1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_TTY_DRIVER_H 3 #define _LINUX_TTY_DRIVER_H 4 5 #include <linux/export.h> 6 #include <linux/fs.h> 7 #include <linux/kref.h> 8 #include <linux/list.h> 9 #include <linux/cdev.h> 10 #include <linux/uaccess.h> 11 #include <linux/termios.h> 12 #include <linux/seq_file.h> 13 14 struct tty_struct; 15 struct tty_driver; 16 struct serial_icounter_struct; 17 struct serial_struct; 18 19 /** 20 * struct tty_operations -- interface between driver and tty 21 * 22 * @lookup: ``struct tty_struct *()(struct tty_driver *self, struct file *, 23 * int idx)`` 24 * 25 * Return the tty device corresponding to @idx, %NULL if there is not 26 * one currently in use and an %ERR_PTR value on error. Called under 27 * %tty_mutex (for now!) 28 * 29 * Optional method. Default behaviour is to use the @self->ttys array. 30 * 31 * @install: ``int ()(struct tty_driver *self, struct tty_struct *tty)`` 32 * 33 * Install a new @tty into the @self's internal tables. Used in 34 * conjunction with @lookup and @remove methods. 35 * 36 * Optional method. Default behaviour is to use the @self->ttys array. 37 * 38 * @remove: ``void ()(struct tty_driver *self, struct tty_struct *tty)`` 39 * 40 * Remove a closed @tty from the @self's internal tables. Used in 41 * conjunction with @lookup and @remove methods. 42 * 43 * Optional method. Default behaviour is to use the @self->ttys array. 44 * 45 * @open: ``int ()(struct tty_struct *tty, struct file *)`` 46 * 47 * This routine is called when a particular @tty device is opened. This 48 * routine is mandatory; if this routine is not filled in, the attempted 49 * open will fail with %ENODEV. 50 * 51 * Required method. Called with tty lock held. May sleep. 52 * 53 * @close: ``void ()(struct tty_struct *tty, struct file *)`` 54 * 55 * This routine is called when a particular @tty device is closed. At the 56 * point of return from this call the driver must make no further ldisc 57 * calls of any kind. 58 * 59 * Remark: called even if the corresponding @open() failed. 60 * 61 * Required method. Called with tty lock held. May sleep. 62 * 63 * @shutdown: ``void ()(struct tty_struct *tty)`` 64 * 65 * This routine is called under the tty lock when a particular @tty device 66 * is closed for the last time. It executes before the @tty resources 67 * are freed so may execute while another function holds a @tty kref. 68 * 69 * @cleanup: ``void ()(struct tty_struct *tty)`` 70 * 71 * This routine is called asynchronously when a particular @tty device 72 * is closed for the last time freeing up the resources. This is 73 * actually the second part of shutdown for routines that might sleep. 74 * 75 * @write: ``int ()(struct tty_struct *tty, const unsigned char *buf, 76 * int count)`` 77 * 78 * This routine is called by the kernel to write a series (@count) of 79 * characters (@buf) to the @tty device. The characters may come from 80 * user space or kernel space. This routine will return the 81 * number of characters actually accepted for writing. 82 * 83 * May occur in parallel in special cases. Because this includes panic 84 * paths drivers generally shouldn't try and do clever locking here. 85 * 86 * Optional: Required for writable devices. May not sleep. 87 * 88 * @put_char: ``int ()(struct tty_struct *tty, unsigned char ch)`` 89 * 90 * This routine is called by the kernel to write a single character @ch to 91 * the @tty device. If the kernel uses this routine, it must call the 92 * @flush_chars() routine (if defined) when it is done stuffing characters 93 * into the driver. If there is no room in the queue, the character is 94 * ignored. 95 * 96 * Optional: Kernel will use the @write method if not provided. Do not 97 * call this function directly, call tty_put_char(). 98 * 99 * @flush_chars: ``void ()(struct tty_struct *tty)`` 100 * 101 * This routine is called by the kernel after it has written a 102 * series of characters to the tty device using @put_char(). 