xref: /linux/drivers/nfc/st21nfca/i2c.c (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
1 /*
2  * I2C Link Layer for ST21NFCA HCI based Driver
3  * Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19 
20 #include <linux/crc-ccitt.h>
21 #include <linux/module.h>
22 #include <linux/i2c.h>
23 #include <linux/gpio.h>
24 #include <linux/of_irq.h>
25 #include <linux/of_gpio.h>
26 #include <linux/miscdevice.h>
27 #include <linux/interrupt.h>
28 #include <linux/delay.h>
29 #include <linux/nfc.h>
30 #include <linux/firmware.h>
31 #include <linux/platform_data/st21nfca.h>
32 #include <asm/unaligned.h>
33 
34 #include <net/nfc/hci.h>
35 #include <net/nfc/llc.h>
36 #include <net/nfc/nfc.h>
37 
38 #include "st21nfca.h"
39 
40 /*
41  * Every frame starts with ST21NFCA_SOF_EOF and ends with ST21NFCA_SOF_EOF.
42  * Because ST21NFCA_SOF_EOF is a possible data value, there is a mecanism
43  * called byte stuffing has been introduced.
44  *
45  * if byte == ST21NFCA_SOF_EOF or ST21NFCA_ESCAPE_BYTE_STUFFING
46  * - insert ST21NFCA_ESCAPE_BYTE_STUFFING (escape byte)
47  * - xor byte with ST21NFCA_BYTE_STUFFING_MASK
48  */
49 #define ST21NFCA_SOF_EOF		0x7e
50 #define ST21NFCA_BYTE_STUFFING_MASK	0x20
51 #define ST21NFCA_ESCAPE_BYTE_STUFFING	0x7d
52 
53 /* SOF + 00 */
54 #define ST21NFCA_FRAME_HEADROOM			2
55 
56 /* 2 bytes crc + EOF */
57 #define ST21NFCA_FRAME_TAILROOM 3
58 #define IS_START_OF_FRAME(buf) (buf[0] == ST21NFCA_SOF_EOF && \
59 				buf[1] == 0)
60 
61 #define ST21NFCA_HCI_I2C_DRIVER_NAME "st21nfca_hci_i2c"
62 
63 static struct i2c_device_id st21nfca_hci_i2c_id_table[] = {
64 	{ST21NFCA_HCI_DRIVER_NAME, 0},
65 	{}
66 };
67 
68 MODULE_DEVICE_TABLE(i2c, st21nfca_hci_i2c_id_table);
69 
70 struct st21nfca_i2c_phy {
71 	struct i2c_client *i2c_dev;
72 	struct nfc_hci_dev *hdev;
73 
74 	unsigned int gpio_ena;
75 	unsigned int irq_polarity;
76 
77 	struct st21nfca_se_status se_status;
78 
79 	struct sk_buff *pending_skb;
80 	int current_read_len;
81 	/*
82 	 * crc might have fail because i2c macro
83 	 * is disable due to other interface activity
84 	 */
85 	int crc_trials;
86 
87 	int powered;
88 	int run_mode;
89 
90 	/*
91 	 * < 0 if hardware error occured (e.g. i2c err)
92 	 * and prevents normal operation.
93 	 */
94 	int hard_fault;
95 	struct mutex phy_lock;
96 };
97 static u8 len_seq[] = { 16, 24, 12, 29 };
98 static u16 wait_tab[] = { 2, 3, 5, 15, 20, 40};
99 
100 #define I2C_DUMP_SKB(info, skb)					\
101 do {								\
102 	pr_debug("%s:\n", info);				\
103 	print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET,	\
104 		       16, 1, (skb)->data, (skb)->len, 0);	\
105 } while (0)
106 
107 /*
108  * In order to get the CLF in a known state we generate an internal reboot
109  * using a proprietary command.
110  * Once the reboot is completed, we expect to receive a ST21NFCA_SOF_EOF
111  * fill buffer.
