xref: /linux/drivers/mfd/dln2.c (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
1 /*
2  * Driver for the Diolan DLN-2 USB adapter
3  *
4  * Copyright (c) 2014 Intel Corporation
5  *
6  * Derived from:
7  *  i2c-diolan-u2c.c
8  *  Copyright (c) 2010-2011 Ericsson AB
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation, version 2.
13  */
14 
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/slab.h>
19 #include <linux/usb.h>
20 #include <linux/i2c.h>
21 #include <linux/mutex.h>
22 #include <linux/platform_device.h>
23 #include <linux/mfd/core.h>
24 #include <linux/mfd/dln2.h>
25 #include <linux/rculist.h>
26 
27 struct dln2_header {
28 	__le16 size;
29 	__le16 id;
30 	__le16 echo;
31 	__le16 handle;
32 };
33 
34 struct dln2_response {
35 	struct dln2_header hdr;
36 	__le16 result;
37 };
38 
39 #define DLN2_GENERIC_MODULE_ID		0x00
40 #define DLN2_GENERIC_CMD(cmd)		DLN2_CMD(cmd, DLN2_GENERIC_MODULE_ID)
41 #define CMD_GET_DEVICE_VER		DLN2_GENERIC_CMD(0x30)
42 #define CMD_GET_DEVICE_SN		DLN2_GENERIC_CMD(0x31)
43 
44 #define DLN2_HW_ID			0x200
45 #define DLN2_USB_TIMEOUT		200	/* in ms */
46 #define DLN2_MAX_RX_SLOTS		16
47 #define DLN2_MAX_URBS			16
48 #define DLN2_RX_BUF_SIZE		512
49 
50 enum dln2_handle {
51 	DLN2_HANDLE_EVENT = 0,		/* don't change, hardware defined */
52 	DLN2_HANDLE_CTRL,
53 	DLN2_HANDLE_GPIO,
54 	DLN2_HANDLE_I2C,
55 	DLN2_HANDLE_SPI,
56 	DLN2_HANDLES
57 };
58 
59 /*
60  * Receive context used between the receive demultiplexer and the transfer
61  * routine. While sending a request the transfer routine will look for a free
62  * receive context and use it to wait for a response and to receive the URB and
63  * thus the response data.
64  */
65 struct dln2_rx_context {
66 	/* completion used to wait for a response */
67 	struct completion done;
68 
69 	/* if non-NULL the URB contains the response */
70 	struct urb *urb;
71 
72 	/* if true then this context is used to wait for a response */
73 	bool in_use;
74 };
75 
76 /*
77  * Receive contexts for a particular DLN2 module (i2c, gpio, etc.). We use the
78  * handle header field to identify the module in dln2_dev.mod_rx_slots and then
79  * the echo header field to index the slots field and find the receive context
80  * for a particular request.
