drivers/usb/serial/kl5kusb105.c

/*
 * KLSI KL5KUSB105 chip RS232 converter driver
 *
 *   Copyright (C) 2001 Utz-Uwe Haus <haus@uuhaus.de>
 *
 *   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.
 *
 * All information about the device was acquired using SniffUSB ans snoopUSB
 * on Windows98.
 * It was written out of frustration with the PalmConnect USB Serial adapter
 * sold by Palm Inc.
 * Neither Palm, nor their contractor (MCCI) or their supplier (KLSI) provided
 * information that was not already available.
 *
 * It seems that KLSI bought some silicon-design information from ScanLogic,
 * whose SL11R processor is at the core of the KL5KUSB chipset from KLSI.
 * KLSI has firmware available for their devices; it is probable that the
 * firmware differs from that used by KLSI in their products. If you have an
 * original KLSI device and can provide some information on it, I would be
 * most interested in adding support for it here. If you have any information
 * on the protocol used (or find errors in my reverse-engineered stuff), please
 * let me know.
 *
 * The code was only tested with a PalmConnect USB adapter; if you
 * are adventurous, try it with any KLSI-based device and let me know how it
 * breaks so that I can fix it!
 */

/* TODO:
 *	check modem line signals
 *	implement handshaking or decide that we do not support it
 */

/* History:
 *   0.3a - implemented pools of write URBs
 *   0.3  - alpha version for public testing
 *   0.2  - TIOCMGET works, so autopilot(1) can be used!
 *   0.1  - can be used to do pilot-xfer -p /dev/ttyUSB0 -l
 *
 *   The driver skeleton is mainly based on mct_u232.c and various other
 *   pieces of code shamelessly copied from the drivers/usb/serial/ directory.
 */


#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/uaccess.h>
#include <asm/unaligned.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include "kl5kusb105.h"

static int debug;

/*
 * Version Information
 */
#define DRIVER_VERSION "v0.3a"
#define DRIVER_AUTHOR "Utz-Uwe Haus <haus@uuhaus.de>"
#define DRIVER_DESC "KLSI KL5KUSB105 chipset USB->Serial Converter driver"


/*
 * Function prototypes
 */
static int  klsi_105_startup(struct usb_serial *serial);
static void klsi_105_disconnect(struct usb_serial *serial);
static void klsi_105_release(struct usb_serial *serial);
static int  klsi_105_open(struct tty_struct *tty, struct usb_serial_port *port);
static void klsi_105_close(struct usb_serial_port *port);
static int  klsi_105_write(struct tty_struct *tty,
	struct usb_serial_port *port, const unsigned char *buf, int count);
static void klsi_105_write_bulk_callback(struct urb *urb);
static int  klsi_105_chars_in_buffer(struct tty_struct *tty);
static int  klsi_105_write_room(struct tty_struct *tty);
static void klsi_105_read_bulk_callback(struct urb *urb);
static void klsi_105_set_termios(struct tty_struct *tty,
			struct usb_serial_port *port, struct ktermios *old);
static void klsi_105_throttle(struct tty_struct *tty);
static void klsi_105_unthrottle(struct tty_struct *tty);
static int  klsi_105_tiocmget(struct tty_struct *tty, struct file *file);
static int  klsi_105_tiocmset(struct tty_struct *tty, struct file *file,
			unsigned int set, unsigned int clear);

/*
 * All of the device info needed for the KLSI converters.
 */
static const struct usb_device_id id_table[] = {
	{ USB_DEVICE(PALMCONNECT_VID, PALMCONNECT_PID) },
	{ USB_DEVICE(KLSI_VID, KLSI_KL5KUSB105D_PID) },
	{ }		/* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, id_table);

static struct usb_driver kl5kusb105d_driver = {
	.name =		"kl5kusb105d",
	.probe =	usb_serial_probe,
	.disconnect =	usb_serial_disconnect,
	.id_table =	id_table,
	.no_dynamic_id =	1,
};

