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/config.h>
21 #include <linux/kernel.h>
22 #include <linux/errno.h>
23 #include <linux/slab.h>
24 #include <linux/tty.h>
25 #include <linux/tty_flip.h>
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/usb.h>
29 #include <asm/uaccess.h>
30 #include "usb-serial.h"
35 #define DRIVER_VERSION "v0.06"
36 #define DRIVER_DESC "Silicon Labs CP2101/CP2102 RS232 serial adaptor driver"
41 static int cp2101_open(struct usb_serial_port*, struct file*);
42 static void cp2101_cleanup(struct usb_serial_port*);
43 static void cp2101_close(struct usb_serial_port*, struct file*);
44 static void cp2101_get_termios(struct usb_serial_port*);
45 static void cp2101_set_termios(struct usb_serial_port*, struct termios*);
46 static int cp2101_tiocmget (struct usb_serial_port *, struct file *);
47 static int cp2101_tiocmset (struct usb_serial_port *, struct file *,
48 unsigned int, unsigned int);
49 static void cp2101_break_ctl(struct usb_serial_port*, int);
50 static int cp2101_startup (struct usb_serial *);
51 static void cp2101_shutdown(struct usb_serial*);
56 static struct usb_device_id id_table [] = {
57 { USB_DEVICE(0x0FCF, 0x1003) }, /* Dynastream ANT development board */
58 { USB_DEVICE(0x10A6, 0xAA26) }, /* Knock-off DCU-11 cable */
59 { USB_DEVICE(0x10AB, 0x10C5) }, /* Siemens MC60 Cable */
60 { USB_DEVICE(0x10B5, 0xAC70) }, /* Nokia CA-42 USB */
61 { USB_DEVICE(0x10C4, 0x807A) }, /* Crumb128 board */
62 { USB_DEVICE(0x10C4, 0x80CA) }, /* Degree Controls Inc */
63 { USB_DEVICE(0x10C4, 0x80F6) }, /* Suunto sports instrument */
64 { USB_DEVICE(0x10C4, 0x813D) }, /* Burnside Telecom Deskmobile */
65 { USB_DEVICE(0x10C4, 0x815E) }, /* Helicomm IP-Link 1220-DVM */
66 { USB_DEVICE(0x10C4, 0xEA60) }, /* Silicon Labs factory default */
67 { USB_DEVICE(0x16D6, 0x0001) }, /* Jablotron serial interface */
68 { } /* Terminating Entry */
71 MODULE_DEVICE_TABLE (usb, id_table);
73 static struct usb_driver cp2101_driver = {
75 .probe = usb_serial_probe,
76 .disconnect = usb_serial_disconnect,
81 static struct usb_serial_driver cp2101_device = {
87 .num_interrupt_in = 0,
92 .close = cp2101_close,
93 .break_ctl = cp2101_break_ctl,
94 .set_termios = cp2101_set_termios,
95 .tiocmget = cp2101_tiocmget,
96 .tiocmset = cp2101_tiocmset,
97 .attach = cp2101_startup,
98 .shutdown = cp2101_shutdown,
101 /* Config request types */
102 #define REQTYPE_HOST_TO_DEVICE 0x41
103 #define REQTYPE_DEVICE_TO_HOST 0xc1
105 /* Config SET requests. To GET, add 1 to the request number */
106 #define CP2101_UART 0x00 /* Enable / Disable */
107 #define CP2101_BAUDRATE 0x01 /* (BAUD_RATE_GEN_FREQ / baudrate) */
108 #define CP2101_BITS 0x03 /* 0x(0)(databits)(parity)(stopbits) */
109 #define CP2101_BREAK 0x05 /* On / Off */
110 #define CP2101_CONTROL 0x07 /* Flow control line states */
111 #define CP2101_MODEMCTL 0x13 /* Modem controls */
112 #define CP2101_CONFIG_6 0x19 /* 6 bytes of config data ??? */
115 #define UART_ENABLE 0x0001
116 #define UART_DISABLE 0x0000
118 /* CP2101_BAUDRATE */
119 #define BAUD_RATE_GEN_FREQ 0x384000
122 #define BITS_DATA_MASK 0X0f00
123 #define BITS_DATA_5 0X0500
124 #define BITS_DATA_6 0X0600
