NFC: HCI based pn544 driver

This is an NFC driver for NXP pn544.
Unlike pn544.c, this one is based on the NFC HCI and SHDLC kernel layers.

Signed-off-by: Eric Lapuyade <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>
Signed-off-by: John W. Linville <[e-mail]>

drivers/nfc/Kconfig

···
 	  To compile this driver as a module, choose m here. The module will
 	  be called pn544.
 
+config PN544_HCI_NFC
+	tristate "HCI PN544 NFC driver"
+	depends on I2C && NFC_SHDLC
+	select CRC_CCITT
+	default n
+	---help---
+	  NXP PN544 i2c driver.
+	  This is a driver based on the SHDLC and HCI NFC kernel layers and
+	  will thus not work with NXP libnfc library.
+
+	  To compile this driver as a module, choose m here. The module will
+	  be called pn544_hci.
+
 config NFC_PN533
 	tristate "NXP PN533 USB driver"
 	depends on USB

drivers/nfc/Makefile

···
 #
 
 obj-$(CONFIG_PN544_NFC)		+= pn544.o
+obj-$(CONFIG_PN544_HCI_NFC)	+= pn544_hci.o
 obj-$(CONFIG_NFC_PN533)		+= pn533.o
 obj-$(CONFIG_NFC_WILINK)	+= nfcwilink.o
 

drivers/nfc/pn544_hci.c

···
+/*
+ * HCI based Driver for NXP PN544 NFC Chip
+ *
+ * Copyright (C) 2012  Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/crc-ccitt.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/miscdevice.h>
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+
+#include <linux/nfc.h>
+#include <net/nfc/hci.h>
+#include <net/nfc/shdlc.h>
+
+#include <linux/nfc/pn544.h>
+
+#define DRIVER_DESC "HCI NFC driver for PN544"
+
+#define PN544_HCI_DRIVER_NAME "pn544_hci"
+
+/* Timing restrictions (ms) */
+#define PN544_HCI_RESETVEN_TIME		30
+
+static struct i2c_device_id pn544_hci_id_table[] = {
+	{"pn544", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, pn544_hci_id_table);
+
+#define HCI_MODE 0
+#define FW_MODE 1
+
+/* framing in HCI mode */
+#define PN544_HCI_LLC_LEN		1
+#define PN544_HCI_LLC_CRC		2
+#define PN544_HCI_LLC_LEN_CRC		(PN544_HCI_LLC_LEN + PN544_HCI_LLC_CRC)
+#define PN544_HCI_LLC_MIN_SIZE		(1 + PN544_HCI_LLC_LEN_CRC)
+#define PN544_HCI_LLC_MAX_PAYLOAD	29
+#define PN544_HCI_LLC_MAX_SIZE		(PN544_HCI_LLC_LEN_CRC + 1 + \
+					 PN544_HCI_LLC_MAX_PAYLOAD)
+
+enum pn544_state {
+	PN544_ST_COLD,
+	PN544_ST_FW_READY,
+	PN544_ST_READY,
+};
+
+#define FULL_VERSION_LEN 11
+
+/* Proprietary commands */
+#define PN544_WRITE		0x3f
+
+/* Proprietary gates, events, commands and registers */
+
+/* NFC_HCI_RF_READER_A_GATE additional registers and commands */
+#define PN544_RF_READER_A_AUTO_ACTIVATION			0x10
+#define PN544_RF_READER_A_CMD_CONTINUE_ACTIVATION		0x12
+#define PN544_MIFARE_CMD					0x21
+
+/* Commands that apply to all RF readers */
+#define PN544_RF_READER_CMD_PRESENCE_CHECK	0x30
+#define PN544_RF_READER_CMD_ACTIVATE_NEXT	0x32
+
+/* NFC_HCI_ID_MGMT_GATE additional registers */
+#define PN544_ID_MGMT_FULL_VERSION_SW		0x10
+
+#define PN544_RF_READER_ISO15693_GATE		0x12
+
+#define PN544_RF_READER_F_GATE			0x14
+#define PN544_FELICA_ID				0x04
+#define PN544_FELICA_RAW			0x20
+
+#define PN544_RF_READER_JEWEL_GATE		0x15
+#define PN544_JEWEL_RAW_CMD			0x23
+
+#define PN544_RF_READER_NFCIP1_INITIATOR_GATE	0x30
+#define PN544_RF_READER_NFCIP1_TARGET_GATE	0x31
+
+#define PN544_SYS_MGMT_GATE			0x90
+#define PN544_SYS_MGMT_INFO_NOTIFICATION	0x02
+
+#define PN544_POLLING_LOOP_MGMT_GATE		0x94
+#define PN544_PL_RDPHASES			0x06
+#define PN544_PL_EMULATION			0x07
+#define PN544_PL_NFCT_DEACTIVATED		0x09
+
+#define PN544_SWP_MGMT_GATE			0xA0
+
+#define PN544_NFC_WI_MGMT_GATE			0xA1
+
+static u8 pn544_custom_gates[] = {
+	PN544_SYS_MGMT_GATE,
+	PN544_SWP_MGMT_GATE,
