2 * Silicon Laboratories CP2101/CP2102 USB to RS232 serial adaptor driver
4 * Copyright (C) 2005 Craig Shelley (craig@microtron.org.uk)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version
8 * 2 as published by the Free Software Foundation.
10 * Support to set flow control line levels using TIOCMGET and TIOCMSET
11 * thanks to Karl Hiramoto karl@hiramoto.org. RTSCTS hardware flow
12 * control thanks to Munir Nassar nassarmu@real-time.com
15 * Buffers are not flushed when the port is opened.
16 * Multiple calls to write() may fail with "Resource temporarily unavailable"
20 #include <linux/kernel.h>
21 #include <linux/errno.h>
22 #include <linux/slab.h>
23 #include <linux/tty.h>
24 #include <linux/tty_flip.h>
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27 #include <linux/usb.h>
28 #include <asm/uaccess.h>
29 #include <linux/usb/serial.h>
34 #define DRIVER_VERSION "v0.07"
35 #define DRIVER_DESC "Silicon Labs CP2101/CP2102 RS232 serial adaptor driver"
40 static int cp2101_open(struct usb_serial_port*, struct file*);
41 static void cp2101_cleanup(struct usb_serial_port*);
42 static void cp2101_close(struct usb_serial_port*, struct file*);
43 static void cp2101_get_termios(struct usb_serial_port*);
44 static void cp2101_set_termios(struct usb_serial_port*, struct ktermios*);
45 static int cp2101_tiocmget (struct usb_serial_port *, struct file *);
46 static int cp2101_tiocmset (struct usb_serial_port *, struct file *,
47 unsigned int, unsigned int);
48 static void cp2101_break_ctl(struct usb_serial_port*, int);
49 static int cp2101_startup (struct usb_serial *);
50 static void cp2101_shutdown(struct usb_serial*);
55 static struct usb_device_id id_table [] = {
56 { USB_DEVICE(0x08e6, 0x5501) }, /* Gemalto Prox-PU/CU contactless smartcard reader */
57 { USB_DEVICE(0x0FCF, 0x1003) }, /* Dynastream ANT development board */
58 { USB_DEVICE(0x0FCF, 0x1004) }, /* Dynastream ANT2USB */
59 { USB_DEVICE(0x10A6, 0xAA26) }, /* Knock-off DCU-11 cable */
60 { USB_DEVICE(0x10AB, 0x10C5) }, /* Siemens MC60 Cable */
61 { USB_DEVICE(0x10B5, 0xAC70) }, /* Nokia CA-42 USB */
62 { USB_DEVICE(0x10C4, 0x800A) }, /* SPORTident BSM7-D-USB main station */
63 { USB_DEVICE(0x10C4, 0x803B) }, /* Pololu USB-serial converter */
64 { USB_DEVICE(0x10C4, 0x8053) }, /* Enfora EDG1228 */
65 { USB_DEVICE(0x10C4, 0x8066) }, /* Argussoft In-System Programmer */
66 { USB_DEVICE(0x10C4, 0x807A) }, /* Crumb128 board */
67 { USB_DEVICE(0x10C4, 0x80CA) }, /* Degree Controls Inc */
68 { USB_DEVICE(0x10C4, 0x80DD) }, /* Tracient RFID */
69 { USB_DEVICE(0x10C4, 0x80F6) }, /* Suunto sports instrument */
70 { USB_DEVICE(0x10C4, 0x813D) }, /* Burnside Telecom Deskmobile */
71 { USB_DEVICE(0x10C4, 0x814A) }, /* West Mountain Radio RIGblaster P&P */
72 { USB_DEVICE(0x10C4, 0x814B) }, /* West Mountain Radio RIGtalk */
73 { USB_DEVICE(0x10C4, 0x815E) }, /* Helicomm IP-Link 1220-DVM */
74 { USB_DEVICE(0x10C4, 0x81C8) }, /* Lipowsky Industrie Elektronik GmbH, Baby-JTAG */
75 { USB_DEVICE(0x10C4, 0x81E2) }, /* Lipowsky Industrie Elektronik GmbH, Baby-LIN */
76 { USB_DEVICE(0x10C4, 0x81E7) }, /* Aerocomm Radio */
