1 /* 2 * Belkin USB Serial Adapter Driver 3 * 4 * Copyright (C) 2000 William Greathouse (wgreathouse@smva.com) 5 * Copyright (C) 2000-2001 Greg Kroah-Hartman (greg@kroah.com) 6 * 7 * This program is largely derived from work by the linux-usb group 8 * and associated source files. Please see the usb/serial files for 9 * individual credits and copyrights. 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License as published by 13 * the Free Software Foundation; either version 2 of the License, or 14 * (at your option) any later version. 15 * 16 * See Documentation/usb/usb-serial.txt for more information on using this driver 17 * 18 * TODO: 19 * -- Add true modem contol line query capability. Currently we track the 20 * states reported by the interrupt and the states we request. 21 * -- Add error reporting back to application for UART error conditions. 22 * Just point me at how to implement this and I'll do it. I've put the 23 * framework in, but haven't analyzed the "tty_flip" interface yet. 24 * -- Add support for flush commands 25 * -- Add everything that is missing :) 26 * 27 * 27-Nov-2001 gkh 28 * compressed all the differnent device entries into 1. 29 * 30 * 30-May-2001 gkh 31 * switched from using spinlock to a semaphore, which fixes lots of problems. 32 * 33 * 08-Apr-2001 gb 34 * - Identify version on module load. 35 * 36 * 12-Mar-2001 gkh 37 * - Added support for the GoHubs GO-COM232 device which is the same as the 38 * Peracom device. 39 * 40 * 06-Nov-2000 gkh 41 * - Added support for the old Belkin and Peracom devices. 42 * - Made the port able to be opened multiple times. 43 * - Added some defaults incase the line settings are things these devices 44 * can't support. 45 * 46 * 18-Oct-2000 William Greathouse 47 * Released into the wild (linux-usb-devel) 48 * 49 * 17-Oct-2000 William Greathouse 50 * Add code to recognize firmware version and set hardware flow control 51 * appropriately. Belkin states that firmware prior to 3.05 does not 52 * operate correctly in hardware handshake mode. I have verified this 53 * on firmware 2.05 -- for both RTS and DTR input flow control, the control 54 * line is not reset. The test performed by the Belkin Win* driver is 55 * to enable hardware flow control for firmware 2.06 or greater and 56 * for 1.00 or prior. I am only enabling for 2.06 or greater. 57 * 58 * 12-Oct-2000 William Greathouse 59 * First cut at supporting Belkin USB Serial Adapter F5U103 60 * I did not have a copy of the original work to support this 61 * adapter, so pardon any stupid mistakes. All of the information 62 * I am using to write this driver was acquired by using a modified 63 * UsbSnoop on Windows2000 and from examining the other USB drivers. 64 */ 65 66 #include <linux/kernel.h> 67 #include <linux/errno.h> 68 #include <linux/init.h> 69 #include <linux/slab.h> 70 #include <linux/tty.h> 71 #include <linux/tty_driver.h> 72 #include <linux/tty_flip.h> 73 #include <linux/module.h> 74 #include <linux/spinlock.h> 75 #include <asm/uaccess.h> 76 #include <linux/usb.h> 77 #include <linux/usb/serial.h> 78 #include "belkin_sa.h" 79 80 static int debug; 81 82 /* 83 * Version Information 84 */ 85 #define DRIVER_VERSION "v1.2" 86 #define DRIVER_AUTHOR "William Greathouse <wgreathouse@smva.com>" 87 #define DRIVER_DESC "USB Belkin Serial converter driver" 88 89 /* function