2 * I2C Link Layer for ST21NFCA HCI based Driver
3 * Copyright (C) 2014 STMicroelectronics SAS. All rights reserved.
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.
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.
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/>.
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
36 #include <net/nfc/hci.h>
37 #include <net/nfc/llc.h>
38 #include <net/nfc/nfc.h>
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.
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
51 #define ST21NFCA_SOF_EOF 0x7e
52 #define ST21NFCA_BYTE_STUFFING_MASK 0x20
53 #define ST21NFCA_ESCAPE_BYTE_STUFFING 0x7d
56 #define ST21NFCA_FRAME_HEADROOM 2
58 /* 2 bytes crc + EOF */
59 #define ST21NFCA_FRAME_TAILROOM 3
60 #define IS_START_OF_FRAME(buf) (buf[0] == ST21NFCA_SOF_EOF && \
63 #define ST21NFCA_HCI_I2C_DRIVER_NAME "st21nfca_hci_i2c"
65 #define ST21NFCA_GPIO_NAME_EN "enable"
67 struct st21nfca_i2c_phy {
68 struct i2c_client *i2c_dev;
69 struct nfc_hci_dev *hdev;
71 unsigned int gpio_ena;
72 unsigned int irq_polarity;
74 struct st21nfca_se_status se_status;
76 struct sk_buff *pending_skb;
79 * crc might have fail because i2c macro
80 * is disable due to other interface activity
88 * < 0 if hardware error occured (e.g. i2c err)
89 * and prevents normal operation.
92 struct mutex phy_lock;
95 static u8 len_seq[] = { 16, 24, 12, 29 };
96 static u16 wait_tab[] = { 2, 3, 5, 15, 20, 40};
98 #define I2C_DUMP_SKB(info, skb) \
100 pr_debug("%s:\n", info); \
101 print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
102 16, 1, (skb)->data, (skb)->len, 0); \
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
111 static int st21nfca_hci_platform_init(struct st21nfca_i2c_phy *phy)
113 u16 wait_reboot[] = { 50, 300, 1000 };
114 char reboot_cmd[] = { 0x7E, 0x66, 0x48, 0xF6, 0x7E };
115 u8 tmp[ST21NFCA_HCI_LLC_MAX_SIZE];
118 for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++) {
119 r = i2c_master_send(phy->i2c_dev, reboot_cmd,
122 msleep(wait_reboot[i]);
127 /* CLF is spending about 20ms to do an internal reboot */
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);
134 msleep(wait_reboot[i]);
139 for (i = 0; i < ST21NFCA_HCI_LLC_MAX_SIZE &&
140 tmp[i] == ST21NFCA_SOF_EOF; i++)
143 if (r != ST21NFCA_HCI_LLC_MAX_SIZE)
146 usleep_range(1000, 1500);
150 static int st21nfca_hci_i2c_enable(void *phy_id)
152 struct st21nfca_i2c_phy *phy = phy_id;
154 gpio_set_value(phy->gpio_ena, 1);
156 phy->run_mode = ST21NFCA_HCI_MODE;
158 usleep_range(10000, 15000);
163 static void st21nfca_hci_i2c_disable(void *phy_id)
165 struct st21nfca_i2c_phy *phy = phy_id;
167 gpio_set_value(phy->gpio_ena, 0);
172 static void st21nfca_hci_add_len_crc(struct sk_buff *skb)
177 *skb_push(skb, 1) = 0;
179 crc = crc_ccitt(0xffff, skb->data, skb->len);
183 *skb_put(skb, 1) = tmp;
185 tmp = (crc >> 8) & 0x00ff;
186 *skb_put(skb, 1) = tmp;
189 static void st21nfca_hci_remove_len_crc(struct sk_buff *skb)
191 skb_pull(skb, ST21NFCA_FRAME_HEADROOM);
192 skb_trim(skb, skb->len - ST21NFCA_FRAME_TAILROOM);
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
200 static int st21nfca_hci_i2c_write(void *phy_id, struct sk_buff *skb)
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];
207 I2C_DUMP_SKB("st21nfca_hci_i2c_write", skb);
209 if (phy->hard_fault != 0)
210 return phy->hard_fault;
213 * Compute CRC before byte stuffing computation on frame
214 * Note st21nfca_hci_add_len_crc is doing a byte stuffing
217 st21nfca_hci_add_len_crc(skb);
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;
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
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;
236 tmp[j] = skb->data[i] ^ ST21NFCA_BYTE_STUFFING_MASK;
238 tmp[j] = skb->data[i];
241 tmp[j] = skb->data[i];
246 * Try 3 times to send data with delay between each
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);
254 mutex_unlock(&phy->phy_lock);
263 st21nfca_hci_remove_len_crc(skb);
268 static int get_frame_size(u8 *buf, int buflen)
272 if (buf[len + 1] == ST21NFCA_SOF_EOF)
275 for (len = 1; len < buflen && buf[len] != ST21NFCA_SOF_EOF; len++)
281 static int check_crc(u8 *buf, int buflen)
285 crc = crc_ccitt(0xffff, buf, buflen - 2);
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],
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);
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.
