xref: /openbmc/linux/drivers/nfc/st21nfca/i2c.c (revision 78700c0a)
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/gpio/consumer.h>
25 #include <linux/of_irq.h>
26 #include <linux/of_gpio.h>
27 #include <linux/acpi.h>
28 #include <linux/miscdevice.h>
29 #include <linux/interrupt.h>
30 #include <linux/delay.h>
31 #include <linux/nfc.h>
32 #include <linux/firmware.h>
33 #include <linux/platform_data/st21nfca.h>
34 #include <asm/unaligned.h>
35 
36 #include <net/nfc/hci.h>
37 #include <net/nfc/llc.h>
38 #include <net/nfc/nfc.h>
39 
40 #include "st21nfca.h"
41 
42 /*
43  * Every frame starts with ST21NFCA_SOF_EOF and ends with ST21NFCA_SOF_EOF.
44  * Because ST21NFCA_SOF_EOF is a possible data value, there is a mecanism
45  * called byte stuffing has been introduced.
46  *
47  * if byte == ST21NFCA_SOF_EOF or ST21NFCA_ESCAPE_BYTE_STUFFING
48  * - insert ST21NFCA_ESCAPE_BYTE_STUFFING (escape byte)
49  * - xor byte with ST21NFCA_BYTE_STUFFING_MASK
50  */
51 #define ST21NFCA_SOF_EOF		0x7e
52 #define ST21NFCA_BYTE_STUFFING_MASK	0x20
53 #define ST21NFCA_ESCAPE_BYTE_STUFFING	0x7d
54 
55 /* SOF + 00 */
56 #define ST21NFCA_FRAME_HEADROOM			2
57 
58 /* 2 bytes crc + EOF */
59 #define ST21NFCA_FRAME_TAILROOM 3
60 #define IS_START_OF_FRAME(buf) (buf[0] == ST21NFCA_SOF_EOF && \
61 				buf[1] == 0)
62 
63 #define ST21NFCA_HCI_I2C_DRIVER_NAME "st21nfca_hci_i2c"
64 
65 #define ST21NFCA_GPIO_NAME_EN "enable"
66 
67 struct st21nfca_i2c_phy {
68 	struct i2c_client *i2c_dev;
69 	struct nfc_hci_dev *hdev;
70 
71 	unsigned int gpio_ena;
72 	unsigned int irq_polarity;
73 
74 	struct st21nfca_se_status se_status;
75 
76 	struct sk_buff *pending_skb;
77 	int current_read_len;
78 	/*
79 	 * crc might have fail because i2c macro
80 	 * is disable due to other interface activity
81 	 */
82 	int crc_trials;
83 
84 	int powered;
85 	int run_mode;
86 
87 	/*
88 	 * < 0 if hardware error occured (e.g. i2c err)
89 	 * and prevents normal operation.
90 	 */
91 	int hard_fault;
92 	struct mutex phy_lock;
93 };
94 
95 static u8 len_seq[] = { 16, 24, 12, 29 };
96 static u16 wait_tab[] = { 2, 3, 5, 15, 20, 40};
97 
98 #define I2C_DUMP_SKB(info, skb)					\
99 do {								\
100 	pr_debug("%s:\n", info);				\
101 	print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET,	\
102 		       16, 1, (skb)->data, (skb)->len, 0);	\
103 } while (0)
104 
105 /*
106  * In order to get the CLF in a known state we generate an internal reboot
107  * using a proprietary command.
108  * Once the reboot is completed, we expect to receive a ST21NFCA_SOF_EOF
109  * fill buffer.
