xref: /haiku/src/add-ons/kernel/drivers/input/wacom/wacom.c (revision 1e60bdeab63fa7a57bc9a55b032052e95a18bd2c)
1 /*
2  * Copyright 2005-2008, Haiku, Inc. All Rights Reserved.
3  * Distributed under the terms of the MIT License.
4  *
5  * Authors:
6  *		Stephan Aßmus <superstippi@gmx.de>
7  *
8  * Portions of this code are based on Be Sample Code released under the
9  * Be Sample Code license. (USB sound device driver sample code IIRC.)
10  */
11 
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15 
16 #include <Drivers.h>
17 #include <KernelExport.h>
18 #include <OS.h>
19 #include <USB3.h>
20 
21 int32 api_version = B_CUR_DRIVER_API_VERSION;
22 
23 #define DEBUG_DRIVER 0
24 
25 #if DEBUG_DRIVER
26 #	define DPRINTF_INFO(x) dprintf x;
27 #	define DPRINTF_ERR(x) dprintf x;
28 #else
29 #	define DPRINTF_INFO(x)
30 #	define DPRINTF_ERR(x) dprintf x;
31 #endif
32 
33 typedef struct wacom_device wacom_device;
34 
35 struct wacom_device {
36 	wacom_device*		next;
37 
38 	int					open;
39 	int					number;
40 
41 	usb_device			dev;
42 
43 	usb_pipe			pipe;
44 	char*				data;
45 	size_t				max_packet_size;
46 	size_t				length;
47 
48 	uint16				vendor;
49 	uint16				product;
50 
51 	sem_id				notify_lock;
52 	uint32				status;
53 };
54 
55 // handy strings for referring to ourself
56 #define ID "wacom: "
57 static const char* kDriverName = "wacom";
58 static const char* kBasePublishPath = "input/wacom/usb/";
59 
60 // list of device instances and names for publishing
61 static wacom_device* sDeviceList = NULL;
62 static sem_id sDeviceListLock = -1;
63 static int sDeviceCount = 0;
64 
65 static char** sDeviceNames = NULL;
66 
67 // handle for the USB bus manager
68 static usb_module_info* usb;
69 
70 // These rather inelegant routines are used to assign numbers to
71 // device instances so that they have unique names in devfs.
72 
73 static uint32 sDeviceNumbers = 0;
74 
75 // get_number
76 static int
77 get_number()
78 {
79 	int num;
80 
81 	for (num = 0; num < 32; num++) {
82 		if (!(sDeviceNumbers & (1 << num))) {
83 			sDeviceNumbers |= (1 << num);
84 			return num;
85 		}
86 	}
87 
88 	return -1;
89 }
90 
91 // put_number
92 static void
93 put_number(int num)
94 {
95 	sDeviceNumbers &= ~(1 << num);
96 }
97 
98 // #pragma mark - Device addition and removal
99 //
100 // add_device() and remove_device() are used to create and tear down
101 // device instances.  They are used from the callbacks device_added()
102 // and device_removed() which are invoked by the USB bus manager.
103 
104 // add_device
105 static wacom_device*
106 add_device(usb_device dev)
107 {
108 	wacom_device *device = NULL;
109 	int num, ifc, alt;
110 	const usb_interface_info *ii;
111 	status_t st;
112 	const usb_device_descriptor* udd;
113 	const usb_configuration_info *conf;
114 	bool setConfiguration = false;
115 
116 	// we need these four for a Wacom tablet
117 	size_t controlTransferLength;
118 	int tryCount;
119 	char repData[2] = { 0x02, 0x02 };
120 	char retData[2] = { 0x00, 0x00 };
121 
122 	conf = usb->get_configuration(dev);
123 	DPRINTF_INFO((ID "add_device(%ld, %p)\n", dev, conf));
124 
125 	if ((num = get_number()) < 0)
126 		return NULL;
127 
128 	udd = usb->get_device_descriptor(dev);
129 	// only pick up wacom tablets
130 	if (udd && udd->vendor_id == 0x056a) {
131 
132 		DPRINTF_ERR((ID "add_device() - wacom detected\n"));
133 
134 		// see if the device has been configured already
135 		if (!conf) {
136 			conf = usb->get_nth_configuration(dev, 0);
137 			setConfiguration = true;
138 		}
139 
140 		if (!conf)
141 			goto fail;
142 
143 		for (ifc = 0; ifc < conf->interface_count; ifc++) {
144 			DPRINTF_INFO((ID "add_device() - examining interface: %d\n", ifc));
145 			for (alt = 0; alt < conf->interface[ifc].alt_count; alt++) {
146 				ii = &conf->interface[ifc].alt[alt];
147 				DPRINTF_INFO((ID "add_device() - examining alt interface: "
148 					"%d\n", alt));
149 
150 
151 				// does it have the correct type of interface?
