gameport.c 20 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Generic gameport layer
  4. *
  5. * Copyright (c) 1999-2002 Vojtech Pavlik
  6. * Copyright (c) 2005 Dmitry Torokhov
  7. */
  8. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  9. #include <linux/stddef.h>
  10. #include <linux/module.h>
  11. #include <linux/ioport.h>
  12. #include <linux/init.h>
  13. #include <linux/gameport.h>
  14. #include <linux/slab.h>
  15. #include <linux/delay.h>
  16. #include <linux/workqueue.h>
  17. #include <linux/sched.h> /* HZ */
  18. #include <linux/mutex.h>
  19. #include <linux/timekeeping.h>
  20. /*#include <asm/io.h>*/
  21. MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  22. MODULE_DESCRIPTION("Generic gameport layer");
  23. MODULE_LICENSE("GPL");
  24. static bool use_ktime = true;
  25. module_param(use_ktime, bool, 0400);
  26. MODULE_PARM_DESC(use_ktime, "Use ktime for measuring I/O speed");
  27. /*
  28. * gameport_mutex protects entire gameport subsystem and is taken
  29. * every time gameport port or driver registrered or unregistered.
  30. */
  31. static DEFINE_MUTEX(gameport_mutex);
  32. static LIST_HEAD(gameport_list);
  33. static struct bus_type gameport_bus;
  34. static void gameport_add_port(struct gameport *gameport);
  35. static void gameport_attach_driver(struct gameport_driver *drv);
  36. static void gameport_reconnect_port(struct gameport *gameport);
  37. static void gameport_disconnect_port(struct gameport *gameport);
  38. #if defined(__i386__)
  39. #include <linux/i8253.h>
  40. #define DELTA(x,y) ((y)-(x)+((y)<(x)?1193182/HZ:0))
  41. #define GET_TIME(x) do { x = get_time_pit(); } while (0)
  42. static unsigned int get_time_pit(void)
  43. {
  44. unsigned long flags;
  45. unsigned int count;
  46. raw_spin_lock_irqsave(&i8253_lock, flags);
  47. outb_p(0x00, 0x43);
  48. count = inb_p(0x40);
  49. count |= inb_p(0x40) << 8;
  50. raw_spin_unlock_irqrestore(&i8253_lock, flags);
  51. return count;
  52. }
  53. #endif
  54. /*
  55. * gameport_measure_speed() measures the gameport i/o speed.
  56. */
  57. static int gameport_measure_speed(struct gameport *gameport)
  58. {
  59. unsigned int i, t, tx;
  60. u64 t1, t2, t3;
  61. unsigned long flags;
  62. if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
  63. return 0;
  64. tx = ~0;
  65. for (i = 0; i < 50; i++) {
  66. local_irq_save(flags);
  67. t1 = ktime_get_ns();
  68. for (t = 0; t < 50; t++)
  69. gameport_read(gameport);
  70. t2 = ktime_get_ns();
  71. t3 = ktime_get_ns();
  72. local_irq_restore(flags);
  73. udelay(i * 10);
  74. t = (t2 - t1) - (t3 - t2);
  75. if (t < tx)
  76. tx = t;
  77. }
  78. gameport_close(gameport);
  79. t = 1000000 * 50;
  80. if (tx)
  81. t /= tx;
  82. return t;
  83. }
  84. static int old_gameport_measure_speed(struct gameport *gameport)
  85. {
  86. #if defined(__i386__)
  87. unsigned int i, t, t1, t2, t3, tx;
  88. unsigned long flags;
  89. if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
  90. return 0;
  91. tx = 1 << 30;
  92. for(i = 0; i < 50; i++) {
  93. local_irq_save(flags);
  94. GET_TIME(t1);
  95. for (t = 0; t < 50; t++) gameport_read(gameport);
  96. GET_TIME(t2);
  97. GET_TIME(t3);
  98. local_irq_restore(flags);
  99. udelay(i * 10);
  100. if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
  101. }
  102. gameport_close(gameport);
  103. return 59659 / (tx < 1 ? 1 : tx);
  104. #elif defined (__x86_64__)
  105. unsigned int i, t;
  106. unsigned long tx, t1, t2, flags;
  107. if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
  108. return 0;
  109. tx = 1 << 30;
  110. for(i = 0; i < 50; i++) {
  111. local_irq_save(flags);
  112. t1 = rdtsc();
  113. for (t = 0; t < 50; t++) gameport_read(gameport);
  114. t2 = rdtsc();
  115. local_irq_restore(flags);
  116. udelay(i * 10);
  117. if (t2 - t1 < tx) tx = t2 - t1;
  118. }
  119. gameport_close(gameport);