77 { USB_DEVICE(0x10C4, 0x8218) }, /* Lipowsky Industrie Elektronik GmbH, HARP-1 */
78 { USB_DEVICE(0x10C4, 0xEA60) }, /* Silicon Labs factory default */
79 { USB_DEVICE(0x10C4, 0xEA61) }, /* Silicon Labs factory default */
80 { USB_DEVICE(0x10C4, 0xF001) }, /* Elan Digital Systems USBscope50 */
81 { USB_DEVICE(0x10C4, 0xF002) }, /* Elan Digital Systems USBwave12 */
82 { USB_DEVICE(0x10C4, 0xF003) }, /* Elan Digital Systems USBpulse100 */
83 { USB_DEVICE(0x10C4, 0xF004) }, /* Elan Digital Systems USBcount50 */
84 { USB_DEVICE(0x10C5, 0xEA61) }, /* Silicon Labs MobiData GPRS USB Modem */
85 { USB_DEVICE(0x13AD, 0x9999) }, /* Baltech card reader */
86 { USB_DEVICE(0x166A, 0x0303) }, /* Clipsal 5500PCU C-Bus USB interface */
87 { USB_DEVICE(0x16D6, 0x0001) }, /* Jablotron serial interface */
88 { } /* Terminating Entry */
91 MODULE_DEVICE_TABLE (usb, id_table);
93 static struct usb_driver cp2101_driver = {
95 .probe = usb_serial_probe,
96 .disconnect = usb_serial_disconnect,
101 static struct usb_serial_driver cp2101_device = {
103 .owner = THIS_MODULE,
106 .usb_driver = &cp2101_driver,
107 .id_table = id_table,
108 .num_interrupt_in = 0,
109 .num_bulk_in = NUM_DONT_CARE,
110 .num_bulk_out = NUM_DONT_CARE,
113 .close = cp2101_close,
114 .break_ctl = cp2101_break_ctl,
115 .set_termios = cp2101_set_termios,
116 .tiocmget = cp2101_tiocmget,
117 .tiocmset = cp2101_tiocmset,
118 .attach = cp2101_startup,
119 .shutdown = cp2101_shutdown,
122 /* Config request types */
123 #define REQTYPE_HOST_TO_DEVICE 0x41
124 #define REQTYPE_DEVICE_TO_HOST 0xc1
126 /* Config SET requests. To GET, add 1 to the request number */
127 #define CP2101_UART 0x00 /* Enable / Disable */
128 #define CP2101_BAUDRATE 0x01 /* (BAUD_RATE_GEN_FREQ / baudrate) */
129 #define CP2101_BITS 0x03 /* 0x(0)(databits)(parity)(stopbits) */
130 #define CP2101_BREAK 0x05 /* On / Off */
131 #define CP2101_CONTROL 0x07 /* Flow control line states */
132 #define CP2101_MODEMCTL 0x13 /* Modem controls */
133 #define CP2101_CONFIG_6 0x19 /* 6 bytes of config data ??? */
136 #define UART_ENABLE 0x0001
137 #define UART_DISABLE 0x0000
139 /* CP2101_BAUDRATE */
140 #define BAUD_RATE_GEN_FREQ 0x384000
143 #define BITS_DATA_MASK 0X0f00
144 #define BITS_DATA_5 0X0500
145 #define BITS_DATA_6 0X0600
146 #define BITS_DATA_7 0X0700
147 #define BITS_DATA_8 0X0800
148 #define BITS_DATA_9 0X0900
150 #define BITS_PARITY_MASK 0x00f0
151 #define BITS_PARITY_NONE 0x0000
152 #define BITS_PARITY_ODD 0x0010
153 #define BITS_PARITY_EVEN 0x0020
154 #define BITS_PARITY_MARK 0x0030
155 #define BITS_PARITY_SPACE 0x0040
157 #define BITS_STOP_MASK 0x000f
158 #define BITS_STOP_1 0x0000
159 #define BITS_STOP_1_5 0x0001
160 #define BITS_STOP_2 0x0002
163 #define BREAK_ON 0x0000
164 #define BREAK_OFF 0x0001
167 #define CONTROL_DTR 0x0001
168 #define CONTROL_RTS 0x0002
169 #define CONTROL_CTS 0x0010
170 #define CONTROL_DSR 0x0020
171 #define CONTROL_RING 0x0040
172 #define CONTROL_DCD 0x0080
173 #define CONTROL_WRITE_DTR 0x0100
174 #define CONTROL_WRITE_RTS 0x0200
178 * Reads from the CP2101 configuration registers
179 * 'size' is specified in bytes.