static struct usb_serial_driver kl5kusb105d_device = {
	.driver = {
		.owner =	THIS_MODULE,
		.name =		"kl5kusb105d",
	},
	.description =		"KL5KUSB105D / PalmConnect",
	.usb_driver =		&kl5kusb105d_driver,
	.id_table =		id_table,
	.num_ports =		1,
	.open =			klsi_105_open,
	.close =		klsi_105_close,
	.write =		klsi_105_write,
	.write_bulk_callback =	klsi_105_write_bulk_callback,
	.chars_in_buffer =	klsi_105_chars_in_buffer,
	.write_room =		klsi_105_write_room,
	.read_bulk_callback =	klsi_105_read_bulk_callback,
	.set_termios =		klsi_105_set_termios,
	/*.break_ctl =		klsi_105_break_ctl,*/
	.tiocmget =		klsi_105_tiocmget,
	.tiocmset =		klsi_105_tiocmset,
	.attach =		klsi_105_startup,
	.disconnect =		klsi_105_disconnect,
	.release =		klsi_105_release,
	.throttle =		klsi_105_throttle,
	.unthrottle =		klsi_105_unthrottle,
};

struct klsi_105_port_settings {
	__u8	pktlen;		/* always 5, it seems */
	__u8	baudrate;
	__u8	databits;
	__u8	unknown1;
	__u8	unknown2;
} __attribute__ ((packed));

/* we implement a pool of NUM_URBS urbs per usb_serial */
#define NUM_URBS			1
#define URB_TRANSFER_BUFFER_SIZE	64
struct klsi_105_private {
	struct klsi_105_port_settings	cfg;
	struct ktermios			termios;
	unsigned long			line_state; /* modem line settings */
	/* write pool */
	struct urb			*write_urb_pool[NUM_URBS];
	spinlock_t			lock;
	unsigned long			bytes_in;
	unsigned long			bytes_out;
};


/*
 * Handle vendor specific USB requests
 */


#define KLSI_TIMEOUT	 5000 /* default urb timeout */

static int klsi_105_chg_port_settings(struct usb_serial_port *port,
				      struct klsi_105_port_settings *settings)
{
	int rc;

	rc = usb_control_msg(port->serial->dev,
			usb_sndctrlpipe(port->serial->dev, 0),
			KL5KUSB105A_SIO_SET_DATA,
			USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_INTERFACE,
			0, /* value */
			0, /* index */
			settings,
			sizeof(struct klsi_105_port_settings),
			KLSI_TIMEOUT);
	if (rc < 0)
		dev_err(&port->dev,
			"Change port settings failed (error = %d)\n", rc);
	dev_info(&port->serial->dev->dev,
		 "%d byte block, baudrate %x, databits %d, u1 %d, u2 %d\n",
		 settings->pktlen, settings->baudrate, settings->databits,
		 settings->unknown1, settings->unknown2);
	return rc;
}

/* translate a 16-bit status value from the device to linux's TIO bits */
static unsigned long klsi_105_status2linestate(const __u16 status)
{
	unsigned long res = 0;

	res =   ((status & KL5KUSB105A_DSR) ? TIOCM_DSR : 0)
	      | ((status & KL5KUSB105A_CTS) ? TIOCM_CTS : 0)
	      ;

	return res;
}

/*
 * Read line control via vendor command and return result through
 * *line_state_p
 */
/* It seems that the status buffer has always only 2 bytes length */
#define KLSI_STATUSBUF_LEN	2
static int klsi_105_get_line_state(struct usb_serial_port *port,
				   unsigned long *line_state_p)
{
	int rc;
	u8 *status_buf;
	__u16 status;

	dev_info(&port->serial->dev->dev, "sending SIO Poll request\n");

	status_buf = kmalloc(KLSI_STATUSBUF_LEN, GFP_KERNEL);
	if (!status_buf) {
		dev_err(&port->dev, "%s - out of memory for status buffer.\n",
				__func__);
		return -ENOMEM;
	}
	status_buf[0] = 0xff;
	status_buf[1] = 0xff;
	rc = usb_control_msg(port->serial->dev,
			     usb_rcvctrlpipe(port->serial->dev, 0),
			     KL5KUSB105A_SIO_POLL,
			     USB_TYPE_VENDOR | USB_DIR_IN,
			     0, /* value */
			     0, /* index */
			     status_buf, KLSI_STATUSBUF_LEN,
			     10000
			     );
	if (rc < 0)
		dev_err(&port->dev, "Reading line status failed (error = %d)\n",
			rc);
	else {
		status = get_unaligned_le16(status_buf);

		dev_info(&port->serial->dev->dev, "read status %x %x",
			 status_buf[0], status_buf[1]);

