/*
   * I2C Link Layer for PN544 HCI based Driver
   *
   * 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, see <http://www.gnu.org/licenses/>.
   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/crc-ccitt.h>
  #include <linux/module.h>
  #include <linux/i2c.h>
  #include <linux/gpio.h>
  #include <linux/miscdevice.h>
  #include <linux/interrupt.h>
  #include <linux/delay.h>
  #include <linux/nfc.h>
  #include <linux/firmware.h>
  #include <linux/unaligned/access_ok.h>
  #include <linux/platform_data/pn544.h>
  
  #include <net/nfc/hci.h>
  #include <net/nfc/llc.h>
  #include <net/nfc/nfc.h>
  
  #include "pn544.h"
  
  #define PN544_I2C_FRAME_HEADROOM 1
  #define PN544_I2C_FRAME_TAILROOM 2
  
  /* framing in HCI mode */
  #define PN544_HCI_I2C_LLC_LEN		1
  #define PN544_HCI_I2C_LLC_CRC		2
  #define PN544_HCI_I2C_LLC_LEN_CRC	(PN544_HCI_I2C_LLC_LEN + \
  					 PN544_HCI_I2C_LLC_CRC)
  #define PN544_HCI_I2C_LLC_MIN_SIZE	(1 + PN544_HCI_I2C_LLC_LEN_CRC)
  #define PN544_HCI_I2C_LLC_MAX_PAYLOAD	29
  #define PN544_HCI_I2C_LLC_MAX_SIZE	(PN544_HCI_I2C_LLC_LEN_CRC + 1 + \
  					 PN544_HCI_I2C_LLC_MAX_PAYLOAD)
  
  static struct i2c_device_id pn544_hci_i2c_id_table[] = {
  	{"pn544", 0},
  	{}
  };
  
  MODULE_DEVICE_TABLE(i2c, pn544_hci_i2c_id_table);
  
  #define PN544_HCI_I2C_DRIVER_NAME "pn544_hci_i2c"
  
  #define PN544_FW_CMD_WRITE 0x08
  #define PN544_FW_CMD_CHECK 0x06
  
  struct pn544_i2c_fw_frame_write {
  	u8 cmd;
  	u16 be_length;
  	u8 be_dest_addr[3];
  	u16 be_datalen;
  	u8 data[];
  } __packed;
  
  struct pn544_i2c_fw_frame_check {
  	u8 cmd;
  	u16 be_length;
  	u8 be_start_addr[3];
  	u16 be_datalen;
  	u16 be_crc;
  } __packed;
  
  struct pn544_i2c_fw_frame_response {
  	u8 status;
  	u16 be_length;
  } __packed;
  
  struct pn544_i2c_fw_blob {
  	u32 be_size;
  	u32 be_destaddr;
  	u8 data[];
  };
  
  #define PN544_FW_CMD_RESULT_TIMEOUT 0x01
  #define PN544_FW_CMD_RESULT_BAD_CRC 0x02
  #define PN544_FW_CMD_RESULT_ACCESS_DENIED 0x08
  #define PN544_FW_CMD_RESULT_PROTOCOL_ERROR 0x0B
  #define PN544_FW_CMD_RESULT_INVALID_PARAMETER 0x11
  #define PN544_FW_CMD_RESULT_INVALID_LENGTH 0x18
  #define PN544_FW_CMD_RESULT_WRITE_FAILED 0x74
  
  #define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
  
  #define PN544_FW_WRITE_BUFFER_MAX_LEN 0x9f7
  #define PN544_FW_I2C_MAX_PAYLOAD PN544_HCI_I2C_LLC_MAX_SIZE
  #define PN544_FW_I2C_WRITE_FRAME_HEADER_LEN 8
  #define PN544_FW_I2C_WRITE_DATA_MAX_LEN MIN((PN544_FW_I2C_MAX_PAYLOAD -\
  					 PN544_FW_I2C_WRITE_FRAME_HEADER_LEN),\
  					 PN544_FW_WRITE_BUFFER_MAX_LEN)
  