152 				if (ii->descr->interface_class != 3) continue;
153 				if (ii->descr->interface_subclass != 1) continue;
154 				if (ii->endpoint_count != 1) continue;
155 
156 				// only accept input endpoints
157 				if (ii->endpoint[0].descr->endpoint_address & 0x80) {
158 					DPRINTF_INFO((ID "add_device() - found input endpoint\n"));
159 					goto got_one;
160 				}
161 			}
162 		}
163 	} else
164 		goto fail;
165 
166 fail:
167 	put_number(num);
168 	if (device) {
169 		free(device->data);
170 		free(device);
171 	}
172 	return NULL;
173 
174 got_one:
175 	if ((device = (wacom_device *) malloc(sizeof(wacom_device))) == NULL)
176 		goto fail;
177 
178 	device->dev = dev;
179 	device->number = num;
180 	device->open = 1;
181 	device->notify_lock = -1;
182 	device->data = NULL;
183 
184 //	if (setConfiguration) {
185 		// the configuration has to be set yet (was not the current one)
186 		DPRINTF_INFO((ID "add_device() - setting configuration...\n"));
187 		if ((st = usb->set_configuration(dev, conf)) != B_OK) {
188 			dprintf(ID "add_device() -> set_configuration() returns %ld\n", st);
189 			goto fail;
190 		} else
191 			DPRINTF_ERR((ID " ... success!\n"));
192 
193 		if (conf->interface[ifc].active != ii) {
194 			// the interface we found is not the active one and has to be set
195 			DPRINTF_INFO((ID "add_device() - setting interface: %p...\n", ii));
196 			if ((st = usb->set_alt_interface(dev, ii)) != B_OK) {
197 				dprintf(ID "add_device() -> set_alt_interface() returns %ld\n",
198 					st);
199 				goto fail;
200 			} else
201 				DPRINTF_ERR((ID " ... success!\n"));
202 		}
203 		// see if the device is a Wacom tablet and needs some special treatment
204 		// let's hope Wacom doesn't produce normal mice any time soon, or this
205 		// check will have to be more specific about product_id...hehe
206 		if (udd->vendor_id == 0x056a) {
207 			// do the control transfers to set up absolute mode (default is HID
208 			// mode)
209 
210 			// see 'Device Class Definition for HID 1.11' (HID1_11.pdf),
211 			// par. 7.2 (available at www.usb.org/developers/hidpage)
212 
213 			// set protocol mode to 'report' (instead of 'boot')
214 			controlTransferLength = 0;
215 			// HID Class-Specific Request, Host to device (=0x21):
216 			// SET_PROTOCOL (=0x0b) to Report Protocol (=1)
217 			// of Interface #0 (=0)
218 			st = usb->send_request(dev, 0x21, 0x0b, 1, 0, 0, 0,
219 				&controlTransferLength);
220 
221 			if (st < B_OK) {
222 				dprintf(ID "add_device() - control transfer 1 failed: %ld\n",
223 					st);
224 			}
225 
226 			// try up to five times to set the tablet to 'Wacom'-mode (enabling
227 			// absolute mode, pressure data, etc.)