		*line_state_p = klsi_105_status2linestate(status);
	}

	kfree(status_buf);
	return rc;
}


/*
 * Driver's tty interface functions
 */

static int klsi_105_startup(struct usb_serial *serial)
{
	struct klsi_105_private *priv;
	int i, j;

	/* check if we support the product id (see keyspan.c)
	 * FIXME
	 */

	/* allocate the private data structure */
	for (i = 0; i < serial->num_ports; i++) {
		priv = kmalloc(sizeof(struct klsi_105_private),
						   GFP_KERNEL);
		if (!priv) {
			dbg("%skmalloc for klsi_105_private failed.", __func__);
			i--;
			goto err_cleanup;
		}
		/* set initial values for control structures */
		priv->cfg.pktlen    = 5;
		priv->cfg.baudrate  = kl5kusb105a_sio_b9600;
		priv->cfg.databits  = kl5kusb105a_dtb_8;
		priv->cfg.unknown1  = 0;
		priv->cfg.unknown2  = 1;

		priv->line_state    = 0;

		priv->bytes_in	    = 0;
		priv->bytes_out	    = 0;
		usb_set_serial_port_data(serial->port[i], priv);

		spin_lock_init(&priv->lock);
		for (j = 0; j < NUM_URBS; j++) {
			struct urb *urb = usb_alloc_urb(0, GFP_KERNEL);

			priv->write_urb_pool[j] = urb;
			if (urb == NULL) {
				dev_err(&serial->dev->dev, "No more urbs???\n");
				goto err_cleanup;
			}

			urb->transfer_buffer =
				kmalloc(URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);
			if (!urb->transfer_buffer) {
				dev_err(&serial->dev->dev,
					"%s - out of memory for urb buffers.\n",
					__func__);
				goto err_cleanup;
			}
		}

		/* priv->termios is left uninitalized until port opening */
		init_waitqueue_head(&serial->port[i]->write_wait);
	}

	return 0;

err_cleanup:
	for (; i >= 0; i--) {
		priv = usb_get_serial_port_data(serial->port[i]);
		for (j = 0; j < NUM_URBS; j++) {
			if (priv->write_urb_pool[j]) {
				kfree(priv->write_urb_pool[j]->transfer_buffer);
				usb_free_urb(priv->write_urb_pool[j]);
			}
		}
		kfree(priv);
		usb_set_serial_port_data(serial->port[i], NULL);
	}
	return -ENOMEM;
}

static void klsi_105_disconnect(struct usb_serial *serial)
{
	int i;

	dbg("%s", __func__);

	/* stop reads and writes on all ports */
	for (i = 0; i < serial->num_ports; ++i) {
		struct klsi_105_private *priv =
				usb_get_serial_port_data(serial->port[i]);

		if (priv) {
			/* kill our write urb pool */
			int j;
			struct urb **write_urbs = priv->write_urb_pool;

			for (j = 0; j < NUM_URBS; j++) {
				if (write_urbs[j]) {
					usb_kill_urb(write_urbs[j]);
					usb_free_urb(write_urbs[j]);
				}
			}
		}
	}
}

static void klsi_105_release(struct usb_serial *serial)
{
	int i;

	dbg("%s", __func__);

	for (i = 0; i < serial->num_ports; ++i) {
		struct klsi_105_private *priv =
				usb_get_serial_port_data(serial->port[i]);

		kfree(priv);
	}
}

static int  klsi_105_open(struct tty_struct *tty, struct usb_serial_port *port)
{
	struct klsi_105_private *priv = usb_get_serial_port_data(port);
	int retval = 0;
	int rc;
	int i;
	unsigned long line_state;
	struct klsi_105_port_settings *cfg;
	unsigned long flags;