  #define FW_WORK_STATE_IDLE 1
  #define FW_WORK_STATE_START 2
  #define FW_WORK_STATE_WAIT_WRITE_ANSWER 3
  #define FW_WORK_STATE_WAIT_CHECK_ANSWER 4
  
  struct pn544_i2c_phy {
  	struct i2c_client *i2c_dev;
  	struct nfc_hci_dev *hdev;
  
  	unsigned int gpio_en;
  	unsigned int gpio_irq;
  	unsigned int gpio_fw;
  	unsigned int en_polarity;
  
  	struct work_struct fw_work;
  	int fw_work_state;
  	char firmware_name[NFC_FIRMWARE_NAME_MAXSIZE + 1];
  	const struct firmware *fw;
  	u32 fw_blob_dest_addr;
  	size_t fw_blob_size;
  	const u8 *fw_blob_data;
  	size_t fw_written;
  	int fw_cmd_result;
  
  	int powered;
  	int run_mode;
  
  	int hard_fault;		/*
  				 * < 0 if hardware error occured (e.g. i2c err)
  				 * and prevents normal operation.
  				 */
  };
  
  #define I2C_DUMP_SKB(info, skb)					\
  do {								\
  	pr_debug("%s:
  ", info);				\
  	print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET,	\
  		       16, 1, (skb)->data, (skb)->len, 0);	\
  } while (0)
  
  static void pn544_hci_i2c_platform_init(struct pn544_i2c_phy *phy)
  {
  	int polarity, retry, ret;
  	char rset_cmd[] = { 0x05, 0xF9, 0x04, 0x00, 0xC3, 0xE5 };
  	int count = sizeof(rset_cmd);
  
  	nfc_info(&phy->i2c_dev->dev, "Detecting nfc_en polarity
  ");
  
  	/* Disable fw download */
  	gpio_set_value(phy->gpio_fw, 0);
  
  	for (polarity = 0; polarity < 2; polarity++) {
  		phy->en_polarity = polarity;
  		retry = 3;
  		while (retry--) {
  			/* power off */
  			gpio_set_value(phy->gpio_en, !phy->en_polarity);
  			usleep_range(10000, 15000);
  
  			/* power on */
  			gpio_set_value(phy->gpio_en, phy->en_polarity);
  			usleep_range(10000, 15000);
  
  			/* send reset */
  			dev_dbg(&phy->i2c_dev->dev, "Sending reset cmd
  ");
  			ret = i2c_master_send(phy->i2c_dev, rset_cmd, count);
  			if (ret == count) {
  				nfc_info(&phy->i2c_dev->dev,
  					 "nfc_en polarity : active %s
  ",
  					 (polarity == 0 ? "low" : "high"));
  				goto out;
  			}
  		}
  	}
  
  	nfc_err(&phy->i2c_dev->dev,
  		"Could not detect nfc_en polarity, fallback to active high
  ");
  
  out:
  	gpio_set_value(phy->gpio_en, !phy->en_polarity);
  }
  
  static void pn544_hci_i2c_enable_mode(struct pn544_i2c_phy *phy, int run_mode)
  {
  	gpio_set_value(phy->gpio_fw, run_mode == PN544_FW_MODE ? 1 : 0);
  	gpio_set_value(phy->gpio_en, phy->en_polarity);
  	usleep_range(10000, 15000);
  
  	phy->run_mode = run_mode;
  }
  
  static int pn544_hci_i2c_enable(void *phy_id)
  {
  	struct pn544_i2c_phy *phy = phy_id;
  
  	pr_info("%s
  ", __func__);
  
  	pn544_hci_i2c_enable_mode(phy, PN544_HCI_MODE);
  
  	phy->powered = 1;
  
  	return 0;
  }
  
  static void pn544_hci_i2c_disable(void *phy_id)
  {
  	struct pn544_i2c_phy *phy = phy_id;
  
  	gpio_set_value(phy->gpio_fw, 0);
  	gpio_set_value(phy->gpio_en, !phy->en_polarity);
  	usleep_range(10000, 15000);
  
  	gpio_set_value(phy->gpio_en, phy->en_polarity);
  	usleep_range(10000, 15000);
  
  	gpio_set_value(phy->gpio_en, !phy->en_polarity);
  	usleep_range(10000, 15000);
  
  	phy->powered = 0;
  }
  
  static void pn544_hci_i2c_add_len_crc(struct sk_buff *skb)
  {
  	u16 crc;
  	int len;
  
  	len = skb->len + 2;
  	*skb_push(skb, 1) = len;
  
  	crc = crc_ccitt(0xffff, skb->data, skb->len);
  	crc = ~crc;
  	*skb_put(skb, 1) = crc & 0xff;
  	*skb_put(skb, 1) = crc >> 8;
  }
  
  static void pn544_hci_i2c_remove_len_crc(struct sk_buff *skb)
  {
  	skb_pull(skb, PN544_I2C_FRAME_HEADROOM);
  	skb_trim(skb, PN544_I2C_FRAME_TAILROOM);
  }
  
