xref: /openbmc/linux/drivers/nfc/st21nfca/i2c.c (revision 0f4630f3)
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 
98 static u8 len_seq[] = { 16, 24, 12, 29 };
99 static u16 wait_tab[] = { 2, 3, 5, 15, 20, 40};
100 
101 #define I2C_DUMP_SKB(info, skb)					\
102 do {								\
103 	pr_debug("%s:\n", info);				\
104 	print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET,	\
105 		       16, 1, (skb)->data, (skb)->len, 0);	\
106 } while (0)
107 
108 /*
109  * In order to get the CLF in a known state we generate an internal reboot
110  * using a proprietary command.
111  * Once the reboot is completed, we expect to receive a ST21NFCA_SOF_EOF
112  * fill buffer.
113  */
114 static int st21nfca_hci_platform_init(struct st21nfca_i2c_phy *phy)
115 {
116 	u16 wait_reboot[] = { 50, 300, 1000 };
117 	char reboot_cmd[] = { 0x7E, 0x66, 0x48, 0xF6, 0x7E };
118 	u8 tmp[ST21NFCA_HCI_LLC_MAX_SIZE];
119 	int i, r = -1;
120 
121 	for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++) {
122 		r = i2c_master_send(phy->i2c_dev, reboot_cmd,
123 				    sizeof(reboot_cmd));
124 		if (r < 0)
125 			msleep(wait_reboot[i]);
126 	}
127 	if (r < 0)
128 		return r;
129 
130 	/* CLF is spending about 20ms to do an internal reboot */
131 	msleep(20);
132 	r = -1;
133 	for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++) {
134 		r = i2c_master_recv(phy->i2c_dev, tmp,
135 				    ST21NFCA_HCI_LLC_MAX_SIZE);
136 		if (r < 0)
137 			msleep(wait_reboot[i]);
138 	}
139 	if (r < 0)
140 		return r;
141 
142 	for (i = 0; i < ST21NFCA_HCI_LLC_MAX_SIZE &&
143 		tmp[i] == ST21NFCA_SOF_EOF; i++)
144 		;
145 
146 	if (r != ST21NFCA_HCI_LLC_MAX_SIZE)
147 		return -ENODEV;
148 
149 	usleep_range(1000, 1500);
150 	return 0;
151 }
152 
153 static int st21nfca_hci_i2c_enable(void *phy_id)
154 {
155 	struct st21nfca_i2c_phy *phy = phy_id;
156 
157 	gpio_set_value(phy->gpio_ena, 1);
158 	phy->powered = 1;
159 	phy->run_mode = ST21NFCA_HCI_MODE;
160 
161 	usleep_range(10000, 15000);
162 
163 	return 0;
164 }
165 
166 static void st21nfca_hci_i2c_disable(void *phy_id)
167 {
168 	struct st21nfca_i2c_phy *phy = phy_id;
169 
170 	pr_info("\n");
171 	gpio_set_value(phy->gpio_ena, 0);
172 
173 	phy->powered = 0;
174 }
175 
176 static void st21nfca_hci_add_len_crc(struct sk_buff *skb)
177 {
178 	u16 crc;
179 	u8 tmp;
180 
181 	*skb_push(skb, 1) = 0;
182 
183 	crc = crc_ccitt(0xffff, skb->data, skb->len);
184 	crc = ~crc;
185 
186 	tmp = crc & 0x00ff;
187 	*skb_put(skb, 1) = tmp;
188 
189 	tmp = (crc >> 8) & 0x00ff;
190 	*skb_put(skb, 1) = tmp;
191 }
192 
193 static void st21nfca_hci_remove_len_crc(struct sk_buff *skb)
194 {
195 	skb_pull(skb, ST21NFCA_FRAME_HEADROOM);
196 	skb_trim(skb, skb->len - ST21NFCA_FRAME_TAILROOM);
197 }
198 
199 /*
200  * Writing a frame must not return the number of written bytes.