prototypes for a Belkin USB Serial Adapter F5U103 */ 90 static int belkin_sa_startup (struct usb_serial *serial); 91 static void belkin_sa_shutdown (struct usb_serial *serial); 92 static int belkin_sa_open (struct usb_serial_port *port, struct file *filp); 93 static void belkin_sa_close (struct usb_serial_port *port, struct file *filp); 94 static void belkin_sa_read_int_callback (struct urb *urb, struct pt_regs *regs); 95 static void belkin_sa_set_termios (struct usb_serial_port *port, struct termios * old); 96 static int belkin_sa_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg); 97 static void belkin_sa_break_ctl (struct usb_serial_port *port, int break_state ); 98 static int belkin_sa_tiocmget (struct usb_serial_port *port, struct file *file); 99 static int belkin_sa_tiocmset (struct usb_serial_port *port, struct file *file, unsigned int set, unsigned int clear); 100 101 102 static struct usb_device_id id_table_combined [] = { 103 { USB_DEVICE(BELKIN_SA_VID, BELKIN_SA_PID) }, 104 { USB_DEVICE(BELKIN_OLD_VID, BELKIN_OLD_PID) }, 105 { USB_DEVICE(PERACOM_VID, PERACOM_PID) }, 106 { USB_DEVICE(GOHUBS_VID, GOHUBS_PID) }, 107 { USB_DEVICE(GOHUBS_VID, HANDYLINK_PID) }, 108 { USB_DEVICE(BELKIN_DOCKSTATION_VID, BELKIN_DOCKSTATION_PID) }, 109 { } /* Terminating entry */ 110 }; 111 112 MODULE_DEVICE_TABLE (usb, id_table_combined); 113 114 static struct usb_driver belkin_driver = { 115 .name = "belkin", 116 .probe = usb_serial_probe, 117 .disconnect = usb_serial_disconnect, 118 .id_table = id_table_combined, 119 .no_dynamic_id = 1, 120 }; 121 122 /* All of the device info needed for the serial converters */ 123 static struct usb_serial_driver belkin_device = { 124 .driver = { 125 .owner = THIS_MODULE, 126 .name = "belkin", 127 }, 128 .description = "Belkin / Peracom / GoHubs USB Serial Adapter", 129 .id_table = id_table_combined, 130 .num_interrupt_in = 1, 131 .num_bulk_in = 1, 132 .num_bulk_out = 1, 133 .num_ports = 1, 134 .open = belkin_sa_open, 135 .close = belkin_sa_close, 136 .read_int_callback = belkin_sa_read_int_callback, /* How we get the status info */ 137 .ioctl = belkin_sa_ioctl, 138 .set_termios = belkin_sa_set_termios, 139 .break_ctl = belkin_sa_break_ctl, 140 .tiocmget = belkin_sa_tiocmget, 141 .tiocmset = belkin_sa_tiocmset, 142 .attach = belkin_sa_startup, 143 .shutdown = belkin_sa_shutdown, 144 }; 145 146 147 struct belkin_sa_private { 148 spinlock_t lock; 149 unsigned long control_state; 150 unsigned char last_lsr; 151 unsigned char last_msr; 152 int bad_flow_control; 153 }; 154 155 156 /* 157 * *************************************************************************** 158 * Belkin USB Serial Adapter F5U103 specific driver functions 159 * *************************************************************************** 160 */ 161 162 #define WDR_TIMEOUT 5000 /* default urb timeout */ 163 164 /* assumes that struct usb_serial *serial is available */ 165 #define BSA_USB_CMD(c,v) usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0), \ 166 (c), BELKIN_SA_SET_REQUEST_TYPE, \ 167 (v), 0, NULL, 0, WDR_TIMEOUT) 168 169 /* do some startup allocations not currently performed by usb_serial_probe() */ 170 static int belkin_sa_startup (struct usb_serial *serial) 171 { 172 struct usb_device *dev = serial->dev; 173 struct belkin_sa_private *priv; 174 175 /* allocate the private data structure */ 176 priv = kmalloc(sizeof(struct belkin_sa_private), GFP_KERNEL); 177 if (!priv) 178 return (-1); /* error */ 179 /* set initial values for control structures */ 180 spin_lock_init(&priv->lock); 181 priv->control_state = 0; 182 priv->last_lsr = 0; 183 priv->last_msr = 0; 184 /* see comments at top of file */ 185 priv->bad_flow_control = (le16_to_cpu(dev->descriptor.bcdDevice) <= 0x0206) ? 