110  */
111 static int st21nfca_hci_platform_init(struct st21nfca_i2c_phy *phy)
112 {
113 	u16 wait_reboot[] = { 50, 300, 1000 };
114 	char reboot_cmd[] = { 0x7E, 0x66, 0x48, 0xF6, 0x7E };
115 	u8 tmp[ST21NFCA_HCI_LLC_MAX_SIZE];
116 	int i, r = -1;
117 
118 	for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++) {
119 		r = i2c_master_send(phy->i2c_dev, reboot_cmd,
120 				    sizeof(reboot_cmd));
121 		if (r < 0)
122 			msleep(wait_reboot[i]);
123 	}
124 	if (r < 0)
125 		return r;
126 
127 	/* CLF is spending about 20ms to do an internal reboot */
128 	msleep(20);
129 	r = -1;
130 	for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++) {
131 		r = i2c_master_recv(phy->i2c_dev, tmp,
132 				    ST21NFCA_HCI_LLC_MAX_SIZE);
133 		if (r < 0)
134 			msleep(wait_reboot[i]);
135 	}
136 	if (r < 0)
137 		return r;
138 
139 	for (i = 0; i < ST21NFCA_HCI_LLC_MAX_SIZE &&
140 		tmp[i] == ST21NFCA_SOF_EOF; i++)
141 		;
142 
143 	if (r != ST21NFCA_HCI_LLC_MAX_SIZE)
144 		return -ENODEV;
145 
146 	usleep_range(1000, 1500);
147 	return 0;
148 }
149 
150 static int st21nfca_hci_i2c_enable(void *phy_id)
151 {
152 	struct st21nfca_i2c_phy *phy = phy_id;
153 
154 	gpio_set_value(phy->gpio_ena, 1);
155 	phy->powered = 1;
156 	phy->run_mode = ST21NFCA_HCI_MODE;
157 
158 	usleep_range(10000, 15000);
159 
160 	return 0;
161 }
162 
163 static void st21nfca_hci_i2c_disable(void *phy_id)
164 {
165 	struct st21nfca_i2c_phy *phy = phy_id;
166 
167 	gpio_set_value(phy->gpio_ena, 0);
168 
169 	phy->powered = 0;
170 }
171 
172 static void st21nfca_hci_add_len_crc(struct sk_buff *skb)
173 {
174 	u16 crc;
175 	u8 tmp;
176 
177 	*skb_push(skb, 1) = 0;
178 
179 	crc = crc_ccitt(0xffff, skb->data, skb->len);
180 	crc = ~crc;
181 
182 	tmp = crc & 0x00ff;
183 	*skb_put(skb, 1) = tmp;
184 
185 	tmp = (crc >> 8) & 0x00ff;
186 	*skb_put(skb, 1) = tmp;
187 }
188 
189 static void st21nfca_hci_remove_len_crc(struct sk_buff *skb)
190 {
191 	skb_pull(skb, ST21NFCA_FRAME_HEADROOM);
192 	skb_trim(skb, skb->len - ST21NFCA_FRAME_TAILROOM);
193 }
194 
195 /*
196  * Writing a frame must not return the number of written bytes.
197  * It must return either zero for success, or <0 for error.
198  * In addition, it must not alter the skb
199  */
200 static int st21nfca_hci_i2c_write(void *phy_id, struct sk_buff *skb)
201 {
202 	int r = -1, i, j;
203 	struct st21nfca_i2c_phy *phy = phy_id;
204 	struct i2c_client *client = phy->i2c_dev;
205 	u8 tmp[ST21NFCA_HCI_LLC_MAX_SIZE * 2];
206 
207 	I2C_DUMP_SKB("st21nfca_hci_i2c_write", skb);
208 
209 	if (phy->hard_fault != 0)
210 		return phy->hard_fault;
211 
212 	/*
213 	 * Compute CRC before byte stuffing computation on frame
214 	 * Note st21nfca_hci_add_len_crc is doing a byte stuffing
215 	 * on its own value
216 	 */
217 	st21nfca_hci_add_len_crc(skb);
218 
219 	/* add ST21NFCA_SOF_EOF on tail */
220 	*skb_put(skb, 1) = ST21NFCA_SOF_EOF;
221 	/* add ST21NFCA_SOF_EOF on head */
222 	*skb_push(skb, 1) = ST21NFCA_SOF_EOF;
223 
224 	/*
225 	 * Compute byte stuffing
226 	 * if byte == ST21NFCA_SOF_EOF or ST21NFCA_ESCAPE_BYTE_STUFFING
227 	 * insert ST21NFCA_ESCAPE_BYTE_STUFFING (escape byte)
228 	 * xor byte with ST21NFCA_BYTE_STUFFING_MASK
229 	 */
230 	tmp[0] = skb->data[0];