103 * 104 * Optional. Do not call this function directly, call 105 * tty_driver_flush_chars(). 106 * 107 * @write_room: ``unsigned int ()(struct tty_struct *tty)`` 108 * 109 * This routine returns the numbers of characters the @tty driver 110 * will accept for queuing to be written. This number is subject 111 * to change as output buffers get emptied, or if the output flow 112 * control is acted. 113 * 114 * The ldisc is responsible for being intelligent about multi-threading of 115 * write_room/write calls 116 * 117 * Required if @write method is provided else not needed. Do not call this 118 * function directly, call tty_write_room() 119 * 120 * @chars_in_buffer: ``unsigned int ()(struct tty_struct *tty)`` 121 * 122 * This routine returns the number of characters in the device private 123 * output queue. Used in tty_wait_until_sent() and for poll() 124 * implementation. 125 * 126 * Optional: if not provided, it is assumed there is no queue on the 127 * device. Do not call this function directly, call tty_chars_in_buffer(). 128 * 129 * @ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd, 130 * unsigned long arg)`` 131 * 132 * This routine allows the @tty driver to implement device-specific 133 * ioctls. If the ioctl number passed in @cmd is not recognized by the 134 * driver, it should return %ENOIOCTLCMD. 135 * 136 * Optional. 137 * 138 * @compat_ioctl: ``long ()(struct tty_struct *tty, unsigned int cmd, 139 * unsigned long arg)`` 140 * 141 * Implement ioctl processing for 32 bit process on 64 bit system. 142 * 143 * Optional. 144 * 145 * @set_termios: ``void ()(struct tty_struct *tty, const struct ktermios *old)`` 146 * 147 * This routine allows the @tty driver to be notified when device's 148 * termios settings have changed. New settings are in @tty->termios. 149 * Previous settings are passed in the @old argument. 150 * 151 * The API is defined such that the driver should return the actual modes 152 * selected. This means that the driver is responsible for modifying any 153 * bits in @tty->termios it cannot fulfill to indicate the actual modes 154 * being used. 155 * 156 * Optional. Called under the @tty->termios_rwsem. May sleep. 157 * 158 * @set_ldisc: ``void ()(struct tty_struct *tty)`` 159 * 160 * This routine allows the @tty driver to be notified when the device's 161 * line discipline is being changed. At the point this is done the 162 * discipline is not yet usable. 163 * 164 * Optional. Called under the @tty->ldisc_sem and @tty->termios_rwsem. 165 * 166 * @throttle: ``void ()(struct tty_struct *tty)`` 167 * 168 * This routine notifies the @tty driver that input buffers for the line 169 * discipline are close to full, and it should somehow signal that no more 170 * characters should be sent to the @tty. 171 * 172 * Serialization including with @unthrottle() is the job of the ldisc 173 * layer. 174 * 175 * Optional: Always invoke via tty_throttle_safe(). Called under the 176 * @tty->termios_rwsem. 177 * 178 * @unthrottle: ``void ()(struct tty_struct *tty)`` 179 * 180 * This routine notifies the @tty driver that it should signal that 181 * characters can now be sent to the @tty without fear of overrunning the 182 * input buffers of the line disciplines. 183 * 184 * Optional. Always invoke via tty_unthrottle(). Called under the 185 * @tty->termios_rwsem. 186 * 187 * @stop: ``void ()(struct tty_struct *tty)`` 188 * 189 * This routine notifies the @tty driver that it should stop outputting 190 * characters to the tty device. 191 * 192 * Called with @tty->flow.lock held. Serialized with @start() method. 193 * 194 * Optional. Always invoke via stop_tty(). 195 * 196 * @start: ``void ()(struct tty_struct *tty)`` 197 * 198 * This routine notifies the @tty driver that it resumed sending 199 * characters to the @tty device. 200 * 201 * Called with @tty->flow.lock held. Serialized with stop() method. 202 * 203 * Optional. Always invoke via start_tty(). 204 * 205 * @hangup: ``void ()(struct tty_struct *tty)`` 206 * 207 * This routine notifies the @tty driver that it should hang up the @tty 208 * device. 