+	PN544_POLLING_LOOP_MGMT_GATE,
+	PN544_NFC_WI_MGMT_GATE,
+	PN544_RF_READER_F_GATE,
+	PN544_RF_READER_JEWEL_GATE,
+	PN544_RF_READER_ISO15693_GATE,
+	PN544_RF_READER_NFCIP1_INITIATOR_GATE,
+	PN544_RF_READER_NFCIP1_TARGET_GATE
+};
+
+/* Largest headroom needed for outgoing custom commands */
+#define PN544_CMDS_HEADROOM	2
+
+struct pn544_hci_info {
+	struct i2c_client *i2c_dev;
+	struct nfc_shdlc *shdlc;
+
+	enum pn544_state state;
+
+	struct mutex info_lock;
+
+	unsigned int gpio_en;
+	unsigned int gpio_irq;
+	unsigned int gpio_fw;
+	unsigned int en_polarity;
+
+	int hard_fault;		/*
+				 * < 0 if hardware error occured (e.g. i2c err)
+				 * and prevents normal operation.
+				 */
+};
+
+static void pn544_hci_platform_init(struct pn544_hci_info *info)
+{
+	int polarity, retry, ret;
+	char rset_cmd[] = { 0x05, 0xF9, 0x04, 0x00, 0xC3, 0xE5 };
+	int count = sizeof(rset_cmd);
+
+	pr_info(DRIVER_DESC ": %s\n", __func__);
+	dev_info(&info->i2c_dev->dev, "Detecting nfc_en polarity\n");
+
+	/* Disable fw download */
+	gpio_set_value(info->gpio_fw, 0);
+
+	for (polarity = 0; polarity < 2; polarity++) {
+		info->en_polarity = polarity;
+		retry = 3;
+		while (retry--) {
+			/* power off */
+			gpio_set_value(info->gpio_en, !info->en_polarity);
+			usleep_range(10000, 15000);
+
+			/* power on */
+			gpio_set_value(info->gpio_en, info->en_polarity);
+			usleep_range(10000, 15000);
+
+			/* send reset */
+			dev_dbg(&info->i2c_dev->dev, "Sending reset cmd\n");
+			ret = i2c_master_send(info->i2c_dev, rset_cmd, count);
+			if (ret == count) {
+				dev_info(&info->i2c_dev->dev,
+					 "nfc_en polarity : active %s\n",
+					 (polarity == 0 ? "low" : "high"));
+				goto out;
+			}
+		}
+	}
+
+	dev_err(&info->i2c_dev->dev,
+		"Could not detect nfc_en polarity, fallback to active high\n");
+
+out:
+	gpio_set_value(info->gpio_en, !info->en_polarity);
+}
+
+static int pn544_hci_enable(struct pn544_hci_info *info, int mode)
+{
+	pr_info(DRIVER_DESC ": %s\n", __func__);
+
+	gpio_set_value(info->gpio_fw, 0);
+	gpio_set_value(info->gpio_en, info->en_polarity);
+	usleep_range(10000, 15000);
+
+	return 0;
+}
+
+static void pn544_hci_disable(struct pn544_hci_info *info)
+{
+	pr_info(DRIVER_DESC ": %s\n", __func__);
+
+	gpio_set_value(info->gpio_fw, 0);
+	gpio_set_value(info->gpio_en, !info->en_polarity);
+	usleep_range(10000, 15000);
+
+	gpio_set_value(info->gpio_en, info->en_polarity);
+	usleep_range(10000, 15000);
+
+	gpio_set_value(info->gpio_en, !info->en_polarity);
+	usleep_range(10000, 15000);
+}
+
+static int pn544_hci_i2c_write(struct i2c_client *client, u8 *buf, int len)
+{
+	int r;
+
+	usleep_range(3000, 6000);
+
+	r = i2c_master_send(client, buf, len);
+
+	if (r == -EREMOTEIO) {	/* Retry, chip was in standby */
+		usleep_range(6000, 10000);
+		r = i2c_master_send(client, buf, len);
+	}
+
+	if (r >= 0 && r != len)
+		r = -EREMOTEIO;
+
+	return r;
+}
+
+static int check_crc(u8 *buf, int buflen)
+{
+	u8 len;
+	u16 crc;
+
+	len = buf[0] + 1;
+	crc = crc_ccitt(0xffff, buf, len - 2);
+	crc = ~crc;
+
+	if (buf[len - 2] != (crc & 0xff) || buf[len - 1] != (crc >> 8)) {
+		pr_err(PN544_HCI_DRIVER_NAME ": CRC error 0x%x != 0x%x 0x%x\n",
+		       crc, buf[len - 1], buf[len - 2]);
+
+		pr_info(DRIVER_DESC ": %s : BAD CRC\n", __func__);
+		print_hex_dump(KERN_DEBUG, "crc: ", DUMP_PREFIX_NONE,
+			       16, 2, buf, buflen, false);
+		return -EPERM;
+	}
+	return 0;
+}
+
+/*
+ * Reads an shdlc frame and returns it in a newly allocated sk_buff. Guarantees
+ * that i2c bus will be flushed and that next read will start on a new frame.