81  */
82 struct dln2_mod_rx_slots {
83 	/* RX slots bitmap */
84 	DECLARE_BITMAP(bmap, DLN2_MAX_RX_SLOTS);
85 
86 	/* used to wait for a free RX slot */
87 	wait_queue_head_t wq;
88 
89 	/* used to wait for an RX operation to complete */
90 	struct dln2_rx_context slots[DLN2_MAX_RX_SLOTS];
91 
92 	/* avoid races between alloc/free_rx_slot and dln2_rx_transfer */
93 	spinlock_t lock;
94 };
95 
96 struct dln2_dev {
97 	struct usb_device *usb_dev;
98 	struct usb_interface *interface;
99 	u8 ep_in;
100 	u8 ep_out;
101 
102 	struct urb *rx_urb[DLN2_MAX_URBS];
103 	void *rx_buf[DLN2_MAX_URBS];
104 
105 	struct dln2_mod_rx_slots mod_rx_slots[DLN2_HANDLES];
106 
107 	struct list_head event_cb_list;
108 	spinlock_t event_cb_lock;
109 
110 	bool disconnect;
111 	int active_transfers;
112 	wait_queue_head_t disconnect_wq;
113 	spinlock_t disconnect_lock;
114 };
115 
116 struct dln2_event_cb_entry {
117 	struct list_head list;
118 	u16 id;
119 	struct platform_device *pdev;
120 	dln2_event_cb_t callback;
121 };
122 
123 int dln2_register_event_cb(struct platform_device *pdev, u16 id,
124 			   dln2_event_cb_t event_cb)
125 {
126 	struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
127 	struct dln2_event_cb_entry *i, *entry;
128 	unsigned long flags;
129 	int ret = 0;
130 
131 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
132 	if (!entry)
133 		return -ENOMEM;
134 
135 	entry->id = id;
136 	entry->callback = event_cb;
137 	entry->pdev = pdev;
138 
139 	spin_lock_irqsave(&dln2->event_cb_lock, flags);
140 
141 	list_for_each_entry(i, &dln2->event_cb_list, list) {
142 		if (i->id == id) {
143 			ret = -EBUSY;
144 			break;
145 		}
146 	}
147 
148 	if (!ret)
149 		list_add_rcu(&entry->list, &dln2->event_cb_list);
150 
151 	spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
152 
153 	if (ret)
154 		kfree(entry);
155 
156 	return ret;
157 }
158 EXPORT_SYMBOL(dln2_register_event_cb);
159 
160 void dln2_unregister_event_cb(struct platform_device *pdev, u16 id)
161 {
162 	struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent);
163 	struct dln2_event_cb_entry *i;
164 	unsigned long flags;
165 	bool found = false;
166 
167 	spin_lock_irqsave(&dln2->event_cb_lock, flags);
168 
169 	list_for_each_entry(i, &dln2->event_cb_list, list) {
170 		if (i->id == id) {
171 			list_del_rcu(&i->list);
172 			found = true;
173 			break;
174 		}
175 	}
176 
177 	spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
178 
179 	if (found) {
180 		synchronize_rcu();
181 		kfree(i);
182 	}
183 }
184 EXPORT_SYMBOL(dln2_unregister_event_cb);
185 
186 /*
187  * Returns true if a valid transfer slot is found. In this case the URB must not
188  * be resubmitted immediately in dln2_rx as we need the data when dln2_transfer
189  * is woke up. It will be resubmitted there.
190  */
191 static bool dln2_transfer_complete(struct dln2_dev *dln2, struct urb *urb,
192 				   u16 handle, u16 rx_slot)
193 {
194 	struct device *dev = &dln2->interface->dev;
195 	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
196 	struct dln2_rx_context *rxc;
197 	bool valid_slot = false;
198 
199 	if (rx_slot >= DLN2_MAX_RX_SLOTS)
200 		goto out;
201 
202 	rxc = &rxs->slots[rx_slot];
203 
204 	/*
205 	 * No need to disable interrupts as this lock is not taken in interrupt
206 	 * context elsewhere in this driver. This function (or its callers) are
207 	 * also not exported to other modules.