201  * It must return either zero for success, or <0 for error.
202  * In addition, it must not alter the skb
203  */
204 static int st21nfca_hci_i2c_write(void *phy_id, struct sk_buff *skb)
205 {
206 	int r = -1, i, j;
207 	struct st21nfca_i2c_phy *phy = phy_id;
208 	struct i2c_client *client = phy->i2c_dev;
209 	u8 tmp[ST21NFCA_HCI_LLC_MAX_SIZE * 2];
210 
211 	I2C_DUMP_SKB("st21nfca_hci_i2c_write", skb);
212 
213 
214 	if (phy->hard_fault != 0)
215 		return phy->hard_fault;
216 
217 	/*
218 	 * Compute CRC before byte stuffing computation on frame
219 	 * Note st21nfca_hci_add_len_crc is doing a byte stuffing
220 	 * on its own value
221 	 */
222 	st21nfca_hci_add_len_crc(skb);
223 
224 	/* add ST21NFCA_SOF_EOF on tail */
225 	*skb_put(skb, 1) = ST21NFCA_SOF_EOF;
226 	/* add ST21NFCA_SOF_EOF on head */
227 	*skb_push(skb, 1) = ST21NFCA_SOF_EOF;
228 
229 	/*
230 	 * Compute byte stuffing
231 	 * if byte == ST21NFCA_SOF_EOF or ST21NFCA_ESCAPE_BYTE_STUFFING
232 	 * insert ST21NFCA_ESCAPE_BYTE_STUFFING (escape byte)
233 	 * xor byte with ST21NFCA_BYTE_STUFFING_MASK
234 	 */
235 	tmp[0] = skb->data[0];
236 	for (i = 1, j = 1; i < skb->len - 1; i++, j++) {
237 		if (skb->data[i] == ST21NFCA_SOF_EOF
238 		    || skb->data[i] == ST21NFCA_ESCAPE_BYTE_STUFFING) {
239 			tmp[j] = ST21NFCA_ESCAPE_BYTE_STUFFING;
240 			j++;
241 			tmp[j] = skb->data[i] ^ ST21NFCA_BYTE_STUFFING_MASK;
242 		} else {
243 			tmp[j] = skb->data[i];
244 		}
245 	}
246 	tmp[j] = skb->data[i];
247 	j++;
248 
249 	/*
250 	 * Manage sleep mode
251 	 * Try 3 times to send data with delay between each
252 	 */
253 	mutex_lock(&phy->phy_lock);
254 	for (i = 0; i < ARRAY_SIZE(wait_tab) && r < 0; i++) {
255 		r = i2c_master_send(client, tmp, j);
256 		if (r < 0)
257 			msleep(wait_tab[i]);
258 	}
259 	mutex_unlock(&phy->phy_lock);
260 
261 	if (r >= 0) {
262 		if (r != j)
263 			r = -EREMOTEIO;
264 		else
265 			r = 0;
266 	}
267 
268 	st21nfca_hci_remove_len_crc(skb);
269 
270 	return r;
271 }
272 
273 static int get_frame_size(u8 *buf, int buflen)
274 {
275 	int len = 0;
276 
277 	if (buf[len + 1] == ST21NFCA_SOF_EOF)
278 		return 0;
279 
280 	for (len = 1; len < buflen && buf[len] != ST21NFCA_SOF_EOF; len++)
281 		;
282 
283 	return len;
284 }
285 
286 static int check_crc(u8 *buf, int buflen)
287 {
288 	u16 crc;
289 
290 	crc = crc_ccitt(0xffff, buf, buflen - 2);
291 	crc = ~crc;
292 
293 	if (buf[buflen - 2] != (crc & 0xff) || buf[buflen - 1] != (crc >> 8)) {
294 		pr_err(ST21NFCA_HCI_DRIVER_NAME
295 		       ": CRC error 0x%x != 0x%x 0x%x\n", crc, buf[buflen - 1],
296 		       buf[buflen - 2]);
297 
298 		pr_info(DRIVER_DESC ": %s : BAD CRC\n", __func__);
299 		print_hex_dump(KERN_DEBUG, "crc: ", DUMP_PREFIX_NONE,
300 			       16, 2, buf, buflen, false);
301 		return -EPERM;
302 	}
303 	return 0;
304 }
305 
306 /*
307  * Prepare received data for upper layer.