125 #define BITS_DATA_7 0X0700
126 #define BITS_DATA_8 0X0800
127 #define BITS_DATA_9 0X0900
129 #define BITS_PARITY_MASK 0x00f0
130 #define BITS_PARITY_NONE 0x0000
131 #define BITS_PARITY_ODD 0x0010
132 #define BITS_PARITY_EVEN 0x0020
133 #define BITS_PARITY_MARK 0x0030
134 #define BITS_PARITY_SPACE 0x0040
136 #define BITS_STOP_MASK 0x000f
137 #define BITS_STOP_1 0x0000
138 #define BITS_STOP_1_5 0x0001
139 #define BITS_STOP_2 0x0002
142 #define BREAK_ON 0x0000
143 #define BREAK_OFF 0x0001
146 #define CONTROL_DTR 0x0001
147 #define CONTROL_RTS 0x0002
148 #define CONTROL_CTS 0x0010
149 #define CONTROL_DSR 0x0020
150 #define CONTROL_RING 0x0040
151 #define CONTROL_DCD 0x0080
152 #define CONTROL_WRITE_DTR 0x0100
153 #define CONTROL_WRITE_RTS 0x0200
157 * Reads from the CP2101 configuration registers
158 * 'size' is specified in bytes.
159 * 'data' is a pointer to a pre-allocated array of integers large
160 * enough to hold 'size' bytes (with 4 bytes to each integer)
162 static int cp2101_get_config(struct usb_serial_port* port, u8 request,
163 unsigned int *data, int size)
165 struct usb_serial *serial = port->serial;
167 int result, i, length;
169 /* Number of integers required to contain the array */
170 length = (((size - 1) | 3) + 1)/4;
172 buf = kmalloc (length * sizeof(u32), GFP_KERNEL);
173 memset(buf, 0, length * sizeof(u32));
176 dev_err(&port->dev, "%s - out of memory.\n", __FUNCTION__);
180 /* For get requests, the request number must be incremented */
183 /* Issue the request, attempting to read 'size' bytes */
184 result = usb_control_msg (serial->dev,usb_rcvctrlpipe (serial->dev, 0),
185 request, REQTYPE_DEVICE_TO_HOST, 0x0000,
188 /* Convert data into an array of integers */
189 for (i=0; i<length; i++)
190 data[i] = le32_to_cpu(buf[i]);
194 if (result != size) {
195 dev_err(&port->dev, "%s - Unable to send config request, "
196 "request=0x%x size=%d result=%d\n",
197 __FUNCTION__, request, size, result);
206 * Writes to the CP2101 configuration registers
207 * Values less than 16 bits wide are sent directly
208 * 'size' is specified in bytes.
210 static int cp2101_set_config(struct usb_serial_port* port, u8 request,
211 unsigned int *data, int size)
213 struct usb_serial *serial = port->serial;
215 int result, i, length;
217 /* Number of integers required to contain the array */
218 length = (((size - 1) | 3) + 1)/4;
220 buf = kmalloc(length * sizeof(u32), GFP_KERNEL);
222 dev_err(&port->dev, "%s - out of memory.\n",
227 /* Array of integers into bytes */
228 for (i = 0; i < length; i++)
229 buf[i] = cpu_to_le32(data[i]);
232 result = usb_control_msg (serial->dev,
233 usb_sndctrlpipe(serial->dev, 0),
234 request, REQTYPE_HOST_TO_DEVICE, 0x0000,
237 result = usb_control_msg (serial->dev,
238 usb_sndctrlpipe(serial->dev, 0),
239 request, REQTYPE_HOST_TO_DEVICE, data[0],
245 if ((size > 2 && result != size) || result < 0) {
246 dev_err(&port->dev, "%s - Unable to send request, "
247 "request=0x%x size=%d result=%d\n",
248 __FUNCTION__, request, size, result);
252 /* Single data value */
253 result = usb_control_msg (serial->dev,
254 usb_sndctrlpipe(serial->dev, 0),
255 request, REQTYPE_HOST_TO_DEVICE, data[0],