  120. return (this_cpu_read(cpu_info.loops_per_jiffy) *
  121. (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
  122. #else
  123. unsigned int j, t = 0;
  124. if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
  125. return 0;
  126. j = jiffies; while (j == jiffies);
  127. j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
  128. gameport_close(gameport);
  129. return t * HZ / 1000;
  130. #endif
  131. }
  132. void gameport_start_polling(struct gameport *gameport)
  133. {
  134. spin_lock(&gameport->timer_lock);
  135. if (!gameport->poll_cnt++) {
  136. BUG_ON(!gameport->poll_handler);
  137. BUG_ON(!gameport->poll_interval);
  138. mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
  139. }
  140. spin_unlock(&gameport->timer_lock);
  141. }
  142. EXPORT_SYMBOL(gameport_start_polling);
  143. void gameport_stop_polling(struct gameport *gameport)
  144. {
  145. spin_lock(&gameport->timer_lock);
  146. if (!--gameport->poll_cnt)
  147. del_timer(&gameport->poll_timer);
  148. spin_unlock(&gameport->timer_lock);
  149. }
  150. EXPORT_SYMBOL(gameport_stop_polling);
  151. static void gameport_run_poll_handler(struct timer_list *t)
  152. {
  153. struct gameport *gameport = from_timer(gameport, t, poll_timer);
  154. gameport->poll_handler(gameport);
  155. if (gameport->poll_cnt)
  156. mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
  157. }
  158. /*
  159. * Basic gameport -> driver core mappings
  160. */
  161. static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
  162. {
  163. int error;
  164. gameport->dev.driver = &drv->driver;
  165. if (drv->connect(gameport, drv)) {
  166. gameport->dev.driver = NULL;
  167. return -ENODEV;
  168. }
  169. error = device_bind_driver(&gameport->dev);
  170. if (error) {
  171. dev_warn(&gameport->dev,
  172. "device_bind_driver() failed for %s (%s) and %s, error: %d\n",
  173. gameport->phys, gameport->name,
  174. drv->description, error);
  175. drv->disconnect(gameport);
  176. gameport->dev.driver = NULL;
  177. return error;
  178. }
  179. return 0;
  180. }
  181. static void gameport_find_driver(struct gameport *gameport)
  182. {
  183. int error;
  184. error = device_attach(&gameport->dev);
  185. if (error < 0)
  186. dev_warn(&gameport->dev,
  187. "device_attach() failed for %s (%s), error: %d\n",
  188. gameport->phys, gameport->name, error);
  189. }
  190. /*
  191. * Gameport event processing.
  192. */
  193. enum gameport_event_type {
  194. GAMEPORT_REGISTER_PORT,
  195. GAMEPORT_ATTACH_DRIVER,
  196. };
  197. struct gameport_event {
  198. enum gameport_event_type type;
  199. void *object;
  200. struct module *owner;
  201. struct list_head node;
  202. };
  203. static DEFINE_SPINLOCK(gameport_event_lock); /* protects gameport_event_list */
  204. static LIST_HEAD(gameport_event_list);
  205. static struct gameport_event *gameport_get_event(void)
  206. {
  207. struct gameport_event *event = NULL;
  208. unsigned long flags;
  209. spin_lock_irqsave(&gameport_event_lock, flags);
  210. if (!list_empty(&gameport_event_list)) {
  211. event = list_first_entry(&gameport_event_list,
  212. struct gameport_event, node);
  213. list_del_init(&event->node);
  214. }
  215. spin_unlock_irqrestore(&gameport_event_lock, flags);
  216. return event;
  217. }
  218. static void gameport_free_event(struct gameport_event *event)
  219. {
  220. module_put(event->owner);
  221. kfree(event);
  222. }
  223. static void gameport_remove_duplicate_events(struct gameport_event *event)
  224. {
  225. struct gameport_event *e, *next;
  226. unsigned long flags;
  227. spin_lock_irqsave(&gameport_event_lock, flags);
  228. list_for_each_entry_safe(e, next, &gameport_event_list, node) {
  229. if (event->object == e->object) {
  230. /*
  231. * If this event is of different type we should not
  232. * look further - we only suppress duplicate events
  233. * that were sent back-to-back.
