiRF protocols */
  			dbg("%s - failed setting baud rate, unsupported speed "
  			    "of %d on Earthmate GPS", __func__, new_rate);
  			return -1;
  		}
  		break;
  	default:
  		break;
  	}
  	return new_rate;
  }
  
  
  /* This function can either set or retrieve the current serial line settings */
  static int cypress_serial_control(struct tty_struct *tty,
  	struct usb_serial_port *port, speed_t baud_rate, 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;
  	const unsigned int feature_len = 5;
  	unsigned long flags;
  
  	priv = usb_get_serial_port_data(port);
  
  	if (!priv->comm_is_ok)
  		return -ENODEV;
  
  	feature_buffer = kcalloc(feature_len, sizeof(u8), GFP_KERNEL);
  	if (!feature_buffer)
  		return -ENOMEM;
  
  	switch (cypress_request_type) {
  	case CYPRESS_SET_CONFIG:
  		/* 0 means 'Hang up' so doesn't change the true bit rate */
  		new_baudrate = priv->baud_rate;
  		if (baud_rate && baud_rate != priv->baud_rate) {
  			dbg("%s - baud rate is changing", __func__);
  			retval = analyze_baud_rate(port, baud_rate);
  			if (retval >= 0) {
  				new_baudrate = retval;
  				dbg("%s - New baud rate set to %d",
  				    __func__, new_baudrate);
  			}
  		}
  		dbg("%s - baud rate is being sent as %d",
  					__func__, new_baudrate);
  
  		/* fill the feature_buffer with new configuration */
  		put_unaligned_le32(new_baudrate, feature_buffer);
  		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:",
  								__func__);
  		dbg("%s - %02X - %02X - %02X - %02X - %02X", __func__,
  			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,
  					feature_len, 500);
  
  			if (tries++ >= 3)
  				break;
  
  		} while (retval != feature_len &&
  			 retval != -ENODEV);
  
  		if (retval != feature_len) {
  			dev_err(&port->dev, "%s - failed sending serial "
  				"line settings - %d\n", __func__, retval);
  			cypress_set_dead(port);
  		} else {
  			spin_lock_irqsave(&priv->lock, flags);
  			priv->baud_rate = new_baudrate;
  			priv->current_config = feature_buffer[4];
  			spin_unlock_irqrestore(&priv->lock, flags);
  			/* If we asked for a speed change encode it */
  			if (baud_rate)
  				tty_encode_baud_rate(tty,
  					new_baudrate, new_baudrate);
  		}
  	break;
  	case CYPRESS_GET_CONFIG:
  		if (priv->get_cfg_unsafe) {
  			/* Not implemented for this device,
  			   and if we try to do it we're likely
  			   to crash the hardware. */
  			retval = -ENOTTY;
  			goto out;
  		}
  		dbg("%s - retreiving serial line settings", __func__);
  		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,
  					feature_len, 500);
  
  			if (tries++ >= 3)
  				break;
  		} while (retval != feature_len
  						&& retval != -ENODEV);
  
  		if (retval != feature_len) {
  			dev_err(&port->dev, "%s - failed to retrieve serial "
  				"line settings - %d\n", __func__, retval);
  			cypress_set_dead(port);
  			goto out;
  		} 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 = get_unaligned_le32(feature_buffer);
  			spin_unlock_irqrestore(&priv->lock, flags);
  		}
  	}
  	spin_lock_irqsave(&priv->lock, flags);
  	++priv->cmd_count;
  	spin_unlock_irqrestore(&priv->lock, flags);
  out:
  	kfree(feature_buffer);
  	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);
  
  	dev_err(&port->dev, "cypress_m8 suspending failing port %d - "
  		"interval might be too short\n", port->number);
  }
  