261 * cp2101_set_config_single
262 * Convenience function for calling cp2101_set_config on single data values
263 * without requiring an integer pointer
265 static inline int cp2101_set_config_single(struct usb_serial_port* port,
266 u8 request, unsigned int data)
268 return cp2101_set_config(port, request, &data, 2);
271 static int cp2101_open (struct usb_serial_port *port, struct file *filp)
273 struct usb_serial *serial = port->serial;
276 dbg("%s - port %d", __FUNCTION__, port->number);
278 if (cp2101_set_config_single(port, CP2101_UART, UART_ENABLE)) {
279 dev_err(&port->dev, "%s - Unable to enable UART\n",
284 /* Start reading from the device */
285 usb_fill_bulk_urb (port->read_urb, serial->dev,
286 usb_rcvbulkpipe(serial->dev,
287 port->bulk_in_endpointAddress),
288 port->read_urb->transfer_buffer,
289 port->read_urb->transfer_buffer_length,
290 serial->type->read_bulk_callback,
292 result = usb_submit_urb(port->read_urb, GFP_KERNEL);
294 dev_err(&port->dev, "%s - failed resubmitting read urb, "
295 "error %d\n", __FUNCTION__, result);
299 /* Configure the termios structure */
300 cp2101_get_termios(port);
302 /* Set the DTR and RTS pins low */
303 cp2101_tiocmset(port, NULL, TIOCM_DTR | TIOCM_RTS, 0);
308 static void cp2101_cleanup (struct usb_serial_port *port)
310 struct usb_serial *serial = port->serial;
312 dbg("%s - port %d", __FUNCTION__, port->number);
315 /* shutdown any bulk reads that might be going on */
316 if (serial->num_bulk_out)
317 usb_kill_urb(port->write_urb);
318 if (serial->num_bulk_in)
319 usb_kill_urb(port->read_urb);
323 static void cp2101_close (struct usb_serial_port *port, struct file * filp)
325 dbg("%s - port %d", __FUNCTION__, port->number);
327 /* shutdown our urbs */
328 dbg("%s - shutting down urbs", __FUNCTION__);
329 usb_kill_urb(port->write_urb);
330 usb_kill_urb(port->read_urb);
332 cp2101_set_config_single(port, CP2101_UART, UART_DISABLE);
337 * Reads the baud rate, data bits, parity, stop bits and flow control mode
338 * from the device, corrects any unsupported values, and configures the
339 * termios structure to reflect the state of the device
341 static void cp2101_get_termios (struct usb_serial_port *port)
343 unsigned int cflag, modem_ctl[4];
347 dbg("%s - port %d", __FUNCTION__, port->number);
349 if ((!port->tty) || (!port->tty->termios)) {
350 dbg("%s - no tty structures", __FUNCTION__);
353 cflag = port->tty->termios->c_cflag;
355 cp2101_get_config(port, CP2101_BAUDRATE, &baud, 2);
356 /* Convert to baudrate */
358 baud = BAUD_RATE_GEN_FREQ / baud;
360 dbg("%s - baud rate = %d", __FUNCTION__, baud);
364 * The baud rates which are commented out below
365 * appear to be supported by the device
366 * but are non-standard
368 case 600: cflag |= B600; break;
369 case 1200: cflag |= B1200; break;
370 case 1800: cflag |= B1800; break;
371 case 2400: cflag |= B2400; break;
372 case 4800: cflag |= B4800; break;
373 /*case 7200: cflag |= B7200; break;*/
374 case 9600: cflag |= B9600; break;
375 /*case 14400: cflag |= B14400; break;*/
376 case 19200: cflag |= B19200; break;
377 /*case 28800: cflag |= B28800; break;*/
378 case 38400: cflag |= B38400; break;