228 			controlTransferLength = 2;
229 
230 			for (tryCount = 0; tryCount < 5; tryCount++) {
231 				// HID Class-Specific Request, Host to device (=0x21):
232 				// SET_REPORT (=0x09) type Feature (=3) with ID 2 (=2) of
233 				// Interface #0 (=0) to repData (== { 0x02, 0x02 })
234 				st = usb->send_request(dev, 0x21, 0x09, (3 << 8) + 2, 0, 2,
235 					repData, &controlTransferLength);
236 
237 				if (st < B_OK) {
238 					dprintf(ID "add_device() - control transfer 2 failed: %ld"
239 						"\n", st);
240 				}
241 
242 				// check if registers are set correctly
243 
244 				// HID Class-Specific Request, Device to host (=0xA1):
245 				// GET_REPORT (=0x01) type Feature (=3) with ID 2 (=2) of
246 				// Interface #0 (=0) to retData
247 				st = usb->send_request(dev, 0xA1, 0x01, (3 << 8) + 2, 0, 2,
248 					retData, &controlTransferLength);
249 
250 				if (st < B_OK) {
251 					dprintf(ID "add_device() - control transfer 3 failed: %ld"
252 						"\n", st);
253 				}
254 
255 				DPRINTF_INFO((ID "add_device() - retData: %u - %u\n",
256 					retData[0], retData[1]));
257 
258 				if (retData[0] == repData[0] && retData[1] == repData[1]) {
259 					DPRINTF_INFO((ID "add_device() - successfully set "
260 						"'Wacom'-mode\n"));
261 					break;
262 				}
263 			}
264 
265 			DPRINTF_INFO((ID "add_device() - number of tries: %u\n",
266 				tryCount + 1));
267 
268 			if (tryCount > 4) {
269 				dprintf(ID "add_device() - set 'Wacom'-mode failed\n");
270 			}
271 		}
272 //	}
273 
274 	// configure the rest of the wacom_device
275 	device->pipe = ii->endpoint[0].handle;
276 //DPRINTF_INFO((ID "add_device() - pipe id = %ld\n", device->pipe));
277 	device->length = 0;
278 	device->max_packet_size = ii->endpoint[0].descr->max_packet_size;
279 	device->data = (char*)malloc(device->max_packet_size);
280 	if (device->data == NULL)
281 		goto fail;
282 //DPRINTF_INFO((ID "add_device() - max packet length = %ld\n",
283 //	device->max_packet_size));
284 	device->status = 0;//B_USB_STATUS_SUCCESS;
285 	device->vendor = udd->vendor_id;
286 	device->product = udd->product_id;
287 
288 	DPRINTF_INFO((ID "add_device() - added %p (/dev/%s%d)\n", device,
289 		kBasePublishPath, num));
290 
291 	// add it to the list of devices so it will be published, etc
292 	acquire_sem(sDeviceListLock);
293 	device->next = sDeviceList;
294 	sDeviceList = device;
295 	sDeviceCount++;
296 	release_sem(sDeviceListLock);
297 
298 	return device;
299 }
300 
301 // remove_device
302 static void
303 remove_device(wacom_device *device)
304 {
305 	put_number(device->number);
306 
307 	usb->cancel_queued_transfers(device->pipe);
308 
309 	delete_sem(device->notify_lock);
310 	if (device->data)
311 		free(device->data);
312 	free(device);
313 }
314 
315 // device_added
316 static status_t
317 device_added(usb_device dev, void** cookie)
318 {
319 	wacom_device* device;
320 
321 	DPRINTF_INFO((ID "device_added(%ld,...)\n", dev));
322 
323 	// first see, if this device is already added
324 	acquire_sem(sDeviceListLock);
325 	for (device = sDeviceList; device; device = device->next) {
326 		DPRINTF_ERR((ID "device_added() - old device: %ld\n", device->dev));
327 		if (device->dev == dev) {
328 			DPRINTF_ERR((ID "device_added() - already added - done!\n"));
329 			*cookie = (void*)device;
330 			release_sem(sDeviceListLock);
331 			return B_OK;
332 		}
333 	}
334 	release_sem(sDeviceListLock);
335 
336 	if ((device = add_device(dev)) != NULL) {
337 		*cookie = (void*)device;
338 		DPRINTF_INFO((ID "device_added() - done!\n"));
339 		return B_OK;
340 	} else
341 		DPRINTF_INFO((ID "device_added() - failed to add device!\n"));
342 
343 	return B_ERROR;
344 }
345 
346 // device_removed
347 static status_t
348 device_removed(void *cookie)
