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/config.h> 67 #include <linux/kernel.h> 68 #include <linux/errno.h> 69 #include <linux/init.h> 70 #include <linux/slab.h> 71 #include <linux/tty.h> 72 #include <linux/tty_driver.h> 73 #include <linux/tty_flip.h> 74 #include <linux/module.h> 75 #include <linux/spinlock.h> 76 #include <asm/uaccess.h> 77 #include <linux/usb.h> 78 #include "usb-serial.h" 79 #include "belkin_sa.h" 80 81 static int debug; 82 83 /* 84 * Version Information 85 */ 86 #define DRIVER_VERSION "v1.2" 87 #define DRIVER_AUTHOR "William Greathouse <wgreathouse@smva.com>" 88 #define DRIVER_DESC "USB Belkin Serial converter driver" 89 90 /* function prototypes for a Belkin USB Serial Adapter F5U103 */ 91 static int belkin_sa_startup (struct usb_serial *serial); 92 static void belkin_sa_shutdown (struct usb_serial *serial); 93 static int belkin_sa_open (struct usb_serial_port *port, struct file *filp); 94 static void belkin_sa_close (struct usb_serial_port *port, struct file *filp); 95 static void belkin_sa_read_int_callback (struct urb *urb, struct pt_regs *regs); 96 static void belkin_sa_set_termios (struct usb_serial_port *port, struct termios * old); 97 static int belkin_sa_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg); 98 static void belkin_sa_break_ctl (struct usb_serial_port *port, int break_state ); 99 static int belkin_sa_tiocmget (struct usb_serial_port *port, struct file *file); 100 static int belkin_sa_tiocmset (struct usb_serial_port *port, struct file *file, unsigned int set, unsigned int clear); 101 102 103 static struct usb_device_id id_table_combined [] = { 104 { USB_DEVICE(BELKIN_SA_VID, BELKIN_SA_PID) }, 105 { USB_DEVICE(BELKIN_OLD_VID, BELKIN_OLD_PID) }, 106 { USB_DEVICE(PERACOM_VID, PERACOM_PID) }, 107 { USB_DEVICE(GOHUBS_VID, GOHUBS_PID) }, 108 { USB_DEVICE(GOHUBS_VID, HANDYLINK_PID) }, 109 { USB_DEVICE(BELKIN_DOCKSTATION_VID, BELKIN_DOCKSTATION_PID) }, 110 { } /* Terminating entry */ 111 }; 112 113 MODULE_DEVICE_TABLE (usb, id_table_combined); 114 115 static struct usb_driver belkin_driver = { 116 .owner = THIS_MODULE, 117 .name = "belkin", 118 .probe = usb_serial_probe, 119 .disconnect = usb_serial_disconnect, 120 .id_table = id_table_combined, 121 }; 122 123 /* All of the device info needed for the serial converters */ 124 static struct usb_serial_driver belkin_device = { 125 .driver = { 126 .owner = THIS_MODULE, 127 .name = "belkin", 128 }, 129 .description = "Belkin / Peracom / GoHubs USB Serial Adapter", 130 .id_table = id_table_combined, 131 .num_interrupt_in = 1, 132 .num_bulk_in = 1, 133 .num_bulk_out = 1, 134 .num_ports = 1, 135 .open = belkin_sa_open, 136 .close = belkin_sa_close, 137 .read_int_callback = belkin_sa_read_int_callback, /* How we get the status info */ 138 .ioctl = belkin_sa_ioctl, 139 .set_termios = belkin_sa_set_termios, 140 .break_ctl = belkin_sa_break_ctl, 141 .tiocmget = belkin_sa_tiocmget, 142 .tiocmset = belkin_sa_tiocmset, 143 .attach = belkin_sa_startup, 144 .shutdown = belkin_sa_shutdown, 145 }; 146 147 148 struct belkin_sa_private { 149 spinlock_t lock; 150 unsigned long control_state; 151 unsigned char last_lsr; 152 unsigned char last_msr; 153 int bad_flow_control; 154 }; 155 156 157 /* 158 * *************************************************************************** 159 * Belkin USB Serial Adapter F5U103 specific driver functions 160 * *************************************************************************** 161 */ 162 163 #define WDR_TIMEOUT 5000 /* default urb timeout */ 164 165 /* assumes that struct usb_serial *serial is available */ 166 #define BSA_USB_CMD(c,v) usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0), \ 167 (c), BELKIN_SA_SET_REQUEST_TYPE, \ 168 (v), 0, NULL, 0, WDR_TIMEOUT) 169 170 /* do some startup allocations not currently performed by usb_serial_probe() */ 171 static int belkin_sa_startup (struct usb_serial *serial) 172 { 173 struct usb_device *dev = serial->dev; 174 struct belkin_sa_private *priv; 175 176 /* allocate the private data structure */ 177 priv = kmalloc(sizeof(struct belkin_sa_private), GFP_KERNEL); 178 if (!priv) 179 return (-1); /* error */ 180 /* set initial values for control structures */ 181 spin_lock_init(&priv->lock); 182 priv->control_state = 0; 183 priv->last_lsr = 0; 184 priv->last_msr = 0; 185 /* see comments at top of file */ 186 priv->bad_flow_control = (le16_to_cpu(dev->descriptor.bcdDevice) <= 0x0206) ? 1 : 0; 187 info("bcdDevice: %04x, bfc: %d", le16_to_cpu(dev->descriptor.bcdDevice), priv->bad_flow_control); 188 189 init_waitqueue_head(&serial->port[0]->write_wait); 190 usb_set_serial_port_data(serial->port[0], priv); 191 192 return (0); 193 } 194 195 196 static void belkin_sa_shutdown (struct usb_serial *serial) 197 { 198 struct belkin_sa_private *priv; 199 int i; 200 201 dbg ("%s", __FUNCTION__); 202 203 /* stop reads and writes on all ports */ 204 for (i=0; i < serial->num_ports; ++i) { 205 /* My special items, the standard routines free my urbs */ 206 priv = usb_get_serial_port_data(serial->port[i]); 207 kfree(priv); 208 } 209 } 210 211 212 static int belkin_sa_open (struct usb_serial_port *port, struct file *filp) 213 { 214 int retval = 0; 215 216 dbg("%s port %d", __FUNCTION__, port->number); 217 218 /*Start reading from the device*/ 219 /* TODO: Look at possibility of submitting multiple URBs to device to 220 * enhance buffering. Win trace shows 16 initial read URBs. 221 */ 222 port->read_urb->dev = port->serial->dev; 223 retval = usb_submit_urb(port->read_urb, GFP_KERNEL); 224 if (retval) { 225 err("usb_submit_urb(read bulk) failed"); 226 goto exit; 227 } 228 229 port->interrupt_in_urb->dev = port->serial->dev; 230 retval = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); 231 if (retval) { 232 usb_kill_urb(port->read_urb); 233 err(" usb_submit_urb(read int) failed"); 234 } 235 236 exit: 237 return retval; 238 } /* belkin_sa_open */ 239 240 241 static void belkin_sa_close (struct usb_serial_port *port, struct file *filp) 242 { 243 dbg("%s port %d", __FUNCTION__, port->number); 244 245 /* shutdown our bulk reads and writes */ 246 usb_kill_urb(port->write_urb); 247 usb_kill_urb(port->read_urb); 248 usb_kill_urb(port->interrupt_in_urb); 249 } /* belkin_sa_close */ 250 251 252 static void belkin_sa_read_int_callback (struct urb *urb, struct pt_regs *regs) 253 { 254 struct usb_serial_port *port = (struct usb_serial_port *)urb->context; 255 struct belkin_sa_private *priv; 256 unsigned char *data = urb->transfer_buffer; 257 int retval; 258 unsigned long flags; 259 260 switch (urb->status) { 261 case 0: 262 /* success */ 263 break; 264 case -ECONNRESET: 265 case -ENOENT: 266 case -ESHUTDOWN: 267 /* this urb is terminated, clean up */ 268 dbg("%s - urb shutting down with status: %d", __FUNCTION__, urb->status); 269 return; 270 default: 271 dbg("%s - nonzero urb status received: %d", __FUNCTION__, urb->status); 272 goto exit; 273 } 274 275 usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data); 276 277 /* Handle known interrupt data */ 278 /* ignore data[0] and data[1] */ 279 280 priv = usb_get_serial_port_data(port); 281 spin_lock_irqsave(&priv->lock, flags); 282 priv->last_msr = data[BELKIN_SA_MSR_INDEX]; 283 284 /* Record Control Line states */ 285 if (priv->last_msr & BELKIN_SA_MSR_DSR) 286 priv->control_state |= TIOCM_DSR; 287 else 288 priv->control_state &= ~TIOCM_DSR; 289 290 if (priv->last_msr & BELKIN_SA_MSR_CTS) 291 priv->control_state |= TIOCM_CTS; 292 else 293 priv->control_state &= ~TIOCM_CTS; 294 295 if (priv->last_msr & BELKIN_SA_MSR_RI) 296 priv->control_state |= TIOCM_RI; 297 else 298 priv->control_state &= ~TIOCM_RI; 299 300 if (priv->last_msr & BELKIN_SA_MSR_CD) 301 priv->control_state |= TIOCM_CD; 302 else 303 priv->control_state &= ~TIOCM_CD; 304 305 /* Now to report any errors */ 306 priv->last_lsr = data[BELKIN_SA_LSR_INDEX]; 307 #if 0 308 /* 309 * fill in the flip buffer here, but I do not know the relation 310 * to the current/next receive buffer or characters. I need 311 * to look in to this before committing any code. 312 */ 313 if (priv->last_lsr & BELKIN_SA_LSR_ERR) { 314 tty = port->tty; 315 /* Overrun Error */ 316 if (priv->last_lsr & BELKIN_SA_LSR_OE) { 317 } 318 /* Parity Error */ 319 if (priv->last_lsr & BELKIN_SA_LSR_PE) { 320 } 321 /* Framing Error */ 322 if (priv->last_lsr & BELKIN_SA_LSR_FE) { 323 } 324 /* Break Indicator */ 325 if (priv->last_lsr & BELKIN_SA_LSR_BI) { 326 } 327 } 328 #endif 329 spin_unlock_irqrestore(&priv->lock, flags); 330 exit: 331 retval = usb_submit_urb (urb, GFP_ATOMIC); 332 if (retval) 333 err ("%s - usb_submit_urb failed with result %d", 334 __FUNCTION__, retval); 335 } 336 337 static void belkin_sa_set_termios (struct usb_serial_port *port, struct termios *old_termios) 338 { 339 struct usb_serial *serial = port->serial; 340 struct belkin_sa_private *priv = usb_get_serial_port_data(port); 341 unsigned int iflag; 342 unsigned int cflag; 343 unsigned int old_iflag = 0; 344 unsigned int old_cflag = 0; 345 __u16 urb_value = 0; /* Will hold the new flags */ 346 unsigned long flags; 347 unsigned long control_state; 348 int bad_flow_control; 349 350 if ((!port->tty) || (!port->tty->termios)) { 351 dbg ("%s - no tty or termios structure", __FUNCTION__); 352 return; 353 } 354 355 iflag = port->tty->termios->c_iflag; 356 cflag = port->tty->termios->c_cflag; 357 358 /* get a local copy of the current port settings */ 359 spin_lock_irqsave(&priv->lock, flags); 360 control_state = priv->control_state; 361 bad_flow_control = priv->bad_flow_control; 362 spin_unlock_irqrestore(&priv->lock, flags); 363 364 /* check that they really want us to change something */ 365 if (old_termios) { 366 if ((cflag == old_termios->c_cflag) && 367 (RELEVANT_IFLAG(port->tty->termios->c_iflag) == RELEVANT_IFLAG(old_termios->c_iflag))) { 368 dbg("%s - nothing to change...", __FUNCTION__); 369 return; 370 } 371 old_iflag = old_termios->c_iflag; 372 old_cflag = old_termios->c_cflag; 373 } 374 375 /* Set the baud rate */ 376 if( (cflag&CBAUD) != (old_cflag&CBAUD) ) { 377 /* reassert DTR and (maybe) RTS on transition from B0 */ 378 if( (old_cflag&CBAUD) == B0 ) { 379 control_state |= (TIOCM_DTR|TIOCM_RTS); 380 if (BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, 1) < 0) 381 err("Set DTR error"); 382 /* don't set RTS if using hardware flow control */ 383 if (!