379 /*case 55854: cflag |= B55054; break;*/
380 case 57600: cflag |= B57600; break;
381 case 115200: cflag |= B115200; break;
382 /*case 127117: cflag |= B127117; break;*/
383 case 230400: cflag |= B230400; break;
384 case 460800: cflag |= B460800; break;
385 case 921600: cflag |= B921600; break;
386 /*case 3686400: cflag |= B3686400; break;*/
388 dbg("%s - Baud rate is not supported, "
389 "using 9600 baud", __FUNCTION__);
391 cp2101_set_config_single(port, CP2101_BAUDRATE,
392 (BAUD_RATE_GEN_FREQ/9600));
396 cp2101_get_config(port, CP2101_BITS, &bits, 2);
398 switch(bits & BITS_DATA_MASK) {
400 dbg("%s - data bits = 5", __FUNCTION__);
404 dbg("%s - data bits = 6", __FUNCTION__);
408 dbg("%s - data bits = 7", __FUNCTION__);
412 dbg("%s - data bits = 8", __FUNCTION__);
416 dbg("%s - data bits = 9 (not supported, "
417 "using 8 data bits)", __FUNCTION__);
419 bits &= ~BITS_DATA_MASK;
421 cp2101_set_config(port, CP2101_BITS, &bits, 2);
424 dbg("%s - Unknown number of data bits, "
425 "using 8", __FUNCTION__);
427 bits &= ~BITS_DATA_MASK;
429 cp2101_set_config(port, CP2101_BITS, &bits, 2);
433 switch(bits & BITS_PARITY_MASK) {
434 case BITS_PARITY_NONE:
435 dbg("%s - parity = NONE", __FUNCTION__);
438 case BITS_PARITY_ODD:
439 dbg("%s - parity = ODD", __FUNCTION__);
440 cflag |= (PARENB|PARODD);
442 case BITS_PARITY_EVEN:
443 dbg("%s - parity = EVEN", __FUNCTION__);
447 case BITS_PARITY_MARK:
448 dbg("%s - parity = MARK (not supported, "
449 "disabling parity)", __FUNCTION__);
451 bits &= ~BITS_PARITY_MASK;
452 cp2101_set_config(port, CP2101_BITS, &bits, 2);
454 case BITS_PARITY_SPACE:
455 dbg("%s - parity = SPACE (not supported, "
456 "disabling parity)", __FUNCTION__);
458 bits &= ~BITS_PARITY_MASK;
459 cp2101_set_config(port, CP2101_BITS, &bits, 2);
462 dbg("%s - Unknown parity mode, "
463 "disabling parity", __FUNCTION__);
465 bits &= ~BITS_PARITY_MASK;
466 cp2101_set_config(port, CP2101_BITS, &bits, 2);
471 switch(bits & BITS_STOP_MASK) {
473 dbg("%s - stop bits = 1", __FUNCTION__);
476 dbg("%s - stop bits = 1.5 (not supported, "
477 "using 1 stop bit)", __FUNCTION__);
478 bits &= ~BITS_STOP_MASK;
479 cp2101_set_config(port, CP2101_BITS, &bits, 2);
482 dbg("%s - stop bits = 2", __FUNCTION__);
486 dbg("%s - Unknown number of stop bits, "
487 "using 1 stop bit", __FUNCTION__);
488 bits &= ~BITS_STOP_MASK;
489 cp2101_set_config(port, CP2101_BITS, &bits, 2);
493 cp2101_get_config(port, CP2101_MODEMCTL, modem_ctl, 16);
494 if (modem_ctl[0] & 0x0008) {
495 dbg("%s - flow control = CRTSCTS", __FUNCTION__);
498 dbg("%s - flow control = NONE", __FUNCTION__);
502 port->tty->termios->c_cflag = cflag;
505 static void cp2101_set_termios (struct usb_serial_port *port,
506 struct termios *old_termios)
508 unsigned int cflag, old_cflag=0;
510 unsigned int modem_ctl[4];
512 dbg("%s - port %d", __FUNCTION__, port->number);
514 if ((!port->tty) || (!port->tty->termios)) {
515 dbg("%s - no tty structures", __FUNCTION__);
518 cflag = port->tty->termios->c_cflag;
520 /* Check that they really want us to change something */
522 if ((cflag == old_termios->c_cflag) &&
523 (RELEVANT_IFLAG(port->tty->termios->c_iflag)
524 == RELEVANT_IFLAG(old_termios->c_iflag))) {