  /*
   * Writing a frame must not return the number of written bytes.
   * It must return either zero for success, or <0 for error.
   * In addition, it must not alter the skb
   */
  static int pn544_hci_i2c_write(void *phy_id, struct sk_buff *skb)
  {
  	int r;
  	struct pn544_i2c_phy *phy = phy_id;
  	struct i2c_client *client = phy->i2c_dev;
  
  	if (phy->hard_fault != 0)
  		return phy->hard_fault;
  
  	usleep_range(3000, 6000);
  
  	pn544_hci_i2c_add_len_crc(skb);
  
  	I2C_DUMP_SKB("i2c frame written", skb);
  
  	r = i2c_master_send(client, skb->data, skb->len);
  
  	if (r == -EREMOTEIO) {	/* Retry, chip was in standby */
  		usleep_range(6000, 10000);
  		r = i2c_master_send(client, skb->data, skb->len);
  	}
  
  	if (r >= 0) {
  		if (r != skb->len)
  			r = -EREMOTEIO;
  		else
  			r = 0;
  	}
  
  	pn544_hci_i2c_remove_len_crc(skb);
  
  	return r;
  }
  
  static int check_crc(u8 *buf, int buflen)
  {
  	int 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("CRC error 0x%x != 0x%x 0x%x
  ",
  		       crc, buf[len - 1], buf[len - 2]);
  		pr_info("%s: BAD CRC
  ", __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 pn544_i2c_phy *phy, struct sk_buff **skb)
  {
  	int r;
  	u8 len;
  	u8 tmp[PN544_HCI_I2C_LLC_MAX_SIZE - 1];
  	struct i2c_client *client = phy->i2c_dev;
  
  	r = i2c_master_recv(client, &len, 1);
  	if (r != 1) {
  		nfc_err(&client->dev, "cannot read len byte
  ");
  		return -EREMOTEIO;
  	}
  
  	if ((len < (PN544_HCI_I2C_LLC_MIN_SIZE - 1)) ||
  	    (len > (PN544_HCI_I2C_LLC_MAX_SIZE - 1))) {
  		nfc_err(&client->dev, "invalid len byte
  ");
  		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;
  	}
  
  	I2C_DUMP_SKB("i2c frame read", *skb);
  
  	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;
  }
  
  static int pn544_hci_i2c_fw_read_status(struct pn544_i2c_phy *phy)
  {
  	int r;
  	struct pn544_i2c_fw_frame_response response;
  	struct i2c_client *client = phy->i2c_dev;
  
  	r = i2c_master_recv(client, (char *) &response, sizeof(response));
  	if (r != sizeof(response)) {
  		nfc_err(&client->dev, "cannot read fw status
  ");
  		return -EIO;
  	}
  
  	usleep_range(3000, 6000);
  
  	switch (response.status) {
  	case 0:
  		return 0;
  	case PN544_FW_CMD_RESULT_TIMEOUT:
  		return -ETIMEDOUT;
  	case PN544_FW_CMD_RESULT_BAD_CRC:
  		return -ENODATA;
  	case PN544_FW_CMD_RESULT_ACCESS_DENIED:
  		return -EACCES;
  	case PN544_FW_CMD_RESULT_PROTOCOL_ERROR:
  		return -EPROTO;
  	case PN544_FW_CMD_RESULT_INVALID_PARAMETER:
  		return -EINVAL;
  	case PN544_FW_CMD_RESULT_INVALID_LENGTH:
  		return -EBADMSG;
  	case PN544_FW_CMD_RESULT_WRITE_FAILED:
  		return -EIO;
  	default:
  		return -EIO;
  	}
  }
  
