// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2015-2020, The Linux Foundation. All rights reserved.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/spinlock.h>
#include <linux/of_gpio.h>
#include <linux/of_device.h>
#include <linux/uaccess.h>
#include "nq-nci.h"
#include <linux/clk.h>
#ifdef CONFIG_COMPAT
#include <linux/compat.h>
#endif
#include <linux/jiffies.h>
#include <linux/regulator/consumer.h>

struct nqx_platform_data {
	unsigned int irq_gpio;
	unsigned int en_gpio;
	unsigned int clkreq_gpio;
	unsigned int firm_gpio;
	unsigned int ese_gpio;
	int vdd_levels[2];
	int max_current;
	const char *clk_src_name;
	/* NFC_CLK pin voting state */
	bool clk_pin_voting;
};

static const struct of_device_id msm_match_table[] = {
	{.compatible = "qcom,nq-nci"},
	{}
};

MODULE_DEVICE_TABLE(of, msm_match_table);

struct nqx_dev {
	wait_queue_head_t	read_wq;
	wait_queue_head_t	cold_reset_read_wq;
	struct	mutex		read_mutex;
	struct	mutex		dev_ref_mutex;
	struct	i2c_client	*client;
	dev_t			devno;
	struct class		*nqx_class;
	struct device		*nqx_device;
	struct cdev		c_dev;
	union  nqx_uinfo	nqx_info;
	/* NFC GPIO variables */
	unsigned int		irq_gpio;
	unsigned int		en_gpio;
	unsigned int		firm_gpio;
	unsigned int		clkreq_gpio;
	unsigned int		ese_gpio;
	/* NFC VEN pin state powered by Nfc */
	bool			nfc_ven_enabled;
	/* NFC state reflected from MW */
	bool			nfc_enabled;
	/* NFC_IRQ state */
	bool			irq_enabled;
	/* NFC_IRQ wake-up state */
	bool			irq_wake_up;
	bool			cold_reset_rsp_pending;
	bool			is_vreg_enabled;
	bool			is_ese_session_active;
	uint8_t			cold_reset_status;
	spinlock_t		irq_enabled_lock;
	unsigned int		count_irq;
	/* NFC_IRQ Count */
	unsigned int		dev_ref_count;
	/* Initial CORE RESET notification */
	unsigned int		core_reset_ntf;
	/* CLK control */
	bool			clk_run;
	struct	clk		*s_clk;
	/* read buffer*/
	size_t kbuflen;
	u8 *kbuf;
	struct nqx_platform_data *pdata;
	struct regulator *reg;
};

static int nfcc_reboot(struct notifier_block *notifier, unsigned long val,
			void *v);
/*clock enable function*/
static int nqx_clock_select(struct nqx_dev *nqx_dev);
/*clock disable function*/
static int nqx_clock_deselect(struct nqx_dev *nqx_dev);
static int nqx_standby_write(struct nqx_dev *nqx_dev,
				const unsigned char *buf, size_t len);

static struct notifier_block nfcc_notifier = {
	.notifier_call	= nfcc_reboot,
	.next			= NULL,
	.priority		= 0
};

unsigned int	disable_ctrl;

static void nqx_init_stat(struct nqx_dev *nqx_dev)
{
	nqx_dev->count_irq = 0;
}

static void nqx_disable_irq(struct nqx_dev *nqx_dev)
{
	unsigned long flags;

	spin_lock_irqsave(&nqx_dev->irq_enabled_lock, flags);
	if (nqx_dev->irq_enabled) {
		disable_irq_nosync(nqx_dev->client->irq);
		nqx_dev->irq_enabled = false;
	}
	spin_unlock_irqrestore(&nqx_dev->irq_enabled_lock, flags);
}

/**
 * nqx_enable_irq()
 *
 * Check if interrupt is enabled or not
 * and enable interrupt
 *
 * Return: void
 */
static void nqx_enable_irq(struct nqx_dev *nqx_dev)
{
	unsigned long flags;

	spin_lock_irqsave(&nqx_dev->irq_enabled_lock, flags);
	if (!nqx_dev->irq_enabled) {
		nqx_dev->irq_enabled = true;
		enable_irq(nqx_dev->client->irq);
	}
	spin_unlock_irqrestore(&nqx_dev->irq_enabled_lock, flags);
}

static irqreturn_t nqx_dev_irq_handler(int irq, void *dev_id)
{
	struct nqx_dev *nqx_dev = dev_id;
	unsigned long flags;

	if (device_may_wakeup(&nqx_dev->client->dev))
		pm_wakeup_event(&nqx_dev->client->dev, WAKEUP_SRC_TIMEOUT);

	nqx_disable_irq(nqx_dev);
	spin_lock_irqsave(&nqx_dev->irq_enabled_lock, flags);
	nqx_dev->count_irq++;
	spin_unlock_irqrestore(&nqx_dev->irq_enabled_lock, flags);
	wake_up(&nqx_dev->read_wq);

	return IRQ_HANDLED;
}

static int is_data_available_for_read(struct nqx_dev *nqx_dev)
{
	int ret;

	nqx_enable_irq(nqx_dev);
	ret = wait_event_interruptible_timeout(nqx_dev->read_wq,
		!nqx_dev->irq_enabled, msecs_to_jiffies(MAX_IRQ_WAIT_TIME));
	return ret;
}

static int send_cold_reset_cmd(struct nqx_dev *nqx_dev)
{
	int ret;
	char *cold_reset_cmd = NULL;

	if (gpio_get_value(nqx_dev->firm_gpio)) {
		dev_err(&nqx_dev->client->dev, "FW download in-progress\n");
		return -EBUSY;
	}
	if (!gpio_get_value(nqx_dev->en_gpio)) {
		dev_err(&nqx_dev->client->dev, "VEN LOW - NFCC powered off\n");
		return -ENODEV;
	}
	cold_reset_cmd = kzalloc(COLD_RESET_CMD_LEN, GFP_DMA | GFP_KERNEL);
	if (!cold_reset_cmd)
		return -ENOMEM;

	cold_reset_cmd[0] = COLD_RESET_CMD_GID;
	cold_reset_cmd[1] = COLD_RESET_OID;
	cold_reset_cmd[2] = COLD_RESET_CMD_PAYLOAD_LEN;

	ret = nqx_standby_write(nqx_dev, cold_reset_cmd, COLD_RESET_CMD_LEN);
	if (ret < 0) {
		dev_err(&nqx_dev->client->dev,
			"%s: write failed after max retry\n", __func__);
	}
	kfree(cold_reset_cmd);
	return ret;
}

static void read_cold_reset_rsp(struct nqx_dev *nqx_dev, bool isNfcEnabled,
				char *header)
{
	int ret = -1;
	char *cold_reset_rsp = NULL;

	cold_reset_rsp = kzalloc(COLD_RESET_RSP_LEN, GFP_DMA | GFP_KERNEL);
	if (!cold_reset_rsp)
		return;