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

	/* Do a defined restart:
	 * Set up sane default baud rate and send the 'READ_ON'
	 * vendor command.
	 * FIXME: set modem line control (how?)
	 * Then read the modem line control and store values in
	 * priv->line_state.
	 */
	cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
	if (!cfg) {
		dev_err(&port->dev, "%s - out of memory for config buffer.\n",
				__func__);
		return -ENOMEM;
	}
	cfg->pktlen   = 5;
	cfg->baudrate = kl5kusb105a_sio_b9600;
	cfg->databits = kl5kusb105a_dtb_8;
	cfg->unknown1 = 0;
	cfg->unknown2 = 1;
	klsi_105_chg_port_settings(port, cfg);

	/* set up termios structure */
	spin_lock_irqsave(&priv->lock, flags);
	priv->termios.c_iflag = tty->termios->c_iflag;
	priv->termios.c_oflag = tty->termios->c_oflag;
	priv->termios.c_cflag = tty->termios->c_cflag;
	priv->termios.c_lflag = tty->termios->c_lflag;
	for (i = 0; i < NCCS; i++)
		priv->termios.c_cc[i] = tty->termios->c_cc[i];
	priv->cfg.pktlen   = cfg->pktlen;
	priv->cfg.baudrate = cfg->baudrate;
	priv->cfg.databits = cfg->databits;
	priv->cfg.unknown1 = cfg->unknown1;
	priv->cfg.unknown2 = cfg->unknown2;
	spin_unlock_irqrestore(&priv->lock, flags);

	/* READ_ON and urb submission */
	usb_fill_bulk_urb(port->read_urb, port->serial->dev,
		      usb_rcvbulkpipe(port->serial->dev,
				      port->bulk_in_endpointAddress),
		      port->read_urb->transfer_buffer,
		      port->read_urb->transfer_buffer_length,
		      klsi_105_read_bulk_callback,
		      port);

	rc = usb_submit_urb(port->read_urb, GFP_KERNEL);
	if (rc) {
		dev_err(&port->dev, "%s - failed submitting read urb, "
			"error %d\n", __func__, rc);
		retval = rc;
		goto exit;
	}

	rc = usb_control_msg(port->serial->dev,
			     usb_sndctrlpipe(port->serial->dev, 0),
			     KL5KUSB105A_SIO_CONFIGURE,
			     USB_TYPE_VENDOR|USB_DIR_OUT|USB_RECIP_INTERFACE,
			     KL5KUSB105A_SIO_CONFIGURE_READ_ON,
			     0, /* index */
			     NULL,
			     0,
			     KLSI_TIMEOUT);
	if (rc < 0) {
		dev_err(&port->dev, "Enabling read failed (error = %d)\n", rc);
		retval = rc;
	} else
		dbg("%s - enabled reading", __func__);

	rc = klsi_105_get_line_state(port, &line_state);
	if (rc >= 0) {
		spin_lock_irqsave(&priv->lock, flags);
		priv->line_state = line_state;
		spin_unlock_irqrestore(&priv->lock, flags);
		dbg("%s - read line state 0x%lx", __func__, line_state);
		retval = 0;
	} else
		retval = rc;

exit:
	kfree(cfg);
	return retval;
}

static void klsi_105_close(struct usb_serial_port *port)
{
	struct klsi_105_private *priv = usb_get_serial_port_data(port);
	int rc;

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

	mutex_lock(&port->serial->disc_mutex);
	if (!port->serial->disconnected) {
		/* send READ_OFF */
		rc = usb_control_msg(port->serial->dev,
				     usb_sndctrlpipe(port->serial->dev, 0),
				     KL5KUSB105A_SIO_CONFIGURE,
				     USB_TYPE_VENDOR | USB_DIR_OUT,
				     KL5KUSB105A_SIO_CONFIGURE_READ_OFF,
				     0, /* index */
				     NULL, 0,
				     KLSI_TIMEOUT);
		if (rc < 0)
			dev_err(&port->dev,
				"Disabling read failed (error = %d)\n", rc);
	}
	mutex_unlock(&port->serial->disc_mutex);