349 {
350 	wacom_device *device = (wacom_device *) cookie;
351 
352 	DPRINTF_INFO((ID "device_removed(%p)\n", device));
353 
354 	if (device) {
355 
356 		acquire_sem(sDeviceListLock);
357 
358 		// remove it from the list of devices
359 		if (device == sDeviceList) {
360 			sDeviceList = device->next;
361 		} else {
362 			wacom_device *n;
363 			for (n = sDeviceList; n; n = n->next) {
364 				if (n->next == device) {
365 					n->next = device->next;
366 					break;
367 				}
368 			}
369 		}
370 		sDeviceCount--;
371 
372 		// tear it down if it's not open --
373 		// otherwise the last device_free() will handle it
374 
375 		device->open--;
376 
377 		DPRINTF_ERR((ID "device_removed() open: %d\n", device->open));
378 
379 		if (device->open == 0) {
380 			remove_device(device);
381 		} else {
382 			dprintf(ID "device /dev/%s%d still open -- marked for removal\n",
383 				kBasePublishPath, device->number);
384 		}
385 
386 		release_sem(sDeviceListLock);
387 	}
388 
389 	return B_OK;
390 }
391 
392 // #pragma mark - Device Hooks
393 //
394 // Here we implement the posixy driver hooks (open/close/read/write/ioctl)
395 
396 // device_open
397 static status_t
398 device_open(const char *dname, uint32 flags, void** cookie)
399 {
400 	wacom_device *device;
401 	int n;
402 	status_t ret = B_ERROR;
403 
404 	char controlDevicePath[1024];
405 	sprintf(controlDevicePath, "%s%s", kBasePublishPath, "control");
406 	if (strcmp(dname, controlDevicePath) == 0) {
407 		dprintf(ID "device_open() -> refuse to open control device\n");
408 		return B_ERROR;
409 	}
410 
411 	n = atoi(dname + strlen(kBasePublishPath));
412 
413 	DPRINTF_INFO((ID "device_open(\"%s\",%d,...)\n", dname, flags));
414 
415 	acquire_sem(sDeviceListLock);
416 	for (device = sDeviceList; device; device = device->next) {
417 		if (device->number == n) {
418 //			if (device->open <= 1) {
419 				device->open++;
420 				*cookie = device;
421 				DPRINTF_ERR((ID "device_open() open: %d\n", device->open));
422 
423 				if (device->notify_lock < 0) {
424 					device->notify_lock = create_sem(0, "notify_lock");
425 					if (device->notify_lock < 0) {
426 						ret = device->notify_lock;
427 						device->open--;
428 						*cookie = NULL;
429 						dprintf(ID "device_open() -> create_sem() returns %ld\n",
430 							ret);
431 					} else {
432 						ret = B_OK;
433 					}
434 				}
435 				release_sem(sDeviceListLock);
436 				return ret;
437 //			} else {
438 //				dprintf(ID "device_open() -> device is already open %ld\n", ret);
439 //				release_sem(sDeviceListLock);
440 //				return B_ERROR;
441 //			}
442 		}
443 	}
444 	release_sem(sDeviceListLock);
445 	return ret;
446 }
447 
448 // device_close
449 static status_t
450 device_close (void *cookie)
451 {
452 #if DEBUG_DRIVER
453 	wacom_device *device = (wacom_device*) cookie;
454 	DPRINTF_ERR((ID "device_close() name = \"%s%d\"\n", kBasePublishPath,
455 		device->number));
456 #endif
457 	return B_OK;
458 }
459 
460 // device_free
461 static status_t
462 device_free(void *cookie)
463 {
464 	wacom_device *device = (wacom_device *)cookie;
465 
466 	DPRINTF_INFO((ID "device_free() name = \"%s%d\"\n", kBasePublishPath,
467 		device->number));
468 
469 	acquire_sem(sDeviceListLock);
470 
471 	device->open--;
472 
473 	DPRINTF_INFO((ID "device_free() open: %ld\n", device->open));
474 
475 	if (device->open == 0) {
476 		remove_device(device);
477 	}
478 	release_sem(sDeviceListLock);
479 
480 	return B_OK;
481 }
482 
483 // device_interupt_callback
484 static void
485 device_interupt_callback(void* cookie, status_t status, void* data,
486 	uint32 actualLength)
487 {
488 	wacom_device* device = (wacom_device*)cookie;
489 	uint32 length = min_c(actualLength, device->max_packet_size);
490 