209 * 210 * Optional. Called with tty lock held. 211 * 212 * @break_ctl: ``int ()(struct tty_struct *tty, int state)`` 213 * 214 * This optional routine requests the @tty driver to turn on or off BREAK 215 * status on the RS-232 port. If @state is -1, then the BREAK status 216 * should be turned on; if @state is 0, then BREAK should be turned off. 217 * 218 * If this routine is implemented, the high-level tty driver will handle 219 * the following ioctls: %TCSBRK, %TCSBRKP, %TIOCSBRK, %TIOCCBRK. 220 * 221 * If the driver sets %TTY_DRIVER_HARDWARE_BREAK in tty_alloc_driver(), 222 * then the interface will also be called with actual times and the 223 * hardware is expected to do the delay work itself. 0 and -1 are still 224 * used for on/off. 225 * 226 * Optional: Required for %TCSBRK/%BRKP/etc. handling. May sleep. 227 * 228 * @flush_buffer: ``void ()(struct tty_struct *tty)`` 229 * 230 * This routine discards device private output buffer. Invoked on close, 231 * hangup, to implement %TCOFLUSH ioctl and similar. 232 * 233 * Optional: if not provided, it is assumed there is no queue on the 234 * device. Do not call this function directly, call 235 * tty_driver_flush_buffer(). 236 * 237 * @wait_until_sent: ``void ()(struct tty_struct *tty, int timeout)`` 238 * 239 * This routine waits until the device has written out all of the 240 * characters in its transmitter FIFO. Or until @timeout (in jiffies) is 241 * reached. 242 * 243 * Optional: If not provided, the device is assumed to have no FIFO. 244 * Usually correct to invoke via tty_wait_until_sent(). May sleep. 245 * 246 * @send_xchar: ``void ()(struct tty_struct *tty, char ch)`` 247 * 248 * This routine is used to send a high-priority XON/XOFF character (@ch) 249 * to the @tty device. 250 * 251 * Optional: If not provided, then the @write method is called under 252 * the @tty->atomic_write_lock to keep it serialized with the ldisc. 253 * 254 * @tiocmget: ``int ()(struct tty_struct *tty)`` 255 * 256 * This routine is used to obtain the modem status bits from the @tty 257 * driver. 258 * 259 * Optional: If not provided, then %ENOTTY is returned from the %TIOCMGET 260 * ioctl. Do not call this function directly, call tty_tiocmget(). 261 * 262 * @tiocmset: ``int ()(struct tty_struct *tty, 263 * unsigned int set, unsigned int clear)`` 264 * 265 * This routine is used to set the modem status bits to the @tty driver. 266 * First, @clear bits should be cleared, then @set bits set. 267 * 268 * Optional: If not provided, then %ENOTTY is returned from the %TIOCMSET 269 * ioctl. Do not call this function directly, call tty_tiocmset(). 270 * 271 * @resize: ``int ()(struct tty_struct *tty, struct winsize *ws)`` 272 * 273 * Called when a termios request is issued which changes the requested 274 * terminal geometry to @ws. 275 * 276 * Optional: the default action is to update the termios structure 277 * without error. This is usually the correct behaviour. Drivers should 278 * not force errors here if they are not resizable objects (e.g. a serial 279 * line). See tty_do_resize() if you need to wrap the standard method 280 * in your own logic -- the usual case. 281 * 282 * @get_icount: ``int ()(struct tty_struct *tty, 283 * struct serial_icounter *icount)`` 284 * 285 * Called when the @tty device receives a %TIOCGICOUNT ioctl. Passed a 286 * kernel structure @icount to complete. 287 * 288 * Optional: called only if provided, otherwise %ENOTTY will be returned. 289 * 290 * @get_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)`` 291 * 292 * Called when the @tty device receives a %TIOCGSERIAL ioctl. Passed a 293 * kernel structure @p (&struct serial_struct) to complete. 294 * 295 * Optional: called only if provided, otherwise %ENOTTY will be returned. 296 * Do not call this function directly, call tty_tiocgserial(). 297 * 298 * @set_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)`` 299 * 300 * Called when the @tty device receives a %TIOCSSERIAL ioctl. Passed a 301 * kernel structure @p (&struct serial_struct) to set the values from. 302 * 303 * Optional: called only if provided, otherwise %ENOTTY will be returned. 