  234. */
  235. if (event->type != e->type)
  236. break;
  237. list_del_init(&e->node);
  238. gameport_free_event(e);
  239. }
  240. }
  241. spin_unlock_irqrestore(&gameport_event_lock, flags);
  242. }
  243. static void gameport_handle_events(struct work_struct *work)
  244. {
  245. struct gameport_event *event;
  246. mutex_lock(&gameport_mutex);
  247. /*
  248. * Note that we handle only one event here to give swsusp
  249. * a chance to freeze kgameportd thread. Gameport events
  250. * should be pretty rare so we are not concerned about
  251. * taking performance hit.
  252. */
  253. if ((event = gameport_get_event())) {
  254. switch (event->type) {
  255. case GAMEPORT_REGISTER_PORT:
  256. gameport_add_port(event->object);
  257. break;
  258. case GAMEPORT_ATTACH_DRIVER:
  259. gameport_attach_driver(event->object);
  260. break;
  261. }
  262. gameport_remove_duplicate_events(event);
  263. gameport_free_event(event);
  264. }
  265. mutex_unlock(&gameport_mutex);
  266. }
  267. static DECLARE_WORK(gameport_event_work, gameport_handle_events);
  268. static int gameport_queue_event(void *object, struct module *owner,
  269. enum gameport_event_type event_type)
  270. {
  271. unsigned long flags;
  272. struct gameport_event *event;
  273. int retval = 0;
  274. spin_lock_irqsave(&gameport_event_lock, flags);
  275. /*
  276. * Scan event list for the other events for the same gameport port,
  277. * starting with the most recent one. If event is the same we
  278. * do not need add new one. If event is of different type we
  279. * need to add this event and should not look further because
  280. * we need to preserve sequence of distinct events.
  281. */
  282. list_for_each_entry_reverse(event, &gameport_event_list, node) {
  283. if (event->object == object) {
  284. if (event->type == event_type)
  285. goto out;
  286. break;
  287. }
  288. }
  289. event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC);
  290. if (!event) {
  291. pr_err("Not enough memory to queue event %d\n", event_type);
  292. retval = -ENOMEM;
  293. goto out;
  294. }
  295. if (!try_module_get(owner)) {
  296. pr_warn("Can't get module reference, dropping event %d\n",
  297. event_type);
  298. kfree(event);
  299. retval = -EINVAL;
  300. goto out;
  301. }
  302. event->type = event_type;
  303. event->object = object;
  304. event->owner = owner;
  305. list_add_tail(&event->node, &gameport_event_list);
  306. queue_work(system_long_wq, &gameport_event_work);
  307. out:
  308. spin_unlock_irqrestore(&gameport_event_lock, flags);
  309. return retval;
  310. }
  311. /*
  312. * Remove all events that have been submitted for a given object,
  313. * be it a gameport port or a driver.
  314. */
  315. static void gameport_remove_pending_events(void *object)
  316. {
  317. struct gameport_event *event, *next;
  318. unsigned long flags;
  319. spin_lock_irqsave(&gameport_event_lock, flags);
  320. list_for_each_entry_safe(event, next, &gameport_event_list, node) {
  321. if (event->object == object) {
  322. list_del_init(&event->node);
  323. gameport_free_event(event);
  324. }
  325. }
  326. spin_unlock_irqrestore(&gameport_event_lock, flags);
  327. }
  328. /*
  329. * Destroy child gameport port (if any) that has not been fully registered yet.
  330. *
  331. * Note that we rely on the fact that port can have only one child and therefore
  332. * only one child registration request can be pending. Additionally, children
  333. * are registered by driver's connect() handler so there can't be a grandchild
  334. * pending registration together with a child.