	/*
	 * read header also if NFC is disabled
	 * for enable case, will be taken care by nfc_read thread
	 */
	if (!isNfcEnabled) {
		ret = i2c_master_recv(nqx_dev->client, cold_reset_rsp,
					NCI_HEADER_LEN);
		if (ret != NCI_HEADER_LEN) {
			dev_err(&nqx_dev->client->dev,
				"%s: failure to read cold reset rsp header\n",
				__func__);
			goto error;
		}
	} else {
		memcpy(cold_reset_rsp, header, NCI_HEADER_LEN);
	}

	if ((NCI_HEADER_LEN + cold_reset_rsp[2]) > COLD_RESET_RSP_LEN) {
		dev_err(&nqx_dev->client->dev,
			"%s: - invalid response for cold_reset\n", __func__);
		ret = -EINVAL;
		goto error;
	}
	ret = i2c_master_recv(nqx_dev->client, &cold_reset_rsp[NCI_PAYLOAD_IDX],
				cold_reset_rsp[2]);
	if (ret != cold_reset_rsp[2]) {
		dev_err(&nqx_dev->client->dev,
			"%s: failure to read cold reset rsp status\n",
			__func__);
		goto error;
	}
	nqx_dev->cold_reset_status = cold_reset_rsp[NCI_PAYLOAD_IDX];
error:
	kfree(cold_reset_rsp);
}

static ssize_t nfc_read(struct file *filp, char __user *buf,
					size_t count, loff_t *offset)
{
	struct nqx_dev *nqx_dev = filp->private_data;
	unsigned char *tmp = NULL;
	int ret;
	int irq_gpio_val = 0;

	if (!nqx_dev) {
		ret = -ENODEV;
		goto out;
	}

	if (count > nqx_dev->kbuflen)
		count = nqx_dev->kbuflen;

	dev_dbg(&nqx_dev->client->dev, "%s : reading %zu bytes.\n",
			__func__, count);

	mutex_lock(&nqx_dev->read_mutex);

	irq_gpio_val = gpio_get_value(nqx_dev->irq_gpio);
	if (irq_gpio_val == 0) {
		if (filp->f_flags & O_NONBLOCK) {
			dev_err(&nqx_dev->client->dev,
			":f_falg has O_NONBLOCK. EAGAIN\n");
			ret = -EAGAIN;
			goto err;
		}
		while (1) {
			ret = 0;
			if (!nqx_dev->irq_enabled) {
				nqx_dev->irq_enabled = true;
				enable_irq(nqx_dev->client->irq);
			}
			if (!gpio_get_value(nqx_dev->irq_gpio)) {
				ret = wait_event_interruptible(nqx_dev->read_wq,
					!nqx_dev->irq_enabled);
			}
			if (ret)
				goto err;
			nqx_disable_irq(nqx_dev);

			if (gpio_get_value(nqx_dev->irq_gpio))
				break;
			dev_err_ratelimited(&nqx_dev->client->dev,
			"gpio is low, no need to read data\n");
		}
	}

	tmp = nqx_dev->kbuf;
	if (!tmp) {
		dev_err(&nqx_dev->client->dev,
			"%s: device doesn't exist anymore\n", __func__);
		ret = -ENODEV;
		goto err;
	}
	memset(tmp, 0x00, count);

	/* Read data */
	ret = i2c_master_recv(nqx_dev->client, tmp, count);
	if (ret < 0) {
		dev_err(&nqx_dev->client->dev,
			"%s: i2c_master_recv returned %d\n", __func__, ret);
		goto err;
	}
	if (ret > count) {
		dev_err(&nqx_dev->client->dev,
			"%s: received too many bytes from i2c (%d)\n",
			__func__, ret);
		ret = -EIO;
		goto err;
	}
	/* check if it's response of cold reset command
	 * NFC HAL process shouldn't receive this data as
	 * command was sent by eSE HAL
	 */
	if (nqx_dev->cold_reset_rsp_pending
		&& (tmp[0] == COLD_RESET_RSP_GID)
		&& (tmp[1] == COLD_RESET_OID)) {
		read_cold_reset_rsp(nqx_dev, true, tmp);
		nqx_dev->cold_reset_rsp_pending = false;
		wake_up_interruptible(&nqx_dev->cold_reset_read_wq);
		mutex_unlock(&nqx_dev->read_mutex);
		/*
		 * NFC process doesn't know about cold reset command
		 * being sent as it was initiated by eSE process
		 * we shouldn't return any data to NFC process
		 */
		return 0;
	}
#ifdef NFC_KERNEL_BU
		dev_dbg(&nqx_dev->client->dev, "%s : NfcNciRx %x %x %x\n",
			__func__, tmp[0], tmp[1], tmp[2]);
#endif
	if (copy_to_user(buf, tmp, ret)) {
		dev_warn(&nqx_dev->client->dev,
			"%s : failed to copy to user space\n", __func__);
		ret = -EFAULT;
		goto err;
	}
	mutex_unlock(&nqx_dev->read_mutex);
	return ret;

err:
	mutex_unlock(&nqx_dev->read_mutex);
out:
	return ret;
}

static ssize_t nfc_write(struct file *filp, const char __user *buf,
				size_t count, loff_t *offset)
{
	struct nqx_dev *nqx_dev = filp->private_data;
	char *tmp = NULL;
	int ret = 0;

	if (!nqx_dev) {
		ret = -ENODEV;
		goto out;
	}
	if (count > nqx_dev->kbuflen) {
		dev_err(&nqx_dev->client->dev, "%s: out of memory\n",
			__func__);
		ret = -ENOMEM;
		goto out;
	}

	tmp = memdup_user(buf, count);
	if (IS_ERR(tmp)) {
		dev_err(&nqx_dev->client->dev, "%s: memdup_user failed\n",
			__func__);
		ret = PTR_ERR(tmp);
		goto out;
	}

	ret = i2c_master_send(nqx_dev->client, tmp, count);
	if (ret != count) {
		dev_err(&nqx_dev->client->dev,
		"%s: failed to write %d\n", __func__, ret);
		ret = -EIO;
		goto out_free;
	}
#ifdef NFC_KERNEL_BU
	dev_dbg(&nqx_dev->client->dev,
			"%s : i2c-%d: NfcNciTx %x %x %x\n",
			__func__, iminor(file_inode(filp)),
			tmp[0], tmp[1], tmp[2]);
#endif
	usleep_range(1000, 1100);
out_free:
	kfree(tmp);
out:
	return ret;
}

/**
 * nqx_standby_write()
 * @buf:       pointer to data buffer
 * @len:       # of bytes need to transfer
 *
 * write data buffer over I2C and retry
 * if NFCC is in stand by mode
 *
 * Return: # of bytes written or -ve value in case of error
 */
static int nqx_standby_write(struct nqx_dev *nqx_dev,
				const unsigned char *buf, size_t len)
{
	int ret = -EINVAL;
	int retry_cnt;

	for (retry_cnt = 1; retry_cnt <= MAX_RETRY_COUNT; retry_cnt++) {
		ret = i2c_master_send(nqx_dev->client, buf, len);
		if (ret < 0) {
			dev_err(&nqx_dev->client->dev,
				"%s: write failed, Maybe in Standby Mode - Retry(%d)\n",
				 __func__, retry_cnt);
			usleep_range(1000, 1100);
		} else if (ret == len)
			break;
	}
	return ret;
}


/*
 * Power management of the SN100 eSE
 * eSE and NFCC both are powered using VEN gpio in SN100,
 * VEN HIGH - eSE and NFCC both are powered on
 * VEN LOW - eSE and NFCC both are power down
 */

static int sn100_ese_pwr(struct nqx_dev *nqx_dev, unsigned long arg)
{
	int r = -1;

	if (arg == ESE_POWER_ON) {
		/**
		 * Let's store the NFC VEN pin state
		 * will check stored value in case of eSE power off request,
		 * to find out if NFC MW also sent request to set VEN HIGH
		 * VEN state will remain HIGH if NFC is enabled otherwise
		 * it will be set as LOW
		 */
		nqx_dev->nfc_ven_enabled =
			gpio_get_value(nqx_dev->en_gpio);
		if (!nqx_dev->nfc_ven_enabled) {
			dev_dbg(&nqx_dev->client->dev, "eSE HAL service setting en_gpio HIGH\n");
			gpio_set_value(nqx_dev->en_gpio, 1);
			/* hardware dependent delay */
			usleep_range(1000, 1100);
		} else {
			dev_dbg(&nqx_dev->client->dev, "en_gpio already HIGH\n");
		}
		nqx_dev->is_ese_session_active = true;
		r = 0;
	} else if (arg == ESE_POWER_OFF) {
		if (!nqx_dev->nfc_ven_enabled) {
			dev_dbg(&nqx_dev->client->dev, "NFC not enabled, disabling en_gpio\n");
			gpio_set_value(nqx_dev->en_gpio, 0);
			/* hardware dependent delay */
			usleep_range(1000, 1100);
		} else {
			dev_dbg(&nqx_dev->client->dev, "keep en_gpio high as NFC is enabled\n");
		}
		nqx_dev->is_ese_session_active = false;
		r = 0;
	} else if (arg == ESE_COLD_RESET) {
		// set default value for status as failure
		nqx_dev->cold_reset_status = EIO;