112  */
113 static int st21nfca_hci_platform_init(struct st21nfca_i2c_phy *phy)
114 {
115 	u16 wait_reboot[] = { 50, 300, 1000 };
116 	char reboot_cmd[] = { 0x7E, 0x66, 0x48, 0xF6, 0x7E };
117 	u8 tmp[ST21NFCA_HCI_LLC_MAX_SIZE];
118 	int i, r = -1;
119 
120 	for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++) {
121 		r = i2c_master_send(phy->i2c_dev, reboot_cmd,
122 				    sizeof(reboot_cmd));
123 		if (r < 0)
124 			msleep(wait_reboot[i]);
125 	}
126 	if (r < 0)
127 		return r;
128 
129 	/* CLF is spending about 20ms to do an internal reboot */
130 	msleep(20);
131 	r = -1;
132 	for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++) {
133 		r = i2c_master_recv(phy->i2c_dev, tmp,
134 				    ST21NFCA_HCI_LLC_MAX_SIZE);
135 		if (r < 0)
136 			msleep(wait_reboot[i]);
137 	}
138 	if (r < 0)
139 		return r;
140 
141 	for (i = 0; i < ST21NFCA_HCI_LLC_MAX_SIZE &&
142 		tmp[i] == ST21NFCA_SOF_EOF; i++)
143 		;
144 
145 	if (r != ST21NFCA_HCI_LLC_MAX_SIZE)
146 		return -ENODEV;
147 
148 	usleep_range(1000, 1500);
149 	return 0;
150 }
151 
152 static int st21nfca_hci_i2c_enable(void *phy_id)
153 {
154 	struct st21nfca_i2c_phy *phy = phy_id;
155 
156 	gpio_set_value(phy->gpio_ena, 1);
157 	phy->powered = 1;
158 	phy->run_mode = ST21NFCA_HCI_MODE;
159 
160 	usleep_range(10000, 15000);
161 
162 	return 0;
163 }
164 
165 static void st21nfca_hci_i2c_disable(void *phy_id)
166 {
167 	struct st21nfca_i2c_phy *phy = phy_id;
168 
169 	pr_info("\n");
170 	gpio_set_value(phy->gpio_ena, 0);
171 
172 	phy->powered = 0;
173 }
174 
175 static void st21nfca_hci_add_len_crc(struct sk_buff *skb)
176 {
177 	u16 crc;
178 	u8 tmp;
179 
180 	*skb_push(skb, 1) = 0;
181 
182 	crc = crc_ccitt(0xffff, skb->data, skb->len);
183 	crc = ~crc;
184 
185 	tmp = crc & 0x00ff;
186 	*skb_put(skb, 1) = tmp;
187 
188 	tmp = (crc >> 8) & 0x00ff;
189 	*skb_put(skb, 1) = tmp;
190 }
191 
192 static void st21nfca_hci_remove_len_crc(struct sk_buff *skb)
193 {
194 	skb_pull(skb, ST21NFCA_FRAME_HEADROOM);
195 	skb_trim(skb, skb->len - ST21NFCA_FRAME_TAILROOM);
196 }
197 
198 /*
199  * Writing a frame must not return the number of written bytes.
200  * It must return either zero for success, or <0 for error.
201  * In addition, it must not alter the skb
202  */
203 static int st21nfca_hci_i2c_write(void *phy_id, struct sk_buff *skb)
204 {
205 	int r = -1, i, j;
206 	struct st21nfca_i2c_phy *phy = phy_id;
207 	struct i2c_client *client = phy->i2c_dev;
208 	u8 tmp[ST21NFCA_HCI_LLC_MAX_SIZE * 2];
209 
210 	I2C_DUMP_SKB("st21nfca_hci_i2c_write", skb);
211 
212 
213 	if (phy->hard_fault != 0)
214 		return phy->hard_fault;
215 
216 	/*
217 	 * Compute CRC before byte stuffing computation on frame
218 	 * Note st21nfca_hci_add_len_crc is doing a byte stuffing
219 	 * on its own value
220 	 */
221 	st21nfca_hci_add_len_crc(skb);
222 
223 	/* add ST21NFCA_SOF_EOF on tail */
224 	*skb_put(skb, 1) = ST21NFCA_SOF_EOF;
225 	/* add ST21NFCA_SOF_EOF on head */
226 	*skb_push(skb, 1) = ST21NFCA_SOF_EOF;
227 
228 	/*
229 	 * Compute byte stuffing
230 	 * if byte == ST21NFCA_SOF_EOF or ST21NFCA_ESCAPE_BYTE_STUFFING
231 	 * insert ST21NFCA_ESCAPE_BYTE_STUFFING (escape byte)
232 	 * xor byte with ST21NFCA_BYTE_STUFFING_MASK
233 	 */
234 	tmp[0] = skb->data[0];