+ * returned skb contains only LLC header and payload.
+ * returns:
+ * -EREMOTEIO : i2c read error (fatal)
+ * -EBADMSG : frame was incorrect and discarded
+ * -ENOMEM : cannot allocate skb, frame dropped
+ */
+static int pn544_hci_i2c_read(struct i2c_client *client, struct sk_buff **skb)
+{
+	int r;
+	u8 len;
+	u8 tmp[PN544_HCI_LLC_MAX_SIZE - 1];
+
+	r = i2c_master_recv(client, &len, 1);
+	if (r != 1) {
+		dev_err(&client->dev, "cannot read len byte\n");
+		return -EREMOTEIO;
+	}
+
+	if ((len < (PN544_HCI_LLC_MIN_SIZE - 1)) ||
+	    (len > (PN544_HCI_LLC_MAX_SIZE - 1))) {
+		dev_err(&client->dev, "invalid len byte\n");
+		r = -EBADMSG;
+		goto flush;
+	}
+
+	*skb = alloc_skb(1 + len, GFP_KERNEL);
+	if (*skb == NULL) {
+		r = -ENOMEM;
+		goto flush;
+	}
+
+	*skb_put(*skb, 1) = len;
+
+	r = i2c_master_recv(client, skb_put(*skb, len), len);
+	if (r != len) {
+		kfree_skb(*skb);
+		return -EREMOTEIO;
+	}
+
+	r = check_crc((*skb)->data, (*skb)->len);
+	if (r != 0) {
+		kfree_skb(*skb);
+		r = -EBADMSG;
+		goto flush;
+	}
+
+	skb_pull(*skb, 1);
+	skb_trim(*skb, (*skb)->len - 2);
+
+	usleep_range(3000, 6000);
+
+	return 0;
+
+flush:
+	if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
+		r = -EREMOTEIO;
+
+	usleep_range(3000, 6000);
+
+	return r;
+}
+
+/*
+ * Reads an shdlc frame from the chip. This is not as straightforward as it
+ * seems. There are cases where we could loose the frame start synchronization.
+ * The frame format is len-data-crc, and corruption can occur anywhere while
+ * transiting on i2c bus, such that we could read an invalid len.
+ * In order to recover synchronization with the next frame, we must be sure
+ * to read the real amount of data without using the len byte. We do this by
+ * assuming the following:
+ * - the chip will always present only one single complete frame on the bus
+ *   before triggering the interrupt
+ * - the chip will not present a new frame until we have completely read
+ *   the previous one (or until we have handled the interrupt).
+ * The tricky case is when we read a corrupted len that is less than the real
+ * len. We must detect this here in order to determine that we need to flush
+ * the bus. This is the reason why we check the crc here.