	/* shutdown our bulk reads and writes */
	usb_kill_urb(port->write_urb);
	usb_kill_urb(port->read_urb);
	/* unlink our write pool */
	/* FIXME */
	/* wgg - do I need this? I think so. */
	usb_kill_urb(port->interrupt_in_urb);
	dev_info(&port->serial->dev->dev,
		 "port stats: %ld bytes in, %ld bytes out\n",
		 priv->bytes_in, priv->bytes_out);
}

/* We need to write a complete 64-byte data block and encode the
 * number actually sent in the first double-byte, LSB-order. That
 * leaves at most 62 bytes of payload.
 */
#define KLSI_105_DATA_OFFSET	2   /* in the bulk urb data block */

static int klsi_105_write(struct tty_struct *tty,
	struct usb_serial_port *port, const unsigned char *buf, int count)
{
	struct klsi_105_private *priv = usb_get_serial_port_data(port);
	int result, size;
	int bytes_sent = 0;

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

	while (count > 0) {
		/* try to find a free urb (write 0 bytes if none) */
		struct urb *urb = NULL;
		unsigned long flags;
		int i;
		/* since the pool is per-port we might not need
		   the spin lock !? */
		spin_lock_irqsave(&priv->lock, flags);
		for (i = 0; i < NUM_URBS; i++) {
			if (priv->write_urb_pool[i]->status != -EINPROGRESS) {
				urb = priv->write_urb_pool[i];
				dbg("%s - using pool URB %d", __func__, i);
				break;
			}
		}
		spin_unlock_irqrestore(&priv->lock, flags);

		if (urb == NULL) {
			dbg("%s - no more free urbs", __func__);
			goto exit;
		}

		if (urb->transfer_buffer == NULL) {
			urb->transfer_buffer =
				kmalloc(URB_TRANSFER_BUFFER_SIZE, GFP_ATOMIC);
			if (urb->transfer_buffer == NULL) {
				dev_err(&port->dev,
					"%s - no more kernel memory...\n",
					__func__);
				goto exit;
			}
		}

		size = min(count, port->bulk_out_size - KLSI_105_DATA_OFFSET);
		size = min(size, URB_TRANSFER_BUFFER_SIZE -
							KLSI_105_DATA_OFFSET);

		memcpy(urb->transfer_buffer + KLSI_105_DATA_OFFSET, buf, size);

		/* write payload size into transfer buffer */
		((__u8 *)urb->transfer_buffer)[0] = (__u8) (size & 0xFF);
		((__u8 *)urb->transfer_buffer)[1] = (__u8) ((size & 0xFF00)>>8);

		/* set up our urb */
		usb_fill_bulk_urb(urb, port->serial->dev,
			      usb_sndbulkpipe(port->serial->dev,
					      port->bulk_out_endpointAddress),
			      urb->transfer_buffer,
			      URB_TRANSFER_BUFFER_SIZE,
			      klsi_105_write_bulk_callback,
			      port);

		/* send the data out the bulk port */
		result = usb_submit_urb(urb, GFP_ATOMIC);
		if (result) {
			dev_err(&port->dev,
				"%s - failed submitting write urb, error %d\n",
				__func__, result);
			goto exit;
		}
		buf += size;
		bytes_sent += size;
		count -= size;
	}
exit:
	/* lockless, but it's for debug info only... */
	priv->bytes_out += bytes_sent;

	return bytes_sent;	/* that's how much we wrote */
}

static void klsi_105_write_bulk_callback(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	int status = urb->status;

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

	if (status) {
		dbg("%s - nonzero write bulk status received: %d", __func__,
		    status);
		return;
	}

	usb_serial_port_softint(port);
}

/* return number of characters currently in the writing process */
static int klsi_105_chars_in_buffer(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	int chars = 0;
	int i;
	unsigned long flags;
	struct klsi_105_private *priv = usb_get_serial_port_data(port);

	spin_lock_irqsave(&priv->lock, flags);

	for (i = 0; i < NUM_URBS; ++i) {
		if (priv->write_urb_pool[i]->status == -EINPROGRESS)
			chars += URB_TRANSFER_BUFFER_SIZE;
	}

	spin_unlock_irqrestore(&priv->lock, flags);