304 * Do not call this function directly, call tty_tiocsserial(). 305 * 306 * @show_fdinfo: ``void ()(struct tty_struct *tty, struct seq_file *m)`` 307 * 308 * Called when the @tty device file descriptor receives a fdinfo request 309 * from VFS (to show in /proc/<pid>/fdinfo/). @m should be filled with 310 * information. 311 * 312 * Optional: called only if provided, otherwise nothing is written to @m. 313 * Do not call this function directly, call tty_show_fdinfo(). 314 * 315 * @poll_init: ``int ()(struct tty_driver *driver, int line, char *options)`` 316 * 317 * kgdboc support (Documentation/dev-tools/kgdb.rst). This routine is 318 * called to initialize the HW for later use by calling @poll_get_char or 319 * @poll_put_char. 320 * 321 * Optional: called only if provided, otherwise skipped as a non-polling 322 * driver. 323 * 324 * @poll_get_char: ``int ()(struct tty_driver *driver, int line)`` 325 * 326 * kgdboc support (see @poll_init). @driver should read a character from a 327 * tty identified by @line and return it. 328 * 329 * Optional: called only if @poll_init provided. 330 * 331 * @poll_put_char: ``void ()(struct tty_driver *driver, int line, char ch)`` 332 * 333 * kgdboc support (see @poll_init). @driver should write character @ch to 334 * a tty identified by @line. 335 * 336 * Optional: called only if @poll_init provided. 337 * 338 * @proc_show: ``int ()(struct seq_file *m, void *driver)`` 339 * 340 * Driver @driver (cast to &struct tty_driver) can show additional info in 341 * /proc/tty/driver/<driver_name>. It is enough to fill in the information 342 * into @m. 343 * 344 * Optional: called only if provided, otherwise no /proc entry created. 345 * 346 * This structure defines the interface between the low-level tty driver and 347 * the tty routines. These routines can be defined. Unless noted otherwise, 348 * they are optional, and can be filled in with a %NULL pointer. 349 */ 350 struct tty_operations { 351 struct tty_struct * (*lookup)(struct tty_driver *driver, 352 struct file *filp, int idx); 353 int (*install)(struct tty_driver *driver, struct tty_struct *tty); 354 void (*remove)(struct tty_driver *driver, struct tty_struct *tty); 355 int (*open)(struct tty_struct * tty, struct file * filp); 356 void (*close)(struct tty_struct * tty, struct file * filp); 357 void (*shutdown)(struct tty_struct *tty); 358 void (*cleanup)(struct tty_struct *tty); 359 int (*write)(struct tty_struct * tty, 360 const unsigned char *buf, int count); 361 int (*put_char)(struct tty_struct *tty, unsigned char ch); 362 void (*flush_chars)(struct tty_struct *tty); 363 unsigned int (*write_room)(struct tty_struct *tty); 364 unsigned int (*chars_in_buffer)(struct tty_struct *tty); 365 int (*ioctl)(struct tty_struct *tty, 366 unsigned int cmd, unsigned long arg); 367 long (*compat_ioctl)(struct tty_struct *tty, 368 unsigned int cmd, unsigned long arg); 369 void (*set_termios)(struct tty_struct *tty, const struct ktermios *old); 370 void (*throttle)(struct tty_struct * tty); 371 void (*unthrottle)(struct tty_struct * tty); 372 void (*stop)(struct tty_struct *tty); 373 void (*start)(struct tty_struct *tty); 374 void (*hangup)(struct tty_struct *tty); 375 int (*break_ctl)(struct tty_struct *tty, int state); 376 void (*flush_buffer)(struct tty_struct *tty); 377 void (*set_ldisc)(struct tty_struct *tty); 378 void (*wait_until_sent)(struct tty_struct *tty, int timeout); 379 void (*send_xchar)(struct tty_struct *tty, char ch); 380 int (*tiocmget)(struct tty_struct *tty); 381 int (*tiocmset)(struct tty_struct *tty, 382 unsigned int set, unsigned int clear); 383 int (*resize)(struct tty_struct *tty, struct winsize *ws); 384 int (*get_icount)(struct tty_struct *tty, 385 struct serial_icounter_struct *icount); 386 int (*get_serial)(struct tty_struct *tty, struct serial_struct *p); 387 int (*set_serial)(struct tty_struct *tty, struct serial_struct *p); 388 void (*show_fdinfo)(struct tty_struct *tty, struct seq_file *m); 389 #ifdef CONFIG_CONSOLE_POLL 390 int (*poll_init)(struct tty_driver *driver, int line, char *options); 391 int (*poll_get_char)(struct tty_driver *driver, int line); 392 void (*poll_put_char)(struct tty_driver *driver, int line, char ch); 393 #endif 394 int (*proc_show)(struct seq_file *m, void *driver); 395 } __randomize_layout; 396 397 /** 398 * struct tty_driver -- driver for TTY devices 399 * 400 * @kref: reference counting. Reaching zero frees all the internals and the 401 * driver. 