		r = send_cold_reset_cmd(nqx_dev);
		if (r <= 0) {
			dev_err(&nqx_dev->client->dev,
				"failed to send cold reset command\n");
			return nqx_dev->cold_reset_status;
		}
		nqx_dev->cold_reset_rsp_pending = true;
		// check if NFC is enabled
		if (nqx_dev->nfc_enabled) {
			/*
			 * nfc_read thread will initiate cold reset response
			 * and it will signal for data available
			 */
			wait_event_interruptible(nqx_dev->cold_reset_read_wq,
				!nqx_dev->cold_reset_rsp_pending);
		} else {
			/*
			 * Read data as NFC thread is not active
			 */
			r = is_data_available_for_read(nqx_dev);
			if (r <= 0) {
				nqx_disable_irq(nqx_dev);
				nqx_dev->cold_reset_rsp_pending = false;
				return nqx_dev->cold_reset_status;
			}
			read_cold_reset_rsp(nqx_dev, false, NULL);
			nqx_dev->cold_reset_rsp_pending = false;
		}
		r = nqx_dev->cold_reset_status;
	} else if (arg == ESE_POWER_STATE) {
		// eSE power state
		r = gpio_get_value(nqx_dev->en_gpio);
	}
	return r;
}

/*
 * Power management of the eSE
 * NFC & eSE ON : NFC_EN high and eSE_pwr_req high.
 * NFC OFF & eSE ON : NFC_EN high and eSE_pwr_req high.
 * NFC OFF & eSE OFF : NFC_EN low and eSE_pwr_req low.
 */
static int nqx_ese_pwr(struct nqx_dev *nqx_dev, unsigned long arg)
{
	int r = -1;
	const unsigned char svdd_off_cmd_warn[] =  {0x2F, 0x31, 0x01, 0x01};
	const unsigned char svdd_off_cmd_done[] =  {0x2F, 0x31, 0x01, 0x00};

	if (!gpio_is_valid(nqx_dev->ese_gpio)) {
		dev_err(&nqx_dev->client->dev,
			"%s: ese_gpio is not valid\n", __func__);
		return -EINVAL;
	}

	if (arg == 0) {
		/*
		 * We want to power on the eSE and to do so we need the
		 * eSE_pwr_req pin and the NFC_EN pin to be high
		 */
		if (gpio_get_value(nqx_dev->ese_gpio)) {
			dev_dbg(&nqx_dev->client->dev, "ese_gpio is already high\n");
			r = 0;
		} else {
			/**
			 * Let's store the NFC_EN pin state
			 * only if the eSE is not yet on
			 */
			nqx_dev->nfc_ven_enabled =
					gpio_get_value(nqx_dev->en_gpio);
			if (!nqx_dev->nfc_ven_enabled) {
				gpio_set_value(nqx_dev->en_gpio, 1);
				/* hardware dependent delay */
				usleep_range(1000, 1100);
			}
			gpio_set_value(nqx_dev->ese_gpio, 1);
			usleep_range(1000, 1100);
			if (gpio_get_value(nqx_dev->ese_gpio)) {
				dev_dbg(&nqx_dev->client->dev, "ese_gpio is enabled\n");
				r = 0;
			}
		}
	} else if (arg == 1) {
		if (nqx_dev->nfc_ven_enabled &&
			((nqx_dev->nqx_info.info.chip_type == NFCC_NQ_220) ||
			(nqx_dev->nqx_info.info.chip_type == NFCC_PN66T))) {
			/**
			 * Let's inform the CLF we're
			 * powering off the eSE
			 */
			r = nqx_standby_write(nqx_dev, svdd_off_cmd_warn,
						sizeof(svdd_off_cmd_warn));
			if (r < 0) {
				dev_err(&nqx_dev->client->dev,
					"%s: write failed after max retry\n",
					 __func__);
				return -ENXIO;
			}
			dev_dbg(&nqx_dev->client->dev,
				"%s: svdd_off_cmd_warn sent\n", __func__);

			/* let's power down the eSE */
			gpio_set_value(nqx_dev->ese_gpio, 0);
			dev_dbg(&nqx_dev->client->dev,
				"%s: nqx_dev->ese_gpio set to 0\n", __func__);

			/**
			 * Time needed for the SVDD capacitor
			 * to get discharged
			 */
			usleep_range(8000, 8100);

			/* Let's inform the CLF the eSE is now off */
			r = nqx_standby_write(nqx_dev, svdd_off_cmd_done,
						sizeof(svdd_off_cmd_done));
			if (r < 0) {
				dev_err(&nqx_dev->client->dev,
					"%s: write failed after max retry\n",
					 __func__);
				return -ENXIO;
			}
			dev_dbg(&nqx_dev->client->dev,
				"%s: svdd_off_cmd_done sent\n", __func__);
		} else {
			/**
			 * In case the NFC is off,
			 * there's no need to send the i2c commands
			 */
			gpio_set_value(nqx_dev->ese_gpio, 0);
			usleep_range(1000, 1100);
		}

		if (!gpio_get_value(nqx_dev->ese_gpio)) {
			dev_dbg(&nqx_dev->client->dev, "ese_gpio is disabled\n");
			r = 0;
		}

		if (!nqx_dev->nfc_ven_enabled) {
			/* hardware dependent delay */
			usleep_range(1000, 1100);
			dev_dbg(&nqx_dev->client->dev, "disabling en_gpio\n");
			gpio_set_value(nqx_dev->en_gpio, 0);
		}
	} else if (arg == 3) {
		r = gpio_get_value(nqx_dev->ese_gpio);
	}
	return r;
}

/**
 * nfc_ldo_vote()
 * @nqx_dev: NFC device containing regulator handle
 *
 * LDO voting based on voltage and current entries in DT
 *
 * Return: 0 on success and -ve on failure
 */
static int nfc_ldo_vote(struct nqx_dev *nqx_dev)
{
	struct device *dev = &nqx_dev->client->dev;
	int ret;

	ret =  regulator_set_voltage(nqx_dev->reg,
			nqx_dev->pdata->vdd_levels[0],
			nqx_dev->pdata->vdd_levels[1]);
	if (ret < 0) {
		dev_err(dev, "%s:set voltage failed\n", __func__);
		return ret;
	}

	/* pass expected current from NFC in uA */
	ret = regulator_set_load(nqx_dev->reg, nqx_dev->pdata->max_current);
	if (ret < 0) {
		dev_err(dev, "%s:set load failed\n", __func__);
		return ret;
	}

	ret = regulator_enable(nqx_dev->reg);
	if (ret < 0)
		dev_err(dev, "%s:regulator_enable failed\n", __func__);
	else
		nqx_dev->is_vreg_enabled = true;
	return ret;
}

/**
 * nfc_ldo_config()
 * @client: I2C client instance, containing node to read DT entry
 * @nqx_dev: NFC device containing regulator handle
 *
 * Configure LDO if entry is present in DT file otherwise
 * with success as it's optional
 *
 * Return: 0 on success and -ve on failure
 */
static int nfc_ldo_config(struct i2c_client *client, struct nqx_dev *nqx_dev)
{
	int r;

	if (of_get_property(client->dev.of_node, NFC_LDO_SUPPLY_NAME, NULL)) {
		// Get the regulator handle
		nqx_dev->reg = regulator_get(&client->dev,
					NFC_LDO_SUPPLY_DT_NAME);
		if (IS_ERR(nqx_dev->reg)) {
			r = PTR_ERR(nqx_dev->reg);
			nqx_dev->reg = NULL;
			dev_err(&client->dev,
				"%s: regulator_get failed, ret = %d\n",
				__func__, r);
			return r;
		}
	} else {
		nqx_dev->reg = NULL;
		dev_err(&client->dev,
			"%s: regulator entry not present\n", __func__);
		// return success as it's optional to configure LDO
		return 0;
	}