491 	DPRINTF_INFO((ID "device_interupt_callback(%p) name = \"%s%d\" -> "
492 		"status: %ld, length: %ld\n", cookie, kBasePublishPath, device->number,
493 		status, actualLength));
494 
495 	device->status = status;
496 	if (device->notify_lock >= 0) {
497 		if (status == B_OK) {
498 			memcpy(device->data, data, length);
499 			device->length = length;
500 		} else {
501 			device->length = 0;
502 		}
503 		release_sem(device->notify_lock);
504 	}
505 
506 	DPRINTF_INFO((ID "device_interupt_callback() - done\n"));
507 }
508 
509 // read_header
510 static void
511 read_header(const wacom_device* device, void* buffer)
512 {
513 	uint16* ids = (uint16*)buffer;
514 	uint32* size = (uint32*)buffer;
515 
516 	ids[0] = device->vendor;
517 	ids[1] = device->product;
518 	size[1] = device->max_packet_size;
519 }
520 
521 // device_read
522 static status_t
523 device_read(void* cookie, off_t pos, void* buf, size_t* count)
524 {
525 	wacom_device* device = (wacom_device*) cookie;
526 	status_t ret = B_BAD_VALUE;
527 	uint8* buffer = (uint8*)buf;
528 	uint32 dataLength;
529 
530 	if (!device)
531 		return ret;
532 
533 	ret = device->notify_lock;
534 
535 	DPRINTF_INFO((ID "device_read(%p,%Ld,0x%x,%d) name = \"%s%d\"\n",
536 			 cookie, pos, buf, *count, kBasePublishPath, device->number));
537 
538 	if (ret >= B_OK) {
539 		// what the client "reads" is decided depending on how much bytes are
540 		// provided 8 bytes are needed to "read" vendor id, product id and max
541 		// packet size in case the client wants to read more than 8 bytes, a usb
542 		// interupt transfer is scheduled, and an error report is returned as
543 		// appropriate
544 		if (*count > 8) {
545 			// queue the interrupt transfer
546 			ret = usb->queue_interrupt(device->pipe, device->data,
547 				device->max_packet_size, device_interupt_callback, device);
548 			if (ret >= B_OK) {
549 				// we will block here until the interrupt transfer has been done
550 				ret = acquire_sem_etc(device->notify_lock, 1,
551 					B_RELATIVE_TIMEOUT, 500 * 1000);
552 				// handle time out
553 				if (ret < B_OK) {
554 					usb->cancel_queued_transfers(device->pipe);
555 					acquire_sem(device->notify_lock);
556 						// collect the sem released by the cancel
557 
558 					if (ret == B_TIMED_OUT) {
559 						// a time_out is ok, since it only means that the device
560 						// had nothing to report (ie mouse/pen was not moved)
561 						// within the given time interval
562 						DPRINTF_INFO((ID "device_read(%p) name = \"%s%d\" -> "
563 							"B_TIMED_OUT\n", cookie, kBasePublishPath,
564 							device->number));
565 						*count = 8;
566 						read_header(device, buffer);
567 						ret = B_OK;
568 					} else {
569 						// any other error trying to acquire the semaphore
570 						*count = 0;
571 					}
572 				} else {
573 					if (device->status == 0/*B_USBD_SUCCESS*/) {
574 						DPRINTF_INFO((ID "interrupt transfer - success\n"));
575 						// copy the data from the buffer
576 						dataLength = min_c(device->length, *count - 8);
577 						*count = dataLength + 8;
578 						read_header(device, buffer);
579 						memcpy(buffer + 8, device->data, dataLength);
580 					} else {
581 						// an error happened during the interrupt transfer
582 						*count = 0;
583 						dprintf(ID "interrupt transfer - failure: %ld\n",
584 							device->status);
585 						ret = B_ERROR;
586 					}
587 				}
588 			} else {
589 				*count = 0;
590 				dprintf(ID "device_read(%p) name = \"%s%d\" -> error queuing "
591 					"interrupt: %ld\n", cookie, kBasePublishPath,
592 					device->number, ret);
593 			}
594 		} else if (*count == 8) {
595 			read_header(device, buffer);
596 			ret = B_OK;
597 		} else {
598 			dprintf(ID "device_read(%p) name = \"%s%d\" -> buffer size must be "