  /*
   * 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_i2c_irq_thread_fn(int irq, void *phy_id)
  {
  	struct pn544_i2c_phy *phy = phy_id;
  	struct i2c_client *client;
  	struct sk_buff *skb = NULL;
  	int r;
  
  	if (!phy || irq != phy->i2c_dev->irq) {
  		WARN_ON_ONCE(1);
  		return IRQ_NONE;
  	}
  
  	client = phy->i2c_dev;
  	dev_dbg(&client->dev, "IRQ
  ");
  
  	if (phy->hard_fault != 0)
  		return IRQ_HANDLED;
  
  	if (phy->run_mode == PN544_FW_MODE) {
  		phy->fw_cmd_result = pn544_hci_i2c_fw_read_status(phy);
  		schedule_work(&phy->fw_work);
  	} else {
  		r = pn544_hci_i2c_read(phy, &skb);
  		if (r == -EREMOTEIO) {
  			phy->hard_fault = r;
  
  			nfc_hci_recv_frame(phy->hdev, NULL);
  
  			return IRQ_HANDLED;
  		} else if ((r == -ENOMEM) || (r == -EBADMSG)) {
  			return IRQ_HANDLED;
  		}
  
  		nfc_hci_recv_frame(phy->hdev, skb);
  	}
  	return IRQ_HANDLED;
  }
  
  static struct nfc_phy_ops i2c_phy_ops = {
  	.write = pn544_hci_i2c_write,
  	.enable = pn544_hci_i2c_enable,
  	.disable = pn544_hci_i2c_disable,
  };
  
  static int pn544_hci_i2c_fw_download(void *phy_id, const char *firmware_name)
  {
  	struct pn544_i2c_phy *phy = phy_id;
  
  	pr_info("Starting Firmware Download (%s)
  ", firmware_name);
  
  	strcpy(phy->firmware_name, firmware_name);
  
  	phy->fw_work_state = FW_WORK_STATE_START;
  
  	schedule_work(&phy->fw_work);
  
  	return 0;
  }
  
  static void pn544_hci_i2c_fw_work_complete(struct pn544_i2c_phy *phy,
  					   int result)
  {
  	pr_info("Firmware Download Complete, result=%d
  ", result);
  
  	pn544_hci_i2c_disable(phy);
  
  	phy->fw_work_state = FW_WORK_STATE_IDLE;
  
  	if (phy->fw) {
  		release_firmware(phy->fw);
  		phy->fw = NULL;
  	}
  
  	nfc_fw_download_done(phy->hdev->ndev, phy->firmware_name, (u32) -result);
  }
  
  static int pn544_hci_i2c_fw_write_cmd(struct i2c_client *client, u32 dest_addr,
  				      const u8 *data, u16 datalen)
  {
  	u8 frame[PN544_FW_I2C_MAX_PAYLOAD];
  	struct pn544_i2c_fw_frame_write *framep;
  	u16 params_len;
  	int framelen;
  	int r;
  
  	if (datalen > PN544_FW_I2C_WRITE_DATA_MAX_LEN)
  		datalen = PN544_FW_I2C_WRITE_DATA_MAX_LEN;
  
  	framep = (struct pn544_i2c_fw_frame_write *) frame;
  
  	params_len = sizeof(framep->be_dest_addr) +
  		     sizeof(framep->be_datalen) + datalen;
  	framelen = params_len + sizeof(framep->cmd) +
  			     sizeof(framep->be_length);
  
  	framep->cmd = PN544_FW_CMD_WRITE;
  
  	put_unaligned_be16(params_len, &framep->be_length);
  
  	framep->be_dest_addr[0] = (dest_addr & 0xff0000) >> 16;
  	framep->be_dest_addr[1] = (dest_addr & 0xff00) >> 8;
  	framep->be_dest_addr[2] = dest_addr & 0xff;
  
  	put_unaligned_be16(datalen, &framep->be_datalen);
  
  	memcpy(framep->data, data, datalen);
  
  	r = i2c_master_send(client, frame, framelen);
  
  	if (r == framelen)
  		return datalen;
  	else if (r < 0)
  		return r;
  	else
  		return -EIO;
  }
  
  static int pn544_hci_i2c_fw_check_cmd(struct i2c_client *client, u32 start_addr,
  				      const u8 *data, u16 datalen)
  {
  	struct pn544_i2c_fw_frame_check frame;
  	int r;
  	u16 crc;
  
  	/* calculate local crc for the data we want to check */
  	crc = crc_ccitt(0xffff, data, datalen);
  
  	frame.cmd = PN544_FW_CMD_CHECK;
  
  	put_unaligned_be16(sizeof(frame.be_start_addr) +
  			   sizeof(frame.be_datalen) + sizeof(frame.be_crc),
  			   &frame.be_length);
  