306 * frame size without sof/eof, header and byte stuffing
307 * -EBADMSG : frame was incorrect and discarded
309 static int st21nfca_hci_i2c_repack(struct sk_buff *skb)
313 if (skb->len < 1 || (skb->len > 1 && skb->data[1] != 0))
316 size = get_frame_size(skb->data, skb->len);
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;
328 skb->data[i] = skb->data[i + j];
330 /* remove byte stuffing useless byte */
331 skb_trim(skb, i - j);
332 /* remove ST21NFCA_SOF_EOF from head */
335 r = check_crc(skb->data, skb->len);
341 /* remove headbyte */
343 /* remove crc. Byte Stuffing is already removed here */
344 skb_trim(skb, skb->len - 2);
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.
355 * frame size : if received frame is complete (find ST21NFCA_SOF_EOF at
357 * -EAGAIN : if received frame is incomplete (not find ST21NFCA_SOF_EOF
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
365 static int st21nfca_hci_i2c_read(struct st21nfca_i2c_phy *phy,
370 u8 buf[ST21NFCA_HCI_LLC_MAX_PAYLOAD];
371 struct i2c_client *client = phy->i2c_dev;
373 if (phy->current_read_len < ARRAY_SIZE(len_seq)) {
374 len = len_seq[phy->current_read_len];
378 * Operation on I2C interface may fail in case of operation on
379 * RF or SWP interface
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);
388 mutex_unlock(&phy->phy_lock);
391 phy->current_read_len = 0;
396 * The first read sequence does not start with SOF.
397 * Data is corrupeted so we drop it.
399 if (!phy->current_read_len && !IS_START_OF_FRAME(buf)) {
401 phy->current_read_len = 0;
403 } else if (phy->current_read_len && IS_START_OF_FRAME(buf)) {
405 * Previous frame transmission was interrupted and
406 * the frame got repeated.
407 * Received frame start with ST21NFCA_SOF_EOF + 00.
410 phy->current_read_len = 0;
413 memcpy(skb_put(skb, len), buf, len);
415 if (skb->data[skb->len - 1] == ST21NFCA_SOF_EOF) {
416 phy->current_read_len = 0;
417 return st21nfca_hci_i2c_repack(skb);
419 phy->current_read_len++;
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.
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.
439 static irqreturn_t st21nfca_hci_irq_thread_fn(int irq, void *phy_id)
441 struct st21nfca_i2c_phy *phy = phy_id;
442 struct i2c_client *client;
446 if (!phy || irq != phy->i2c_dev->irq) {
451 client = phy->i2c_dev;
452 dev_dbg(&client->dev, "IRQ\n");
454 if (phy->hard_fault != 0)
457 r = st21nfca_hci_i2c_read(phy, phy->pending_skb);
458 if (r == -EREMOTEIO) {
461 nfc_hci_recv_frame(phy->hdev, NULL);
464 } else if (r == -EAGAIN || r == -EIO) {
466 } else if (r == -EBADMSG && phy->crc_trials < ARRAY_SIZE(wait_tab)) {
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.