  335. */
  336. static struct gameport *gameport_get_pending_child(struct gameport *parent)
  337. {
  338. struct gameport_event *event;
  339. struct gameport *gameport, *child = NULL;
  340. unsigned long flags;
  341. spin_lock_irqsave(&gameport_event_lock, flags);
  342. list_for_each_entry(event, &gameport_event_list, node) {
  343. if (event->type == GAMEPORT_REGISTER_PORT) {
  344. gameport = event->object;
  345. if (gameport->parent == parent) {
  346. child = gameport;
  347. break;
  348. }
  349. }
  350. }
  351. spin_unlock_irqrestore(&gameport_event_lock, flags);
  352. return child;
  353. }
  354. /*
  355. * Gameport port operations
  356. */
  357. static ssize_t gameport_description_show(struct device *dev, struct device_attribute *attr, char *buf)
  358. {
  359. struct gameport *gameport = to_gameport_port(dev);
  360. return sprintf(buf, "%s\n", gameport->name);
  361. }
  362. static DEVICE_ATTR(description, S_IRUGO, gameport_description_show, NULL);
  363. static ssize_t drvctl_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  364. {
  365. struct gameport *gameport = to_gameport_port(dev);
  366. struct device_driver *drv;
  367. int error;
  368. error = mutex_lock_interruptible(&gameport_mutex);
  369. if (error)
  370. return error;
  371. if (!strncmp(buf, "none", count)) {
  372. gameport_disconnect_port(gameport);
  373. } else if (!strncmp(buf, "reconnect", count)) {
  374. gameport_reconnect_port(gameport);
  375. } else if (!strncmp(buf, "rescan", count)) {
  376. gameport_disconnect_port(gameport);
  377. gameport_find_driver(gameport);
  378. } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
  379. gameport_disconnect_port(gameport);
  380. error = gameport_bind_driver(gameport, to_gameport_driver(drv));
  381. } else {
  382. error = -EINVAL;
  383. }
  384. mutex_unlock(&gameport_mutex);
  385. return error ? error : count;
  386. }
  387. static DEVICE_ATTR_WO(drvctl);
  388. static struct attribute *gameport_device_attrs[] = {
  389. &dev_attr_description.attr,
  390. &dev_attr_drvctl.attr,
  391. NULL,
  392. };
  393. ATTRIBUTE_GROUPS(gameport_device);
  394. static void gameport_release_port(struct device *dev)
  395. {
  396. struct gameport *gameport = to_gameport_port(dev);
  397. kfree(gameport);
  398. module_put(THIS_MODULE);
  399. }
  400. void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
  401. {
  402. va_list args;
  403. va_start(args, fmt);
  404. vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
  405. va_end(args);
  406. }
  407. EXPORT_SYMBOL(gameport_set_phys);
  408. /*
  409. * Prepare gameport port for registration.
  410. */
  411. static void gameport_init_port(struct gameport *gameport)
  412. {
  413. static atomic_t gameport_no = ATOMIC_INIT(-1);
  414. __module_get(THIS_MODULE);
  415. mutex_init(&gameport->drv_mutex);
  416. device_initialize(&gameport->dev);
  417. dev_set_name(&gameport->dev, "gameport%lu",
  418. (unsigned long)atomic_inc_return(&gameport_no));
  419. gameport->dev.bus = &gameport_bus;
  420. gameport->dev.release = gameport_release_port;
  421. if (gameport->parent)
  422. gameport->dev.parent = &gameport->parent->dev;
  423. INIT_LIST_HEAD(&gameport->node);
  424. spin_lock_init(&gameport->timer_lock);
  425. timer_setup(&gameport->poll_timer, gameport_run_poll_handler, 0);
  426. }
  427. /*
  428. * Complete gameport port registration.
  429. * Driver core will attempt to find appropriate driver for the port.
  430. */
  431. static void gameport_add_port(struct gameport *gameport)
  432. {
  433. int error;
  434. if (gameport->parent)
  435. gameport->parent->child = gameport;
  436. gameport->speed = use_ktime ?