308  * Received data include byte stuffing, crc and sof/eof
309  * which is not usable by hci part.
310  * returns:
311  * frame size without sof/eof, header and byte stuffing
312  * -EBADMSG : frame was incorrect and discarded
313  */
314 static int st21nfca_hci_i2c_repack(struct sk_buff *skb)
315 {
316 	int i, j, r, size;
317 
318 	if (skb->len < 1 || (skb->len > 1 && skb->data[1] != 0))
319 		return -EBADMSG;
320 
321 	size = get_frame_size(skb->data, skb->len);
322 	if (size > 0) {
323 		skb_trim(skb, size);
324 		/* remove ST21NFCA byte stuffing for upper layer */
325 		for (i = 1, j = 0; i < skb->len; i++) {
326 			if (skb->data[i + j] ==
327 					(u8) ST21NFCA_ESCAPE_BYTE_STUFFING) {
328 				skb->data[i] = skb->data[i + j + 1]
329 						| ST21NFCA_BYTE_STUFFING_MASK;
330 				i++;
331 				j++;
332 			}
333 			skb->data[i] = skb->data[i + j];
334 		}
335 		/* remove byte stuffing useless byte */
336 		skb_trim(skb, i - j);
337 		/* remove ST21NFCA_SOF_EOF from head */
338 		skb_pull(skb, 1);
339 
340 		r = check_crc(skb->data, skb->len);
341 		if (r != 0) {
342 			i = 0;
343 			return -EBADMSG;
344 		}
345 
346 		/* remove headbyte */
347 		skb_pull(skb, 1);
348 		/* remove crc. Byte Stuffing is already removed here */
349 		skb_trim(skb, skb->len - 2);
350 		return skb->len;
351 	}
352 	return 0;
353 }
354 
355 /*
356  * Reads an shdlc frame and returns it in a newly allocated sk_buff. Guarantees
357  * that i2c bus will be flushed and that next read will start on a new frame.
358  * returned skb contains only LLC header and payload.
359  * returns:
360  * frame size : if received frame is complete (find ST21NFCA_SOF_EOF at
361  * end of read)
362  * -EAGAIN : if received frame is incomplete (not find ST21NFCA_SOF_EOF
363  * at end of read)
364  * -EREMOTEIO : i2c read error (fatal)
365  * -EBADMSG : frame was incorrect and discarded
366  * (value returned from st21nfca_hci_i2c_repack)
367  * -EIO : if no ST21NFCA_SOF_EOF is found after reaching
368  * the read length end sequence
369  */
370 static int st21nfca_hci_i2c_read(struct st21nfca_i2c_phy *phy,
371 				 struct sk_buff *skb)
372 {
373 	int r, i;
374 	u8 len;
375 	u8 buf[ST21NFCA_HCI_LLC_MAX_PAYLOAD];
376 	struct i2c_client *client = phy->i2c_dev;
377 
378 	if (phy->current_read_len < ARRAY_SIZE(len_seq)) {
379 		len = len_seq[phy->current_read_len];
380 
381 		/*
382 		 * Add retry mecanism
383 		 * Operation on I2C interface may fail in case of operation on
384 		 * RF or SWP interface
385 		 */
386 		r = 0;
387 		mutex_lock(&phy->phy_lock);
388 		for (i = 0; i < ARRAY_SIZE(wait_tab) && r <= 0; i++) {
389 			r = i2c_master_recv(client, buf, len);
390 			if (r < 0)
391 				msleep(wait_tab[i]);
392 		}
393 		mutex_unlock(&phy->phy_lock);
394 
395 		if (r != len) {
396 			phy->current_read_len = 0;
397 			return -EREMOTEIO;
398 		}
399 
400 		/*
401 		 * The first read sequence does not start with SOF.