(old_cflag&CRTSCTS) ) 384 if (BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, 1) < 0) 385 err("Set RTS error"); 386 } 387 388 switch(cflag & CBAUD) { 389 case B0: /* handled below */ break; 390 case B300: urb_value = BELKIN_SA_BAUD(300); break; 391 case B600: urb_value = BELKIN_SA_BAUD(600); break; 392 case B1200: urb_value = BELKIN_SA_BAUD(1200); break; 393 case B2400: urb_value = BELKIN_SA_BAUD(2400); break; 394 case B4800: urb_value = BELKIN_SA_BAUD(4800); break; 395 case B9600: urb_value = BELKIN_SA_BAUD(9600); break; 396 case B19200: urb_value = BELKIN_SA_BAUD(19200); break; 397 case B38400: urb_value = BELKIN_SA_BAUD(38400); break; 398 case B57600: urb_value = BELKIN_SA_BAUD(57600); break; 399 case B115200: urb_value = BELKIN_SA_BAUD(115200); break; 400 case B230400: urb_value = BELKIN_SA_BAUD(230400); break; 401 default: err("BELKIN USB Serial Adapter: unsupported baudrate request, using default of 9600"); 402 urb_value = BELKIN_SA_BAUD(9600); break; 403 } 404 if ((cflag & CBAUD) != B0 ) { 405 if (BSA_USB_CMD(BELKIN_SA_SET_BAUDRATE_REQUEST, urb_value) < 0) 406 err("Set baudrate error"); 407 } else { 408 /* Disable flow control */ 409 if (BSA_USB_CMD(BELKIN_SA_SET_FLOW_CTRL_REQUEST, BELKIN_SA_FLOW_NONE) < 0) 410 err("Disable flowcontrol error"); 411 412 /* Drop RTS and DTR */ 413 control_state &= ~(TIOCM_DTR | TIOCM_RTS); 414 if (BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, 0) < 0) 415 err("DTR LOW error"); 416 if (BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, 0) < 0) 417 err("RTS LOW error"); 418 } 419 } 420 421 /* set the parity */ 422 if( (cflag&(PARENB|PARODD)) != (old_cflag&(PARENB|PARODD)) ) { 423 if (cflag & PARENB) 424 urb_value = (cflag & PARODD) ? BELKIN_SA_PARITY_ODD : BELKIN_SA_PARITY_EVEN; 425 else 426 urb_value = BELKIN_SA_PARITY_NONE; 427 if (BSA_USB_CMD(BELKIN_SA_SET_PARITY_REQUEST, urb_value) < 0) 428 err("Set parity error"); 429 } 430 431 /* set the number of data bits */ 432 if( (cflag&CSIZE) != (old_cflag&CSIZE) ) { 433 switch (cflag & CSIZE) { 434 case CS5: urb_value = BELKIN_SA_DATA_BITS(5); break; 435 case CS6: urb_value = BELKIN_SA_DATA_BITS(6); break; 436 case CS7: urb_value = BELKIN_SA_DATA_BITS(7); break; 437 case CS8: urb_value = BELKIN_SA_DATA_BITS(8); break; 438 default: err("CSIZE was not CS5-CS8, using default of 8"); 439 urb_value = BELKIN_SA_DATA_BITS(8); 440 break; 441 } 442 if (BSA_USB_CMD(BELKIN_SA_SET_DATA_BITS_REQUEST, urb_value) < 0) 443 err("Set data bits error"); 444 } 445 446 /* set the number of stop bits */ 447 if( (cflag&CSTOPB) != (old_cflag&CSTOPB) ) { 448 urb_value = (cflag & CSTOPB) ? BELKIN_SA_STOP_BITS(2) : BELKIN_SA_STOP_BITS(1); 449 if (BSA_USB_CMD(BELKIN_SA_SET_STOP_BITS_REQUEST, urb_value) < 0) 450 err("Set stop bits error"); 451 } 452 453 /* Set flow control */ 454 if( (iflag&IXOFF) != (old_iflag&IXOFF) 455 || (iflag&IXON) != (old_iflag&IXON) 456 || (cflag&CRTSCTS) != (old_cflag&CRTSCTS) ) { 457 urb_value = 0; 458 if ((iflag & IXOFF) || (iflag & IXON)) 459 urb_value |= (BELKIN_SA_FLOW_OXON | BELKIN_SA_FLOW_IXON); 460 else 461 urb_value &= ~(BELKIN_SA_FLOW_OXON | BELKIN_SA_FLOW_IXON); 462 463 if (cflag & CRTSCTS) 464 urb_value |= (BELKIN_SA_FLOW_OCTS | BELKIN_SA_FLOW_IRTS); 465 else 466 urb_value &= ~(BELKIN_SA_FLOW_OCTS | BELKIN_SA_FLOW_IRTS); 467 468 if (bad_flow_control) 469 urb_value &= ~(BELKIN_SA_FLOW_IRTS); 470 471 if (BSA_USB_CMD(BELKIN_SA_SET_FLOW_CTRL_REQUEST, urb_value) < 0) 472 err("Set flow control error"); 473 } 474 475 /* save off the modified port settings */ 476 spin_lock_irqsave(&priv->lock, flags); 477 priv->control_state = control_state; 478 spin_unlock_irqrestore(&priv->lock, flags); 479 } /* belkin_sa_set_termios */ 480 481 482 static void belkin_sa_break_ctl( struct usb_serial_port *port, int break_state ) 483 { 484 struct usb_serial *serial = port->serial; 485 486 if (BSA_USB_CMD(BELKIN_SA_SET_BREAK_REQUEST, break_state ? 