599 				"at least 8 bytes!\n", cookie, kBasePublishPath,
600 				device->number);
601 			*count = 0;
602 			ret = B_BAD_VALUE;
603 		}
604 	}
605 
606 	return ret;
607 }
608 
609 // device_write
610 static status_t
611 device_write(void *cookie, off_t pos, const void *buf, size_t *count)
612 {
613 	return B_ERROR;
614 }
615 
616 // device_control
617 static status_t
618 device_control (void *cookie, uint32 msg, void *arg1, size_t len)
619 {
620 	return B_ERROR;
621 }
622 
623 // #pragma mark - Driver Hooks
624 //
625 // These functions provide the glue used by DevFS to load/unload
626 // the driver and also handle registering with the USB bus manager
627 // to receive device added and removed events
628 
629 static usb_notify_hooks notify_hooks =
630 {
631 	&device_added,
632 	&device_removed
633 };
634 
635 static const usb_support_descriptor kSupportedDevices[] =
636 {
637 	{ 3, 1, 2, 0, 0 }
638 };
639 
640 // init_hardware
641 status_t
642 init_hardware(void)
643 {
644 	return B_OK;
645 }
646 
647 // init_driver
648 status_t
649 init_driver(void)
650 {
651 	DPRINTF_INFO((ID "init_driver(), built %s %s\n", __DATE__, __TIME__));
652 
653 #if DEBUG_DRIVER && !defined(__HAIKU__)
654 	if (load_driver_symbols(kDriverName) == B_OK) {
655 		DPRINTF_INFO((ID "loaded symbols\n"));
656 	} else {
657 		DPRINTF_ERR((ID "no driver symbols loaded!\n"));
658 	}
659 #endif
660 
661 	if (get_module(B_USB_MODULE_NAME, (module_info**) &usb) != B_OK) {
662 		DPRINTF_ERR((ID "cannot get module \"%s\"\n", B_USB_MODULE_NAME));
663 		return B_ERROR;
664 	}
665 
666 	if ((sDeviceListLock = create_sem(1,"sDeviceListLock")) < 0) {
667 		put_module(B_USB_MODULE_NAME);
668 		return sDeviceListLock;
669 	}
670 
671 	usb->register_driver(kDriverName, kSupportedDevices, 1, NULL);
672 	usb->install_notify(kDriverName, &notify_hooks);
673 
674 	return B_OK;
675 }
676 
677 // uninit_driver
678 void
679 uninit_driver(void)
680 {
681 	int i;
682 
683 	DPRINTF_INFO((ID "uninit_driver()\n"));
684 
685 	usb->uninstall_notify(kDriverName);
686 
687 	delete_sem(sDeviceListLock);
688 
689 	put_module(B_USB_MODULE_NAME);
690 
691 	if (sDeviceNames) {
692 		for (i = 0; sDeviceNames[i]; i++)
693 			free(sDeviceNames[i]);
694 		free(sDeviceNames);
695 	}
696 
697 	DPRINTF_INFO((ID "uninit_driver() done\n"));
698 }
699 
700 // publish_devices
701 const char**
702 publish_devices()
703 {
704 	wacom_device *device;
705 	int i;
706 
707 	DPRINTF_INFO((ID "publish_devices()\n"));
708 
709 	if (sDeviceNames) {
710 		for (i = 0; sDeviceNames[i]; i++)
711 			free((char *) sDeviceNames[i]);
712 		free(sDeviceNames);
713 	}
714 
715 	acquire_sem(sDeviceListLock);
716 	sDeviceNames = (char**)malloc(sizeof(char*) * (sDeviceCount + 2));
717 	if (sDeviceNames) {
718 		for (i = 0, device = sDeviceList; device; device = device->next) {
719 			sDeviceNames[i] = (char*)malloc(strlen(kBasePublishPath) + 4);
720 			if (sDeviceNames[i]) {
721 				sprintf(sDeviceNames[i],"%s%d",kBasePublishPath,device->number);
722 				DPRINTF_INFO((ID "publishing: \"/dev/%s\"\n",sDeviceNames[i]));
723 				i++;
724 			}
725 		}
726 		// publish the currently fake control device
727 		sDeviceNames[i] = (char*)malloc(strlen(kBasePublishPath) + 8);
728 		if (sDeviceNames[i])
729 			sprintf(sDeviceNames[i], "%s%s", kBasePublishPath, "control");
730 
731 		sDeviceNames[i + 1] = NULL;
732 	}
733 
734 	release_sem(sDeviceListLock);
735 
736 	return (const char**)sDeviceNames;
737 }
738 
739 static device_hooks sDeviceHooks = {
740 	device_open,
741 	device_close,
742 	device_free,
743 	device_control,
744 	device_read,
745 	device_write
746 };
747 
748 // find_device
749 device_hooks*
750 find_device(const char* name)
751 {
752 	return &sDeviceHooks;
753 }
754