208 	 */
209 	spin_lock(&rxs->lock);
210 	if (rxc->in_use && !rxc->urb) {
211 		rxc->urb = urb;
212 		complete(&rxc->done);
213 		valid_slot = true;
214 	}
215 	spin_unlock(&rxs->lock);
216 
217 out:
218 	if (!valid_slot)
219 		dev_warn(dev, "bad/late response %d/%d\n", handle, rx_slot);
220 
221 	return valid_slot;
222 }
223 
224 static void dln2_run_event_callbacks(struct dln2_dev *dln2, u16 id, u16 echo,
225 				     void *data, int len)
226 {
227 	struct dln2_event_cb_entry *i;
228 
229 	rcu_read_lock();
230 
231 	list_for_each_entry_rcu(i, &dln2->event_cb_list, list) {
232 		if (i->id == id) {
233 			i->callback(i->pdev, echo, data, len);
234 			break;
235 		}
236 	}
237 
238 	rcu_read_unlock();
239 }
240 
241 static void dln2_rx(struct urb *urb)
242 {
243 	struct dln2_dev *dln2 = urb->context;
244 	struct dln2_header *hdr = urb->transfer_buffer;
245 	struct device *dev = &dln2->interface->dev;
246 	u16 id, echo, handle, size;
247 	u8 *data;
248 	int len;
249 	int err;
250 
251 	switch (urb->status) {
252 	case 0:
253 		/* success */
254 		break;
255 	case -ECONNRESET:
256 	case -ENOENT:
257 	case -ESHUTDOWN:
258 	case -EPIPE:
259 		/* this urb is terminated, clean up */
260 		dev_dbg(dev, "urb shutting down with status %d\n", urb->status);
261 		return;
262 	default:
263 		dev_dbg(dev, "nonzero urb status received %d\n", urb->status);
264 		goto out;
265 	}
266 
267 	if (urb->actual_length < sizeof(struct dln2_header)) {
268 		dev_err(dev, "short response: %d\n", urb->actual_length);
269 		goto out;
270 	}
271 
272 	handle = le16_to_cpu(hdr->handle);
273 	id = le16_to_cpu(hdr->id);
274 	echo = le16_to_cpu(hdr->echo);
275 	size = le16_to_cpu(hdr->size);
276 
277 	if (size != urb->actual_length) {
278 		dev_err(dev, "size mismatch: handle %x cmd %x echo %x size %d actual %d\n",
279 			handle, id, echo, size, urb->actual_length);
280 		goto out;
281 	}
282 
283 	if (handle >= DLN2_HANDLES) {
284 		dev_warn(dev, "invalid handle %d\n", handle);
285 		goto out;
286 	}
287 
288 	data = urb->transfer_buffer + sizeof(struct dln2_header);
289 	len = urb->actual_length - sizeof(struct dln2_header);
290 
291 	if (handle == DLN2_HANDLE_EVENT) {
292 		dln2_run_event_callbacks(dln2, id, echo, data, len);
293 	} else {
294 		/* URB will be re-submitted in _dln2_transfer (free_rx_slot) */
295 		if (dln2_transfer_complete(dln2, urb, handle, echo))
296 			return;
297 	}
298 
299 out:
300 	err = usb_submit_urb(urb, GFP_ATOMIC);
301 	if (err < 0)
302 		dev_err(dev, "failed to resubmit RX URB: %d\n", err);
303 }
304 
305 static void *dln2_prep_buf(u16 handle, u16 cmd, u16 echo, const void *obuf,
306 			   int *obuf_len, gfp_t gfp)
307 {
308 	int len;
309 	void *buf;
310 	struct dln2_header *hdr;
311 
312 	len = *obuf_len + sizeof(*hdr);
313 	buf = kmalloc(len, gfp);
314 	if (!buf)
315 		return NULL;
316 
317 	hdr = (struct dln2_header *)buf;
318 	hdr->id = cpu_to_le16(cmd);
319 	hdr->size = cpu_to_le16(len);
320 	hdr->echo = cpu_to_le16(echo);
321 	hdr->handle = cpu_to_le16(handle);