235 	for (i = 1, j = 1; i < skb->len - 1; i++, j++) {
236 		if (skb->data[i] == ST21NFCA_SOF_EOF
237 		    || skb->data[i] == ST21NFCA_ESCAPE_BYTE_STUFFING) {
238 			tmp[j] = ST21NFCA_ESCAPE_BYTE_STUFFING;
239 			j++;
240 			tmp[j] = skb->data[i] ^ ST21NFCA_BYTE_STUFFING_MASK;
241 		} else {
242 			tmp[j] = skb->data[i];
243 		}
244 	}
245 	tmp[j] = skb->data[i];
246 	j++;
247 
248 	/*
249 	 * Manage sleep mode
250 	 * Try 3 times to send data with delay between each
251 	 */
252 	mutex_lock(&phy->phy_lock);
253 	for (i = 0; i < ARRAY_SIZE(wait_tab) && r < 0; i++) {
254 		r = i2c_master_send(client, tmp, j);
255 		if (r < 0)
256 			msleep(wait_tab[i]);
257 	}
258 	mutex_unlock(&phy->phy_lock);
259 
260 	if (r >= 0) {
261 		if (r != j)
262 			r = -EREMOTEIO;
263 		else
264 			r = 0;
265 	}
266 
267 	st21nfca_hci_remove_len_crc(skb);
268 
269 	return r;
270 }
271 
272 static int get_frame_size(u8 *buf, int buflen)
273 {
274 	int len = 0;
275 
276 	if (buf[len + 1] == ST21NFCA_SOF_EOF)
277 		return 0;
278 
279 	for (len = 1; len < buflen && buf[len] != ST21NFCA_SOF_EOF; len++)
280 		;
281 
282 	return len;
283 }
284 
285 static int check_crc(u8 *buf, int buflen)
286 {
287 	u16 crc;
288 
289 	crc = crc_ccitt(0xffff, buf, buflen - 2);
290 	crc = ~crc;
291 
292 	if (buf[buflen - 2] != (crc & 0xff) || buf[buflen - 1] != (crc >> 8)) {
293 		pr_err(ST21NFCA_HCI_DRIVER_NAME
294 		       ": CRC error 0x%x != 0x%x 0x%x\n", crc, buf[buflen - 1],
295 		       buf[buflen - 2]);
296 
297 		pr_info(DRIVER_DESC ": %s : BAD CRC\n", __func__);
298 		print_hex_dump(KERN_DEBUG, "crc: ", DUMP_PREFIX_NONE,
299 			       16, 2, buf, buflen, false);
300 		return -EPERM;
301 	}
302 	return 0;
303 }
304 
305 /*
306  * Prepare received data for upper layer.
307  * Received data include byte stuffing, crc and sof/eof
308  * which is not usable by hci part.
309  * returns:
310  * frame size without sof/eof, header and byte stuffing
311  * -EBADMSG : frame was incorrect and discarded
312  */
313 static int st21nfca_hci_i2c_repack(struct sk_buff *skb)
314 {
315 	int i, j, r, size;
316 
317 	if (skb->len < 1 || (skb->len > 1 && skb->data[1] != 0))
318 		return -EBADMSG;
319 
320 	size = get_frame_size(skb->data, skb->len);
321 	if (size > 0) {
322 		skb_trim(skb, size);
323 		/* remove ST21NFCA byte stuffing for upper layer */
324 		for (i = 1, j = 0; i < skb->len; i++) {
325 			if (skb->data[i + j] ==
326 					(u8) ST21NFCA_ESCAPE_BYTE_STUFFING) {
327 				skb->data[i] = skb->data[i + j + 1]
328 						| ST21NFCA_BYTE_STUFFING_MASK;
329 				i++;
330 				j++;
331 			}
332 			skb->data[i] = skb->data[i + j];
333 		}
334 		/* remove byte stuffing useless byte */
335 		skb_trim(skb, i - j);
336 		/* remove ST21NFCA_SOF_EOF from head */
337 		skb_pull(skb, 1);
338 
339 		r = check_crc(skb->data, skb->len);
340 		if (r != 0) {
341 			i = 0;
342 			return -EBADMSG;
343 		}
344 
345 		/* remove headbyte */
346 		skb_pull(skb, 1);
347 		/* remove crc. Byte Stuffing is already removed here */
348 		skb_trim(skb, skb->len - 2);
349 		return skb->len;
350 	}
351 	return 0;
352 }
353 
354 /*
355  * Reads an shdlc frame and returns it in a newly allocated sk_buff. Guarantees
356  * that i2c bus will be flushed and that next read will start on a new frame.