231 	for (i = 1, j = 1; i < skb->len - 1; i++, j++) {
232 		if (skb->data[i] == ST21NFCA_SOF_EOF
233 		    || skb->data[i] == ST21NFCA_ESCAPE_BYTE_STUFFING) {
234 			tmp[j] = ST21NFCA_ESCAPE_BYTE_STUFFING;
235 			j++;
236 			tmp[j] = skb->data[i] ^ ST21NFCA_BYTE_STUFFING_MASK;
237 		} else {
238 			tmp[j] = skb->data[i];
239 		}
240 	}
241 	tmp[j] = skb->data[i];
242 	j++;
243 
244 	/*
245 	 * Manage sleep mode
246 	 * Try 3 times to send data with delay between each
247 	 */
248 	mutex_lock(&phy->phy_lock);
249 	for (i = 0; i < ARRAY_SIZE(wait_tab) && r < 0; i++) {
250 		r = i2c_master_send(client, tmp, j);
251 		if (r < 0)
252 			msleep(wait_tab[i]);
253 	}
254 	mutex_unlock(&phy->phy_lock);
255 
256 	if (r >= 0) {
257 		if (r != j)
258 			r = -EREMOTEIO;
259 		else
260 			r = 0;
261 	}
262 
263 	st21nfca_hci_remove_len_crc(skb);
264 
265 	return r;
266 }
267 
268 static int get_frame_size(u8 *buf, int buflen)
269 {
270 	int len = 0;
271 
272 	if (buf[len + 1] == ST21NFCA_SOF_EOF)
273 		return 0;
274 
275 	for (len = 1; len < buflen && buf[len] != ST21NFCA_SOF_EOF; len++)
276 		;
277 
278 	return len;
279 }
280 
281 static int check_crc(u8 *buf, int buflen)
282 {
283 	u16 crc;
284 
285 	crc = crc_ccitt(0xffff, buf, buflen - 2);
286 	crc = ~crc;
287 
288 	if (buf[buflen - 2] != (crc & 0xff) || buf[buflen - 1] != (crc >> 8)) {
289 		pr_err(ST21NFCA_HCI_DRIVER_NAME
290 		       ": CRC error 0x%x != 0x%x 0x%x\n", crc, buf[buflen - 1],
291 		       buf[buflen - 2]);
292 
293 		pr_info(DRIVER_DESC ": %s : BAD CRC\n", __func__);
294 		print_hex_dump(KERN_DEBUG, "crc: ", DUMP_PREFIX_NONE,
295 			       16, 2, buf, buflen, false);
296 		return -EPERM;
297 	}
298 	return 0;
299 }
300 
301 /*
302  * Prepare received data for upper layer.
303  * Received data include byte stuffing, crc and sof/eof
304  * which is not usable by hci part.
305  * returns:
306  * frame size without sof/eof, header and byte stuffing
307  * -EBADMSG : frame was incorrect and discarded
308  */
309 static int st21nfca_hci_i2c_repack(struct sk_buff *skb)
310 {
311 	int i, j, r, size;
312 
313 	if (skb->len < 1 || (skb->len > 1 && skb->data[1] != 0))
314 		return -EBADMSG;
315 
316 	size = get_frame_size(skb->data, skb->len);
317 	if (size > 0) {
318 		skb_trim(skb, size);
319 		/* remove ST21NFCA byte stuffing for upper layer */
320 		for (i = 1, j = 0; i < skb->len; i++) {
321 			if (skb->data[i + j] ==
322 					(u8) ST21NFCA_ESCAPE_BYTE_STUFFING) {
323 				skb->data[i] = skb->data[i + j + 1]
324 						| ST21NFCA_BYTE_STUFFING_MASK;
325 				i++;
326 				j++;
327 			}
328 			skb->data[i] = skb->data[i + j];
329 		}
330 		/* remove byte stuffing useless byte */
331 		skb_trim(skb, i - j);
332 		/* remove ST21NFCA_SOF_EOF from head */
333 		skb_pull(skb, 1);
334 
335 		r = check_crc(skb->data, skb->len);
336 		if (r != 0) {
337 			i = 0;
338 			return -EBADMSG;
339 		}
340 
341 		/* remove headbyte */
342 		skb_pull(skb, 1);
343 		/* remove crc. Byte Stuffing is already removed here */
344 		skb_trim(skb, skb->len - 2);
345 		return skb->len;
346 	}
347 	return 0;
348 }
349 
350 /*
351  * Reads an shdlc frame and returns it in a newly allocated sk_buff. Guarantees
352  * that i2c bus will be flushed and that next read will start on a new frame.