402 		 * Data is corrupeted so we drop it.
403 		 */
404 		if (!phy->current_read_len && !IS_START_OF_FRAME(buf)) {
405 			skb_trim(skb, 0);
406 			phy->current_read_len = 0;
407 			return -EIO;
408 		} else if (phy->current_read_len && IS_START_OF_FRAME(buf)) {
409 			/*
410 			 * Previous frame transmission was interrupted and
411 			 * the frame got repeated.
412 			 * Received frame start with ST21NFCA_SOF_EOF + 00.
413 			 */
414 			skb_trim(skb, 0);
415 			phy->current_read_len = 0;
416 		}
417 
418 		memcpy(skb_put(skb, len), buf, len);
419 
420 		if (skb->data[skb->len - 1] == ST21NFCA_SOF_EOF) {
421 			phy->current_read_len = 0;
422 			return st21nfca_hci_i2c_repack(skb);
423 		}
424 		phy->current_read_len++;
425 		return -EAGAIN;
426 	}
427 	return -EIO;
428 }
429 
430 /*
431  * Reads an shdlc frame from the chip. This is not as straightforward as it
432  * seems. The frame format is data-crc, and corruption can occur anywhere
433  * while transiting on i2c bus, such that we could read an invalid data.
434  * The tricky case is when we read a corrupted data or crc. We must detect
435  * this here in order to determine that data can be transmitted to the hci
436  * core. This is the reason why we check the crc here.
437  * The CLF will repeat a frame until we send a RR on that frame.
438  *
439  * On ST21NFCA, IRQ goes in idle when read starts. As no size information are
440  * available in the incoming data, other IRQ might come. Every IRQ will trigger
441  * a read sequence with different length and will fill the current frame.
442  * The reception is complete once we reach a ST21NFCA_SOF_EOF.
443  */
444 static irqreturn_t st21nfca_hci_irq_thread_fn(int irq, void *phy_id)
445 {
446 	struct st21nfca_i2c_phy *phy = phy_id;
447 	struct i2c_client *client;
448 
449 	int r;
450 
451 	if (!phy || irq != phy->i2c_dev->irq) {
452 		WARN_ON_ONCE(1);
453 		return IRQ_NONE;
454 	}
455 
456 	client = phy->i2c_dev;
457 	dev_dbg(&client->dev, "IRQ\n");
458 
459 	if (phy->hard_fault != 0)
460 		return IRQ_HANDLED;
461 
462 	r = st21nfca_hci_i2c_read(phy, phy->pending_skb);
463 	if (r == -EREMOTEIO) {
464 		phy->hard_fault = r;
465 
466 		nfc_hci_recv_frame(phy->hdev, NULL);
467 
468 		return IRQ_HANDLED;
469 	} else if (r == -EAGAIN || r == -EIO) {
470 		return IRQ_HANDLED;
471 	} else if (r == -EBADMSG && phy->crc_trials < ARRAY_SIZE(wait_tab)) {
472 		/*
473 		 * With ST21NFCA, only one interface (I2C, RF or SWP)
474 		 * may be active at a time.
475 		 * Having incorrect crc is usually due to i2c macrocell
476 		 * deactivation in the middle of a transmission.
477 		 * It may generate corrupted data on i2c.
478 		 * We give sometime to get i2c back.
479 		 * The complete frame will be repeated.
480 		 */
481 		msleep(wait_tab[phy->crc_trials]);
482 		phy->crc_trials++;
483 		phy->current_read_len = 0;
484 		kfree_skb(phy->pending_skb);
485 	} else if (r > 0) {
486 		/*
487 		 * We succeeded to read data from the CLF and
488 		 * data is valid.