	// LDO config supported by platform DT
	r = nfc_ldo_vote(nqx_dev);
	if (r < 0) {
		dev_err(&client->dev,
			"%s: LDO voting failed, ret = %d\n", __func__, r);
		regulator_put(nqx_dev->reg);
	}
	return r;
}

/**
 * nfc_ldo_unvote()
 * @nqx_dev: NFC device containing regulator handle
 *
 * set voltage and load to zero and disable regulator
 *
 * Return: 0 on success and -ve on failure
 */
static int nfc_ldo_unvote(struct nqx_dev *nqx_dev)
{
	struct device *dev = &nqx_dev->client->dev;
	int ret;

	if (!nqx_dev->is_vreg_enabled) {
		dev_err(dev, "%s: regulator already disabled\n", __func__);
		return -EINVAL;
	}

	ret = regulator_disable(nqx_dev->reg);
	if (ret < 0) {
		dev_err(dev, "%s:regulator_disable failed\n", __func__);
		return ret;
	}
	nqx_dev->is_vreg_enabled = false;

	ret =  regulator_set_voltage(nqx_dev->reg, 0, NFC_VDDIO_MAX);
	if (ret < 0) {
		dev_err(dev, "%s:set voltage failed\n", __func__);
		return ret;
	}

	ret = regulator_set_load(nqx_dev->reg, 0);
	if (ret < 0)
		dev_err(dev, "%s:set load failed\n", __func__);
	return ret;
}

static int nfc_open(struct inode *inode, struct file *filp)
{
	struct nqx_dev *nqx_dev = container_of(inode->i_cdev,
				struct nqx_dev, c_dev);

	filp->private_data = nqx_dev;
	nqx_init_stat(nqx_dev);

	mutex_lock(&nqx_dev->dev_ref_mutex);

	if (nqx_dev->dev_ref_count == 0) {
		nqx_enable_irq(nqx_dev);

		if (gpio_is_valid(nqx_dev->firm_gpio)) {
			gpio_set_value(nqx_dev->firm_gpio, 0);
			usleep_range(10000, 10100);
		}
	}

	nqx_dev->dev_ref_count = nqx_dev->dev_ref_count + 1;

	mutex_unlock(&nqx_dev->dev_ref_mutex);

	dev_dbg(&nqx_dev->client->dev,
			"%s: %d,%d\n", __func__, imajor(inode), iminor(inode));
	return 0;
}

static int nfc_close(struct inode *inode, struct file *filp)
{
	struct nqx_dev *nqx_dev = container_of(inode->i_cdev,
				struct nqx_dev, c_dev);

	mutex_lock(&nqx_dev->dev_ref_mutex);

	if (nqx_dev->dev_ref_count == 1) {
		nqx_disable_irq(nqx_dev);

		if (gpio_is_valid(nqx_dev->firm_gpio)) {
			gpio_set_value(nqx_dev->firm_gpio, 0);
			usleep_range(10000, 10100);
		}
	}

	if (nqx_dev->dev_ref_count > 0)
		nqx_dev->dev_ref_count = nqx_dev->dev_ref_count - 1;

	mutex_unlock(&nqx_dev->dev_ref_mutex);

	filp->private_data = NULL;

	return 0;
}

/*
 * nfc_ioctl_power_states() - power control
 * @filp:	pointer to the file descriptor
 * @arg:	mode that we want to move to
 *
 * Device power control. Depending on the arg value, device moves to
 * different states
 * (arg = 0): NFC_ENABLE	GPIO = 0, FW_DL GPIO = 0
 * (arg = 1): NFC_ENABLE	GPIO = 1, FW_DL GPIO = 0
 * (arg = 2): FW_DL GPIO = 1
 *
 * Return: -ENOIOCTLCMD if arg is not supported, 0 in any other case
 */
int nfc_ioctl_power_states(struct file *filp, unsigned long arg)
{
	int r = 0;
	struct nqx_dev *nqx_dev = filp->private_data;

	if (arg == NFC_POWER_OFF) {
		/*
		 * We are attempting a hardware reset so let us disable
		 * interrupts to avoid spurious notifications to upper
		 * layers.
		 */
		nqx_disable_irq(nqx_dev);
		dev_dbg(&nqx_dev->client->dev,
			"gpio_set_value disable: %s: info: %p\n",
			__func__, nqx_dev);
		if (gpio_is_valid(nqx_dev->firm_gpio)) {
			gpio_set_value(nqx_dev->firm_gpio, 0);
			usleep_range(10000, 10100);
		}

		if (gpio_is_valid(nqx_dev->ese_gpio)) {
			if (!gpio_get_value(nqx_dev->ese_gpio)) {
				dev_dbg(&nqx_dev->client->dev, "disabling en_gpio\n");
				gpio_set_value(nqx_dev->en_gpio, 0);
				usleep_range(10000, 10100);
			} else {
				dev_dbg(&nqx_dev->client->dev, "keeping en_gpio high\n");
			}
		} else {
			dev_dbg(&nqx_dev->client->dev, "ese_gpio invalid, set en_gpio to low\n");
			gpio_set_value(nqx_dev->en_gpio, 0);
			usleep_range(10000, 10100);
		}
		if (nqx_dev->pdata->clk_pin_voting) {
			r = nqx_clock_deselect(nqx_dev);
			if (r < 0)
				dev_err(&nqx_dev->client->dev, "unable to disable clock\n");
		}
		nqx_dev->nfc_ven_enabled = false;
	} else if (arg == NFC_POWER_ON) {
		nqx_enable_irq(nqx_dev);
		dev_dbg(&nqx_dev->client->dev,
			"gpio_set_value enable: %s: info: %p\n",
			__func__, nqx_dev);
		if (gpio_is_valid(nqx_dev->firm_gpio)) {
			gpio_set_value(nqx_dev->firm_gpio, 0);
			usleep_range(10000, 10100);
		}
		gpio_set_value(nqx_dev->en_gpio, 1);
		usleep_range(10000, 10100);
		if (nqx_dev->pdata->clk_pin_voting) {
			r = nqx_clock_select(nqx_dev);
			if (r < 0)
				dev_err(&nqx_dev->client->dev, "unable to enable clock\n");
		}
		nqx_dev->nfc_ven_enabled = true;
	} else if (arg == NFC_FW_DWL_VEN_TOGGLE) {
		/*
		 * We are switching to Dowload Mode, toggle the enable pin
		 * in order to set the NFCC in the new mode
		 */
		if (gpio_is_valid(nqx_dev->ese_gpio)) {
			if (gpio_get_value(nqx_dev->ese_gpio)) {
				dev_err(&nqx_dev->client->dev,
				"FW download forbidden while ese is on\n");
				return -EBUSY; /* Device or resource busy */
			}
		}
		gpio_set_value(nqx_dev->en_gpio, 1);
		usleep_range(10000, 10100);
		if (gpio_is_valid(nqx_dev->firm_gpio)) {
			gpio_set_value(nqx_dev->firm_gpio, 1);
			usleep_range(10000, 10100);
		}
		gpio_set_value(nqx_dev->en_gpio, 0);
		usleep_range(10000, 10100);
		gpio_set_value(nqx_dev->en_gpio, 1);
		usleep_range(10000, 10100);
	} else if (arg == NFC_FW_DWL_HIGH) {
		/*
		 * Setting firmware download gpio to HIGH for SN100U
		 * before FW download start
		 */
		dev_dbg(&nqx_dev->client->dev, "SN100 fw gpio HIGH\n");
		if (gpio_is_valid(nqx_dev->firm_gpio)) {
			gpio_set_value(nqx_dev->firm_gpio, 1);
			usleep_range(10000, 10100);
		} else
			dev_err(&nqx_dev->client->dev,
				"firm_gpio is invalid\n");
	} else if (arg == NFC_FW_DWL_LOW) {
		/*
		 * Setting firmware download gpio to LOW for SN100U
		 * FW download finished
		 */
		dev_dbg(&nqx_dev->client->dev, "SN100 fw gpio LOW\n");
		if (gpio_is_valid(nqx_dev->firm_gpio)) {
			gpio_set_value(nqx_dev->firm_gpio, 0);
			usleep_range(10000, 10100);
		} else {
			dev_err(&nqx_dev->client->dev,
				"firm_gpio is invalid\n");
		}
	} else if (arg == NFC_ENABLE) {
		/*
		 * Setting flag true when NFC is enabled
		 */
		nqx_dev->nfc_enabled = true;
	} else if (arg == NFC_DISABLE) {
		/*
		 * Setting flag false when NFC is disabled
		 */
		nqx_dev->nfc_enabled = false;
	} else {
		r = -ENOIOCTLCMD;
	}