353  * returned skb contains only LLC header and payload.
354  * returns:
355  * frame size : if received frame is complete (find ST21NFCA_SOF_EOF at
356  * end of read)
357  * -EAGAIN : if received frame is incomplete (not find ST21NFCA_SOF_EOF
358  * at end of read)
359  * -EREMOTEIO : i2c read error (fatal)
360  * -EBADMSG : frame was incorrect and discarded
361  * (value returned from st21nfca_hci_i2c_repack)
362  * -EIO : if no ST21NFCA_SOF_EOF is found after reaching
363  * the read length end sequence
364  */
365 static int st21nfca_hci_i2c_read(struct st21nfca_i2c_phy *phy,
366 				 struct sk_buff *skb)
367 {
368 	int r, i;
369 	u8 len;
370 	u8 buf[ST21NFCA_HCI_LLC_MAX_PAYLOAD];
371 	struct i2c_client *client = phy->i2c_dev;
372 
373 	if (phy->current_read_len < ARRAY_SIZE(len_seq)) {
374 		len = len_seq[phy->current_read_len];
375 
376 		/*
377 		 * Add retry mecanism
378 		 * Operation on I2C interface may fail in case of operation on
379 		 * RF or SWP interface
380 		 */
381 		r = 0;
382 		mutex_lock(&phy->phy_lock);
383 		for (i = 0; i < ARRAY_SIZE(wait_tab) && r <= 0; i++) {
384 			r = i2c_master_recv(client, buf, len);
385 			if (r < 0)
386 				msleep(wait_tab[i]);
387 		}
388 		mutex_unlock(&phy->phy_lock);
389 
390 		if (r != len) {
391 			phy->current_read_len = 0;
392 			return -EREMOTEIO;
393 		}
394 
395 		/*
396 		 * The first read sequence does not start with SOF.
397 		 * Data is corrupeted so we drop it.
398 		 */
399 		if (!phy->current_read_len && !IS_START_OF_FRAME(buf)) {
400 			skb_trim(skb, 0);
401 			phy->current_read_len = 0;
402 			return -EIO;
403 		} else if (phy->current_read_len && IS_START_OF_FRAME(buf)) {
404 			/*
405 			 * Previous frame transmission was interrupted and
406 			 * the frame got repeated.
407 			 * Received frame start with ST21NFCA_SOF_EOF + 00.
408 			 */
409 			skb_trim(skb, 0);
410 			phy->current_read_len = 0;
411 		}
412 
413 		memcpy(skb_put(skb, len), buf, len);
414 
415 		if (skb->data[skb->len - 1] == ST21NFCA_SOF_EOF) {
416 			phy->current_read_len = 0;
417 			return st21nfca_hci_i2c_repack(skb);
418 		}
419 		phy->current_read_len++;
420 		return -EAGAIN;
421 	}
422 	return -EIO;
423 }
424 
425 /*
426  * Reads an shdlc frame from the chip. This is not as straightforward as it
427  * seems. The frame format is data-crc, and corruption can occur anywhere
428  * while transiting on i2c bus, such that we could read an invalid data.