  437. gameport_measure_speed(gameport) :
  438. old_gameport_measure_speed(gameport);
  439. list_add_tail(&gameport->node, &gameport_list);
  440. if (gameport->io)
  441. dev_info(&gameport->dev, "%s is %s, io %#x, speed %dkHz\n",
  442. gameport->name, gameport->phys, gameport->io, gameport->speed);
  443. else
  444. dev_info(&gameport->dev, "%s is %s, speed %dkHz\n",
  445. gameport->name, gameport->phys, gameport->speed);
  446. error = device_add(&gameport->dev);
  447. if (error)
  448. dev_err(&gameport->dev,
  449. "device_add() failed for %s (%s), error: %d\n",
  450. gameport->phys, gameport->name, error);
  451. }
  452. /*
  453. * gameport_destroy_port() completes deregistration process and removes
  454. * port from the system
  455. */
  456. static void gameport_destroy_port(struct gameport *gameport)
  457. {
  458. struct gameport *child;
  459. child = gameport_get_pending_child(gameport);
  460. if (child) {
  461. gameport_remove_pending_events(child);
  462. put_device(&child->dev);
  463. }
  464. if (gameport->parent) {
  465. gameport->parent->child = NULL;
  466. gameport->parent = NULL;
  467. }
  468. if (device_is_registered(&gameport->dev))
  469. device_del(&gameport->dev);
  470. list_del_init(&gameport->node);
  471. gameport_remove_pending_events(gameport);
  472. put_device(&gameport->dev);
  473. }
  474. /*
  475. * Reconnect gameport port and all its children (re-initialize attached devices)
  476. */
  477. static void gameport_reconnect_port(struct gameport *gameport)
  478. {
  479. do {
  480. if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
  481. gameport_disconnect_port(gameport);
  482. gameport_find_driver(gameport);
  483. /* Ok, old children are now gone, we are done */
  484. break;
  485. }
  486. gameport = gameport->child;
  487. } while (gameport);
  488. }
  489. /*
  490. * gameport_disconnect_port() unbinds a port from its driver. As a side effect
  491. * all child ports are unbound and destroyed.
  492. */
  493. static void gameport_disconnect_port(struct gameport *gameport)
  494. {
  495. struct gameport *s, *parent;
  496. if (gameport->child) {
  497. /*
  498. * Children ports should be disconnected and destroyed
  499. * first, staring with the leaf one, since we don't want
  500. * to do recursion
  501. */
  502. for (s = gameport; s->child; s = s->child)
  503. /* empty */;
  504. do {
  505. parent = s->parent;
  506. device_release_driver(&s->dev);
  507. gameport_destroy_port(s);
  508. } while ((s = parent) != gameport);
  509. }
  510. /*
  511. * Ok, no children left, now disconnect this port
  512. */
  513. device_release_driver(&gameport->dev);
  514. }
  515. /*
  516. * Submits register request to kgameportd for subsequent execution.
  517. * Note that port registration is always asynchronous.
  518. */
  519. void __gameport_register_port(struct gameport *gameport, struct module *owner)
  520. {
  521. gameport_init_port(gameport);
  522. gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
  523. }
  524. EXPORT_SYMBOL(__gameport_register_port);
  525. /*
  526. * Synchronously unregisters gameport port.
  527. */
  528. void gameport_unregister_port(struct gameport *gameport)
  529. {
  530. mutex_lock(&gameport_mutex);
  531. gameport_disconnect_port(gameport);
  532. gameport_destroy_port(gameport);
  533. mutex_unlock(&gameport_mutex);
  534. }
  535. EXPORT_SYMBOL(gameport_unregister_port);
  536. /*
  537. * Gameport driver operations
  538. */
  539. static ssize_t description_show(struct device_driver *drv, char *buf)
  540. {
  541. struct gameport_driver *driver = to_gameport_driver(drv);
  542. return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
  543. }
  544. static DRIVER_ATTR_RO(description);
  545. static struct attribute *gameport_driver_attrs[] = {
  546. &driver_attr_description.attr,
  547. NULL
  548. };
  549. ATTRIBUTE_GROUPS(gameport_driver);
  550. static int gameport_driver_probe(struct device *dev)
  551. {
  552. struct gameport *gameport = to_gameport_port(dev);
  553. struct gameport_driver *drv = to_gameport_driver(dev->driver);
  554. drv->connect(gameport, drv);
  555. return gameport->drv ? 0 : -ENODEV;