+ */
+static irqreturn_t pn544_hci_irq_thread_fn(int irq, void *dev_id)
+{
+	struct pn544_hci_info *info = dev_id;
+	struct i2c_client *client = info->i2c_dev;
+	struct sk_buff *skb = NULL;
+	int r;
+
+	BUG_ON(!info);
+	BUG_ON(irq != info->i2c_dev->irq);
+
+	dev_dbg(&client->dev, "IRQ\n");
+
+	if (info->hard_fault != 0)
+		return IRQ_HANDLED;
+
+	r = pn544_hci_i2c_read(client, &skb);
+	if (r == -EREMOTEIO) {
+		info->hard_fault = r;
+
+		nfc_shdlc_recv_frame(info->shdlc, NULL);
+
+		return IRQ_HANDLED;
+	} else if ((r == -ENOMEM) || (r == -EBADMSG)) {
+		return IRQ_HANDLED;
+	}
+
+	nfc_shdlc_recv_frame(info->shdlc, skb);
+
+	return IRQ_HANDLED;
+}
+
+static int pn544_hci_open(struct nfc_shdlc *shdlc)
+{
+	struct pn544_hci_info *info = nfc_shdlc_get_clientdata(shdlc);
+	int r = 0;
+
+	mutex_lock(&info->info_lock);
+
+	if (info->state != PN544_ST_COLD) {
+		r = -EBUSY;
+		goto out;
+	}
+
+	r = pn544_hci_enable(info, HCI_MODE);
+
+out:
+	mutex_unlock(&info->info_lock);
+	return r;
+}
+
+static void pn544_hci_close(struct nfc_shdlc *shdlc)
+{
+	struct pn544_hci_info *info = nfc_shdlc_get_clientdata(shdlc);
+
+	mutex_lock(&info->info_lock);
+
+	if (info->state == PN544_ST_COLD)
+		goto out;
+
+	pn544_hci_disable(info);
+
+out:
+	mutex_unlock(&info->info_lock);
+}
+
+static int pn544_hci_ready(struct nfc_shdlc *shdlc)
+{
+	struct nfc_hci_dev *hdev = nfc_shdlc_get_hci_dev(shdlc);
+	struct sk_buff *skb;
+	static struct hw_config {
+		u8 adr[2];
+		u8 value;
+	} hw_config[] = {
+		{{0x9f, 0x9a}, 0x00},
+
+		{{0x98, 0x10}, 0xbc},
+
+		{{0x9e, 0x71}, 0x00},
+
+		{{0x98, 0x09}, 0x00},
+
+		{{0x9e, 0xb4}, 0x00},
+
+		{{0x9e, 0xd9}, 0xff},
+		{{0x9e, 0xda}, 0xff},
+		{{0x9e, 0xdb}, 0x23},
+		{{0x9e, 0xdc}, 0x21},
+		{{0x9e, 0xdd}, 0x22},
+		{{0x9e, 0xde}, 0x24},
+
+		{{0x9c, 0x01}, 0x08},
+
+		{{0x9e, 0xaa}, 0x01},
+
+		{{0x9b, 0xd1}, 0x0d},
+		{{0x9b, 0xd2}, 0x24},
+		{{0x9b, 0xd3}, 0x0a},
+		{{0x9b, 0xd4}, 0x22},
+		{{0x9b, 0xd5}, 0x08},
+		{{0x9b, 0xd6}, 0x1e},
+		{{0x9b, 0xdd}, 0x1c},
+
+		{{0x9b, 0x84}, 0x13},
+		{{0x99, 0x81}, 0x7f},
+		{{0x99, 0x31}, 0x70},
+
+		{{0x98, 0x00}, 0x3f},
+
+		{{0x9f, 0x09}, 0x00},
+
+		{{0x9f, 0x0a}, 0x05},
+
+		{{0x9e, 0xd1}, 0xa1},
+		{{0x99, 0x23}, 0x00},
+
+		{{0x9e, 0x74}, 0x80},
+
+		{{0x9f, 0x28}, 0x10},
+
+		{{0x9f, 0x35}, 0x14},
+
+		{{0x9f, 0x36}, 0x60},
+
+		{{0x9c, 0x31}, 0x00},
+
+		{{0x9c, 0x32}, 0xc8},
+
+		{{0x9c, 0x19}, 0x40},
+
+		{{0x9c, 0x1a}, 0x40},
+
+		{{0x9c, 0x0c}, 0x00},
+
+		{{0x9c, 0x0d}, 0x00},
+
+		{{0x9c, 0x12}, 0x00},
+
+		{{0x9c, 0x13}, 0x00},
+
+		{{0x98, 0xa2}, 0x0e},
+
+		{{0x98, 0x93}, 0x40},
+
+		{{0x98, 0x7d}, 0x02},
+		{{0x98, 0x7e}, 0x00},
+		{{0x9f, 0xc8}, 0x01},
+	};
+	struct hw_config *p = hw_config;
+	int count = ARRAY_SIZE(hw_config);
+	struct sk_buff *res_skb;
+	u8 param[4];
+	int r;
+
+	param[0] = 0;
+	while (count--) {
+		param[1] = p->adr[0];
+		param[2] = p->adr[1];
+		param[3] = p->value;
+
+		r = nfc_hci_send_cmd(hdev, PN544_SYS_MGMT_GATE, PN544_WRITE,