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

static int klsi_105_write_room(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	unsigned long flags;
	int i;
	int room = 0;
	struct klsi_105_private *priv = usb_get_serial_port_data(port);

	spin_lock_irqsave(&priv->lock, flags);
	for (i = 0; i < NUM_URBS; ++i) {
		if (priv->write_urb_pool[i]->status != -EINPROGRESS)
			room += URB_TRANSFER_BUFFER_SIZE;
	}

	spin_unlock_irqrestore(&priv->lock, flags);

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

static void klsi_105_read_bulk_callback(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	struct klsi_105_private *priv = usb_get_serial_port_data(port);
	struct tty_struct *tty;
	unsigned char *data = urb->transfer_buffer;
	int rc;
	int status = urb->status;

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

	/* The urb might have been killed. */
	if (status) {
		dbg("%s - nonzero read bulk status received: %d", __func__,
		    status);
		return;
	}

	/* The data received is again preceded by a length double-byte in LSB-
	 * first order (see klsi_105_write() )
	 */
	if (urb->actual_length == 0) {
		/* empty urbs seem to happen, we ignore them */
		/* dbg("%s - emtpy URB", __func__); */
	       ;
	} else if (urb->actual_length <= 2) {
		dbg("%s - size %d URB not understood", __func__,
		    urb->actual_length);
		usb_serial_debug_data(debug, &port->dev, __func__,
				      urb->actual_length, data);
	} else {
		int bytes_sent = ((__u8 *) data)[0] +
				 ((unsigned int) ((__u8 *) data)[1] << 8);
		tty = tty_port_tty_get(&port->port);
		/* we should immediately resubmit the URB, before attempting
		 * to pass the data on to the tty layer. But that needs locking
		 * against re-entry an then mixed-up data because of
		 * intermixed tty_flip_buffer_push()s
		 * FIXME
		 */
		usb_serial_debug_data(debug, &port->dev, __func__,
				      urb->actual_length, data);

		if (bytes_sent + 2 > urb->actual_length) {
			dbg("%s - trying to read more data than available"
			    " (%d vs. %d)", __func__,
			    bytes_sent+2, urb->actual_length);
			/* cap at implied limit */
			bytes_sent = urb->actual_length - 2;
		}

		tty_insert_flip_string(tty, data + 2, bytes_sent);
		tty_flip_buffer_push(tty);
		tty_kref_put(tty);

		/* again lockless, but debug info only */
		priv->bytes_in += bytes_sent;
	}
	/* Continue trying to always read  */
	usb_fill_bulk_urb(port->read_urb, port->serial->dev,
		      usb_rcvbulkpipe(port->serial->dev,
				      port->bulk_in_endpointAddress),
		      port->read_urb->transfer_buffer,
		      port->read_urb->transfer_buffer_length,
		      klsi_105_read_bulk_callback,
		      port);
	rc = usb_submit_urb(port->read_urb, GFP_ATOMIC);
	if (rc)
		dev_err(&port->dev,
			"%s - failed resubmitting read urb, error %d\n",
			__func__, rc);
}

static void klsi_105_set_termios(struct tty_struct *tty,
				 struct usb_serial_port *port,
				 struct ktermios *old_termios)
{
	struct klsi_105_private *priv = usb_get_serial_port_data(port);
	unsigned int iflag = tty->termios->c_iflag;
	unsigned int old_iflag = old_termios->c_iflag;
	unsigned int cflag = tty->termios->c_cflag;
	unsigned int old_cflag = old_termios->c_cflag;
	struct klsi_105_port_settings *cfg;
	unsigned long flags;
	speed_t baud;

	cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
	if (!cfg) {
		dev_err(&port->dev, "%s - out of memory for config buffer.\n",
				__func__);
		return;
	}

	/* lock while we are modifying the settings */
	spin_lock_irqsave(&priv->lock, flags);