357  * returned skb contains only LLC header and payload.
358  * returns:
359  * frame size : if received frame is complete (find ST21NFCA_SOF_EOF at
360  * end of read)
361  * -EAGAIN : if received frame is incomplete (not find ST21NFCA_SOF_EOF
362  * at end of read)
363  * -EREMOTEIO : i2c read error (fatal)
364  * -EBADMSG : frame was incorrect and discarded
365  * (value returned from st21nfca_hci_i2c_repack)
366  * -EIO : if no ST21NFCA_SOF_EOF is found after reaching
367  * the read length end sequence
368  */
369 static int st21nfca_hci_i2c_read(struct st21nfca_i2c_phy *phy,
370 				 struct sk_buff *skb)
371 {
372 	int r, i;
373 	u8 len;
374 	u8 buf[ST21NFCA_HCI_LLC_MAX_PAYLOAD];
375 	struct i2c_client *client = phy->i2c_dev;
376 
377 	if (phy->current_read_len < ARRAY_SIZE(len_seq)) {
378 		len = len_seq[phy->current_read_len];
379 
380 		/*
381 		 * Add retry mecanism
382 		 * Operation on I2C interface may fail in case of operation on
383 		 * RF or SWP interface
384 		 */
385 		r = 0;
386 		mutex_lock(&phy->phy_lock);
387 		for (i = 0; i < ARRAY_SIZE(wait_tab) && r <= 0; i++) {
388 			r = i2c_master_recv(client, buf, len);
389 			if (r < 0)
390 				msleep(wait_tab[i]);
391 		}
392 		mutex_unlock(&phy->phy_lock);
393 
394 		if (r != len) {
395 			phy->current_read_len = 0;
396 			return -EREMOTEIO;
397 		}
398 
399 		/*
400 		 * The first read sequence does not start with SOF.
401 		 * Data is corrupeted so we drop it.
402 		 */
403 		if (!phy->current_read_len && !IS_START_OF_FRAME(buf)) {
404 			skb_trim(skb, 0);
405 			phy->current_read_len = 0;
406 			return -EIO;
407 		} else if (phy->current_read_len && IS_START_OF_FRAME(buf)) {
408 			/*
409 			 * Previous frame transmission was interrupted and
410 			 * the frame got repeated.
411 			 * Received frame start with ST21NFCA_SOF_EOF + 00.
412 			 */
413 			skb_trim(skb, 0);
414 			phy->current_read_len = 0;
415 		}
416 
417 		memcpy(skb_put(skb, len), buf, len);
418 
419 		if (skb->data[skb->len - 1] == ST21NFCA_SOF_EOF) {
420 			phy->current_read_len = 0;
421 			return st21nfca_hci_i2c_repack(skb);
422 		}
423 		phy->current_read_len++;
424 		return -EAGAIN;
425 	}
426 	return -EIO;
427 }
428 
429 /*
430  * Reads an shdlc frame from the chip. This is not as straightforward as it
431  * seems. The frame format is data-crc, and corruption can occur anywhere
432  * while transiting on i2c bus, such that we could read an invalid data.
433  * The tricky case is when we read a corrupted data or crc. We must detect
434  * this here in order to determine that data can be transmitted to the hci
435  * core. This is the reason why we check the crc here.
436  * The CLF will repeat a frame until we send a RR on that frame.
437  *
438  * On ST21NFCA, IRQ goes in idle when read starts. As no size information are
439  * available in the incoming data, other IRQ might come. Every IRQ will trigger
440  * a read sequence with different length and will fill the current frame.
441  * The reception is complete once we reach a ST21NFCA_SOF_EOF.
442  */
443 static irqreturn_t st21nfca_hci_irq_thread_fn(int irq, void *phy_id)
444 {
445 	struct st21nfca_i2c_phy *phy = phy_id;
446 	struct i2c_client *client;
447 
448 	int r;
449 
450 	if (!phy || irq != phy->i2c_dev->irq) {
451 		WARN_ON_ONCE(1);
452 		return IRQ_NONE;
453 	}
454 
455 	client = phy->i2c_dev;
456 	dev_dbg(&client->dev, "IRQ\n");
457 
458 	if (phy->hard_fault != 0)
459 		return IRQ_HANDLED;
460 
461 	r = st21nfca_hci_i2c_read(phy, phy->pending_skb);
462 	if (r == -EREMOTEIO) {
463 		phy->hard_fault = r;
464 
465 		nfc_hci_recv_frame(phy->hdev, NULL);
466 
467 		return IRQ_HANDLED;
468 	} else if (r == -EAGAIN || r == -EIO) {
469 		return IRQ_HANDLED;
470 	} else if (r == -EBADMSG && phy->crc_trials < ARRAY_SIZE(wait_tab)) {
471 		/*
472 		 * With ST21NFCA, only one interface (I2C, RF or SWP)
473 		 * may be active at a time.