525 dbg("%s - nothing to change...", __FUNCTION__);
529 old_cflag = old_termios->c_cflag;
532 /* If the baud rate is to be updated*/
533 if ((cflag & CBAUD) != (old_cflag & CBAUD)) {
534 switch (cflag & CBAUD) {
536 * The baud rates which are commented out below
537 * appear to be supported by the device
538 * but are non-standard
540 case B0: baud = 0; break;
541 case B600: baud = 600; break;
542 case B1200: baud = 1200; break;
543 case B1800: baud = 1800; break;
544 case B2400: baud = 2400; break;
545 case B4800: baud = 4800; break;
546 /*case B7200: baud = 7200; break;*/
547 case B9600: baud = 9600; break;
548 /*ase B14400: baud = 14400; break;*/
549 case B19200: baud = 19200; break;
550 /*case B28800: baud = 28800; break;*/
551 case B38400: baud = 38400; break;
552 /*case B55854: baud = 55054; break;*/
553 case B57600: baud = 57600; break;
554 case B115200: baud = 115200; break;
555 /*case B127117: baud = 127117; break;*/
556 case B230400: baud = 230400; break;
557 case B460800: baud = 460800; break;
558 case B921600: baud = 921600; break;
559 /*case B3686400: baud = 3686400; break;*/
561 dev_err(&port->dev, "cp2101 driver does not "
562 "support the baudrate requested\n");
567 dbg("%s - Setting baud rate to %d baud", __FUNCTION__,
569 if (cp2101_set_config_single(port, CP2101_BAUDRATE,
570 (BAUD_RATE_GEN_FREQ / baud)))
571 dev_err(&port->dev, "Baud rate requested not "
572 "supported by device\n");
576 /* If the number of data bits is to be updated */
577 if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
578 cp2101_get_config(port, CP2101_BITS, &bits, 2);
579 bits &= ~BITS_DATA_MASK;
580 switch (cflag & CSIZE) {
583 dbg("%s - data bits = 5", __FUNCTION__);
587 dbg("%s - data bits = 6", __FUNCTION__);
591 dbg("%s - data bits = 7", __FUNCTION__);
595 dbg("%s - data bits = 8", __FUNCTION__);
599 dbg("%s - data bits = 9", __FUNCTION__);
602 dev_err(&port->dev, "cp2101 driver does not "
603 "support the number of bits requested,"
604 " using 8 bit mode\n");
608 if (cp2101_set_config(port, CP2101_BITS, &bits, 2))
609 dev_err(&port->dev, "Number of data bits requested "
610 "not supported by device\n");
613 if ((cflag & (PARENB|PARODD)) != (old_cflag & (PARENB|PARODD))) {
614 cp2101_get_config(port, CP2101_BITS, &bits, 2);
615 bits &= ~BITS_PARITY_MASK;
616 if (cflag & PARENB) {
617 if (cflag & PARODD) {
618 bits |= BITS_PARITY_ODD;
619 dbg("%s - parity = ODD", __FUNCTION__);
621 bits |= BITS_PARITY_EVEN;
622 dbg("%s - parity = EVEN", __FUNCTION__);
625 if (cp2101_set_config(port, CP2101_BITS, &bits, 2))
626 dev_err(&port->dev, "Parity mode not supported "
630 if ((cflag & CSTOPB) != (old_cflag & CSTOPB)) {
631 cp2101_get_config(port, CP2101_BITS, &bits, 2);
632 bits &= ~BITS_STOP_MASK;
633 if (cflag & CSTOPB) {
635 dbg("%s - stop bits = 2", __FUNCTION__);
638 dbg("%s - stop bits = 1", __FUNCTION__);
640 if (cp2101_set_config(port, CP2101_BITS, &bits, 2))
641 dev_err(&port->dev, "Number of stop bits requested "
642 "not supported by device\n");
645 if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {
646 cp2101_get_config(port, CP2101_MODEMCTL, modem_ctl, 16);