489 		 * Reset counter.
490 		 */
491 		nfc_hci_recv_frame(phy->hdev, phy->pending_skb);
492 		phy->crc_trials = 0;
493 	} else {
494 		kfree_skb(phy->pending_skb);
495 	}
496 
497 	phy->pending_skb = alloc_skb(ST21NFCA_HCI_LLC_MAX_SIZE * 2, GFP_KERNEL);
498 	if (phy->pending_skb == NULL) {
499 		phy->hard_fault = -ENOMEM;
500 		nfc_hci_recv_frame(phy->hdev, NULL);
501 	}
502 
503 	return IRQ_HANDLED;
504 }
505 
506 static struct nfc_phy_ops i2c_phy_ops = {
507 	.write = st21nfca_hci_i2c_write,
508 	.enable = st21nfca_hci_i2c_enable,
509 	.disable = st21nfca_hci_i2c_disable,
510 };
511 
512 #ifdef CONFIG_OF
513 static int st21nfca_hci_i2c_of_request_resources(struct i2c_client *client)
514 {
515 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
516 	struct device_node *pp;
517 	int gpio;
518 	int r;
519 
520 	pp = client->dev.of_node;
521 	if (!pp)
522 		return -ENODEV;
523 
524 	/* Get GPIO from device tree */
525 	gpio = of_get_named_gpio(pp, "enable-gpios", 0);
526 	if (gpio < 0) {
527 		nfc_err(&client->dev, "Failed to retrieve enable-gpios from device tree\n");
528 		return gpio;
529 	}
530 
531 	/* GPIO request and configuration */
532 	r = devm_gpio_request_one(&client->dev, gpio, GPIOF_OUT_INIT_HIGH,
533 				  "clf_enable");
534 	if (r) {
535 		nfc_err(&client->dev, "Failed to request enable pin\n");
536 		return r;
537 	}
538 
539 	phy->gpio_ena = gpio;
540 
541 	phy->irq_polarity = irq_get_trigger_type(client->irq);
542 
543 	phy->se_status.is_ese_present =
544 				of_property_read_bool(pp, "ese-present");
545 	phy->se_status.is_uicc_present =
546 				of_property_read_bool(pp, "uicc-present");
547 
548 	return 0;
549 }
550 #else
551 static int st21nfca_hci_i2c_of_request_resources(struct i2c_client *client)
552 {
553 	return -ENODEV;
554 }
555 #endif
556 
557 static int st21nfca_hci_i2c_request_resources(struct i2c_client *client)
558 {
559 	struct st21nfca_nfc_platform_data *pdata;
560 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
561 	int r;
562 
563 	pdata = client->dev.platform_data;
564 	if (pdata == NULL) {
565 		nfc_err(&client->dev, "No platform data\n");
566 		return -EINVAL;
567 	}
568 
569 	/* store for later use */
570 	phy->gpio_ena = pdata->gpio_ena;
571 	phy->irq_polarity = pdata->irq_polarity;
572 
573 	if (phy->gpio_ena > 0) {
574 		r = devm_gpio_request_one(&client->dev, phy->gpio_ena,
575 					  GPIOF_OUT_INIT_HIGH, "clf_enable");
576 		if (r) {
577 			pr_err("%s : ena gpio_request failed\n", __FILE__);
578 			return r;
579 		}
580 	}
581 
582 	phy->se_status.is_ese_present = pdata->is_ese_present;
583 	phy->se_status.is_uicc_present = pdata->is_uicc_present;
584 
585 	return 0;
586 }
587 
588 static int st21nfca_hci_i2c_probe(struct i2c_client *client,
589 				  const struct i2c_device_id *id)
590 {
591 	struct st21nfca_i2c_phy *phy;
592 	struct st21nfca_nfc_platform_data *pdata;
593 	int r;
594 
595 	dev_dbg(&client->dev, "%s\n", __func__);