474 		 * Having incorrect crc is usually due to i2c macrocell
475 		 * deactivation in the middle of a transmission.
476 		 * It may generate corrupted data on i2c.
477 		 * We give sometime to get i2c back.
478 		 * The complete frame will be repeated.
479 		 */
480 		msleep(wait_tab[phy->crc_trials]);
481 		phy->crc_trials++;
482 		phy->current_read_len = 0;
483 		kfree_skb(phy->pending_skb);
484 	} else if (r > 0) {
485 		/*
486 		 * We succeeded to read data from the CLF and
487 		 * data is valid.
488 		 * Reset counter.
489 		 */
490 		nfc_hci_recv_frame(phy->hdev, phy->pending_skb);
491 		phy->crc_trials = 0;
492 	} else {
493 		kfree_skb(phy->pending_skb);
494 	}
495 
496 	phy->pending_skb = alloc_skb(ST21NFCA_HCI_LLC_MAX_SIZE * 2, GFP_KERNEL);
497 	if (phy->pending_skb == NULL) {
498 		phy->hard_fault = -ENOMEM;
499 		nfc_hci_recv_frame(phy->hdev, NULL);
500 	}
501 
502 	return IRQ_HANDLED;
503 }
504 
505 static struct nfc_phy_ops i2c_phy_ops = {
506 	.write = st21nfca_hci_i2c_write,
507 	.enable = st21nfca_hci_i2c_enable,
508 	.disable = st21nfca_hci_i2c_disable,
509 };
510 
511 #ifdef CONFIG_OF
512 static int st21nfca_hci_i2c_of_request_resources(struct i2c_client *client)
513 {
514 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
515 	struct device_node *pp;
516 	int gpio;
517 	int r;
518 
519 	pp = client->dev.of_node;
520 	if (!pp)
521 		return -ENODEV;
522 
523 	/* Get GPIO from device tree */
524 	gpio = of_get_named_gpio(pp, "enable-gpios", 0);
525 	if (gpio < 0) {
526 		nfc_err(&client->dev, "Failed to retrieve enable-gpios from device tree\n");
527 		return gpio;
528 	}
529 
530 	/* GPIO request and configuration */
531 	r = devm_gpio_request_one(&client->dev, gpio, GPIOF_OUT_INIT_HIGH,
532 				  "clf_enable");
533 	if (r) {
534 		nfc_err(&client->dev, "Failed to request enable pin\n");
535 		return r;
536 	}
537 
538 	phy->gpio_ena = gpio;
539 
540 	phy->irq_polarity = irq_get_trigger_type(client->irq);
541 
542 	phy->se_status.is_ese_present =
543 				of_property_read_bool(pp, "ese-present");
544 	phy->se_status.is_uicc_present =
545 				of_property_read_bool(pp, "uicc-present");
546 
547 	return 0;
548 }
549 #else
550 static int st21nfca_hci_i2c_of_request_resources(struct i2c_client *client)
551 {
552 	return -ENODEV;
553 }
554 #endif
555 
556 static int st21nfca_hci_i2c_request_resources(struct i2c_client *client)
557 {
558 	struct st21nfca_nfc_platform_data *pdata;
559 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
560 	int r;
561 
562 	pdata = client->dev.platform_data;
563 	if (pdata == NULL) {
564 		nfc_err(&client->dev, "No platform data\n");
565 		return -EINVAL;
566 	}
567 
568 	/* store for later use */
569 	phy->gpio_ena = pdata->gpio_ena;
570 	phy->irq_polarity = pdata->irq_polarity;
571 
572 	if (phy->gpio_ena > 0) {
573 		r = devm_gpio_request_one(&client->dev, phy->gpio_ena,
574 					  GPIOF_OUT_INIT_HIGH, "clf_enable");
575 		if (r) {
576 			pr_err("%s : ena gpio_request failed\n", __FILE__);
577 			return r;
578 		}
579 	}
580 
581 	phy->se_status.is_ese_present = pdata->is_ese_present;
582 	phy->se_status.is_uicc_present = pdata->is_uicc_present;
583 
584 	return 0;
585 }