402 * @cdevs: allocated/registered character /dev devices 403 * @owner: modules owning this driver. Used drivers cannot be rmmod'ed. 404 * Automatically set by tty_alloc_driver(). 405 * @driver_name: name of the driver used in /proc/tty 406 * @name: used for constructing /dev node name 407 * @name_base: used as a number base for constructing /dev node name 408 * @major: major /dev device number (zero for autoassignment) 409 * @minor_start: the first minor /dev device number 410 * @num: number of devices allocated 411 * @type: type of tty driver (%TTY_DRIVER_TYPE_) 412 * @subtype: subtype of tty driver (%SYSTEM_TYPE_, %PTY_TYPE_, %SERIAL_TYPE_) 413 * @init_termios: termios to set to each tty initially (e.g. %tty_std_termios) 414 * @flags: tty driver flags (%TTY_DRIVER_) 415 * @proc_entry: proc fs entry, used internally 416 * @other: driver of the linked tty; only used for the PTY driver 417 * @ttys: array of active &struct tty_struct, set by tty_standard_install() 418 * @ports: array of &struct tty_port; can be set during initialization by 419 * tty_port_link_device() and similar 420 * @termios: storage for termios at each TTY close for the next open 421 * @driver_state: pointer to driver's arbitrary data 422 * @ops: driver hooks for TTYs. Set them using tty_set_operations(). Use &struct 423 * tty_port helpers in them as much as possible. 424 * @tty_drivers: used internally to link tty_drivers together 425 * 426 * The usual handling of &struct tty_driver is to allocate it by 427 * tty_alloc_driver(), set up all the necessary members, and register it by 428 * tty_register_driver(). At last, the driver is torn down by calling 429 * tty_unregister_driver() followed by tty_driver_kref_put(). 430 * 431 * The fields required to be set before calling tty_register_driver() include 432 * @driver_name, @name, @type, @subtype, @init_termios, and @ops. 433 */ 434 struct tty_driver { 435 struct kref kref; 436 struct cdev **cdevs; 437 struct module *owner; 438 const char *driver_name; 439 const char *name; 440 int name_base; 441 int major; 442 int minor_start; 443 unsigned int num; 444 short type; 445 short subtype; 446 struct ktermios init_termios; 447 unsigned long flags; 448 struct proc_dir_entry *proc_entry; 449 struct tty_driver *other; 450 451 /* 452 * Pointer to the tty data structures 453 */ 454 struct tty_struct **ttys; 455 struct tty_port **ports; 456 struct ktermios **termios; 457 void *driver_state; 458 459 /* 460 * Driver methods 461 */ 462 463 const struct tty_operations *ops; 464 struct list_head tty_drivers; 465 } __randomize_layout; 466 467 extern struct list_head tty_drivers; 468 469 struct tty_driver *__tty_alloc_driver(unsigned int lines, struct module *owner, 470 unsigned long flags); 471 struct tty_driver *tty_find_polling_driver(char *name, int *line); 472 473 void tty_driver_kref_put(struct tty_driver *driver); 474 475 /* Use TTY_DRIVER_* flags below */ 476 #define tty_alloc_driver(lines, flags) \ 477 __tty_alloc_driver(lines, THIS_MODULE, flags) 478 479 static inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d) 480 { 481 kref_get(&d->kref); 482 return d; 483 } 484 485 static inline void tty_set_operations(struct tty_driver *driver, 486 const struct tty_operations *op) 487 { 488 driver->ops = op; 489 } 490 491 /** 492 * DOC: TTY Driver Flags 493 * 494 * TTY_DRIVER_RESET_TERMIOS 495 * Requests the tty layer to reset the termios setting when the last 496 * process has closed the device. Used for PTYs, in particular. 