180 * 'data' is a pointer to a pre-allocated array of integers large
181 * enough to hold 'size' bytes (with 4 bytes to each integer)
183 static int cp2101_get_config(struct usb_serial_port* port, u8 request,
184 unsigned int *data, int size)
186 struct usb_serial *serial = port->serial;
188 int result, i, length;
190 /* Number of integers required to contain the array */
191 length = (((size - 1) | 3) + 1)/4;
193 buf = kcalloc(length, sizeof(__le32), GFP_KERNEL);
195 dev_err(&port->dev, "%s - out of memory.\n", __FUNCTION__);
199 /* For get requests, the request number must be incremented */
202 /* Issue the request, attempting to read 'size' bytes */
203 result = usb_control_msg (serial->dev,usb_rcvctrlpipe (serial->dev, 0),
204 request, REQTYPE_DEVICE_TO_HOST, 0x0000,
207 /* Convert data into an array of integers */
208 for (i=0; i<length; i++)
209 data[i] = le32_to_cpu(buf[i]);
213 if (result != size) {
214 dev_err(&port->dev, "%s - Unable to send config request, "
215 "request=0x%x size=%d result=%d\n",
216 __FUNCTION__, request, size, result);
225 * Writes to the CP2101 configuration registers
226 * Values less than 16 bits wide are sent directly
227 * 'size' is specified in bytes.
229 static int cp2101_set_config(struct usb_serial_port* port, u8 request,
230 unsigned int *data, int size)
232 struct usb_serial *serial = port->serial;
234 int result, i, length;
236 /* Number of integers required to contain the array */
237 length = (((size - 1) | 3) + 1)/4;
239 buf = kmalloc(length * sizeof(__le32), GFP_KERNEL);
241 dev_err(&port->dev, "%s - out of memory.\n",
246 /* Array of integers into bytes */
247 for (i = 0; i < length; i++)
248 buf[i] = cpu_to_le32(data[i]);
251 result = usb_control_msg (serial->dev,
252 usb_sndctrlpipe(serial->dev, 0),
253 request, REQTYPE_HOST_TO_DEVICE, 0x0000,
256 result = usb_control_msg (serial->dev,
257 usb_sndctrlpipe(serial->dev, 0),
258 request, REQTYPE_HOST_TO_DEVICE, data[0],
264 if ((size > 2 && result != size) || result < 0) {
265 dev_err(&port->dev, "%s - Unable to send request, "
266 "request=0x%x size=%d result=%d\n",
267 __FUNCTION__, request, size, result);
271 /* Single data value */
272 result = usb_control_msg (serial->dev,
273 usb_sndctrlpipe(serial->dev, 0),
274 request, REQTYPE_HOST_TO_DEVICE, data[0],
280 * cp2101_set_config_single
281 * Convenience function for calling cp2101_set_config on single data values
282 * without requiring an integer pointer
284 static inline int cp2101_set_config_single(struct usb_serial_port* port,
285 u8 request, unsigned int data)
287 return cp2101_set_config(port, request, &data, 2);
290 static int cp2101_open (struct usb_serial_port *port, struct file *filp)
292 struct usb_serial *serial = port->serial;
295 dbg("%s - port %d", __FUNCTION__, port->number);
297 if (cp2101_set_config_single(port, CP2101_UART, UART_ENABLE)) {
298 dev_err(&port->dev, "%s - Unable to enable UART\n",
303 /* Start reading from the device */
304 usb_fill_bulk_urb (port->read_urb, serial->dev,
305 usb_rcvbulkpipe(serial->dev,
306 port->bulk_in_endpointAddress),
307 port->read_urb->transfer_buffer,
308 port->read_urb->transfer_buffer_length,
309 serial->type->read_bulk_callback,
311 result = usb_submit_urb(port->read_urb, GFP_KERNEL);