+				     param, 4, &res_skb);
+		if (r < 0)
+			return r;
+
+		if (res_skb->len != 1) {
+			kfree_skb(res_skb);
+			return -EPROTO;
+		}
+
+		if (res_skb->data[0] != p->value) {
+			kfree_skb(res_skb);
+			return -EIO;
+		}
+
+		kfree_skb(res_skb);
+
+		p++;
+	}
+
+	param[0] = NFC_HCI_UICC_HOST_ID;
+	r = nfc_hci_set_param(hdev, NFC_HCI_ADMIN_GATE,
+			      NFC_HCI_ADMIN_WHITELIST, param, 1);
+	if (r < 0)
+		return r;
+
+	param[0] = 0x3d;
+	r = nfc_hci_set_param(hdev, PN544_SYS_MGMT_GATE,
+			      PN544_SYS_MGMT_INFO_NOTIFICATION, param, 1);
+	if (r < 0)
+		return r;
+
+	param[0] = 0x0;
+	r = nfc_hci_set_param(hdev, NFC_HCI_RF_READER_A_GATE,
+			      PN544_RF_READER_A_AUTO_ACTIVATION, param, 1);
+	if (r < 0)
+		return r;
+
+	r = nfc_hci_send_event(hdev, NFC_HCI_RF_READER_A_GATE,
+			       NFC_HCI_EVT_END_OPERATION, NULL, 0);
+	if (r < 0)
+		return r;
+
+	param[0] = 0x1;
+	r = nfc_hci_set_param(hdev, PN544_POLLING_LOOP_MGMT_GATE,
+			      PN544_PL_NFCT_DEACTIVATED, param, 1);
+	if (r < 0)
+		return r;
+
+	param[0] = 0x0;
+	r = nfc_hci_set_param(hdev, PN544_POLLING_LOOP_MGMT_GATE,
+			      PN544_PL_RDPHASES, param, 1);
+	if (r < 0)
+		return r;
+
+	r = nfc_hci_get_param(hdev, NFC_HCI_ID_MGMT_GATE,
+			      PN544_ID_MGMT_FULL_VERSION_SW, &skb);
+	if (r < 0)
+		return r;
+
+	if (skb->len != FULL_VERSION_LEN) {
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+
+	print_hex_dump(KERN_DEBUG, "FULL VERSION SOFTWARE INFO: ",
+		       DUMP_PREFIX_NONE, 16, 1,
+		       skb->data, FULL_VERSION_LEN, false);
+
+	kfree_skb(skb);
+
+	return 0;
+}
+
+static int pn544_hci_xmit(struct nfc_shdlc *shdlc, struct sk_buff *skb)
+{
+	struct pn544_hci_info *info = nfc_shdlc_get_clientdata(shdlc);
+	struct i2c_client *client = info->i2c_dev;
+
+	if (info->hard_fault != 0)
+		return info->hard_fault;
+
+	return pn544_hci_i2c_write(client, skb->data, skb->len);
+}
+
+static int pn544_hci_start_poll(struct nfc_shdlc *shdlc, u32 protocols)
+{
+	struct nfc_hci_dev *hdev = nfc_shdlc_get_hci_dev(shdlc);
+	u8 phases = 0;
+	int r;
+	u8 duration[2];
+	u8 activated;
+
+	pr_info(DRIVER_DESC ": %s protocols = %d\n", __func__, protocols);
+
+	r = nfc_hci_send_event(hdev, NFC_HCI_RF_READER_A_GATE,
+			       NFC_HCI_EVT_END_OPERATION, NULL, 0);
+	if (r < 0)
+		return r;
+
+	duration[0] = 0x18;
+	duration[1] = 0x6a;
+	r = nfc_hci_set_param(hdev, PN544_POLLING_LOOP_MGMT_GATE,
+			      PN544_PL_EMULATION, duration, 2);
+	if (r < 0)
+		return r;
+
+	activated = 0;
+	r = nfc_hci_set_param(hdev, PN544_POLLING_LOOP_MGMT_GATE,
+			      PN544_PL_NFCT_DEACTIVATED, &activated, 1);
+	if (r < 0)
+		return r;
+
+	if (protocols & (NFC_PROTO_ISO14443_MASK | NFC_PROTO_MIFARE_MASK |
+			 NFC_PROTO_JEWEL_MASK))
+		phases |= 1;		/* Type A */
+	if (protocols & NFC_PROTO_FELICA_MASK) {
+		phases |= (1 << 2);	/* Type F 212 */
+		phases |= (1 << 3);	/* Type F 424 */
+	}
+
+	phases |= (1 << 5);		/* NFC active */
+
+	r = nfc_hci_set_param(hdev, PN544_POLLING_LOOP_MGMT_GATE,
+			      PN544_PL_RDPHASES, &phases, 1);