497 * 498 * TTY_DRIVER_REAL_RAW 499 * Indicates that the driver will guarantee not to set any special 500 * character handling flags if this is set for the tty: 501 * 502 * ``(IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR || !INPCK)`` 503 * 504 * That is, if there is no reason for the driver to 505 * send notifications of parity and break characters up to the line 506 * driver, it won't do so. This allows the line driver to optimize for 507 * this case if this flag is set. (Note that there is also a promise, if 508 * the above case is true, not to signal overruns, either.) 509 * 510 * TTY_DRIVER_DYNAMIC_DEV 511 * The individual tty devices need to be registered with a call to 512 * tty_register_device() when the device is found in the system and 513 * unregistered with a call to tty_unregister_device() so the devices will 514 * be show up properly in sysfs. If not set, all &tty_driver.num entries 515 * will be created by the tty core in sysfs when tty_register_driver() is 516 * called. This is to be used by drivers that have tty devices that can 517 * appear and disappear while the main tty driver is registered with the 518 * tty core. 519 * 520 * TTY_DRIVER_DEVPTS_MEM 521 * Don't use the standard arrays (&tty_driver.ttys and 522 * &tty_driver.termios), instead use dynamic memory keyed through the 523 * devpts filesystem. This is only applicable to the PTY driver. 524 * 525 * TTY_DRIVER_HARDWARE_BREAK 526 * Hardware handles break signals. Pass the requested timeout to the 527 * &tty_operations.break_ctl instead of using a simple on/off interface. 528 * 529 * TTY_DRIVER_DYNAMIC_ALLOC 530 * Do not allocate structures which are needed per line for this driver 531 * (&tty_driver.ports) as it would waste memory. The driver will take 532 * care. This is only applicable to the PTY driver. 533 * 534 * TTY_DRIVER_UNNUMBERED_NODE 535 * Do not create numbered ``/dev`` nodes. For example, create 536 * ``/dev/ttyprintk`` and not ``/dev/ttyprintk0``. Applicable only when a 537 * driver for a single tty device is being allocated. 538 */ 539 #define TTY_DRIVER_INSTALLED 0x0001 540 #define TTY_DRIVER_RESET_TERMIOS 0x0002 541 #define TTY_DRIVER_REAL_RAW 0x0004 542 #define TTY_DRIVER_DYNAMIC_DEV 0x0008 543 #define TTY_DRIVER_DEVPTS_MEM 0x0010 544 #define TTY_DRIVER_HARDWARE_BREAK 0x0020 545 #define TTY_DRIVER_DYNAMIC_ALLOC 0x0040 546 #define TTY_DRIVER_UNNUMBERED_NODE 0x0080 547 548 /* tty driver types */ 549 #define TTY_DRIVER_TYPE_SYSTEM 0x0001 550 #define TTY_DRIVER_TYPE_CONSOLE 0x0002 551 #define TTY_DRIVER_TYPE_SERIAL 0x0003 552 #define TTY_DRIVER_TYPE_PTY 0x0004 553 #define TTY_DRIVER_TYPE_SCC 0x0005 /* scc driver */ 554 #define TTY_DRIVER_TYPE_SYSCONS 0x0006 555 556 /* system subtypes (magic, used by tty_io.c) */ 557 #define SYSTEM_TYPE_TTY 0x0001 558 #define SYSTEM_TYPE_CONSOLE 0x0002 559 #define SYSTEM_TYPE_SYSCONS 0x0003 560 #define SYSTEM_TYPE_SYSPTMX 0x0004 561 562 /* pty subtypes (magic, used by tty_io.c) */ 563 #define PTY_TYPE_MASTER 0x0001 564 #define PTY_TYPE_SLAVE 0x0002 565 566 /* serial subtype definitions */ 567 #define SERIAL_TYPE_NORMAL 1 568 569 int tty_register_driver(struct tty_driver *driver); 570 void tty_unregister_driver(struct tty_driver *driver); 571 struct device *tty_register_device(struct tty_driver *driver, unsigned index, 572 struct device *dev); 573 struct device *tty_register_device_attr(struct tty_driver *driver, 574 unsigned index, struct device *device, void *drvdata, 575 const struct attribute_group **attr_grp); 576 void tty_unregister_device(struct tty_driver *driver, unsigned index); 577 578 #ifdef CONFIG_PROC_FS 579 void proc_tty_register_driver(struct tty_driver *); 580 void proc_tty_unregister_driver(struct tty_driver *); 581 #else 582 static inline void proc_tty_register_driver(struct tty_driver *d) {} 583 static inline void proc_tty_unregister_driver(struct tty_driver *d) {} 584 #endif 585 586 #endif /* #ifdef _LINUX_TTY_DRIVER_H */ 587