	return r;
}

#ifdef CONFIG_COMPAT
static long nfc_compat_ioctl(struct file *pfile, unsigned int cmd,
				unsigned long arg)
{
	long r = 0;

	arg = (compat_u64)arg;
	switch (cmd) {
	case NFC_SET_PWR:
		nfc_ioctl_power_states(pfile, arg);
		break;
	case ESE_SET_PWR:
		nqx_ese_pwr(pfile->private_data, arg);
		break;
	case ESE_GET_PWR:
		nqx_ese_pwr(pfile->private_data, 3);
		break;
	case SET_RX_BLOCK:
		break;
	case SET_EMULATOR_TEST_POINT:
		break;
	default:
		r = -ENOTTY;
	}
	return r;
}
#endif

/*
 * nfc_ioctl_core_reset_ntf()
 * @filp:       pointer to the file descriptor
 *
 * Allows callers to determine if a CORE_RESET_NTF has arrived
 *
 * Return: the value of variable core_reset_ntf
 */
int nfc_ioctl_core_reset_ntf(struct file *filp)
{
	struct nqx_dev *nqx_dev = filp->private_data;

	dev_dbg(&nqx_dev->client->dev, "%s: returning = %d\n", __func__,
		nqx_dev->core_reset_ntf);
	return nqx_dev->core_reset_ntf;
}

/*
 * Inside nfc_ioctl_nfcc_info
 *
 * @brief   nfc_ioctl_nfcc_info
 *
 * Check the NQ Chipset and firmware version details
 */
unsigned int nfc_ioctl_nfcc_info(struct file *filp, unsigned long arg)
{
	unsigned int r = 0;
	struct nqx_dev *nqx_dev = filp->private_data;

	r = nqx_dev->nqx_info.i;
	dev_dbg(&nqx_dev->client->dev,
		"nqx nfc : %s r = %d\n", __func__, r);

	return r;
}

static long nfc_ioctl(struct file *pfile, unsigned int cmd,
			unsigned long arg)
{
	int r = 0;
	struct nqx_dev *nqx_dev = pfile->private_data;

	if (!nqx_dev)
		return -ENODEV;

	switch (cmd) {
	case NFC_SET_PWR:
		r = nfc_ioctl_power_states(pfile, arg);
		break;
	case ESE_SET_PWR:
		if ((nqx_dev->nqx_info.info.chip_type == NFCC_SN100_A) ||
			(nqx_dev->nqx_info.info.chip_type == NFCC_SN100_B))
			r = sn100_ese_pwr(nqx_dev, arg);
		else
			r = nqx_ese_pwr(nqx_dev, arg);
		break;
	case ESE_GET_PWR:
		if ((nqx_dev->nqx_info.info.chip_type == NFCC_SN100_A) ||
			(nqx_dev->nqx_info.info.chip_type == NFCC_SN100_B))
			r = sn100_ese_pwr(nqx_dev, 3);
		else
			r = nqx_ese_pwr(nqx_dev, 3);
		break;
	case SET_RX_BLOCK:
		break;
	case SET_EMULATOR_TEST_POINT:
		break;
	case NFCC_INITIAL_CORE_RESET_NTF:
		r = nfc_ioctl_core_reset_ntf(pfile);
		break;
	case NFCC_GET_INFO:
		r = nfc_ioctl_nfcc_info(pfile, arg);
		break;
	default:
		r = -ENOIOCTLCMD;
	}
	return r;
}

static const struct file_operations nfc_dev_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.read  = nfc_read,
	.write = nfc_write,
	.open = nfc_open,
	.release = nfc_close,
	.unlocked_ioctl = nfc_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = nfc_compat_ioctl
#endif
};

/*
 * function: get_nfcc_hw_info()
 *
 * @client:                     pointer to i2c_client
 * @nqx_dev:                    pointer to nqx_dev structure
 * @nci_reset_rsp_payload_len:  payload length of NCI reset cmd
 *
 * Retrieves NFCC HW information based on the type of NFC chip
 * used on the device. Depending on the nci_reset_rsp_payload_len
 * value, core INIT command will be sent.
 *
 * NFC HW               NCI version     Send Core INIT cmd
 * NQ3xx or old         1.0             Yes
 * NQ4xx                2.0             No
 * Sn1x0x               2.0             No
 *
 * Return:      error codes in case of any failure,
 *              number of bytes read otherwise
 */
static int get_nfcc_hw_info(struct i2c_client *client,
		struct nqx_dev *nqx_dev, char nci_reset_rsp_payload_len)
{
	int ret = 0;

	char *nci_init_cmd = NULL;
	char *nci_init_rsp = NULL;
	char *nci_reset_ntf = NULL;
	char *nfcc_hw_info = NULL;
	unsigned char nfcc_hw_info_len = 0;

	nci_init_cmd = kzalloc(NCI_INIT_CMD_LEN + 1, GFP_DMA | GFP_KERNEL);
	if (!nci_init_cmd) {
		ret = -ENOMEM;
		goto err_nfcc_hw_info;
	}

	nci_init_rsp = kzalloc(NCI_INIT_RSP_LEN + 1,  GFP_DMA | GFP_KERNEL);
	if (!nci_init_rsp) {
		ret = -ENOMEM;
		goto err_nfcc_hw_info;
	}

	nci_reset_ntf = kzalloc(NCI_RESET_NTF_LEN + 1,  GFP_DMA | GFP_KERNEL);
	if (!nci_reset_ntf) {
		ret = -ENOMEM;
		goto err_nfcc_hw_info;
	}

	if (nci_reset_rsp_payload_len == NCI_1_0_RESET_RSP_PAYLOAD_LEN) {
		/*
		 * Chipset is NQ330 or older.
		 * Send core INIT command to get HW info.
		 */
		nci_init_cmd[0] = 0x20;
		nci_init_cmd[1] = 0x01;
		nci_init_cmd[2] = 0x00;
		ret = nqx_standby_write(nqx_dev, nci_init_cmd,
					NCI_INIT_CMD_LEN);
		if (ret < 0) {
			dev_dbg(&client->dev,
			"%s: - i2c_master_send failed for Core INIT\n",
					__func__);
			goto err_nfcc_hw_info;
		}

		ret = is_data_available_for_read(nqx_dev);
		if (ret <= 0) {
			nqx_disable_irq(nqx_dev);
			goto err_nfcc_hw_info;
		}

		/* Read Response of INIT command */
		ret = i2c_master_recv(client, nci_init_rsp, NCI_INIT_RSP_LEN);
		if (ret < 0) {
			dev_dbg(&client->dev,
			"%s: - i2c_master_recv get INIT rsp Error\n",
					__func__);
			goto err_nfcc_hw_info;
		}
		nfcc_hw_info = nci_init_rsp;
	} else {
		/*
		 * Chipset is NQ4xx or later.
		 * Retrieve NTF data from wait queue.
		 */
		ret = is_data_available_for_read(nqx_dev);
		if (ret <= 0) {
			nqx_disable_irq(nqx_dev);
			goto err_nfcc_hw_info;
		}

		/* Read Notification of RESET command */
		ret = i2c_master_recv(client, nci_reset_ntf, NCI_RESET_NTF_LEN);
		if (ret < 0) {
			dev_dbg(&client->dev,
			"%s: - i2c_master_recv get RESET ntf Error\n",
					__func__);
			goto err_nfcc_hw_info;
		}
		nfcc_hw_info = nci_reset_ntf;
	}