1 : 0; 186 info("bcdDevice: %04x, bfc: %d", le16_to_cpu(dev->descriptor.bcdDevice), priv->bad_flow_control); 187 188 init_waitqueue_head(&serial->port[0]->write_wait); 189 usb_set_serial_port_data(serial->port[0], priv); 190 191 return (0); 192 } 193 194 195 static void belkin_sa_shutdown (struct usb_serial *serial) 196 { 197 struct belkin_sa_private *priv; 198 int i; 199 200 dbg ("%s", __FUNCTION__); 201 202 /* stop reads and writes on all ports */ 203 for (i=0; i < serial->num_ports; ++i) { 204 /* My special items, the standard routines free my urbs */ 205 priv = usb_get_serial_port_data(serial->port[i]); 206 kfree(priv); 207 } 208 } 209 210 211 static int belkin_sa_open (struct usb_serial_port *port, struct file *filp) 212 { 213 int retval = 0; 214 215 dbg("%s port %d", __FUNCTION__, port->number); 216 217 /*Start reading from the device*/ 218 /* TODO: Look at possibility of submitting multiple URBs to device to 219 * enhance buffering. Win trace shows 16 initial read URBs. 220 */ 221 port->read_urb->dev = port->serial->dev; 222 retval = usb_submit_urb(port->read_urb, GFP_KERNEL); 223 if (retval) { 224 err("usb_submit_urb(read bulk) failed"); 225 goto exit; 226 } 227 228 port->interrupt_in_urb->dev = port->serial->dev; 229 retval = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 230 if (retval) { 231 usb_kill_urb(port->read_urb); 232 err(" usb_submit_urb(read int) failed"); 233 } 234 235 exit: 236 return retval; 237 } /* belkin_sa_open */ 238 239 240 static void belkin_sa_close (struct usb_serial_port *port, struct file *filp) 241 { 242 dbg("%s port %d", __FUNCTION__, port->number); 243 244 /* shutdown our bulk reads and writes */ 245 usb_kill_urb(port->write_urb); 246 usb_kill_urb(port->read_urb); 247 usb_kill_urb(port->interrupt_in_urb); 248 } /* belkin_sa_close */ 249 250 251 static void belkin_sa_read_int_callback (struct urb *urb, struct pt_regs *regs) 252 { 253 struct usb_serial_port *port = (struct usb_serial_port *)urb->context; 254 struct belkin_sa_private *priv; 255 unsigned char *data = urb->transfer_buffer; 256 int retval; 257 unsigned long flags; 258 259 switch (urb->status) { 260 case 0: 261 /* success */ 262 break; 263 case -ECONNRESET: 264 case -ENOENT: 265 case -ESHUTDOWN: 266 /* this urb is terminated, clean up */ 267 dbg("%s - urb shutting down with status: %d", __FUNCTION__, urb->status); 268 return; 269 default: 270 dbg("%s - nonzero urb status received: %d", __FUNCTION__, urb->status); 271 goto exit; 272 } 273 274 usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data); 275 276 /* Handle known interrupt data */ 277 /* ignore data[0] and data[1] */ 278 279 priv = usb_get_serial_port_data(port); 280 spin_lock_irqsave(&priv->lock, flags); 281 priv->last_msr = data[BELKIN_SA_MSR_INDEX]; 282 283 /* Record Control Line states */ 284 if (priv->last_msr & BELKIN_SA_MSR_DSR) 285 priv->control_state |= TIOCM_DSR; 286 else 287 priv->control_state &= ~TIOCM_DSR; 288 