586 
587 static int st21nfca_hci_i2c_probe(struct i2c_client *client,
588 				  const struct i2c_device_id *id)
589 {
590 	struct st21nfca_i2c_phy *phy;
591 	struct st21nfca_nfc_platform_data *pdata;
592 	int r;
593 
594 	dev_dbg(&client->dev, "%s\n", __func__);
595 	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
596 
597 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
598 		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
599 		return -ENODEV;
600 	}
601 
602 	phy = devm_kzalloc(&client->dev, sizeof(struct st21nfca_i2c_phy),
603 			   GFP_KERNEL);
604 	if (!phy)
605 		return -ENOMEM;
606 
607 	phy->i2c_dev = client;
608 	phy->pending_skb = alloc_skb(ST21NFCA_HCI_LLC_MAX_SIZE * 2, GFP_KERNEL);
609 	if (phy->pending_skb == NULL)
610 		return -ENOMEM;
611 
612 	phy->current_read_len = 0;
613 	phy->crc_trials = 0;
614 	mutex_init(&phy->phy_lock);
615 	i2c_set_clientdata(client, phy);
616 
617 	pdata = client->dev.platform_data;
618 	if (!pdata && client->dev.of_node) {
619 		r = st21nfca_hci_i2c_of_request_resources(client);
620 		if (r) {
621 			nfc_err(&client->dev, "No platform data\n");
622 			return r;
623 		}
624 	} else if (pdata) {
625 		r = st21nfca_hci_i2c_request_resources(client);
626 		if (r) {
627 			nfc_err(&client->dev, "Cannot get platform resources\n");
628 			return r;
629 		}
630 	} else {
631 		nfc_err(&client->dev, "st21nfca platform resources not available\n");
632 		return -ENODEV;
633 	}
634 
635 	r = st21nfca_hci_platform_init(phy);
636 	if (r < 0) {
637 		nfc_err(&client->dev, "Unable to reboot st21nfca\n");
638 		return r;
639 	}
640 
641 	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
642 				st21nfca_hci_irq_thread_fn,
643 				phy->irq_polarity | IRQF_ONESHOT,
644 				ST21NFCA_HCI_DRIVER_NAME, phy);
645 	if (r < 0) {
646 		nfc_err(&client->dev, "Unable to register IRQ handler\n");
647 		return r;
648 	}
649 
650 	return st21nfca_hci_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
651 					ST21NFCA_FRAME_HEADROOM,
652 					ST21NFCA_FRAME_TAILROOM,
653 					ST21NFCA_HCI_LLC_MAX_PAYLOAD,
654 					&phy->hdev,
655 					&phy->se_status);
656 }
657 
658 static int st21nfca_hci_i2c_remove(struct i2c_client *client)
659 {
660 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
661 
662 	dev_dbg(&client->dev, "%s\n", __func__);
663 
664 	st21nfca_hci_remove(phy->hdev);
665 
666 	if (phy->powered)
667 		st21nfca_hci_i2c_disable(phy);
668 
669 	return 0;
670 }
671 
672 #ifdef CONFIG_OF
673 static const struct of_device_id of_st21nfca_i2c_match[] = {
674 	{ .compatible = "st,st21nfca-i2c", },
675 	{ .compatible = "st,st21nfca_i2c", },
676 	{}
677 };
678 MODULE_DEVICE_TABLE(of, of_st21nfca_i2c_match);
679 #endif
680 
681 static struct i2c_driver st21nfca_hci_i2c_driver = {
682 	.driver = {
683 		.owner = THIS_MODULE,
684 		.name = ST21NFCA_HCI_I2C_DRIVER_NAME,
685 		.of_match_table = of_match_ptr(of_st21nfca_i2c_match),
686 	},
687 	.probe = st21nfca_hci_i2c_probe,
688 	.id_table = st21nfca_hci_i2c_id_table,
689 	.remove = st21nfca_hci_i2c_remove,
690 };
691 
692 module_i2c_driver(st21nfca_hci_i2c_driver);
693 
694 MODULE_LICENSE("GPL");
695 MODULE_DESCRIPTION(DRIVER_DESC);
696