313 dev_err(&port->dev, "%s - failed resubmitting read urb, "
314 "error %d\n", __FUNCTION__, result);
318 /* Configure the termios structure */
319 cp2101_get_termios(port);
321 /* Set the DTR and RTS pins low */
322 cp2101_tiocmset(port, NULL, TIOCM_DTR | TIOCM_RTS, 0);
327 static void cp2101_cleanup (struct usb_serial_port *port)
329 struct usb_serial *serial = port->serial;
331 dbg("%s - port %d", __FUNCTION__, port->number);
334 /* shutdown any bulk reads that might be going on */
335 if (serial->num_bulk_out)
336 usb_kill_urb(port->write_urb);
337 if (serial->num_bulk_in)
338 usb_kill_urb(port->read_urb);
342 static void cp2101_close (struct usb_serial_port *port, struct file * filp)
344 dbg("%s - port %d", __FUNCTION__, port->number);
346 /* shutdown our urbs */
347 dbg("%s - shutting down urbs", __FUNCTION__);
348 usb_kill_urb(port->write_urb);
349 usb_kill_urb(port->read_urb);
351 cp2101_set_config_single(port, CP2101_UART, UART_DISABLE);
356 * Reads the baud rate, data bits, parity, stop bits and flow control mode
357 * from the device, corrects any unsupported values, and configures the
358 * termios structure to reflect the state of the device
360 static void cp2101_get_termios (struct usb_serial_port *port)
362 unsigned int cflag, modem_ctl[4];
366 dbg("%s - port %d", __FUNCTION__, port->number);
368 if (!port->tty || !port->tty->termios) {
369 dbg("%s - no tty structures", __FUNCTION__);
373 cp2101_get_config(port, CP2101_BAUDRATE, &baud, 2);
374 /* Convert to baudrate */
376 baud = BAUD_RATE_GEN_FREQ / baud;
378 dbg("%s - baud rate = %d", __FUNCTION__, baud);
380 tty_encode_baud_rate(port->tty, baud, baud);
381 cflag = port->tty->termios->c_cflag;
383 cp2101_get_config(port, CP2101_BITS, &bits, 2);
385 switch(bits & BITS_DATA_MASK) {
387 dbg("%s - data bits = 5", __FUNCTION__);
391 dbg("%s - data bits = 6", __FUNCTION__);
395 dbg("%s - data bits = 7", __FUNCTION__);
399 dbg("%s - data bits = 8", __FUNCTION__);
403 dbg("%s - data bits = 9 (not supported, "
404 "using 8 data bits)", __FUNCTION__);
406 bits &= ~BITS_DATA_MASK;
408 cp2101_set_config(port, CP2101_BITS, &bits, 2);
411 dbg("%s - Unknown number of data bits, "
412 "using 8", __FUNCTION__);
414 bits &= ~BITS_DATA_MASK;
416 cp2101_set_config(port, CP2101_BITS, &bits, 2);
420 switch(bits & BITS_PARITY_MASK) {
421 case BITS_PARITY_NONE:
422 dbg("%s - parity = NONE", __FUNCTION__);
425 case BITS_PARITY_ODD:
426 dbg("%s - parity = ODD", __FUNCTION__);
427 cflag |= (PARENB|PARODD);
429 case BITS_PARITY_EVEN:
430 dbg("%s - parity = EVEN", __FUNCTION__);
434 case BITS_PARITY_MARK:
435 dbg("%s - parity = MARK (not supported, "
436 "disabling parity)", __FUNCTION__);
438 bits &= ~BITS_PARITY_MASK;
439 cp2101_set_config(port, CP2101_BITS, &bits, 2);
441 case BITS_PARITY_SPACE:
442 dbg("%s - parity = SPACE (not supported, "
443 "disabling parity)", __FUNCTION__);
445 bits &= ~BITS_PARITY_MASK;
446 cp2101_set_config(port, CP2101_BITS, &bits, 2);
449 dbg("%s - Unknown parity mode, "
450 "disabling parity", __FUNCTION__);
452 bits &= ~BITS_PARITY_MASK;
453 cp2101_set_config(port, CP2101_BITS, &bits, 2);
458 switch(bits & BITS_STOP_MASK) {
460 dbg("%s - stop bits = 1", __FUNCTION__);