289 if (priv->last_msr & BELKIN_SA_MSR_CTS) 290 priv->control_state |= TIOCM_CTS; 291 else 292 priv->control_state &= ~TIOCM_CTS; 293 294 if (priv->last_msr & BELKIN_SA_MSR_RI) 295 priv->control_state |= TIOCM_RI; 296 else 297 priv->control_state &= ~TIOCM_RI; 298 299 if (priv->last_msr & BELKIN_SA_MSR_CD) 300 priv->control_state |= TIOCM_CD; 301 else 302 priv->control_state &= ~TIOCM_CD; 303 304 /* Now to report any errors */ 305 priv->last_lsr = data[BELKIN_SA_LSR_INDEX]; 306 #if 0 307 /* 308 * fill in the flip buffer here, but I do not know the relation 309 * to the current/next receive buffer or characters. I need 310 * to look in to this before committing any code. 311 */ 312 if (priv->last_lsr & BELKIN_SA_LSR_ERR) { 313 tty = port->tty; 314 /* Overrun Error */ 315 if (priv->last_lsr & BELKIN_SA_LSR_OE) { 316 } 317 /* Parity Error */ 318 if (priv->last_lsr & BELKIN_SA_LSR_PE) { 319 } 320 /* Framing Error */ 321 if (priv->last_lsr & BELKIN_SA_LSR_FE) { 322 } 323 /* Break Indicator */ 324 if (priv->last_lsr & BELKIN_SA_LSR_BI) { 325 } 326 } 327 #endif 328 spin_unlock_irqrestore(&priv->lock, flags); 329 exit: 330 retval = usb_submit_urb (urb, GFP_ATOMIC); 331 if (retval) 332 err ("%s - usb_submit_urb failed with result %d", 333 __FUNCTION__, retval); 334 } 335 336 static void belkin_sa_set_termios (struct usb_serial_port *port, struct termios *old_termios) 337 { 338 struct usb_serial *serial = port->serial; 339 struct belkin_sa_private *priv = usb_get_serial_port_data(port); 340 unsigned int iflag; 341 unsigned int cflag; 342 unsigned int old_iflag = 0; 343 unsigned int old_cflag = 0; 344 __u16 urb_value = 0; /* Will hold the new flags */ 345 unsigned long flags; 346 unsigned long control_state; 347 int bad_flow_control; 348 349 if ((!port->tty) || (!port->tty->termios)) { 350 dbg ("%s - no tty or termios structure", __FUNCTION__); 351 return; 352 } 353 354 iflag = port->tty->termios->c_iflag; 355 cflag = port->tty->termios->c_cflag; 356 357 /* get a local copy of the current port settings */ 358 spin_lock_irqsave(&priv->lock, flags); 359 control_state = priv->control_state; 360 bad_flow_control = priv->bad_flow_control; 361 spin_unlock_irqrestore(&priv->lock, flags); 362 363 /* check that they really want us to change something */ 364 if (old_termios) { 365 if ((cflag == old_termios->c_cflag) && 366 (RELEVANT_IFLAG(port->tty->termios->c_iflag) == RELEVANT_IFLAG(old_termios->c_iflag))) { 367 dbg("%s - nothing to change...", __FUNCTION__); 368 return; 369 } 370 old_iflag = old_termios->c_iflag; 371 old_cflag = old_termios->c_cflag; 372 } 373 374 /* Set the baud rate */ 375 if( (cflag&CBAUD) != (old_cflag&CBAUD) ) { 376 /* reassert DTR and (maybe) RTS on transition from B0 */ 377 if( (old_cflag&CBAUD) == B0 ) { 378 control_state |= (TIOCM_DTR|TIOCM_RTS); 379 if (BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, 1) < 0) 380 err("Set DTR error"); 381 /* don't set RTS if using hardware flow control */ 382 if (!