  
  /*****************************************************************************
   * Cypress serial driver functions
   *****************************************************************************/
  
  
  static int generic_startup(struct usb_serial *serial)
  {
  	struct cypress_private *priv;
  	struct usb_serial_port *port = serial->port[0];
  
  	priv = kzalloc(sizeof(struct cypress_private), GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
  
  	priv->comm_is_ok = !0;
  	spin_lock_init(&priv->lock);
  	if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
  		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;
  	/* Default packet format setting is determined by packet size.
  	   Anything with a size larger then 9 must have a separate
  	   count field since the 3 bit count field is otherwise too
  	   small.  Otherwise we can use the slightly more compact
  	   format.  This is in accordance with the cypress_m8 serial
  	   converter app note. */
  	if (port->interrupt_out_size > 9)
  		priv->pkt_fmt = packet_format_1;
  	else
  		priv->pkt_fmt = packet_format_2;
  
  	if (interval > 0) {
  		priv->write_urb_interval = interval;
  		priv->read_urb_interval = interval;
  		dbg("%s - port %d read & write intervals forced to %d",
  		    __func__, 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",
  		    __func__, 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;
  	struct usb_serial_port *port = serial->port[0];
  
  	if (generic_startup(serial)) {
  		dbg("%s - Failed setting up port %d", __func__,
  				port->number);
  		return 1;
  	}
  
  	priv = usb_get_serial_port_data(port);
  	priv->chiptype = CT_EARTHMATE;
  	/* All Earthmate devices use the separated-count packet
  	   format!  Idiotic. */
  	priv->pkt_fmt = packet_format_1;
  	if (serial->dev->descriptor.idProduct !=
  				cpu_to_le16(PRODUCT_ID_EARTHMATEUSB)) {
  		/* The old original USB Earthmate seemed able to
  		   handle GET_CONFIG requests; everything they've
  		   produced since that time crashes if this command is
  		   attempted :-( */
  		dbg("%s - Marking this device as unsafe for GET_CONFIG "
  		    "commands", __func__);
  		priv->get_cfg_unsafe = !0;
  	}
  
  	return 0;
  } /* cypress_earthmate_startup */
  
  
  static int cypress_hidcom_startup(struct usb_serial *serial)
  {
  	struct cypress_private *priv;
  
  	if (generic_startup(serial)) {
  		dbg("%s - Failed setting up port %d", __func__,
  				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;
  
  	if (generic_startup(serial)) {
  		dbg("%s - Failed setting up port %d", __func__,
  				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_release(struct usb_serial *serial)
  {
  	struct cypress_private *priv;
  
  	/* all open ports are closed at this point */
  	priv = usb_get_serial_port_data(serial->port[0]);
  
  	if (priv) {
  		kfifo_free(&priv->write_fifo);
  		kfree(priv);
  	}
  }
  
  
  static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
  {
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	struct usb_serial *serial = port->serial;
  	unsigned long flags;
  	int result = 0;
  
  	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);
  
  	/* Set termios */
  	cypress_send(port);
  
  	if (tty)
  		cypress_set_termios(tty, port, &priv->tmp_termios);
  
  	/* setup the port and start reading from the device */
  	if (!port->interrupt_in_urb) {
  		dev_err(&port->dev, "%s - interrupt_in_urb is empty!\n",
  			__func__);
  		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",
  							__func__, result);
  		cypress_set_dead(port);
  	}
  	port->port.drain_delay = 256;
  	return result;
  } /* cypress_open */
  
  static void cypress_dtr_rts(struct usb_serial_port *port, int on)
  {
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	/* drop dtr and rts */
  	spin_lock_irq(&priv->lock);
  	if (on == 0)
  		priv->line_control = 0;
  	else 
  		priv->line_control = CONTROL_DTR | CONTROL_RTS;
  	priv->cmd_ctrl = 1;
  	spin_unlock_irq(&priv->lock);
  	cypress_write(NULL, port, NULL, 0);
  }
  
  static void cypress_close(struct usb_serial_port *port)
  {
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	unsigned long flags;
  