463 dbg("%s - stop bits = 1.5 (not supported, "
464 "using 1 stop bit)", __FUNCTION__);
465 bits &= ~BITS_STOP_MASK;
466 cp2101_set_config(port, CP2101_BITS, &bits, 2);
469 dbg("%s - stop bits = 2", __FUNCTION__);
473 dbg("%s - Unknown number of stop bits, "
474 "using 1 stop bit", __FUNCTION__);
475 bits &= ~BITS_STOP_MASK;
476 cp2101_set_config(port, CP2101_BITS, &bits, 2);
480 cp2101_get_config(port, CP2101_MODEMCTL, modem_ctl, 16);
481 if (modem_ctl[0] & 0x0008) {
482 dbg("%s - flow control = CRTSCTS", __FUNCTION__);
485 dbg("%s - flow control = NONE", __FUNCTION__);
489 port->tty->termios->c_cflag = cflag;
492 static void cp2101_set_termios (struct usb_serial_port *port,
493 struct ktermios *old_termios)
495 unsigned int cflag, old_cflag;
497 unsigned int modem_ctl[4];
499 dbg("%s - port %d", __FUNCTION__, port->number);
501 if (!port->tty || !port->tty->termios) {
502 dbg("%s - no tty structures", __FUNCTION__);
505 port->tty->termios->c_cflag &= ~CMSPAR;
507 cflag = port->tty->termios->c_cflag;
508 old_cflag = old_termios->c_cflag;
509 baud = tty_get_baud_rate(port->tty);
511 /* If the baud rate is to be updated*/
512 if (baud != tty_termios_baud_rate(old_termios)) {
541 dbg("%s - Setting baud rate to %d baud", __FUNCTION__,
543 if (cp2101_set_config_single(port, CP2101_BAUDRATE,
544 (BAUD_RATE_GEN_FREQ / baud))) {
545 dev_err(&port->dev, "Baud rate requested not "
546 "supported by device\n");
547 baud = tty_termios_baud_rate(old_termios);
551 /* Report back the resulting baud rate */
552 tty_encode_baud_rate(port->tty, baud, baud);
554 /* If the number of data bits is to be updated */
555 if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
556 cp2101_get_config(port, CP2101_BITS, &bits, 2);
557 bits &= ~BITS_DATA_MASK;
558 switch (cflag & CSIZE) {
561 dbg("%s - data bits = 5", __FUNCTION__);
565 dbg("%s - data bits = 6", __FUNCTION__);
569 dbg("%s - data bits = 7", __FUNCTION__);
573 dbg("%s - data bits = 8", __FUNCTION__);
577 dbg("%s - data bits = 9", __FUNCTION__);
580 dev_err(&port->dev, "cp2101 driver does not "
581 "support the number of bits requested,"
582 " using 8 bit mode\n");
586 if (cp2101_set_config(port, CP2101_BITS, &bits, 2))
587 dev_err(&port->dev, "Number of data bits requested "
588 "not supported by device\n");
591 if ((cflag & (PARENB|PARODD)) != (old_cflag & (PARENB|PARODD))) {
592 cp2101_get_config(port, CP2101_BITS, &bits, 2);
593 bits &= ~BITS_PARITY_MASK;
594 if (cflag & PARENB) {
595 if (cflag & PARODD) {
596 bits |= BITS_PARITY_ODD;
597 dbg("%s - parity = ODD", __FUNCTION__);
599 bits |= BITS_PARITY_EVEN;
600 dbg("%s - parity = EVEN", __FUNCTION__);
603 if (cp2101_set_config(port, CP2101_BITS, &bits, 2))
604 dev_err(&port->dev, "Parity mode not supported "
608 if ((cflag & CSTOPB) != (old_cflag & CSTOPB)) {
609 cp2101_get_config(port, CP2101_BITS, &bits, 2);
610 bits &= ~BITS_STOP_MASK;
611 if (cflag & CSTOPB) {
613 dbg("%s - stop bits = 2", __FUNCTION__);
616 dbg("%s - stop bits = 1", __FUNCTION__);
618 if (cp2101_set_config(port, CP2101_BITS, &bits, 2))
619 dev_err(&port->dev, "Number of stop bits requested "
620 "not supported by device\n");
623 if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {
624 cp2101_get_config(port, CP2101_MODEMCTL, modem_ctl, 16);