647 dbg("%s - read modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x",
648 __FUNCTION__, modem_ctl[0], modem_ctl[1],
649 modem_ctl[2], modem_ctl[3]);
651 if (cflag & CRTSCTS) {
652 modem_ctl[0] &= ~0x7B;
653 modem_ctl[0] |= 0x09;
655 dbg("%s - flow control = CRTSCTS", __FUNCTION__);
657 modem_ctl[0] &= ~0x7B;
658 modem_ctl[0] |= 0x01;
659 modem_ctl[1] |= 0x40;
660 dbg("%s - flow control = NONE", __FUNCTION__);
663 dbg("%s - write modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x",
664 __FUNCTION__, modem_ctl[0], modem_ctl[1],
665 modem_ctl[2], modem_ctl[3]);
666 cp2101_set_config(port, CP2101_MODEMCTL, modem_ctl, 16);
671 static int cp2101_tiocmset (struct usb_serial_port *port, struct file *file,
672 unsigned int set, unsigned int clear)
676 dbg("%s - port %d", __FUNCTION__, port->number);
678 if (set & TIOCM_RTS) {
679 control |= CONTROL_RTS;
680 control |= CONTROL_WRITE_RTS;
682 if (set & TIOCM_DTR) {
683 control |= CONTROL_DTR;
684 control |= CONTROL_WRITE_DTR;
686 if (clear & TIOCM_RTS) {
687 control &= ~CONTROL_RTS;
688 control |= CONTROL_WRITE_RTS;
690 if (clear & TIOCM_DTR) {
691 control &= ~CONTROL_DTR;
692 control |= CONTROL_WRITE_DTR;
695 dbg("%s - control = 0x%.4x", __FUNCTION__, control);
697 return cp2101_set_config(port, CP2101_CONTROL, &control, 2);
701 static int cp2101_tiocmget (struct usb_serial_port *port, struct file *file)
705 dbg("%s - port %d", __FUNCTION__, port->number);
707 cp2101_get_config(port, CP2101_CONTROL, &control, 1);
709 result = ((control & CONTROL_DTR) ? TIOCM_DTR : 0)
710 |((control & CONTROL_RTS) ? TIOCM_RTS : 0)
711 |((control & CONTROL_CTS) ? TIOCM_CTS : 0)
712 |((control & CONTROL_DSR) ? TIOCM_DSR : 0)
713 |((control & CONTROL_RING)? TIOCM_RI : 0)
714 |((control & CONTROL_DCD) ? TIOCM_CD : 0);
716 dbg("%s - control = 0x%.2x", __FUNCTION__, control);
721 static void cp2101_break_ctl (struct usb_serial_port *port, int break_state)
725 dbg("%s - port %d", __FUNCTION__, port->number);
726 if (break_state == 0)
730 dbg("%s - turning break %s", __FUNCTION__,
731 state==BREAK_OFF ? "off" : "on");
732 cp2101_set_config(port, CP2101_BREAK, &state, 2);
735 static int cp2101_startup (struct usb_serial *serial)
737 /* CP2101 buffers behave strangely unless device is reset */
738 usb_reset_device(serial->dev);
742 static void cp2101_shutdown (struct usb_serial *serial)
746 dbg("%s", __FUNCTION__);
748 /* Stop reads and writes on all ports */
749 for (i=0; i < serial->num_ports; ++i) {
750 cp2101_cleanup(serial->port[i]);
754 static int __init cp2101_init (void)
758 retval = usb_serial_register(&cp2101_device);
760 return retval; /* Failed to register */
762 retval = usb_register(&cp2101_driver);
764 /* Failed to register */
765 usb_serial_deregister(&cp2101_device);
770 info(DRIVER_DESC " " DRIVER_VERSION);
774 static void __exit cp2101_exit (void)
776 usb_deregister (&cp2101_driver);
777 usb_serial_deregister (&cp2101_device);
780 module_init(cp2101_init);
781 module_exit(cp2101_exit);
783 MODULE_DESCRIPTION(DRIVER_DESC);
784 MODULE_VERSION(DRIVER_VERSION);
785 MODULE_LICENSE("GPL");
787 module_param(debug, bool, S_IRUGO | S_IWUSR);
788 MODULE_PARM_DESC(debug, "Enable verbose debugging messages");