	/* Save NFCC HW info */
	nfcc_hw_info_len =
		NCI_HEADER_LEN + nfcc_hw_info[NCI_PAYLOAD_LENGTH_INDEX];
	if (nfcc_hw_info_len > PAYLOAD_HEADER_LENGTH) {
		nqx_dev->nqx_info.info.chip_type =
			nfcc_hw_info[nfcc_hw_info_len -
					NFCC_HW_CHIP_ID_OFFSET];
		nqx_dev->nqx_info.info.rom_version =
			nfcc_hw_info[nfcc_hw_info_len -
					NFCC_HW_ROM_VER_OFFSET];
		nqx_dev->nqx_info.info.fw_major =
			nfcc_hw_info[nfcc_hw_info_len -
					NFCC_HW_MAJOR_NO_OFFSET];
		nqx_dev->nqx_info.info.fw_minor =
			nfcc_hw_info[nfcc_hw_info_len -
					NFCC_HW_MINOR_NO_OFFSET];
	}

err_nfcc_hw_info:

	kfree(nci_reset_ntf);
	kfree(nci_init_rsp);
	kfree(nci_init_cmd);

	return ret;
}

/* Check for availability of NQ_ NFC controller hardware */
static int nfcc_hw_check(struct i2c_client *client, struct nqx_dev *nqx_dev)
{
	int ret = 0;


	unsigned int enable_gpio = nqx_dev->en_gpio;
	char *nci_reset_cmd = NULL;
	char *nci_reset_rsp = NULL;

	char *nci_get_version_cmd = NULL;
	char *nci_get_version_rsp = NULL;

	nci_reset_cmd = kzalloc(NCI_RESET_CMD_LEN + 1, GFP_DMA | GFP_KERNEL);
	if (!nci_reset_cmd) {
		ret = -ENOMEM;
		goto done;
	}

	nci_reset_rsp = kzalloc(NCI_RESET_RSP_LEN + 1,  GFP_DMA | GFP_KERNEL);
	if (!nci_reset_rsp) {
		ret = -ENOMEM;
		goto done;
	}
	nci_get_version_cmd = kzalloc(NCI_GET_VERSION_CMD_LEN + 1,
					GFP_DMA | GFP_KERNEL);
	if (!nci_get_version_cmd) {
		ret = -ENOMEM;
		goto done;
	}

	nci_get_version_rsp = kzalloc(NCI_GET_VERSION_RSP_LEN + 1,
					GFP_DMA | GFP_KERNEL);
	if (!nci_get_version_rsp) {
		ret = -ENOMEM;
		goto done;
	}

	/* making sure that the NFCC starts in a clean state. */
	gpio_set_value(enable_gpio, 1);/* HPD : Enable*/
	/* hardware dependent delay */
	usleep_range(10000, 10100);
	gpio_set_value(enable_gpio, 0);/* ULPM: Disable */
	/* hardware dependent delay */
	usleep_range(10000, 10100);
	gpio_set_value(enable_gpio, 1);/* HPD : Enable*/
	/* hardware dependent delay */
	usleep_range(10000, 10100);

	nci_reset_cmd[0] = 0x20;
	nci_reset_cmd[1] = 0x00;
	nci_reset_cmd[2] = 0x01;
	nci_reset_cmd[3] = 0x00;
	/* send NCI CORE RESET CMD with Keep Config parameters */
	ret = i2c_master_send(client, nci_reset_cmd, NCI_RESET_CMD_LEN);
	if (ret < 0) {
		dev_err(&client->dev,
		"%s: - i2c_master_send core reset Error\n", __func__);

		if (gpio_is_valid(nqx_dev->firm_gpio)) {
			gpio_set_value(nqx_dev->firm_gpio, 1);
			usleep_range(10000, 10100);
		}
		gpio_set_value(nqx_dev->en_gpio, 0);
		usleep_range(10000, 10100);
		gpio_set_value(nqx_dev->en_gpio, 1);
		usleep_range(10000, 10100);

		nci_get_version_cmd[0] = 0x00;
		nci_get_version_cmd[1] = 0x04;
		nci_get_version_cmd[2] = 0xF1;
		nci_get_version_cmd[3] = 0x00;
		nci_get_version_cmd[4] = 0x00;
		nci_get_version_cmd[5] = 0x00;
		nci_get_version_cmd[6] = 0x6E;
		nci_get_version_cmd[7] = 0xEF;
		ret = i2c_master_send(client, nci_get_version_cmd,
						NCI_GET_VERSION_CMD_LEN);

		if (ret < 0) {
			dev_err(&client->dev,
				"%s: - i2c_master_send get version cmd Error\n",
				__func__);
			goto err_nfcc_hw_check;
		}
		/* hardware dependent delay */
		usleep_range(10000, 10100);

		ret = i2c_master_recv(client, nci_get_version_rsp,
						NCI_GET_VERSION_RSP_LEN);
		if (ret < 0) {
			dev_err(&client->dev,
				"%s: - i2c_master_recv get version rsp Error\n",
				__func__);
			goto err_nfcc_hw_check;
		} else {
			nqx_dev->nqx_info.info.chip_type =
				nci_get_version_rsp[3];
			nqx_dev->nqx_info.info.rom_version =
				nci_get_version_rsp[4];
			nqx_dev->nqx_info.info.fw_minor =
				nci_get_version_rsp[6];
			nqx_dev->nqx_info.info.fw_major =
				nci_get_version_rsp[7];
		}
		goto err_nfcc_reset_failed;
	}

	ret = is_data_available_for_read(nqx_dev);
	if (ret <= 0) {
		nqx_disable_irq(nqx_dev);
		goto err_nfcc_hw_check;
	}


	/* Read Header of RESET command */
	ret = i2c_master_recv(client, nci_reset_rsp, NCI_HEADER_LEN);
	if (ret != NCI_HEADER_LEN) {
		dev_dbg(&client->dev,
		"%s: - i2c_master_recv get RESET rsp header Error\n", __func__);
		goto err_nfcc_hw_check;
	}
	ret = i2c_master_recv(client, &nci_reset_rsp[NCI_PAYLOAD_START_INDEX],
				nci_reset_rsp[NCI_PAYLOAD_LENGTH_INDEX]);
	if (ret != nci_reset_rsp[NCI_PAYLOAD_LENGTH_INDEX]) {
		dev_dbg(&client->dev,
		"%s: - i2c_master_recv get RESET rsp data Error\n", __func__);
		goto err_nfcc_hw_check;
	}

	/* Retrieve NFCC HW info */
	ret = get_nfcc_hw_info(client, nqx_dev,
			nci_reset_rsp[NCI_PAYLOAD_LENGTH_INDEX]);
	if (ret < 0) {
		dev_dbg(&client->dev,
			"%s: - Error in getting NFCC HW info\n", __func__);
		goto err_nfcc_hw_check;
	}


	dev_dbg(&client->dev,
		"%s: - nq - reset cmd answer : NfcNciRx %x %x %x\n",
		__func__, nci_reset_rsp[0],
		nci_reset_rsp[1], nci_reset_rsp[2]);

err_nfcc_reset_failed:
	dev_dbg(&nqx_dev->client->dev, "NQ NFCC chip_type = %x\n",
		nqx_dev->nqx_info.info.chip_type);
	dev_dbg(&nqx_dev->client->dev, "NQ fw version = %x.%x.%x\n",
		nqx_dev->nqx_info.info.rom_version,
		nqx_dev->nqx_info.info.fw_major,
		nqx_dev->nqx_info.info.fw_minor);

	switch (nqx_dev->nqx_info.info.chip_type) {
	case NFCC_NQ_310:
		dev_dbg(&client->dev,
		"%s: ## NFCC == NQ310 ##\n", __func__);
		break;
	case NFCC_NQ_330:
		dev_dbg(&client->dev,
		"%s: ## NFCC == NQ330 ##\n", __func__);
		break;
	case NFCC_PN66T:
		dev_dbg(&client->dev,
		"%s: ## NFCC == PN66T ##\n", __func__);
		break;
	case NFCC_SN100_A:
	case NFCC_SN100_B:
		dev_dbg(&client->dev,
		"%s: ## NFCC == SN100x ##\n", __func__);
		break;
	default:
		dev_err(&client->dev,
		"%s: - NFCC HW not Supported\n", __func__);
		break;
	}