(old_cflag&CRTSCTS) ) 383 if (BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, 1) < 0) 384 err("Set RTS error"); 385 } 386 387 switch(cflag & CBAUD) { 388 case B0: /* handled below */ break; 389 case B300: urb_value = BELKIN_SA_BAUD(300); break; 390 case B600: urb_value = BELKIN_SA_BAUD(600); break; 391 case B1200: urb_value = BELKIN_SA_BAUD(1200); break; 392 case B2400: urb_value = BELKIN_SA_BAUD(2400); break; 393 case B4800: urb_value = BELKIN_SA_BAUD(4800); break; 394 case B9600: urb_value = BELKIN_SA_BAUD(9600); break; 395 case B19200: urb_value = BELKIN_SA_BAUD(19200); break; 396 case B38400: urb_value = BELKIN_SA_BAUD(38400); break; 397 case B57600: urb_value = BELKIN_SA_BAUD(57600); break; 398 case B115200: urb_value = BELKIN_SA_BAUD(115200); break; 399 case B230400: urb_value = BELKIN_SA_BAUD(230400); break; 400 default: err("BELKIN USB Serial Adapter: unsupported baudrate request, using default of 9600"); 401 urb_value = BELKIN_SA_BAUD(9600); break; 402 } 403 if ((cflag & CBAUD) != B0 ) { 404 if (BSA_USB_CMD(BELKIN_SA_SET_BAUDRATE_REQUEST, urb_value) < 0) 405 err("Set baudrate error"); 406 } else { 407 /* Disable flow control */ 408 if (BSA_USB_CMD(BELKIN_SA_SET_FLOW_CTRL_REQUEST, BELKIN_SA_FLOW_NONE) < 0) 409 err("Disable flowcontrol error"); 410 411 /* Drop RTS and DTR */ 412 control_state &= ~(TIOCM_DTR | TIOCM_RTS); 413 if (BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, 0) < 0) 414 err("DTR LOW error"); 415 if (BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, 0) < 0) 416 err("RTS LOW error"); 417 } 418 } 419 420 /* set the parity */ 421 if( (cflag&(PARENB|PARODD)) != (old_cflag&(PARENB|PARODD)) ) { 422 if (cflag & PARENB) 423 urb_value = (cflag & PARODD) ? BELKIN_SA_PARITY_ODD : BELKIN_SA_PARITY_EVEN; 424 else 425 urb_value = BELKIN_SA_PARITY_NONE; 426 if (BSA_USB_CMD(BELKIN_SA_SET_PARITY_REQUEST, urb_value) < 0) 427 err("Set parity error"); 428 } 429 430 /* set the number of data bits */ 431 if( (cflag&CSIZE) != (old_cflag&CSIZE) ) { 432 switch (cflag & CSIZE) { 433 case CS5: urb_value = BELKIN_SA_DATA_BITS(5); break; 434 case CS6: urb_value = BELKIN_SA_DATA_BITS(6); break; 435 case CS7: urb_value = BELKIN_SA_DATA_BITS(7); break; 436 case CS8: urb_value = BELKIN_SA_DATA_BITS(8); break; 437 default: err("CSIZE was not CS5-CS8, using default of 8"); 438 urb_value = BELKIN_SA_DATA_BITS(8); 439 break; 440 } 441 if (BSA_USB_CMD(BELKIN_SA_SET_DATA_BITS_REQUEST, urb_value) < 0) 442 err("Set data bits error"); 443 } 444 445 /* set the number of stop bits */ 446 if( (cflag&CSTOPB) != (old_cflag&CSTOPB) ) { 447 urb_value = (cflag & CSTOPB) ? BELKIN_SA_STOP_BITS(2) : BELKIN_SA_STOP_BITS(1); 448 if (BSA_USB_CMD(BELKIN_SA_SET_STOP_BITS_REQUEST, urb_value) < 0) 449 err("Set stop bits error"); 450 } 451 452 /* Set flow control */ 453 if( (iflag&IXOFF) != (old_iflag&IXOFF) 454 || (iflag&IXON) != (old_iflag&IXON) 455 || (cflag&CRTSCTS) != (old_cflag&CRTSCTS) ) { 456 urb_value = 0; 457 if ((iflag & IXOFF) || (iflag & IXON)) 458 urb_value |= (BELKIN_SA_FLOW_OXON | BELKIN_SA_FLOW_IXON); 459 else 460 urb_value &= ~(BELKIN_SA_FLOW_OXON | BELKIN_SA_FLOW_IXON); 461 462 if (cflag & CRTSCTS) 463 urb_value |= (BELKIN_SA_FLOW_OCTS | BELKIN_SA_FLOW_IRTS); 464 else 465 urb_value &= ~(BELKIN_SA_FLOW_OCTS | BELKIN_SA_FLOW_IRTS); 466 467 if (bad_flow_control) 468 urb_value &= ~(BELKIN_SA_FLOW_IRTS); 469 470 if (BSA_USB_CMD(BELKIN_SA_SET_FLOW_CTRL_REQUEST, urb_value) < 0) 471 err("Set flow control error"); 472 } 473 474 /* save off the modified port settings */ 475 spin_lock_irqsave(&priv->lock, flags); 476 priv->control_state = control_state; 477 spin_unlock_irqrestore(&priv->lock, flags); 478 } /* belkin_sa_set_termios */ 479 480 481 static void belkin_sa_break_ctl( struct usb_serial_port *port, int break_state ) 482 { 483 struct usb_serial *serial = port->serial; 484 485 if (BSA_USB_CMD(BELKIN_SA_SET_BREAK_REQUEST, break_state ? 