  	/* writing is potentially harmful, lock must be taken */
  	mutex_lock(&port->serial->disc_mutex);
  	if (port->serial->disconnected) {
  		mutex_unlock(&port->serial->disc_mutex);
  		return;
  	}
  	spin_lock_irqsave(&priv->lock, flags);
  	kfifo_reset_out(&priv->write_fifo);
  	spin_unlock_irqrestore(&priv->lock, flags);
  
  	dbg("%s - stopping urbs", __func__);
  	usb_kill_urb(port->interrupt_in_urb);
  	usb_kill_urb(port->interrupt_out_urb);
  
  	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);
  	mutex_unlock(&port->serial->disc_mutex);
  } /* cypress_close */
  
  
  static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
  					const unsigned char *buf, int count)
  {
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  
  	dbg("%s - port %d, %d bytes", __func__, 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;
  
  	count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);
  
  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 - interrupt out size is %d", __func__,
  						port->interrupt_out_size);
  
  	spin_lock_irqsave(&priv->lock, flags);
  	if (priv->write_urb_in_use) {
  		dbg("%s - can't write, urb in use", __func__);
  		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 (priv->pkt_fmt) {
  	default:
  	case packet_format_1:
  		/* this is for the CY7C64013... */
  		offset = 2;
  		port->interrupt_out_buffer[0] = priv->line_control;
  		break;
  	case packet_format_2:
  		/* this is for the CY7C63743... */
  		offset = 1;
  		port->interrupt_out_buffer[0] = priv->line_control;
  		break;
  	}
  
  	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", __func__);
  		spin_unlock_irqrestore(&priv->lock, flags);
  		goto send;
  	} else
  		spin_unlock_irqrestore(&priv->lock, flags);
  
  	count = kfifo_out_locked(&priv->write_fifo,
  					&port->interrupt_out_buffer[offset],
  					port->interrupt_out_size - offset,
  					&priv->lock);
  	if (count == 0)
  		return;
  
  	switch (priv->pkt_fmt) {
  	default:
  	case packet_format_1:
  		port->interrupt_out_buffer[1] = count;
  		break;
  	case packet_format_2:
  		port->interrupt_out_buffer[0] |= count;
  	}
  
  	dbg("%s - count is %d", __func__, 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 +
  			      (priv->pkt_fmt == packet_format_1 ? 2 : 1);
  
  	usb_serial_debug_data(debug, &port->dev, __func__,
  		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_console(port,
  				"%s - failed submitting write urb, error %d\n",
  							__func__, 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;
  
  	/* do not count the line control and size bytes */
  	priv->bytes_out += count;
  	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 tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	int room = 0;
  	unsigned long flags;
  
  	spin_lock_irqsave(&priv->lock, flags);
  	room = kfifo_avail(&priv->write_fifo);
  	spin_unlock_irqrestore(&priv->lock, flags);
  
  	dbg("%s - returns %d", __func__, room);
  	return room;
  }
  
  
  static int cypress_tiocmget(struct tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	__u8 status, control;
  	unsigned int result = 0;
  	unsigned long flags;
  
  	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", __func__, result);
  
  	return result;
  }
  
  
  static int cypress_tiocmset(struct tty_struct *tty,
  			       unsigned int set, unsigned int clear)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	unsigned long flags;
  
  	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;
  	priv->cmd_ctrl = 1;
  	spin_unlock_irqrestore(&priv->lock, flags);
  
  	return cypress_write(tty, port, NULL, 0);
  }
  
  
  static int cypress_ioctl(struct tty_struct *tty,
  					unsigned int cmd, unsigned long arg)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  
  	dbg("%s - port %d, cmd 0x%.4x", __func__, port->number, cmd);
  
  	switch (cmd) {
  	/* 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;
  	default:
  		break;
  	}
  	dbg("%s - arg not supported - it was 0x%04x - check include/asm/ioctls.h", __func__, cmd);
  	return -ENOIOCTLCMD;
  } /* cypress_ioctl */
  