  556. }
  557. static int gameport_driver_remove(struct device *dev)
  558. {
  559. struct gameport *gameport = to_gameport_port(dev);
  560. struct gameport_driver *drv = to_gameport_driver(dev->driver);
  561. drv->disconnect(gameport);
  562. return 0;
  563. }
  564. static void gameport_attach_driver(struct gameport_driver *drv)
  565. {
  566. int error;
  567. error = driver_attach(&drv->driver);
  568. if (error)
  569. pr_err("driver_attach() failed for %s, error: %d\n",
  570. drv->driver.name, error);
  571. }
  572. int __gameport_register_driver(struct gameport_driver *drv, struct module *owner,
  573. const char *mod_name)
  574. {
  575. int error;
  576. drv->driver.bus = &gameport_bus;
  577. drv->driver.owner = owner;
  578. drv->driver.mod_name = mod_name;
  579. /*
  580. * Temporarily disable automatic binding because probing
  581. * takes long time and we are better off doing it in kgameportd
  582. */
  583. drv->ignore = true;
  584. error = driver_register(&drv->driver);
  585. if (error) {
  586. pr_err("driver_register() failed for %s, error: %d\n",
  587. drv->driver.name, error);
  588. return error;
  589. }
  590. /*
  591. * Reset ignore flag and let kgameportd bind the driver to free ports
  592. */
  593. drv->ignore = false;
  594. error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER);
  595. if (error) {
  596. driver_unregister(&drv->driver);
  597. return error;
  598. }
  599. return 0;
  600. }
  601. EXPORT_SYMBOL(__gameport_register_driver);
  602. void gameport_unregister_driver(struct gameport_driver *drv)
  603. {
  604. struct gameport *gameport;
  605. mutex_lock(&gameport_mutex);
  606. drv->ignore = true; /* so gameport_find_driver ignores it */
  607. gameport_remove_pending_events(drv);
  608. start_over:
  609. list_for_each_entry(gameport, &gameport_list, node) {
  610. if (gameport->drv == drv) {
  611. gameport_disconnect_port(gameport);
  612. gameport_find_driver(gameport);
  613. /* we could've deleted some ports, restart */
  614. goto start_over;
  615. }
  616. }
  617. driver_unregister(&drv->driver);
  618. mutex_unlock(&gameport_mutex);
  619. }
  620. EXPORT_SYMBOL(gameport_unregister_driver);
  621. static int gameport_bus_match(struct device *dev, struct device_driver *drv)
  622. {
  623. struct gameport_driver *gameport_drv = to_gameport_driver(drv);
  624. return !gameport_drv->ignore;
  625. }
  626. static struct bus_type gameport_bus = {
  627. .name = "gameport",
  628. .dev_groups = gameport_device_groups,
  629. .drv_groups = gameport_driver_groups,
  630. .match = gameport_bus_match,
  631. .probe = gameport_driver_probe,
  632. .remove = gameport_driver_remove,
  633. };
  634. static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
  635. {
  636. mutex_lock(&gameport->drv_mutex);
  637. gameport->drv = drv;
  638. mutex_unlock(&gameport->drv_mutex);
  639. }
  640. int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
  641. {
  642. if (gameport->open) {
  643. if (gameport->open(gameport, mode)) {
  644. return -1;
  645. }
  646. } else {
  647. if (mode != GAMEPORT_MODE_RAW)
  648. return -1;
  649. }
  650. gameport_set_drv(gameport, drv);
  651. return 0;
  652. }
  653. EXPORT_SYMBOL(gameport_open);
  654. void gameport_close(struct gameport *gameport)
  655. {
  656. del_timer_sync(&gameport->poll_timer);
  657. gameport->poll_handler = NULL;
  658. gameport->poll_interval = 0;
  659. gameport_set_drv(gameport, NULL);
  660. if (gameport->close)
  661. gameport->close(gameport);
  662. }
  663. EXPORT_SYMBOL(gameport_close);
  664. static int __init gameport_init(void)
  665. {
  666. int error;
  667. error = bus_register(&gameport_bus);
  668. if (error) {
  669. pr_err("failed to register gameport bus, error: %d\n", error);
  670. return error;
  671. }
  672. return 0;
  673. }
  674. static void __exit gameport_exit(void)
  675. {
  676. bus_unregister(&gameport_bus);
  677. /*
  678. * There should not be any outstanding events but work may
  679. * still be scheduled so simply cancel it.
  680. */
  681. cancel_work_sync(&gameport_event_work);
  682. }
  683. subsys_initcall(gameport_init);
  684. module_exit(gameport_exit);