429  * The tricky case is when we read a corrupted data or crc. We must detect
430  * this here in order to determine that data can be transmitted to the hci
431  * core. This is the reason why we check the crc here.
432  * The CLF will repeat a frame until we send a RR on that frame.
433  *
434  * On ST21NFCA, IRQ goes in idle when read starts. As no size information are
435  * available in the incoming data, other IRQ might come. Every IRQ will trigger
436  * a read sequence with different length and will fill the current frame.
437  * The reception is complete once we reach a ST21NFCA_SOF_EOF.
438  */
439 static irqreturn_t st21nfca_hci_irq_thread_fn(int irq, void *phy_id)
440 {
441 	struct st21nfca_i2c_phy *phy = phy_id;
442 	struct i2c_client *client;
443 
444 	int r;
445 
446 	if (!phy || irq != phy->i2c_dev->irq) {
447 		WARN_ON_ONCE(1);
448 		return IRQ_NONE;
449 	}
450 
451 	client = phy->i2c_dev;
452 	dev_dbg(&client->dev, "IRQ\n");
453 
454 	if (phy->hard_fault != 0)
455 		return IRQ_HANDLED;
456 
457 	r = st21nfca_hci_i2c_read(phy, phy->pending_skb);
458 	if (r == -EREMOTEIO) {
459 		phy->hard_fault = r;
460 
461 		nfc_hci_recv_frame(phy->hdev, NULL);
462 
463 		return IRQ_HANDLED;
464 	} else if (r == -EAGAIN || r == -EIO) {
465 		return IRQ_HANDLED;
466 	} else if (r == -EBADMSG && phy->crc_trials < ARRAY_SIZE(wait_tab)) {
467 		/*
468 		 * With ST21NFCA, only one interface (I2C, RF or SWP)
469 		 * may be active at a time.
470 		 * Having incorrect crc is usually due to i2c macrocell
471 		 * deactivation in the middle of a transmission.
472 		 * It may generate corrupted data on i2c.
473 		 * We give sometime to get i2c back.
474 		 * The complete frame will be repeated.
475 		 */
476 		msleep(wait_tab[phy->crc_trials]);
477 		phy->crc_trials++;
478 		phy->current_read_len = 0;
479 		kfree_skb(phy->pending_skb);
480 	} else if (r > 0) {
481 		/*
482 		 * We succeeded to read data from the CLF and
483 		 * data is valid.
484 		 * Reset counter.
485 		 */
486 		nfc_hci_recv_frame(phy->hdev, phy->pending_skb);
487 		phy->crc_trials = 0;
488 	} else {
489 		kfree_skb(phy->pending_skb);
490 	}
491 
492 	phy->pending_skb = alloc_skb(ST21NFCA_HCI_LLC_MAX_SIZE * 2, GFP_KERNEL);
493 	if (phy->pending_skb == NULL) {
494 		phy->hard_fault = -ENOMEM;
495 		nfc_hci_recv_frame(phy->hdev, NULL);
496 	}
497 
498 	return IRQ_HANDLED;
499 }
500 
501 static struct nfc_phy_ops i2c_phy_ops = {
502 	.write = st21nfca_hci_i2c_write,
503 	.enable = st21nfca_hci_i2c_enable,
504 	.disable = st21nfca_hci_i2c_disable,
505 };
506 
507 static int st21nfca_hci_i2c_acpi_request_resources(struct i2c_client *client)
508 {
509 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
510 	struct gpio_desc *gpiod_ena;
511 	struct device *dev = &client->dev;
512 	u8 tmp;
513 
514 	/* Get EN GPIO from ACPI */
515 	gpiod_ena = devm_gpiod_get_index(dev, ST21NFCA_GPIO_NAME_EN, 1,
516 					 GPIOD_OUT_LOW);
517 	if (!IS_ERR(gpiod_ena)) {
518 		nfc_err(dev, "Unable to get ENABLE GPIO\n");
519 		return -ENODEV;
520 	}
521 
522 	phy->gpio_ena = desc_to_gpio(gpiod_ena);
523 