	/*
	 * Update baud rate
	 */
	baud = tty_get_baud_rate(tty);

	if ((cflag & CBAUD) != (old_cflag & CBAUD)) {
		/* reassert DTR and (maybe) RTS on transition from B0 */
		if ((old_cflag & CBAUD) == B0) {
			dbg("%s: baud was B0", __func__);
#if 0
			priv->control_state |= TIOCM_DTR;
			/* don't set RTS if using hardware flow control */
			if (!(old_cflag & CRTSCTS))
				priv->control_state |= TIOCM_RTS;
			mct_u232_set_modem_ctrl(serial, priv->control_state);
#endif
		}
	}
	switch (baud) {
	case 0: /* handled below */
		break;
	case 1200:
		priv->cfg.baudrate = kl5kusb105a_sio_b1200;
		break;
	case 2400:
		priv->cfg.baudrate = kl5kusb105a_sio_b2400;
		break;
	case 4800:
		priv->cfg.baudrate = kl5kusb105a_sio_b4800;
		break;
	case 9600:
		priv->cfg.baudrate = kl5kusb105a_sio_b9600;
		break;
	case 19200:
		priv->cfg.baudrate = kl5kusb105a_sio_b19200;
		break;
	case 38400:
		priv->cfg.baudrate = kl5kusb105a_sio_b38400;
		break;
	case 57600:
		priv->cfg.baudrate = kl5kusb105a_sio_b57600;
		break;
	case 115200:
		priv->cfg.baudrate = kl5kusb105a_sio_b115200;
		break;
	default:
		dbg("KLSI USB->Serial converter:"
		    " unsupported baudrate request, using default of 9600");
			priv->cfg.baudrate = kl5kusb105a_sio_b9600;
		baud = 9600;
		break;
	}
	if ((cflag & CBAUD) == B0) {
		dbg("%s: baud is B0", __func__);
		/* Drop RTS and DTR */
		/* maybe this should be simulated by sending read
		 * disable and read enable messages?
		 */
		;
#if 0
		priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
		mct_u232_set_modem_ctrl(serial, priv->control_state);
#endif
	}
	tty_encode_baud_rate(tty, baud, baud);

	if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
		/* set the number of data bits */
		switch (cflag & CSIZE) {
		case CS5:
			dbg("%s - 5 bits/byte not supported", __func__);
			spin_unlock_irqrestore(&priv->lock, flags);
			goto err;
		case CS6:
			dbg("%s - 6 bits/byte not supported", __func__);
			spin_unlock_irqrestore(&priv->lock, flags);
			goto err;
		case CS7:
			priv->cfg.databits = kl5kusb105a_dtb_7;
			break;
		case CS8:
			priv->cfg.databits = kl5kusb105a_dtb_8;
			break;
		default:
			dev_err(&port->dev,
				"CSIZE was not CS5-CS8, using default of 8\n");
			priv->cfg.databits = kl5kusb105a_dtb_8;
			break;
		}
	}

	/*
	 * Update line control register (LCR)
	 */
	if ((cflag & (PARENB|PARODD)) != (old_cflag & (PARENB|PARODD))
	    || (cflag & CSTOPB) != (old_cflag & CSTOPB)) {
		/* Not currently supported */
		tty->termios->c_cflag &= ~(PARENB|PARODD|CSTOPB);
#if 0
		priv->last_lcr = 0;

		/* set the parity */
		if (cflag & PARENB)
			priv->last_lcr |= (cflag & PARODD) ?
				MCT_U232_PARITY_ODD : MCT_U232_PARITY_EVEN;
		else
			priv->last_lcr |= MCT_U232_PARITY_NONE;

		/* set the number of stop bits */
		priv->last_lcr |= (cflag & CSTOPB) ?
			MCT_U232_STOP_BITS_2 : MCT_U232_STOP_BITS_1;

		mct_u232_set_line_ctrl(serial, priv->last_lcr);
#endif
		;
	}
	/*
	 * Set flow control: well, I do not really now how to handle DTR/RTS.
	 * Just do what we have seen with SniffUSB on Win98.
	 */
	if ((iflag & IXOFF) != (old_iflag & IXOFF)
	    || (iflag & IXON) != (old_iflag & IXON)
	    ||  (cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {
		/* Not currently supported */
		tty->termios->c_cflag &= ~CRTSCTS;
		/* Drop DTR/RTS if no flow control otherwise assert */
#if 0
		if ((iflag & IXOFF) || (iflag & IXON) || (cflag & CRTSCTS))
			priv->control_state |= TIOCM_DTR | TIOCM_RTS;
		else
			priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
		mct_u232_set_modem_ctrl(serial, priv->control_state);
#endif
		;
	}
	memcpy(cfg, &priv->cfg, sizeof(*cfg));
	spin_unlock_irqrestore(&priv->lock, flags);