322 
323 	memcpy(buf + sizeof(*hdr), obuf, *obuf_len);
324 
325 	*obuf_len = len;
326 
327 	return buf;
328 }
329 
330 static int dln2_send_wait(struct dln2_dev *dln2, u16 handle, u16 cmd, u16 echo,
331 			  const void *obuf, int obuf_len)
332 {
333 	int ret = 0;
334 	int len = obuf_len;
335 	void *buf;
336 	int actual;
337 
338 	buf = dln2_prep_buf(handle, cmd, echo, obuf, &len, GFP_KERNEL);
339 	if (!buf)
340 		return -ENOMEM;
341 
342 	ret = usb_bulk_msg(dln2->usb_dev,
343 			   usb_sndbulkpipe(dln2->usb_dev, dln2->ep_out),
344 			   buf, len, &actual, DLN2_USB_TIMEOUT);
345 
346 	kfree(buf);
347 
348 	return ret;
349 }
350 
351 static bool find_free_slot(struct dln2_dev *dln2, u16 handle, int *slot)
352 {
353 	struct dln2_mod_rx_slots *rxs;
354 	unsigned long flags;
355 
356 	if (dln2->disconnect) {
357 		*slot = -ENODEV;
358 		return true;
359 	}
360 
361 	rxs = &dln2->mod_rx_slots[handle];
362 
363 	spin_lock_irqsave(&rxs->lock, flags);
364 
365 	*slot = find_first_zero_bit(rxs->bmap, DLN2_MAX_RX_SLOTS);
366 
367 	if (*slot < DLN2_MAX_RX_SLOTS) {
368 		struct dln2_rx_context *rxc = &rxs->slots[*slot];
369 
370 		set_bit(*slot, rxs->bmap);
371 		rxc->in_use = true;
372 	}
373 
374 	spin_unlock_irqrestore(&rxs->lock, flags);
375 
376 	return *slot < DLN2_MAX_RX_SLOTS;
377 }
378 
379 static int alloc_rx_slot(struct dln2_dev *dln2, u16 handle)
380 {
381 	int ret;
382 	int slot;
383 
384 	/*
385 	 * No need to timeout here, the wait is bounded by the timeout in
386 	 * _dln2_transfer.
387 	 */
388 	ret = wait_event_interruptible(dln2->mod_rx_slots[handle].wq,
389 				       find_free_slot(dln2, handle, &slot));
390 	if (ret < 0)
391 		return ret;
392 
393 	return slot;
394 }
395 
396 static void free_rx_slot(struct dln2_dev *dln2, u16 handle, int slot)
397 {
398 	struct dln2_mod_rx_slots *rxs;
399 	struct urb *urb = NULL;
400 	unsigned long flags;
401 	struct dln2_rx_context *rxc;
402 
403 	rxs = &dln2->mod_rx_slots[handle];
404 
405 	spin_lock_irqsave(&rxs->lock, flags);
406 
407 	clear_bit(slot, rxs->bmap);
408 
409 	rxc = &rxs->slots[slot];
410 	rxc->in_use = false;
411 	urb = rxc->urb;
412 	rxc->urb = NULL;
413 	reinit_completion(&rxc->done);
414 
415 	spin_unlock_irqrestore(&rxs->lock, flags);
416 
417 	if (urb) {
418 		int err;
419 		struct device *dev = &dln2->interface->dev;
420 
421 		err = usb_submit_urb(urb, GFP_KERNEL);
422 		if (err < 0)
423 			dev_err(dev, "failed to resubmit RX URB: %d\n", err);
424 	}
425 
426 	wake_up_interruptible(&rxs->wq);
427 }
428 
429 static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd,
430 			  const void *obuf, unsigned obuf_len,
431 			  void *ibuf, unsigned *ibuf_len)
432 {
433 	int ret = 0;
434 	int rx_slot;
435 	struct dln2_response *rsp;
436 	struct dln2_rx_context *rxc;
437 	struct device *dev = &dln2->interface->dev;
438 	const unsigned long timeout = DLN2_USB_TIMEOUT * HZ / 1000;
439 	struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle];
440 	int size;
441 