524 	phy->irq_polarity = irq_get_trigger_type(client->irq);
525 
526 	phy->se_status.is_ese_present = false;
527 	phy->se_status.is_uicc_present = false;
528 
529 	if (device_property_present(dev, "ese-present")) {
530 		device_property_read_u8(dev, "ese-present", &tmp);
531 		phy->se_status.is_ese_present = tmp;
532 	}
533 
534 	if (device_property_present(dev, "uicc-present")) {
535 		device_property_read_u8(dev, "uicc-present", &tmp);
536 		phy->se_status.is_uicc_present = tmp;
537 	}
538 
539 	return 0;
540 }
541 
542 static int st21nfca_hci_i2c_of_request_resources(struct i2c_client *client)
543 {
544 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
545 	struct device_node *pp;
546 	int gpio;
547 	int r;
548 
549 	pp = client->dev.of_node;
550 	if (!pp)
551 		return -ENODEV;
552 
553 	/* Get GPIO from device tree */
554 	gpio = of_get_named_gpio(pp, "enable-gpios", 0);
555 	if (gpio < 0) {
556 		nfc_err(&client->dev, "Failed to retrieve enable-gpios from device tree\n");
557 		return gpio;
558 	}
559 
560 	/* GPIO request and configuration */
561 	r = devm_gpio_request_one(&client->dev, gpio, GPIOF_OUT_INIT_HIGH,
562 				  ST21NFCA_GPIO_NAME_EN);
563 	if (r) {
564 		nfc_err(&client->dev, "Failed to request enable pin\n");
565 		return r;
566 	}
567 
568 	phy->gpio_ena = gpio;
569 
570 	phy->irq_polarity = irq_get_trigger_type(client->irq);
571 
572 	phy->se_status.is_ese_present =
573 				of_property_read_bool(pp, "ese-present");
574 	phy->se_status.is_uicc_present =
575 				of_property_read_bool(pp, "uicc-present");
576 
577 	return 0;
578 }
579 
580 static int st21nfca_hci_i2c_request_resources(struct i2c_client *client)
581 {
582 	struct st21nfca_nfc_platform_data *pdata;
583 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
584 	int r;
585 
586 	pdata = client->dev.platform_data;
587 	if (pdata == NULL) {
588 		nfc_err(&client->dev, "No platform data\n");
589 		return -EINVAL;
590 	}
591 
592 	/* store for later use */
593 	phy->gpio_ena = pdata->gpio_ena;
594 	phy->irq_polarity = pdata->irq_polarity;
595 
596 	if (phy->gpio_ena > 0) {
597 		r = devm_gpio_request_one(&client->dev, phy->gpio_ena,
598 					  GPIOF_OUT_INIT_HIGH,
599 					  ST21NFCA_GPIO_NAME_EN);
600 		if (r) {
601 			pr_err("%s : ena gpio_request failed\n", __FILE__);
602 			return r;
603 		}
604 	}
605 
606 	phy->se_status.is_ese_present = pdata->is_ese_present;
607 	phy->se_status.is_uicc_present = pdata->is_uicc_present;
608 
609 	return 0;
610 }
611 
612 static int st21nfca_hci_i2c_probe(struct i2c_client *client,
613 				  const struct i2c_device_id *id)
614 {
615 	struct st21nfca_i2c_phy *phy;
616 	struct st21nfca_nfc_platform_data *pdata;
617 	int r;
618 
619 	dev_dbg(&client->dev, "%s\n", __func__);
620 	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
621 
622 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
623 		nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
624 		return -ENODEV;
625 	}
626 
627 	phy = devm_kzalloc(&client->dev, sizeof(struct st21nfca_i2c_phy),
628 			   GFP_KERNEL);
629 	if (!phy)
630 		return -ENOMEM;
631 
632 	phy->i2c_dev = client;