+	if (r < 0)
+		return r;
+
+	r = nfc_hci_send_event(hdev, NFC_HCI_RF_READER_A_GATE,
+			       NFC_HCI_EVT_READER_REQUESTED, NULL, 0);
+	if (r < 0)
+		nfc_hci_send_event(hdev, NFC_HCI_RF_READER_A_GATE,
+				   NFC_HCI_EVT_END_OPERATION, NULL, 0);
+
+	return r;
+}
+
+static int pn544_hci_target_from_gate(struct nfc_shdlc *shdlc, u8 gate,
+				      struct nfc_target *target)
+{
+	switch (gate) {
+	case PN544_RF_READER_F_GATE:
+		target->supported_protocols = NFC_PROTO_FELICA_MASK;
+		break;
+	case PN544_RF_READER_JEWEL_GATE:
+		target->supported_protocols = NFC_PROTO_JEWEL_MASK;
+		target->sens_res = 0x0c00;
+		break;
+	default:
+		return -EPROTO;
+	}
+
+	return 0;
+}
+
+static int pn544_hci_complete_target_discovered(struct nfc_shdlc *shdlc,
+						u8 gate,
+						struct nfc_target *target)
+{
+	struct nfc_hci_dev *hdev = nfc_shdlc_get_hci_dev(shdlc);
+	struct sk_buff *uid_skb;
+	int r = 0;
+
+	if (target->supported_protocols & NFC_PROTO_MIFARE_MASK) {
+		if (target->nfcid1_len != 4 && target->nfcid1_len != 7 &&
+		    target->nfcid1_len != 10)
+			return -EPROTO;
+
+		r = nfc_hci_send_cmd(hdev, NFC_HCI_RF_READER_A_GATE,
+				     PN544_RF_READER_CMD_ACTIVATE_NEXT,
+				     target->nfcid1, target->nfcid1_len, NULL);
+	} else if (target->supported_protocols & NFC_PROTO_FELICA_MASK) {
+		r = nfc_hci_get_param(hdev, PN544_RF_READER_F_GATE,
+				      PN544_FELICA_ID, &uid_skb);
+		if (r < 0)
+			return r;
+
+		if (uid_skb->len != 8) {
+			kfree_skb(uid_skb);
+			return -EPROTO;
+		}
+
+		r = nfc_hci_send_cmd(hdev, PN544_RF_READER_F_GATE,
+				     PN544_RF_READER_CMD_ACTIVATE_NEXT,
+				     uid_skb->data, uid_skb->len, NULL);
+		kfree_skb(uid_skb);
+	} else if (target->supported_protocols & NFC_PROTO_ISO14443_MASK) {
+		/*
+		 * TODO: maybe other ISO 14443 require some kind of continue
+		 * activation, but for now we've seen only this one below.
+		 */
+		if (target->sens_res == 0x4403)	/* Type 4 Mifare DESFire */
+			r = nfc_hci_send_cmd(hdev, NFC_HCI_RF_READER_A_GATE,
+			      PN544_RF_READER_A_CMD_CONTINUE_ACTIVATION,
+			      NULL, 0, NULL);
+	}
+
+	return r;
+}
+
+#define MIFARE_CMD_AUTH_KEY_A	0x60
+#define MIFARE_CMD_AUTH_KEY_B	0x61
+#define MIFARE_CMD_HEADER	2
+#define MIFARE_UID_LEN		4
+#define MIFARE_KEY_LEN		6
+#define MIFARE_CMD_LEN		12
+/*
+ * Returns:
+ * <= 0: driver handled the data exchange
+ *    1: driver doesn't especially handle, please do standard processing
+ */
+static int pn544_hci_data_exchange(struct nfc_shdlc *shdlc,
+				   struct nfc_target *target,
+				   struct sk_buff *skb,
+				   struct sk_buff **res_skb)
+{
+	struct nfc_hci_dev *hdev = nfc_shdlc_get_hci_dev(shdlc);
+	int r;
+
+	pr_info(DRIVER_DESC ": %s for gate=%d\n", __func__,
+		target->hci_reader_gate);
+
+	switch (target->hci_reader_gate) {
+	case NFC_HCI_RF_READER_A_GATE:
+		if (target->supported_protocols & NFC_PROTO_MIFARE_MASK) {
+			/*
+			 * It seems that pn544 is inverting key and UID for
+			 * MIFARE authentication commands.