442 	spin_lock(&dln2->disconnect_lock);
443 	if (!dln2->disconnect)
444 		dln2->active_transfers++;
445 	else
446 		ret = -ENODEV;
447 	spin_unlock(&dln2->disconnect_lock);
448 
449 	if (ret)
450 		return ret;
451 
452 	rx_slot = alloc_rx_slot(dln2, handle);
453 	if (rx_slot < 0) {
454 		ret = rx_slot;
455 		goto out_decr;
456 	}
457 
458 	ret = dln2_send_wait(dln2, handle, cmd, rx_slot, obuf, obuf_len);
459 	if (ret < 0) {
460 		dev_err(dev, "USB write failed: %d\n", ret);
461 		goto out_free_rx_slot;
462 	}
463 
464 	rxc = &rxs->slots[rx_slot];
465 
466 	ret = wait_for_completion_interruptible_timeout(&rxc->done, timeout);
467 	if (ret <= 0) {
468 		if (!ret)
469 			ret = -ETIMEDOUT;
470 		goto out_free_rx_slot;
471 	} else {
472 		ret = 0;
473 	}
474 
475 	if (dln2->disconnect) {
476 		ret = -ENODEV;
477 		goto out_free_rx_slot;
478 	}
479 
480 	/* if we got here we know that the response header has been checked */
481 	rsp = rxc->urb->transfer_buffer;
482 	size = le16_to_cpu(rsp->hdr.size);
483 
484 	if (size < sizeof(*rsp)) {
485 		ret = -EPROTO;
486 		goto out_free_rx_slot;
487 	}
488 
489 	if (le16_to_cpu(rsp->result) > 0x80) {
490 		dev_dbg(dev, "%d received response with error %d\n",
491 			handle, le16_to_cpu(rsp->result));
492 		ret = -EREMOTEIO;
493 		goto out_free_rx_slot;
494 	}
495 
496 	if (!ibuf)
497 		goto out_free_rx_slot;
498 
499 	if (*ibuf_len > size - sizeof(*rsp))
500 		*ibuf_len = size - sizeof(*rsp);
501 
502 	memcpy(ibuf, rsp + 1, *ibuf_len);
503 
504 out_free_rx_slot:
505 	free_rx_slot(dln2, handle, rx_slot);
506 out_decr:
507 	spin_lock(&dln2->disconnect_lock);
508 	dln2->active_transfers--;
509 	spin_unlock(&dln2->disconnect_lock);
510 	if (dln2->disconnect)
511 		wake_up(&dln2->disconnect_wq);
512 
513 	return ret;
514 }
515 
516 int dln2_transfer(struct platform_device *pdev, u16 cmd,
517 		  const void *obuf, unsigned obuf_len,
518 		  void *ibuf, unsigned *ibuf_len)
519 {
520 	struct dln2_platform_data *dln2_pdata;
521 	struct dln2_dev *dln2;
522 	u16 handle;
523 
524 	dln2 = dev_get_drvdata(pdev->dev.parent);
525 	dln2_pdata = dev_get_platdata(&pdev->dev);
526 	handle = dln2_pdata->handle;
527 
528 	return _dln2_transfer(dln2, handle, cmd, obuf, obuf_len, ibuf,
529 			      ibuf_len);
530 }
531 EXPORT_SYMBOL(dln2_transfer);
532 
533 static int dln2_check_hw(struct dln2_dev *dln2)
534 {
535 	int ret;
536 	__le32 hw_type;
537 	int len = sizeof(hw_type);
538 
539 	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_VER,
540 			     NULL, 0, &hw_type, &len);
541 	if (ret < 0)
542 		return ret;
543 	if (len < sizeof(hw_type))
544 		return -EREMOTEIO;
545 
546 	if (le32_to_cpu(hw_type) != DLN2_HW_ID) {
547 		dev_err(&dln2->interface->dev, "Device ID 0x%x not supported\n",
548 			le32_to_cpu(hw_type));
549 		return -ENODEV;
550 	}
551 
552 	return 0;
553 }
554 
555 static int dln2_print_serialno(struct dln2_dev *dln2)
556 {
557 	int ret;
558 	__le32 serial_no;
559 	int len = sizeof(serial_no);
560 	struct device *dev = &dln2->interface->dev;