625 dbg("%s - read modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x",
626 __FUNCTION__, modem_ctl[0], modem_ctl[1],
627 modem_ctl[2], modem_ctl[3]);
629 if (cflag & CRTSCTS) {
630 modem_ctl[0] &= ~0x7B;
631 modem_ctl[0] |= 0x09;
633 dbg("%s - flow control = CRTSCTS", __FUNCTION__);
635 modem_ctl[0] &= ~0x7B;
636 modem_ctl[0] |= 0x01;
637 modem_ctl[1] |= 0x40;
638 dbg("%s - flow control = NONE", __FUNCTION__);
641 dbg("%s - write modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x",
642 __FUNCTION__, modem_ctl[0], modem_ctl[1],
643 modem_ctl[2], modem_ctl[3]);
644 cp2101_set_config(port, CP2101_MODEMCTL, modem_ctl, 16);
649 static int cp2101_tiocmset (struct usb_serial_port *port, struct file *file,
650 unsigned int set, unsigned int clear)
654 dbg("%s - port %d", __FUNCTION__, port->number);
656 if (set & TIOCM_RTS) {
657 control |= CONTROL_RTS;
658 control |= CONTROL_WRITE_RTS;
660 if (set & TIOCM_DTR) {
661 control |= CONTROL_DTR;
662 control |= CONTROL_WRITE_DTR;
664 if (clear & TIOCM_RTS) {
665 control &= ~CONTROL_RTS;
666 control |= CONTROL_WRITE_RTS;
668 if (clear & TIOCM_DTR) {
669 control &= ~CONTROL_DTR;
670 control |= CONTROL_WRITE_DTR;
673 dbg("%s - control = 0x%.4x", __FUNCTION__, control);
675 return cp2101_set_config(port, CP2101_CONTROL, &control, 2);
679 static int cp2101_tiocmget (struct usb_serial_port *port, struct file *file)
683 dbg("%s - port %d", __FUNCTION__, port->number);
685 cp2101_get_config(port, CP2101_CONTROL, &control, 1);
687 result = ((control & CONTROL_DTR) ? TIOCM_DTR : 0)
688 |((control & CONTROL_RTS) ? TIOCM_RTS : 0)
689 |((control & CONTROL_CTS) ? TIOCM_CTS : 0)
690 |((control & CONTROL_DSR) ? TIOCM_DSR : 0)
691 |((control & CONTROL_RING)? TIOCM_RI : 0)
692 |((control & CONTROL_DCD) ? TIOCM_CD : 0);
694 dbg("%s - control = 0x%.2x", __FUNCTION__, control);
699 static void cp2101_break_ctl (struct usb_serial_port *port, int break_state)
703 dbg("%s - port %d", __FUNCTION__, port->number);
704 if (break_state == 0)
708 dbg("%s - turning break %s", __FUNCTION__,
709 state==BREAK_OFF ? "off" : "on");
710 cp2101_set_config(port, CP2101_BREAK, &state, 2);
713 static int cp2101_startup (struct usb_serial *serial)
715 /* CP2101 buffers behave strangely unless device is reset */
716 usb_reset_device(serial->dev);
720 static void cp2101_shutdown (struct usb_serial *serial)
724 dbg("%s", __FUNCTION__);
726 /* Stop reads and writes on all ports */
727 for (i=0; i < serial->num_ports; ++i) {
728 cp2101_cleanup(serial->port[i]);
732 static int __init cp2101_init (void)
736 retval = usb_serial_register(&cp2101_device);
738 return retval; /* Failed to register */
740 retval = usb_register(&cp2101_driver);
742 /* Failed to register */
743 usb_serial_deregister(&cp2101_device);
748 info(DRIVER_DESC " " DRIVER_VERSION);
752 static void __exit cp2101_exit (void)
754 usb_deregister (&cp2101_driver);
755 usb_serial_deregister (&cp2101_device);
758 module_init(cp2101_init);
759 module_exit(cp2101_exit);
761 MODULE_DESCRIPTION(DRIVER_DESC);
762 MODULE_VERSION(DRIVER_VERSION);
763 MODULE_LICENSE("GPL");
765 module_param(debug, bool, S_IRUGO | S_IWUSR);
766 MODULE_PARM_DESC(debug, "Enable verbose debugging messages");