	/* now commit changes to device */
	klsi_105_chg_port_settings(port, cfg);
err:
	kfree(cfg);
}

#if 0
static void mct_u232_break_ctl(struct tty_struct *tty, int break_state)
{
	struct usb_serial_port *port = tty->driver_data;
	struct usb_serial *serial = port->serial;
	struct mct_u232_private *priv =
				(struct mct_u232_private *)port->private;
	unsigned char lcr = priv->last_lcr;

	dbg("%sstate=%d", __func__, break_state);

	/* LOCKING */
	if (break_state)
		lcr |= MCT_U232_SET_BREAK;

	mct_u232_set_line_ctrl(serial, lcr);
}
#endif

static int klsi_105_tiocmget(struct tty_struct *tty, struct file *file)
{
	struct usb_serial_port *port = tty->driver_data;
	struct klsi_105_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	int rc;
	unsigned long line_state;
	dbg("%s - request, just guessing", __func__);

	rc = klsi_105_get_line_state(port, &line_state);
	if (rc < 0) {
		dev_err(&port->dev,
			"Reading line control failed (error = %d)\n", rc);
		/* better return value? EAGAIN? */
		return rc;
	}

	spin_lock_irqsave(&priv->lock, flags);
	priv->line_state = line_state;
	spin_unlock_irqrestore(&priv->lock, flags);
	dbg("%s - read line state 0x%lx", __func__, line_state);
	return (int)line_state;
}

static int klsi_105_tiocmset(struct tty_struct *tty, struct file *file,
			     unsigned int set, unsigned int clear)
{
	int retval = -EINVAL;

	dbg("%s", __func__);

/* if this ever gets implemented, it should be done something like this:
	struct usb_serial *serial = port->serial;
	struct klsi_105_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	int control;

	spin_lock_irqsave (&priv->lock, flags);
	if (set & TIOCM_RTS)
		priv->control_state |= TIOCM_RTS;
	if (set & TIOCM_DTR)
		priv->control_state |= TIOCM_DTR;
	if (clear & TIOCM_RTS)
		priv->control_state &= ~TIOCM_RTS;
	if (clear & TIOCM_DTR)
		priv->control_state &= ~TIOCM_DTR;
	control = priv->control_state;
	spin_unlock_irqrestore (&priv->lock, flags);
	retval = mct_u232_set_modem_ctrl(serial, control);
*/
	return retval;
}

static void klsi_105_throttle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	dbg("%s - port %d", __func__, port->number);
	usb_kill_urb(port->read_urb);
}

static void klsi_105_unthrottle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	int result;

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

	port->read_urb->dev = port->serial->dev;
	result = usb_submit_urb(port->read_urb, GFP_KERNEL);
	if (result)
		dev_err(&port->dev,
			"%s - failed submitting read urb, error %d\n",
			__func__, result);
}


static int __init klsi_105_init(void)
{
	int retval;
	retval = usb_serial_register(&kl5kusb105d_device);
	if (retval)
		goto failed_usb_serial_register;
	retval = usb_register(&kl5kusb105d_driver);
	if (retval)
		goto failed_usb_register;

	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
	       DRIVER_DESC "\n");
	return 0;
failed_usb_register:
	usb_serial_deregister(&kl5kusb105d_device);
failed_usb_serial_register:
	return retval;
}

static void __exit klsi_105_exit(void)
{
	usb_deregister(&kl5kusb105d_driver);
	usb_serial_deregister(&kl5kusb105d_device);
}


module_init(klsi_105_init);
module_exit(klsi_105_exit);

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


module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "enable extensive debugging messages");