  
  static void cypress_set_termios(struct tty_struct *tty,
  	struct usb_serial_port *port, struct ktermios *old_termios)
  {
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	int data_bits, stop_bits, parity_type, parity_enable;
  	unsigned cflag, iflag;
  	unsigned long flags;
  	__u8 oldlines;
  	int linechange = 0;
  
  	spin_lock_irqsave(&priv->lock, flags);
  	/* We can't clean this one up as we don't know the device type
  	   early enough */
  	if (!priv->termios_initialized) {
  		if (priv->chiptype == CT_EARTHMATE) {
  			*(tty->termios) = tty_std_termios;
  			tty->termios->c_cflag = B4800 | CS8 | CREAD | HUPCL |
  				CLOCAL;
  			tty->termios->c_ispeed = 4800;
  			tty->termios->c_ospeed = 4800;
  		} else if (priv->chiptype == CT_CYPHIDCOM) {
  			*(tty->termios) = tty_std_termios;
  			tty->termios->c_cflag = B9600 | CS8 | CREAD | HUPCL |
  				CLOCAL;
  			tty->termios->c_ispeed = 9600;
  			tty->termios->c_ospeed = 9600;
  		} else if (priv->chiptype == CT_CA42V2) {
  			*(tty->termios) = tty_std_termios;
  			tty->termios->c_cflag = B9600 | CS8 | CREAD | HUPCL |
  				CLOCAL;
  			tty->termios->c_ispeed = 9600;
  			tty->termios->c_ospeed = 9600;
  		}
  		priv->termios_initialized = 1;
  	}
  	spin_unlock_irqrestore(&priv->lock, flags);
  
  	/* Unsupported features need clearing */
  	tty->termios->c_cflag &= ~(CMSPAR|CRTSCTS);
  
  	cflag = tty->termios->c_cflag;
  	iflag = tty->termios->c_iflag;
  
  	/* check if there are new settings */
  	if (old_termios) {
  		spin_lock_irqsave(&priv->lock, flags);
  		priv->tmp_termios = *(tty->termios);
  		spin_unlock_irqrestore(&priv->lock, flags);
  	}
  
  	/* 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;
  
  	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:
  		dev_err(&port->dev, "%s - CSIZE was set, but not CS5-CS8\n",
  			__func__);
  		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", __func__);
  		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
  	} else
  		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)", __func__, stop_bits,
  			parity_enable, parity_type, data_bits);
  
  	cypress_serial_control(tty, port, tty_get_baud_rate(tty),
  			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(tty, 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(tty, port, NULL, 0);
  	}
  } /* cypress_set_termios */
  
  
  /* returns amount of data still left in soft buffer */
  static int cypress_chars_in_buffer(struct tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	int chars = 0;
  	unsigned long flags;
  
  	spin_lock_irqsave(&priv->lock, flags);
  	chars = kfifo_len(&priv->write_fifo);
  	spin_unlock_irqrestore(&priv->lock, flags);
  
  	dbg("%s - returns %d", __func__, chars);
  	return chars;
  }
  
  
  static void cypress_throttle(struct tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  
  	spin_lock_irq(&priv->lock);
  	priv->rx_flags = THROTTLED;
  	spin_unlock_irq(&priv->lock);
  }
  
  
  static void cypress_unthrottle(struct tty_struct *tty)
  {
  	struct usb_serial_port *port = tty->driver_data;
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	int actually_throttled, result;
  
  	spin_lock_irq(&priv->lock);
  	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
  	priv->rx_flags = 0;
  	spin_unlock_irq(&priv->lock);
  
  	if (!priv->comm_is_ok)
  		return;
  
  	if (actually_throttled) {
  		result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
  		if (result) {
  			dev_err(&port->dev, "%s - failed submitting read urb, "
  					"error %d\n", __func__, result);
  			cypress_set_dead(port);
  		}
  	}
  }
  
  
  static void cypress_read_int_callback(struct urb *urb)
  {
  	struct usb_serial_port *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;
  	int status = urb->status;
  