  	/* tell the chip the memory region to which our crc applies */
  	frame.be_start_addr[0] = (start_addr & 0xff0000) >> 16;
  	frame.be_start_addr[1] = (start_addr & 0xff00) >> 8;
  	frame.be_start_addr[2] = start_addr & 0xff;
  
  	put_unaligned_be16(datalen, &frame.be_datalen);
  
  	/*
  	 * and give our local crc. Chip will calculate its own crc for the
  	 * region and compare with ours.
  	 */
  	put_unaligned_be16(crc, &frame.be_crc);
  
  	r = i2c_master_send(client, (const char *) &frame, sizeof(frame));
  
  	if (r == sizeof(frame))
  		return 0;
  	else if (r < 0)
  		return r;
  	else
  		return -EIO;
  }
  
  static int pn544_hci_i2c_fw_write_chunk(struct pn544_i2c_phy *phy)
  {
  	int r;
  
  	r = pn544_hci_i2c_fw_write_cmd(phy->i2c_dev,
  				       phy->fw_blob_dest_addr + phy->fw_written,
  				       phy->fw_blob_data + phy->fw_written,
  				       phy->fw_blob_size - phy->fw_written);
  	if (r < 0)
  		return r;
  
  	phy->fw_written += r;
  	phy->fw_work_state = FW_WORK_STATE_WAIT_WRITE_ANSWER;
  
  	return 0;
  }
  
  static void pn544_hci_i2c_fw_work(struct work_struct *work)
  {
  	struct pn544_i2c_phy *phy = container_of(work, struct pn544_i2c_phy,
  						fw_work);
  	int r;
  	struct pn544_i2c_fw_blob *blob;
  
  	switch (phy->fw_work_state) {
  	case FW_WORK_STATE_START:
  		pn544_hci_i2c_enable_mode(phy, PN544_FW_MODE);
  
  		r = request_firmware(&phy->fw, phy->firmware_name,
  				     &phy->i2c_dev->dev);
  		if (r < 0)
  			goto exit_state_start;
  
  		blob = (struct pn544_i2c_fw_blob *) phy->fw->data;
  		phy->fw_blob_size = get_unaligned_be32(&blob->be_size);
  		phy->fw_blob_dest_addr = get_unaligned_be32(&blob->be_destaddr);
  		phy->fw_blob_data = blob->data;
  
  		phy->fw_written = 0;
  		r = pn544_hci_i2c_fw_write_chunk(phy);
  
  exit_state_start:
  		if (r < 0)
  			pn544_hci_i2c_fw_work_complete(phy, r);
  		break;
  
  	case FW_WORK_STATE_WAIT_WRITE_ANSWER:
  		r = phy->fw_cmd_result;
  		if (r < 0)
  			goto exit_state_wait_write_answer;
  
  		if (phy->fw_written == phy->fw_blob_size) {
  			r = pn544_hci_i2c_fw_check_cmd(phy->i2c_dev,
  						       phy->fw_blob_dest_addr,
  						       phy->fw_blob_data,
  						       phy->fw_blob_size);
  			if (r < 0)
  				goto exit_state_wait_write_answer;
  			phy->fw_work_state = FW_WORK_STATE_WAIT_CHECK_ANSWER;
  			break;
  		}
  
  		r = pn544_hci_i2c_fw_write_chunk(phy);
  
  exit_state_wait_write_answer:
  		if (r < 0)
  			pn544_hci_i2c_fw_work_complete(phy, r);
  		break;
  
  	case FW_WORK_STATE_WAIT_CHECK_ANSWER:
  		r = phy->fw_cmd_result;
  		if (r < 0)
  			goto exit_state_wait_check_answer;
  
  		blob = (struct pn544_i2c_fw_blob *) (phy->fw_blob_data +
  		       phy->fw_blob_size);
  		phy->fw_blob_size = get_unaligned_be32(&blob->be_size);
  		if (phy->fw_blob_size != 0) {
  			phy->fw_blob_dest_addr =
  					get_unaligned_be32(&blob->be_destaddr);
  			phy->fw_blob_data = blob->data;
  
  			phy->fw_written = 0;
  			r = pn544_hci_i2c_fw_write_chunk(phy);
  		}
  
  exit_state_wait_check_answer:
  		if (r < 0 || phy->fw_blob_size == 0)
  			pn544_hci_i2c_fw_work_complete(phy, r);
  		break;
  