633 	phy->pending_skb = alloc_skb(ST21NFCA_HCI_LLC_MAX_SIZE * 2, GFP_KERNEL);
634 	if (phy->pending_skb == NULL)
635 		return -ENOMEM;
636 
637 	phy->current_read_len = 0;
638 	phy->crc_trials = 0;
639 	mutex_init(&phy->phy_lock);
640 	i2c_set_clientdata(client, phy);
641 
642 	pdata = client->dev.platform_data;
643 	if (!pdata && client->dev.of_node) {
644 		r = st21nfca_hci_i2c_of_request_resources(client);
645 		if (r) {
646 			nfc_err(&client->dev, "No platform data\n");
647 			return r;
648 		}
649 	} else if (pdata) {
650 		r = st21nfca_hci_i2c_request_resources(client);
651 		if (r) {
652 			nfc_err(&client->dev, "Cannot get platform resources\n");
653 			return r;
654 		}
655 	} else if (ACPI_HANDLE(&client->dev)) {
656 		r = st21nfca_hci_i2c_acpi_request_resources(client);
657 		if (r) {
658 			nfc_err(&client->dev, "Cannot get ACPI data\n");
659 			return r;
660 		}
661 	} else {
662 		nfc_err(&client->dev, "st21nfca platform resources not available\n");
663 		return -ENODEV;
664 	}
665 
666 	r = st21nfca_hci_platform_init(phy);
667 	if (r < 0) {
668 		nfc_err(&client->dev, "Unable to reboot st21nfca\n");
669 		return r;
670 	}
671 
672 	r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
673 				st21nfca_hci_irq_thread_fn,
674 				phy->irq_polarity | IRQF_ONESHOT,
675 				ST21NFCA_HCI_DRIVER_NAME, phy);
676 	if (r < 0) {
677 		nfc_err(&client->dev, "Unable to register IRQ handler\n");
678 		return r;
679 	}
680 
681 	return st21nfca_hci_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
682 					ST21NFCA_FRAME_HEADROOM,
683 					ST21NFCA_FRAME_TAILROOM,
684 					ST21NFCA_HCI_LLC_MAX_PAYLOAD,
685 					&phy->hdev,
686 					&phy->se_status);
687 }
688 
689 static int st21nfca_hci_i2c_remove(struct i2c_client *client)
690 {
691 	struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
692 
693 	dev_dbg(&client->dev, "%s\n", __func__);
694 
695 	st21nfca_hci_remove(phy->hdev);
696 
697 	if (phy->powered)
698 		st21nfca_hci_i2c_disable(phy);
699 
700 	return 0;
701 }
702 
703 static struct i2c_device_id st21nfca_hci_i2c_id_table[] = {
704 	{ST21NFCA_HCI_DRIVER_NAME, 0},
705 	{}
706 };
707 MODULE_DEVICE_TABLE(i2c, st21nfca_hci_i2c_id_table);
708 
709 static const struct acpi_device_id st21nfca_hci_i2c_acpi_match[] = {
710 	{"SMO2100", 0},
711 	{}
712 };
713 MODULE_DEVICE_TABLE(acpi, st21nfca_hci_i2c_acpi_match);
714 
715 static const struct of_device_id of_st21nfca_i2c_match[] = {
716 	{ .compatible = "st,st21nfca-i2c", },
717 	{ .compatible = "st,st21nfca_i2c", },
718 	{}
719 };
720 MODULE_DEVICE_TABLE(of, of_st21nfca_i2c_match);
721 
722 static struct i2c_driver st21nfca_hci_i2c_driver = {
723 	.driver = {
724 		.name = ST21NFCA_HCI_I2C_DRIVER_NAME,
725 		.of_match_table = of_match_ptr(of_st21nfca_i2c_match),
726 		.acpi_match_table = ACPI_PTR(st21nfca_hci_i2c_acpi_match),
727 	},
728 	.probe = st21nfca_hci_i2c_probe,
729 	.id_table = st21nfca_hci_i2c_id_table,
730 	.remove = st21nfca_hci_i2c_remove,
731 };
732 module_i2c_driver(st21nfca_hci_i2c_driver);
733 
734 MODULE_LICENSE("GPL");
735 MODULE_DESCRIPTION(DRIVER_DESC);
736