561 
562 	ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_SN, NULL, 0,
563 			     &serial_no, &len);
564 	if (ret < 0)
565 		return ret;
566 	if (len < sizeof(serial_no))
567 		return -EREMOTEIO;
568 
569 	dev_info(dev, "Diolan DLN2 serial %u\n", le32_to_cpu(serial_no));
570 
571 	return 0;
572 }
573 
574 static int dln2_hw_init(struct dln2_dev *dln2)
575 {
576 	int ret;
577 
578 	ret = dln2_check_hw(dln2);
579 	if (ret < 0)
580 		return ret;
581 
582 	return dln2_print_serialno(dln2);
583 }
584 
585 static void dln2_free_rx_urbs(struct dln2_dev *dln2)
586 {
587 	int i;
588 
589 	for (i = 0; i < DLN2_MAX_URBS; i++) {
590 		usb_kill_urb(dln2->rx_urb[i]);
591 		usb_free_urb(dln2->rx_urb[i]);
592 		kfree(dln2->rx_buf[i]);
593 	}
594 }
595 
596 static void dln2_free(struct dln2_dev *dln2)
597 {
598 	dln2_free_rx_urbs(dln2);
599 	usb_put_dev(dln2->usb_dev);
600 	kfree(dln2);
601 }
602 
603 static int dln2_setup_rx_urbs(struct dln2_dev *dln2,
604 			      struct usb_host_interface *hostif)
605 {
606 	int i;
607 	int ret;
608 	const int rx_max_size = DLN2_RX_BUF_SIZE;
609 	struct device *dev = &dln2->interface->dev;
610 
611 	for (i = 0; i < DLN2_MAX_URBS; i++) {
612 		dln2->rx_buf[i] = kmalloc(rx_max_size, GFP_KERNEL);
613 		if (!dln2->rx_buf[i])
614 			return -ENOMEM;
615 
616 		dln2->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL);
617 		if (!dln2->rx_urb[i])
618 			return -ENOMEM;
619 
620 		usb_fill_bulk_urb(dln2->rx_urb[i], dln2->usb_dev,
621 				  usb_rcvbulkpipe(dln2->usb_dev, dln2->ep_in),
622 				  dln2->rx_buf[i], rx_max_size, dln2_rx, dln2);
623 
624 		ret = usb_submit_urb(dln2->rx_urb[i], GFP_KERNEL);
625 		if (ret < 0) {
626 			dev_err(dev, "failed to submit RX URB: %d\n", ret);
627 			return ret;
628 		}
629 	}
630 
631 	return 0;
632 }
633 
634 static struct dln2_platform_data dln2_pdata_gpio = {
635 	.handle = DLN2_HANDLE_GPIO,
636 };
637 
638 /* Only one I2C port seems to be supported on current hardware */
639 static struct dln2_platform_data dln2_pdata_i2c = {
640 	.handle = DLN2_HANDLE_I2C,
641 	.port = 0,
642 };
643 
644 /* Only one SPI port supported */
645 static struct dln2_platform_data dln2_pdata_spi = {
646 	.handle = DLN2_HANDLE_SPI,
647 	.port = 0,
648 };
649 
650 static const struct mfd_cell dln2_devs[] = {
651 	{
652 		.name = "dln2-gpio",
653 		.platform_data = &dln2_pdata_gpio,
654 		.pdata_size = sizeof(struct dln2_platform_data),
655 	},
656 	{
657 		.name = "dln2-i2c",
658 		.platform_data = &dln2_pdata_i2c,
659 		.pdata_size = sizeof(struct dln2_platform_data),
660 	},
661 	{
662 		.name = "dln2-spi",
663 		.platform_data = &dln2_pdata_spi,
664 		.pdata_size = sizeof(struct dln2_platform_data),
665 	},
666 };
667 
668 static void dln2_disconnect(struct usb_interface *interface)
669 {
670 	struct dln2_dev *dln2 = usb_get_intfdata(interface);
671 	int i, j;
672 
673 	/* don't allow starting new transfers */
674 	spin_lock(&dln2->disconnect_lock);
675 	dln2->disconnect = true;