1 : 0) < 0) 486 err("Set break_ctl %d", break_state); 487 } 488 489 490 static int belkin_sa_tiocmget (struct usb_serial_port *port, struct file *file) 491 { 492 struct belkin_sa_private *priv = usb_get_serial_port_data(port); 493 unsigned long control_state; 494 unsigned long flags; 495 496 dbg("%s", __FUNCTION__); 497 498 spin_lock_irqsave(&priv->lock, flags); 499 control_state = priv->control_state; 500 spin_unlock_irqrestore(&priv->lock, flags); 501 502 return control_state; 503 } 504 505 506 static int belkin_sa_tiocmset (struct usb_serial_port *port, struct file *file, 507 unsigned int set, unsigned int clear) 508 { 509 struct usb_serial *serial = port->serial; 510 struct belkin_sa_private *priv = usb_get_serial_port_data(port); 511 unsigned long control_state; 512 unsigned long flags; 513 int retval; 514 int rts = 0; 515 int dtr = 0; 516 517 dbg("%s", __FUNCTION__); 518 519 spin_lock_irqsave(&priv->lock, flags); 520 control_state = priv->control_state; 521 522 if (set & TIOCM_RTS) { 523 control_state |= TIOCM_RTS; 524 rts = 1; 525 } 526 if (set & TIOCM_DTR) { 527 control_state |= TIOCM_DTR; 528 dtr = 1; 529 } 530 if (clear & TIOCM_RTS) { 531 control_state &= ~TIOCM_RTS; 532 rts = 0; 533 } 534 if (clear & TIOCM_DTR) { 535 control_state &= ~TIOCM_DTR; 536 dtr = 0; 537 } 538 539 priv->control_state = control_state; 540 spin_unlock_irqrestore(&priv->lock, flags); 541 542 retval = BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, rts); 543 if (retval < 0) { 544 err("Set RTS error %d", retval); 545 goto exit; 546 } 547 548 retval = BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, dtr); 549 if (retval < 0) { 550 err("Set DTR error %d", retval); 551 goto exit; 552 } 553 exit: 554 return retval; 555 } 556 557 558 static int belkin_sa_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg) 559 { 560 switch (cmd) { 561 case TIOCMIWAIT: 562 /* wait for any of the 4 modem inputs (DCD,RI,DSR,CTS)*/ 563 /* TODO */ 564 return( 0 ); 565 566 case TIOCGICOUNT: 567 /* return count of modemline transitions */ 568 /* TODO */ 569 return 0; 570 571 default: 572 dbg("belkin_sa_ioctl arg not supported - 0x%04x",cmd); 573 return(-ENOIOCTLCMD); 574 break; 575 } 576 return 0; 577 } /* belkin_sa_ioctl */ 578 579 580 static int __init belkin_sa_init (void) 581 { 582 int retval; 583 retval = usb_serial_register(&belkin_device); 584 if (retval) 585 goto failed_usb_serial_register; 586 retval = usb_register(&belkin_driver); 587 if (retval) 588 goto failed_usb_register; 589 info(DRIVER_DESC " " DRIVER_VERSION); 590 return 0; 591 failed_usb_register: 592 usb_serial_deregister(&belkin_device); 593 failed_usb_serial_register: 594 return retval; 595 } 596 597 598 static void __exit belkin_sa_exit (void) 599 { 600 usb_deregister (&belkin_driver); 601 usb_serial_deregister (&belkin_device); 602 } 603 604 605 module_init (belkin_sa_init); 606 module_exit (belkin_sa_exit); 607 608 MODULE_AUTHOR( DRIVER_AUTHOR ); 609 MODULE_DESCRIPTION( DRIVER_DESC ); 610 MODULE_VERSION( DRIVER_VERSION ); 611 MODULE_LICENSE("GPL"); 612 613 module_param(debug, bool, S_IRUGO | S_IWUSR); 614 MODULE_PARM_DESC(debug, "Debug enabled or not"); 615