	ret = 0;
	nqx_dev->nfc_ven_enabled = true;
	goto done;

err_nfcc_hw_check:
	ret = -ENXIO;
	dev_err(&client->dev,
		"%s: - NFCC HW not available\n", __func__);

done:
	kfree(nci_reset_rsp);
	kfree(nci_reset_cmd);
	kfree(nci_get_version_cmd);
	kfree(nci_get_version_rsp);

	return ret;
}

/*
 * Routine to enable clock.
 * this routine can be extended to select from multiple
 * sources based on clk_src_name.
 */
static int nqx_clock_select(struct nqx_dev *nqx_dev)
{
	int r = 0;

	nqx_dev->s_clk = clk_get(&nqx_dev->client->dev, "ref_clk");

	if (nqx_dev->s_clk == NULL)
		goto err_clk;

	if (!nqx_dev->clk_run)
		r = clk_prepare_enable(nqx_dev->s_clk);

	if (r)
		goto err_clk;

	nqx_dev->clk_run = true;

	return r;

err_clk:
	r = -1;
	return r;
}

/*
 * Routine to disable clocks
 */
static int nqx_clock_deselect(struct nqx_dev *nqx_dev)
{
	int r = -1;

	if (nqx_dev->s_clk != NULL) {
		if (nqx_dev->clk_run) {
			clk_disable_unprepare(nqx_dev->s_clk);
			nqx_dev->clk_run = false;
		}
		return 0;
	}
	return r;
}

static int nfc_parse_dt(struct device *dev, struct nqx_platform_data *pdata)
{
	int r = 0;
	struct device_node *np = dev->of_node;

	pdata->en_gpio = of_get_named_gpio(np, "qcom,nq-ven", 0);
	if ((!gpio_is_valid(pdata->en_gpio)))
		return -EINVAL;
	disable_ctrl = pdata->en_gpio;

	pdata->irq_gpio = of_get_named_gpio(np, "qcom,nq-irq", 0);
	if ((!gpio_is_valid(pdata->irq_gpio)))
		return -EINVAL;

	pdata->firm_gpio = of_get_named_gpio(np, "qcom,nq-firm", 0);
	if (!gpio_is_valid(pdata->firm_gpio)) {
		dev_warn(dev,
			"FIRM GPIO <OPTIONAL> error getting from OF node\n");
		pdata->firm_gpio = -EINVAL;
	}

	pdata->ese_gpio = of_get_named_gpio(np, "qcom,nq-esepwr", 0);
	if (!gpio_is_valid(pdata->ese_gpio)) {
		dev_warn(dev,
			"ese GPIO <OPTIONAL> error getting from OF node\n");
		pdata->ese_gpio = -EINVAL;
	}

	if (of_property_read_string(np, "qcom,clk-src", &pdata->clk_src_name))
		pdata->clk_pin_voting = false;
	else
		pdata->clk_pin_voting = true;

	// optional property
	r = of_property_read_u32_array(np, NFC_LDO_VOL_DT_NAME,
			(u32 *) pdata->vdd_levels,
			ARRAY_SIZE(pdata->vdd_levels));
	if (r) {
		dev_err(dev, "error reading NFC VDDIO min and max value\n");
		// set default as per datasheet
		pdata->vdd_levels[0] = NFC_VDDIO_MIN;
		pdata->vdd_levels[1] = NFC_VDDIO_MAX;
	}

	// optional property
	r = of_property_read_u32(np, NFC_LDO_CUR_DT_NAME, &pdata->max_current);
	if (r) {
		dev_err(dev, "error reading NFC current value\n");
		// set default as per datasheet
		pdata->max_current = NFC_CURRENT_MAX;
	}

	pdata->clkreq_gpio = of_get_named_gpio(np, "qcom,nq-clkreq", 0);

	// return success as above properties are optional
	return 0;
}

static inline int gpio_input_init(const struct device * const dev,
			const int gpio, const char * const gpio_name)
{
	int r = gpio_request(gpio, gpio_name);

	if (r) {
		dev_err(dev, "unable to request gpio [%d]\n", gpio);
		return r;
	}

	r = gpio_direction_input(gpio);
	if (r)
		dev_err(dev, "unable to set direction for gpio [%d]\n", gpio);

	return r;
}

static int nqx_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	int r = 0;
	int irqn = 0;
	struct nqx_platform_data *platform_data;
	struct nqx_dev *nqx_dev;

	dev_dbg(&client->dev, "%s: enter\n", __func__);
	if (client->dev.of_node) {
		platform_data = devm_kzalloc(&client->dev,
			sizeof(struct nqx_platform_data), GFP_KERNEL);
		if (!platform_data) {
			r = -ENOMEM;
			goto err_platform_data;
		}
		r = nfc_parse_dt(&client->dev, platform_data);
		if (r)
			goto err_free_data;
	} else
		platform_data = client->dev.platform_data;

	dev_dbg(&client->dev,
		"%s, inside nfc-nci flags = %x\n",
		__func__, client->flags);

	if (platform_data == NULL) {
		dev_err(&client->dev, "%s: failed\n", __func__);
		r = -ENODEV;
		goto err_platform_data;
	}
	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
		dev_err(&client->dev, "%s: need I2C_FUNC_I2C\n", __func__);
		r = -ENODEV;
		goto err_free_data;
	}
	nqx_dev = kzalloc(sizeof(*nqx_dev), GFP_KERNEL);
	if (nqx_dev == NULL) {
		r = -ENOMEM;
		goto err_free_data;
	}
	nqx_dev->client = client;
	nqx_dev->kbuflen = MAX_BUFFER_SIZE;
	nqx_dev->kbuf = kzalloc(MAX_BUFFER_SIZE, GFP_KERNEL);
	if (!nqx_dev->kbuf) {
		dev_err(&client->dev,
			"failed to allocate memory for nqx_dev->kbuf\n");
		r = -ENOMEM;
		goto err_free_dev;
	}

	if (gpio_is_valid(platform_data->en_gpio)) {
		r = gpio_request(platform_data->en_gpio, "nfc_reset_gpio");
		if (r) {
			dev_err(&client->dev,
			"%s: unable to request nfc reset gpio [%d]\n",
				__func__,
				platform_data->en_gpio);
			goto err_mem;
		}
		r = gpio_direction_output(platform_data->en_gpio, 0);
		if (r) {
			dev_err(&client->dev,
				"%s: unable to set direction for nfc reset gpio [%d]\n",
					__func__,
					platform_data->en_gpio);
			goto err_en_gpio;
		}
	} else {
		dev_err(&client->dev,
		"%s: nfc reset gpio not provided\n", __func__);
		goto err_mem;
	}