676 	spin_unlock(&dln2->disconnect_lock);
677 
678 	/* cancel in progress transfers */
679 	for (i = 0; i < DLN2_HANDLES; i++) {
680 		struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[i];
681 		unsigned long flags;
682 
683 		spin_lock_irqsave(&rxs->lock, flags);
684 
685 		/* cancel all response waiters */
686 		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++) {
687 			struct dln2_rx_context *rxc = &rxs->slots[j];
688 
689 			if (rxc->in_use)
690 				complete(&rxc->done);
691 		}
692 
693 		spin_unlock_irqrestore(&rxs->lock, flags);
694 	}
695 
696 	/* wait for transfers to end */
697 	wait_event(dln2->disconnect_wq, !dln2->active_transfers);
698 
699 	mfd_remove_devices(&interface->dev);
700 
701 	dln2_free(dln2);
702 }
703 
704 static int dln2_probe(struct usb_interface *interface,
705 		      const struct usb_device_id *usb_id)
706 {
707 	struct usb_host_interface *hostif = interface->cur_altsetting;
708 	struct device *dev = &interface->dev;
709 	struct dln2_dev *dln2;
710 	int ret;
711 	int i, j;
712 
713 	if (hostif->desc.bInterfaceNumber != 0 ||
714 	    hostif->desc.bNumEndpoints < 2)
715 		return -ENODEV;
716 
717 	dln2 = kzalloc(sizeof(*dln2), GFP_KERNEL);
718 	if (!dln2)
719 		return -ENOMEM;
720 
721 	dln2->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
722 	dln2->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
723 	dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface));
724 	dln2->interface = interface;
725 	usb_set_intfdata(interface, dln2);
726 	init_waitqueue_head(&dln2->disconnect_wq);
727 
728 	for (i = 0; i < DLN2_HANDLES; i++) {
729 		init_waitqueue_head(&dln2->mod_rx_slots[i].wq);
730 		spin_lock_init(&dln2->mod_rx_slots[i].lock);
731 		for (j = 0; j < DLN2_MAX_RX_SLOTS; j++)
732 			init_completion(&dln2->mod_rx_slots[i].slots[j].done);
733 	}
734 
735 	spin_lock_init(&dln2->event_cb_lock);
736 	spin_lock_init(&dln2->disconnect_lock);
737 	INIT_LIST_HEAD(&dln2->event_cb_list);
738 
739 	ret = dln2_setup_rx_urbs(dln2, hostif);
740 	if (ret)
741 		goto out_cleanup;
742 
743 	ret = dln2_hw_init(dln2);
744 	if (ret < 0) {
745 		dev_err(dev, "failed to initialize hardware\n");
746 		goto out_cleanup;
747 	}
748 
749 	ret = mfd_add_hotplug_devices(dev, dln2_devs, ARRAY_SIZE(dln2_devs));
750 	if (ret != 0) {
751 		dev_err(dev, "failed to add mfd devices to core\n");
752 		goto out_cleanup;
753 	}
754 
755 	return 0;
756 
757 out_cleanup:
758 	dln2_free(dln2);
759 
760 	return ret;
761 }
762 
763 static const struct usb_device_id dln2_table[] = {
764 	{ USB_DEVICE(0xa257, 0x2013) },
765 	{ }
766 };
767 
768 MODULE_DEVICE_TABLE(usb, dln2_table);
769 
770 static struct usb_driver dln2_driver = {
771 	.name = "dln2",
772 	.probe = dln2_probe,
773 	.disconnect = dln2_disconnect,
774 	.id_table = dln2_table,
775 };
776 
777 module_usb_driver(dln2_driver);
778 
779 MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
780 MODULE_DESCRIPTION("Core driver for the Diolan DLN2 interface adapter");
781 MODULE_LICENSE("GPL v2");
782