  	default:
  		break;
  	}
  }
  
  static int pn544_hci_i2c_probe(struct i2c_client *client,
  			       const struct i2c_device_id *id)
  {
  	struct pn544_i2c_phy *phy;
  	struct pn544_nfc_platform_data *pdata;
  	int r = 0;
  
  	dev_dbg(&client->dev, "%s
  ", __func__);
  	dev_dbg(&client->dev, "IRQ: %d
  ", client->irq);
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
  		nfc_err(&client->dev, "Need I2C_FUNC_I2C
  ");
  		return -ENODEV;
  	}
  
  	phy = devm_kzalloc(&client->dev, sizeof(struct pn544_i2c_phy),
  			   GFP_KERNEL);
  	if (!phy) {
  		nfc_err(&client->dev,
  			"Cannot allocate memory for pn544 i2c phy.
  ");
  		return -ENOMEM;
  	}
  
  	INIT_WORK(&phy->fw_work, pn544_hci_i2c_fw_work);
  	phy->fw_work_state = FW_WORK_STATE_IDLE;
  
  	phy->i2c_dev = client;
  	i2c_set_clientdata(client, phy);
  
  	pdata = client->dev.platform_data;
  	if (pdata == NULL) {
  		nfc_err(&client->dev, "No platform data
  ");
  		return -EINVAL;
  	}
  
  	if (pdata->request_resources == NULL) {
  		nfc_err(&client->dev, "request_resources() missing
  ");
  		return -EINVAL;
  	}
  
  	r = pdata->request_resources(client);
  	if (r) {
  		nfc_err(&client->dev, "Cannot get platform resources
  ");
  		return r;
  	}
  
  	phy->gpio_en = pdata->get_gpio(NFC_GPIO_ENABLE);
  	phy->gpio_fw = pdata->get_gpio(NFC_GPIO_FW_RESET);
  	phy->gpio_irq = pdata->get_gpio(NFC_GPIO_IRQ);
  
  	pn544_hci_i2c_platform_init(phy);
  
  	r = request_threaded_irq(client->irq, NULL, pn544_hci_i2c_irq_thread_fn,
  				 IRQF_TRIGGER_RISING | IRQF_ONESHOT,
  				 PN544_HCI_I2C_DRIVER_NAME, phy);
  	if (r < 0) {
  		nfc_err(&client->dev, "Unable to register IRQ handler
  ");
  		goto err_rti;
  	}
  
  	r = pn544_hci_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
  			    PN544_I2C_FRAME_HEADROOM, PN544_I2C_FRAME_TAILROOM,
  			    PN544_HCI_I2C_LLC_MAX_PAYLOAD,
  			    pn544_hci_i2c_fw_download, &phy->hdev);
  	if (r < 0)
  		goto err_hci;
  
  	return 0;
  
  err_hci:
  	free_irq(client->irq, phy);
  
  err_rti:
  	if (pdata->free_resources != NULL)
  		pdata->free_resources();
  
  	return r;
  }
  
  static int pn544_hci_i2c_remove(struct i2c_client *client)
  {
  	struct pn544_i2c_phy *phy = i2c_get_clientdata(client);
  	struct pn544_nfc_platform_data *pdata = client->dev.platform_data;
  
  	dev_dbg(&client->dev, "%s
  ", __func__);
  
  	cancel_work_sync(&phy->fw_work);
  	if (phy->fw_work_state != FW_WORK_STATE_IDLE)
  		pn544_hci_i2c_fw_work_complete(phy, -ENODEV);
  
  	pn544_hci_remove(phy->hdev);
  
  	if (phy->powered)
  		pn544_hci_i2c_disable(phy);
  
  	free_irq(client->irq, phy);
  	if (pdata->free_resources)
  		pdata->free_resources();
  
  	return 0;
  }
  
  static struct i2c_driver pn544_hci_i2c_driver = {
  	.driver = {
  		   .name = PN544_HCI_I2C_DRIVER_NAME,
  		  },
  	.probe = pn544_hci_i2c_probe,
  	.id_table = pn544_hci_i2c_id_table,
  	.remove = pn544_hci_i2c_remove,
  };
  
  module_i2c_driver(pn544_hci_i2c_driver);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION(DRIVER_DESC);