  	switch (status) {
  	case 0: /* success */
  		break;
  	case -ECONNRESET:
  	case -ENOENT:
  	case -ESHUTDOWN:
  		/* precursor to disconnect so just go away */
  		return;
  	case -EPIPE:
  		/* Can't call usb_clear_halt while in_interrupt */
  		/* FALLS THROUGH */
  	default:
  		/* something ugly is going on... */
  		dev_err(&urb->dev->dev,
  			"%s - unexpected nonzero read status received: %d\n",
  							__func__, status);
  		cypress_set_dead(port);
  		return;
  	}
  
  	spin_lock_irqsave(&priv->lock, flags);
  	if (priv->rx_flags & THROTTLED) {
  		dbg("%s - now throttling", __func__);
  		priv->rx_flags |= ACTUALLY_THROTTLED;
  		spin_unlock_irqrestore(&priv->lock, flags);
  		return;
  	}
  	spin_unlock_irqrestore(&priv->lock, flags);
  
  	tty = tty_port_tty_get(&port->port);
  	if (!tty) {
  		dbg("%s - bad tty pointer - exiting", __func__);
  		return;
  	}
  
  	spin_lock_irqsave(&priv->lock, flags);
  	result = urb->actual_length;
  	switch (priv->pkt_fmt) {
  	default:
  	case packet_format_1:
  		/* This is for the CY7C64013... */
  		priv->current_status = data[0] & 0xF8;
  		bytes = data[1] + 2;
  		i = 2;
  		if (bytes > 2)
  			havedata = 1;
  		break;
  	case packet_format_2:
  		/* This is for the CY7C63743... */
  		priv->current_status = data[0] & 0xF8;
  		bytes = (data[0] & 0x07) + 1;
  		i = 1;
  		if (bytes > 1)
  			havedata = 1;
  		break;
  	}
  	spin_unlock_irqrestore(&priv->lock, flags);
  	if (result < bytes) {
  		dbg("%s - wrong packet size - received %d bytes but packet "
  		    "said %d bytes", __func__, result, bytes);
  		goto continue_read;
  	}
  
  	usb_serial_debug_data(debug, &port->dev, __func__,
  						urb->actual_length, data);
  
  	spin_lock_irqsave(&priv->lock, flags);
  	/* check to see if status has changed */
  	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", __func__);
  		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", __func__);
  	} else
  		spin_unlock_irqrestore(&priv->lock, flags);
  
  	/* process read if there is data other than line status */
  	if (tty && bytes > i) {
  		tty_insert_flip_string_fixed_flag(tty, data + i,
  				tty_flag, bytes - i);
  		tty_flip_buffer_push(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:
  	tty_kref_put(tty);
  
  	/* Continue trying to always read */
  
  	if (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 && result != -EPERM) {
  			dev_err(&urb->dev->dev, "%s - failed resubmitting "
  					"read urb, error %d\n", __func__,
  					result);
  			cypress_set_dead(port);
  		}
  	}
  } /* cypress_read_int_callback */
  
  
  static void cypress_write_int_callback(struct urb *urb)
  {
  	struct usb_serial_port *port = urb->context;
  	struct cypress_private *priv = usb_get_serial_port_data(port);
  	int result;
  	int status = urb->status;
  
  	switch (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",
  						__func__, 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",
  			__func__, status);
  		port->interrupt_out_urb->transfer_buffer_length = 1;
  		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",
  							__func__, result);
  		cypress_set_dead(port);
  		break;
  	default:
  		dev_err(&urb->dev->dev,
  			 "%s - unexpected nonzero write status received: %d\n",
  							__func__, status);
  		cypress_set_dead(port);
  		break;
  	}
  	priv->write_urb_in_use = 0;
  
  	/* send any buffered data */
  	cypress_send(port);
  }
  
  module_usb_serial_driver(serial_drivers, id_table_combined);
  
  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");
  module_param(unstable_bauds, bool, S_IRUGO | S_IWUSR);
  MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");
  