476 msleep(wait_tab[phy->crc_trials]);
478 phy->current_read_len = 0;
479 kfree_skb(phy->pending_skb);
482 * We succeeded to read data from the CLF and
486 nfc_hci_recv_frame(phy->hdev, phy->pending_skb);
489 kfree_skb(phy->pending_skb);
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);
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,
507 static int st21nfca_hci_i2c_acpi_request_resources(struct i2c_client *client)
509 struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
510 struct gpio_desc *gpiod_ena;
511 struct device *dev = &client->dev;
514 /* Get EN GPIO from ACPI */
515 gpiod_ena = devm_gpiod_get_index(dev, ST21NFCA_GPIO_NAME_EN, 1,
517 if (!IS_ERR(gpiod_ena)) {
518 nfc_err(dev, "Unable to get ENABLE GPIO\n");
522 phy->gpio_ena = desc_to_gpio(gpiod_ena);
524 phy->irq_polarity = irq_get_trigger_type(client->irq);
526 phy->se_status.is_ese_present = false;
527 phy->se_status.is_uicc_present = false;
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;
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;
542 static int st21nfca_hci_i2c_of_request_resources(struct i2c_client *client)
544 struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
545 struct device_node *pp;
549 pp = client->dev.of_node;
553 /* Get GPIO from device tree */
554 gpio = of_get_named_gpio(pp, "enable-gpios", 0);
556 nfc_err(&client->dev, "Failed to retrieve enable-gpios from device tree\n");
560 /* GPIO request and configuration */
561 r = devm_gpio_request_one(&client->dev, gpio, GPIOF_OUT_INIT_HIGH,
562 ST21NFCA_GPIO_NAME_EN);
564 nfc_err(&client->dev, "Failed to request enable pin\n");
568 phy->gpio_ena = gpio;
570 phy->irq_polarity = irq_get_trigger_type(client->irq);
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");
580 static int st21nfca_hci_i2c_request_resources(struct i2c_client *client)
582 struct st21nfca_nfc_platform_data *pdata;
583 struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
586 pdata = client->dev.platform_data;
588 nfc_err(&client->dev, "No platform data\n");
592 /* store for later use */
593 phy->gpio_ena = pdata->gpio_ena;
594 phy->irq_polarity = pdata->irq_polarity;
596 if (phy->gpio_ena > 0) {
597 r = devm_gpio_request_one(&client->dev, phy->gpio_ena,
599 ST21NFCA_GPIO_NAME_EN);
601 pr_err("%s : ena gpio_request failed\n", __FILE__);
606 phy->se_status.is_ese_present = pdata->is_ese_present;
607 phy->se_status.is_uicc_present = pdata->is_uicc_present;
612 static int st21nfca_hci_i2c_probe(struct i2c_client *client,
613 const struct i2c_device_id *id)
615 struct st21nfca_i2c_phy *phy;
616 struct st21nfca_nfc_platform_data *pdata;
619 dev_dbg(&client->dev, "%s\n", __func__);
620 dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
622 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
623 nfc_err(&client->dev, "Need I2C_FUNC_I2C\n");
627 phy = devm_kzalloc(&client->dev, sizeof(struct st21nfca_i2c_phy),
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)
637 phy->current_read_len = 0;
639 mutex_init(&phy->phy_lock);
640 i2c_set_clientdata(client, phy);
642 pdata = client->dev.platform_data;
643 if (!pdata && client->dev.of_node) {
644 r = st21nfca_hci_i2c_of_request_resources(client);
646 nfc_err(&client->dev, "No platform data\n");
650 r = st21nfca_hci_i2c_request_resources(client);
652 nfc_err(&client->dev, "Cannot get platform resources\n");
655 } else if (ACPI_HANDLE(&client->dev)) {
656 r = st21nfca_hci_i2c_acpi_request_resources(client);
658 nfc_err(&client->dev, "Cannot get ACPI data\n");
662 nfc_err(&client->dev, "st21nfca platform resources not available\n");
666 r = st21nfca_hci_platform_init(phy);
668 nfc_err(&client->dev, "Unable to reboot st21nfca\n");
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);
677 nfc_err(&client->dev, "Unable to register IRQ handler\n");
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,
689 static int st21nfca_hci_i2c_remove(struct i2c_client *client)
691 struct st21nfca_i2c_phy *phy = i2c_get_clientdata(client);
693 dev_dbg(&client->dev, "%s\n", __func__);
695 st21nfca_hci_remove(phy->hdev);
698 st21nfca_hci_i2c_disable(phy);
703 static struct i2c_device_id st21nfca_hci_i2c_id_table[] = {
704 {ST21NFCA_HCI_DRIVER_NAME, 0},
707 MODULE_DEVICE_TABLE(i2c, st21nfca_hci_i2c_id_table);
709 static const struct acpi_device_id st21nfca_hci_i2c_acpi_match[] = {
713 MODULE_DEVICE_TABLE(acpi, st21nfca_hci_i2c_acpi_match);
715 static const struct of_device_id of_st21nfca_i2c_match[] = {
716 { .compatible = "st,st21nfca-i2c", },
717 { .compatible = "st,st21nfca_i2c", },
720 MODULE_DEVICE_TABLE(of, of_st21nfca_i2c_match);
722 static struct i2c_driver st21nfca_hci_i2c_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),
728 .probe = st21nfca_hci_i2c_probe,
729 .id_table = st21nfca_hci_i2c_id_table,
730 .remove = st21nfca_hci_i2c_remove,
732 module_i2c_driver(st21nfca_hci_i2c_driver);
734 MODULE_LICENSE("GPL");
735 MODULE_DESCRIPTION(DRIVER_DESC);