+			 */
+			if (skb->len == MIFARE_CMD_LEN &&
+			    (skb->data[0] == MIFARE_CMD_AUTH_KEY_A ||
+			     skb->data[0] == MIFARE_CMD_AUTH_KEY_B)) {
+				u8 uid[MIFARE_UID_LEN];
+				u8 *data = skb->data + MIFARE_CMD_HEADER;
+
+				memcpy(uid, data + MIFARE_KEY_LEN,
+				       MIFARE_UID_LEN);
+				memmove(data + MIFARE_UID_LEN, data,
+					MIFARE_KEY_LEN);
+				memcpy(data, uid, MIFARE_UID_LEN);
+			}
+
+			return nfc_hci_send_cmd(hdev, target->hci_reader_gate,
+						PN544_MIFARE_CMD,
+						skb->data, skb->len, res_skb);
+		} else
+			return 1;
+	case PN544_RF_READER_F_GATE:
+		*skb_push(skb, 1) = 0;
+		*skb_push(skb, 1) = 0;
+
+		r = nfc_hci_send_cmd(hdev, target->hci_reader_gate,
+				     PN544_FELICA_RAW,
+				     skb->data, skb->len, res_skb);
+		if (r == 0)
+			skb_pull(*res_skb, 1);
+		return r;
+	case PN544_RF_READER_JEWEL_GATE:
+		return nfc_hci_send_cmd(hdev, target->hci_reader_gate,
+					PN544_JEWEL_RAW_CMD,
+					skb->data, skb->len, res_skb);
+	default:
+		return 1;
+	}
+}
+
+static int pn544_hci_check_presence(struct nfc_shdlc *shdlc,
+				   struct nfc_target *target)
+{
+	struct nfc_hci_dev *hdev = nfc_shdlc_get_hci_dev(shdlc);
+
+	return nfc_hci_send_cmd(hdev, target->hci_reader_gate,
+				PN544_RF_READER_CMD_PRESENCE_CHECK,
+				NULL, 0, NULL);
+}
+
+static struct nfc_shdlc_ops pn544_shdlc_ops = {
+	.open = pn544_hci_open,
+	.close = pn544_hci_close,
+	.hci_ready = pn544_hci_ready,
+	.xmit = pn544_hci_xmit,
+	.start_poll = pn544_hci_start_poll,
+	.target_from_gate = pn544_hci_target_from_gate,
+	.complete_target_discovered = pn544_hci_complete_target_discovered,
+	.data_exchange = pn544_hci_data_exchange,
+	.check_presence = pn544_hci_check_presence,
+};
+
+static int __devinit pn544_hci_probe(struct i2c_client *client,
+				     const struct i2c_device_id *id)
+{
+	struct pn544_hci_info *info;
+	struct pn544_nfc_platform_data *pdata;
+	int r = 0;
+	u32 protocols;
+	struct nfc_hci_init_data init_data;
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+	dev_dbg(&client->dev, "IRQ: %d\n", client->irq);
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		dev_err(&client->dev, "Need I2C_FUNC_I2C\n");
+		return -ENODEV;
+	}
+
+	info = kzalloc(sizeof(struct pn544_hci_info), GFP_KERNEL);
+	if (!info) {
+		dev_err(&client->dev,
+			"Cannot allocate memory for pn544_hci_info.\n");
+		r = -ENOMEM;
+		goto err_info_alloc;
+	}
+
+	info->i2c_dev = client;
+	info->state = PN544_ST_COLD;
+	mutex_init(&info->info_lock);
+	i2c_set_clientdata(client, info);
+
+	pdata = client->dev.platform_data;
+	if (pdata == NULL) {
+		dev_err(&client->dev, "No platform data\n");
+		r = -EINVAL;
+		goto err_pdata;
+	}
+
+	if (pdata->request_resources == NULL) {
+		dev_err(&client->dev, "request_resources() missing\n");
+		r = -EINVAL;
+		goto err_pdata;
+	}
+
+	r = pdata->request_resources(client);
+	if (r) {
+		dev_err(&client->dev, "Cannot get platform resources\n");
+		goto err_pdata;
+	}
+
+	info->gpio_en = pdata->get_gpio(NFC_GPIO_ENABLE);