596 	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
597 
598 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
599 		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
600 		return -ENODEV;
601 	}
602 
603 	phy = devm_kzalloc(&client->dev, sizeof(struct st21nfca_i2c_phy),
604 			   GFP_KERNEL);
605 	if (!phy)
606 		return -ENOMEM;
607 
608 	phy->i2c_dev = client;
609 	phy->pending_skb = alloc_skb(ST21NFCA_HCI_LLC_MAX_SIZE * 2, GFP_KERNEL);
610 	if (phy->pending_skb == NULL)
611 		return -ENOMEM;
612 
613 	phy->current_read_len = 0;
614 	phy->crc_trials = 0;
615 	mutex_init(&phy->phy_lock);
616 	i2c_set_clientdata(client, phy);
617 
618 	pdata = client->dev.platform_data;
619 	if (!pdata && client->dev.of_node) {
620 		r = st21nfca_hci_i2c_of_request_resources(client);
621 		if (r) {
622 			nfc_err(&client->dev, "No platform data\n");
623 			return r;
624 		}
625 	} else if (pdata) {
626 		r = st21nfca_hci_i2c_request_resources(client);
627 		if (r) {
628 			nfc_err(&client->dev, "Cannot get platform resources\n");
629 			return r;
630 		}
631 	} else {
632 		nfc_err(&client->dev, "st21nfca platform resources not available\n");
633 		return -ENODEV;
634 	}
635 
636 	r = st21nfca_hci_platform_init(phy);
637 	if (r < 0) {
638 		nfc_err(&client->dev, "Unable to reboot st21nfca\n");
639 		return r;
640 	}
641 
642 	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
643 				st21nfca_hci_irq_thread_fn,
644 				phy->irq_polarity | IRQF_ONESHOT,
645 				ST21NFCA_HCI_DRIVER_NAME, phy);
646 	if (r < 0) {
647 		nfc_err(&client->dev, "Unable to register IRQ handler\n");
648 		return r;
649 	}
650 
651 	return st21nfca_hci_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
652 					ST21NFCA_FRAME_HEADROOM,
653 					ST21NFCA_FRAME_TAILROOM,
654 					ST21NFCA_HCI_LLC_MAX_PAYLOAD,
655 					&phy->hdev,
656 					&phy->se_status);
657 }
658 
659 static int st21nfca_hci_i2c_remove(struct i2c_client *client)
660 {
661 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
662 
663 	dev_dbg(&client->dev, "%s\n", __func__);
664 
665 	st21nfca_hci_remove(phy->hdev);
666 
667 	if (phy->powered)
668 		st21nfca_hci_i2c_disable(phy);
669 
670 	return 0;
671 }
672 
673 #ifdef CONFIG_OF
674 static const struct of_device_id of_st21nfca_i2c_match[] = {
675 	{ .compatible = "st,st21nfca-i2c", },
676 	{ .compatible = "st,st21nfca_i2c", },
677 	{}
678 };
679 MODULE_DEVICE_TABLE(of, of_st21nfca_i2c_match);
680 #endif
681 
682 static struct i2c_driver st21nfca_hci_i2c_driver = {
683 	.driver = {
684 		.owner = THIS_MODULE,
685 		.name = ST21NFCA_HCI_I2C_DRIVER_NAME,
686 		.of_match_table = of_match_ptr(of_st21nfca_i2c_match),
687 	},
688 	.probe = st21nfca_hci_i2c_probe,
689 	.id_table = st21nfca_hci_i2c_id_table,
690 	.remove = st21nfca_hci_i2c_remove,
691 };
692 
693 module_i2c_driver(st21nfca_hci_i2c_driver);
694 
695 MODULE_LICENSE("GPL");
696 MODULE_DESCRIPTION(DRIVER_DESC);
697