1 : 0) < 0) 487 err("Set break_ctl %d", break_state); 488 } 489 490 491 static int belkin_sa_tiocmget (struct usb_serial_port *port, struct file *file) 492 { 493 struct belkin_sa_private *priv = usb_get_serial_port_data(port); 494 unsigned long control_state; 495 unsigned long flags; 496 497 dbg("%s", __FUNCTION__); 498 499 spin_lock_irqsave(&priv->lock, flags); 500 control_state = priv->control_state; 501 spin_unlock_irqrestore(&priv->lock, flags); 502 503 return control_state; 504 } 505 506 507 static int belkin_sa_tiocmset (struct usb_serial_port *port, struct file *file, 508 unsigned int set, unsigned int clear) 509 { 510 struct usb_serial *serial = port->serial; 511 struct belkin_sa_private *priv = usb_get_serial_port_data(port); 512 unsigned long control_state; 513 unsigned long flags; 514 int retval; 515 int rts = 0; 516 int dtr = 0; 517 518 dbg("%s", __FUNCTION__); 519 520 spin_lock_irqsave(&priv->lock, flags); 521 control_state = priv->control_state; 522 523 if (set & TIOCM_RTS) { 524 control_state |= TIOCM_RTS; 525 rts = 1; 526 } 527 if (set & TIOCM_DTR) { 528 control_state |= TIOCM_DTR; 529 dtr = 1; 530 } 531 if (clear & TIOCM_RTS) { 532 control_state &= ~TIOCM_RTS; 533 rts = 0; 534 } 535 if (clear & TIOCM_DTR) { 536 control_state &= ~TIOCM_DTR; 537 dtr = 0; 538 } 539 540 priv->control_state = control_state; 541 spin_unlock_irqrestore(&priv->lock, flags); 542 543 retval = BSA_USB_CMD(BELKIN_SA_SET_RTS_REQUEST, rts); 544 if (retval < 0) { 545 err("Set RTS error %d", retval); 546 goto exit; 547 } 548 549 retval = BSA_USB_CMD(BELKIN_SA_SET_DTR_REQUEST, dtr); 550 if (retval < 0) { 551 err("Set DTR error %d", retval); 552 goto exit; 553 } 554 exit: 555 return retval; 556 } 557 558 559 static int belkin_sa_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg) 560 { 561 switch (cmd) { 562 case TIOCMIWAIT: 563 /* wait for any of the 4 modem inputs (DCD,RI,DSR,CTS)*/ 564 /* TODO */ 565 return( 0 ); 566 567 case TIOCGICOUNT: 568 /* return count of modemline transitions */ 569 /* TODO */ 570 return 0; 571 572 default: 573 dbg("belkin_sa_ioctl arg not supported - 0x%04x",cmd); 574 return(-ENOIOCTLCMD); 575 break; 576 } 577 return 0; 578 } /* belkin_sa_ioctl */ 579 580 581 static int __init belkin_sa_init (void) 582 { 583 int retval; 584 retval = usb_serial_register(&belkin_device); 585 if (retval) 586 goto failed_usb_serial_register; 587 retval = usb_register(&belkin_driver); 588 if (retval) 589 goto failed_usb_register; 590 info(DRIVER_DESC " " DRIVER_VERSION); 591 return 0; 592 failed_usb_register: 593 usb_serial_deregister(&belkin_device); 594 failed_usb_serial_register: 595 return retval; 596 } 597 598 599 static void __exit belkin_sa_exit (void) 600 { 601 usb_deregister (&belkin_driver); 602 usb_serial_deregister (&belkin_device); 603 } 604 605 606 module_init (belkin_sa_init); 607 module_exit (belkin_sa_exit); 608 609 MODULE_AUTHOR( DRIVER_AUTHOR ); 610 MODULE_DESCRIPTION( DRIVER_DESC ); 611 MODULE_VERSION( DRIVER_VERSION ); 612 MODULE_LICENSE("GPL"); 613 614 module_param(debug, bool, S_IRUGO | S_IWUSR); 615 MODULE_PARM_DESC(debug, "Debug enabled or not"); 616