+	info->gpio_fw = pdata->get_gpio(NFC_GPIO_FW_RESET);
+	info->gpio_irq = pdata->get_gpio(NFC_GPIO_IRQ);
+
+	pn544_hci_platform_init(info);
+
+	r = request_threaded_irq(client->irq, NULL, pn544_hci_irq_thread_fn,
+				 IRQF_TRIGGER_RISING, PN544_HCI_DRIVER_NAME,
+				 info);
+	if (r < 0) {
+		dev_err(&client->dev, "Unable to register IRQ handler\n");
+		goto err_rti;
+	}
+
+	init_data.gate_count = ARRAY_SIZE(pn544_custom_gates);
+
+	memcpy(init_data.gates, pn544_custom_gates,
+	       ARRAY_SIZE(pn544_custom_gates));
+
+	/*
+	 * TODO: Session id must include the driver name + some bus addr
+	 * persistent info to discriminate 2 identical chips
+	 */
+	strcpy(init_data.session_id, "ID544HCI");
+
+	protocols = NFC_PROTO_JEWEL_MASK |
+		    NFC_PROTO_MIFARE_MASK |
+		    NFC_PROTO_FELICA_MASK |
+		    NFC_PROTO_ISO14443_MASK |
+		    NFC_PROTO_NFC_DEP_MASK;
+
+	info->shdlc = nfc_shdlc_allocate(&pn544_shdlc_ops,
+					 &init_data, protocols,
+					 PN544_CMDS_HEADROOM, 0,
+					 PN544_HCI_LLC_MAX_PAYLOAD,
+					 dev_name(&client->dev));
+	if (!info->shdlc) {
+		dev_err(&client->dev, "Cannot allocate nfc shdlc.\n");
+		r = -ENOMEM;
+		goto err_allocshdlc;
+	}
+
+	nfc_shdlc_set_clientdata(info->shdlc, info);
+
+	return 0;
+
+err_allocshdlc:
+	free_irq(client->irq, info);
+
+err_rti:
+	if (pdata->free_resources != NULL)
+		pdata->free_resources();
+
+err_pdata:
+	kfree(info);
+
+err_info_alloc:
+	return r;
+}
+
+static __devexit int pn544_hci_remove(struct i2c_client *client)
+{
+	struct pn544_hci_info *info = i2c_get_clientdata(client);
+	struct pn544_nfc_platform_data *pdata = client->dev.platform_data;
+
+	dev_dbg(&client->dev, "%s\n", __func__);
+
+	nfc_shdlc_free(info->shdlc);
+
+	if (info->state != PN544_ST_COLD) {
+		if (pdata->disable)
+			pdata->disable();
+	}
+
+	free_irq(client->irq, info);
+	if (pdata->free_resources)
+		pdata->free_resources();
+
+	kfree(info);
+
+	return 0;
+}
+
+static struct i2c_driver pn544_hci_driver = {
+	.driver = {
+		   .name = PN544_HCI_DRIVER_NAME,
+		  },
+	.probe = pn544_hci_probe,
+	.id_table = pn544_hci_id_table,
+	.remove = __devexit_p(pn544_hci_remove),
+};
+
+static int __init pn544_hci_init(void)
+{
+	int r;
+
+	pr_debug(DRIVER_DESC ": %s\n", __func__);
+
+	r = i2c_add_driver(&pn544_hci_driver);
+	if (r) {
+		pr_err(PN544_HCI_DRIVER_NAME ": driver registration failed\n");
+		return r;
+	}
+
+	return 0;
+}
+
+static void __exit pn544_hci_exit(void)
+{
+	i2c_del_driver(&pn544_hci_driver);
+}
+
+module_init(pn544_hci_init);
+module_exit(pn544_hci_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);

include/linux/nfc/pn544.h

···
 };
 
 #ifdef __KERNEL__
+enum {
+	NFC_GPIO_ENABLE,
+	NFC_GPIO_FW_RESET,
+	NFC_GPIO_IRQ
+};
+
 /* board config */
 struct pn544_nfc_platform_data {
 	int (*request_resources) (struct i2c_client *client);
···
 	void (*enable) (int fw);
 	int (*test) (void);
 	void (*disable) (void);
+	int (*get_gpio)(int type);
 };
 #endif /* __KERNEL__ */