	if (gpio_is_valid(platform_data->irq_gpio)) {
		r = gpio_request(platform_data->irq_gpio, "nfc_irq_gpio");
		if (r) {
			dev_err(&client->dev, "%s: unable to request nfc irq gpio [%d]\n",
				__func__, platform_data->irq_gpio);
			goto err_en_gpio;
		}
		r = gpio_direction_input(platform_data->irq_gpio);
		if (r) {
			dev_err(&client->dev,
			"%s: unable to set direction for nfc irq gpio [%d]\n",
				__func__,
				platform_data->irq_gpio);
			goto err_irq_gpio;
		}
		irqn = gpio_to_irq(platform_data->irq_gpio);
		if (irqn < 0) {
			r = irqn;
			goto err_irq_gpio;
		}
		client->irq = irqn;
	} else {
		dev_err(&client->dev, "%s: irq gpio not provided\n", __func__);
		goto err_en_gpio;
	}
	if (gpio_is_valid(platform_data->firm_gpio)) {
		r = gpio_request(platform_data->firm_gpio,
			"nfc_firm_gpio");
		if (r) {
			dev_err(&client->dev,
				"%s: unable to request nfc firmware gpio [%d]\n",
				__func__, platform_data->firm_gpio);
			goto err_irq_gpio;
		}
		r = gpio_direction_output(platform_data->firm_gpio, 0);
		if (r) {
			dev_err(&client->dev,
			"%s: cannot set direction for nfc firmware gpio [%d]\n",
			__func__, platform_data->firm_gpio);
			goto err_firm_gpio;
		}
	} else {
		dev_err(&client->dev,
			"%s: firm gpio not provided\n", __func__);
		goto err_irq_gpio;
	}
	if (gpio_is_valid(platform_data->ese_gpio)) {
		r = gpio_request(platform_data->ese_gpio,
				"nfc-ese_pwr");
		if (r) {
			nqx_dev->ese_gpio = -EINVAL;
			dev_err(&client->dev,
				"%s: unable to request nfc ese gpio [%d]\n",
					__func__, platform_data->ese_gpio);
			/* ese gpio optional so we should continue */
		} else {
			nqx_dev->ese_gpio = platform_data->ese_gpio;
			r = gpio_direction_output(platform_data->ese_gpio, 0);
			if (r) {
				/*
				 * free ese gpio and set invalid
				 * to avoid further use
				 */
				gpio_free(platform_data->ese_gpio);
				nqx_dev->ese_gpio = -EINVAL;
				dev_err(&client->dev,
					"%s: cannot set direction for nfc ese gpio [%d]\n",
					__func__, platform_data->ese_gpio);
				/* ese gpio optional so we should continue */
			}
		}
	} else {
		nqx_dev->ese_gpio = -EINVAL;
		dev_err(&client->dev,
			"%s: ese gpio not provided\n", __func__);
		/* ese gpio optional so we should continue */
	}
	if (gpio_is_valid(platform_data->clkreq_gpio)) {
		r = gpio_request(platform_data->clkreq_gpio,
			"nfc_clkreq_gpio");
		if (r) {
			dev_err(&client->dev,
				"%s: unable to request nfc clkreq gpio [%d]\n",
				__func__, platform_data->clkreq_gpio);
			goto err_ese_gpio;
		}
		r = gpio_direction_input(platform_data->clkreq_gpio);
		if (r) {
			dev_err(&client->dev,
			"%s: cannot set direction for nfc clkreq gpio [%d]\n",
			__func__, platform_data->clkreq_gpio);
			goto err_clkreq_gpio;
		}
	} else {
		dev_err(&client->dev,
			"%s: clkreq gpio not provided\n", __func__);
		goto err_ese_gpio;
	}

	nqx_dev->en_gpio = platform_data->en_gpio;
	nqx_dev->irq_gpio = platform_data->irq_gpio;
	nqx_dev->firm_gpio  = platform_data->firm_gpio;
	nqx_dev->clkreq_gpio = platform_data->clkreq_gpio;
	nqx_dev->pdata = platform_data;

	/* init mutex and queues */
	init_waitqueue_head(&nqx_dev->read_wq);
	init_waitqueue_head(&nqx_dev->cold_reset_read_wq);
	mutex_init(&nqx_dev->read_mutex);
	mutex_init(&nqx_dev->dev_ref_mutex);
	spin_lock_init(&nqx_dev->irq_enabled_lock);

	r = alloc_chrdev_region(&nqx_dev->devno, 0, DEV_COUNT, DEVICE_NAME);
	if (r < 0) {
		dev_err(&client->dev,
			"%s: failed to alloc chrdev region\n", __func__);
		goto err_char_dev_register;
	}

	nqx_dev->nqx_class = class_create(THIS_MODULE, CLASS_NAME);
	if (IS_ERR(nqx_dev->nqx_class)) {
		dev_err(&client->dev,
			"%s: failed to register device class\n", __func__);
		goto err_class_create;
	}

	cdev_init(&nqx_dev->c_dev, &nfc_dev_fops);
	r = cdev_add(&nqx_dev->c_dev, nqx_dev->devno, DEV_COUNT);
	if (r < 0) {
		dev_err(&client->dev, "%s: failed to add cdev\n", __func__);
		goto err_cdev_add;
	}

	nqx_dev->nqx_device = device_create(nqx_dev->nqx_class, NULL,
					nqx_dev->devno, nqx_dev, DEVICE_NAME);
	if (IS_ERR(nqx_dev->nqx_device)) {
		dev_err(&client->dev,
			"%s: failed to create the device\n", __func__);
		goto err_device_create;
	}

	/* NFC_INT IRQ */
	nqx_dev->irq_enabled = true;
	r = request_irq(client->irq, nqx_dev_irq_handler,
			  IRQF_TRIGGER_HIGH, client->name, nqx_dev);
	if (r) {
		dev_err(&client->dev, "%s: request_irq failed\n", __func__);
		goto err_request_irq_failed;
	}
	nqx_disable_irq(nqx_dev);

	r = nfc_ldo_config(client, nqx_dev);
	if (r) {
		dev_err(&client->dev, "%s: LDO config failed\n", __func__);
		goto err_ldo_config_failed;
	}

	/*
	 * To be efficient we need to test whether nfcc hardware is physically
	 * present before attempting further hardware initialisation.
	 *
	 */
	r = nfcc_hw_check(client, nqx_dev);
	if (r) {
		/* make sure NFCC is not enabled */
		gpio_set_value(platform_data->en_gpio, 0);
		/* We don't think there is hardware switch NFC OFF */
		goto err_request_hw_check_failed;
	}

	/* Register reboot notifier here */
	r = register_reboot_notifier(&nfcc_notifier);
	if (r) {
		dev_err(&client->dev,
			"%s: cannot register reboot notifier(err = %d)\n",
			__func__, r);
		/*
		 * nfcc_hw_check function not doing memory
		 * allocation so using same goto target here
		 */
		goto err_request_hw_check_failed;
	}

#ifdef NFC_KERNEL_BU
	r = nqx_clock_select(nqx_dev);
	if (r < 0) {
		dev_err(&client->dev,
			"%s: nqx_clock_select failed\n", __func__);
		goto err_clock_en_failed;
	}
	gpio_set_value(platform_data->en_gpio, 1);
#endif
	device_init_wakeup(&client->dev, true);
	device_set_wakeup_capable(&client->dev, true);
	i2c_set_clientdata(client, nqx_dev);
	nqx_dev->irq_wake_up = false;
	nqx_dev->cold_reset_rsp_pending = false;
	nqx_dev->nfc_enabled = false;
	nqx_dev->is_ese_session_active = false;

	dev_err(&client->dev,
	"%s: probing NFCC NQxxx exited successfully\n",
		 __func__);
	return 0;

#ifdef NFC_KERNEL_BU
err_clock_en_failed:
	unregister_reboot_notifier(&nfcc_notifier);
#endif
err_request_hw_check_failed:
	if (nqx_dev->reg) {
		nfc_ldo_unvote(nqx_dev);
		regulator_put(nqx_dev->reg);
	}
err_ldo_config_failed:
	free_irq(client->irq, nqx_dev);
err_request_irq_failed:
	device_destroy(nqx_dev->nqx_class, nqx_dev->devno);
err_device_create:
	cdev_del(&nqx_dev->c_dev);
err_cdev_add:
	class_destroy(nqx_dev->nqx_class);
err_class_create:
	unregister_chrdev_region(nqx_dev->devno, DEV_COUNT);
err_char_dev_register:
	mutex_destroy(&nqx_dev->read_mutex);
err_clkreq_gpio:
	gpio_free(platform_data->clkreq_gpio);
err_ese_gpio:
	/* optional gpio, not sure was configured in probe */
	if (gpio_is_valid(platform_data->ese_gpio))
		gpio_free(platform_data->ese_gpio);
err_firm_gpio:
	gpio_free(platform_data->firm_gpio);
err_irq_gpio:
	gpio_free(platform_data->irq_gpio);
err_en_gpio:
	gpio_free(platform_data->en_gpio);
err_mem:
	kfree(nqx_dev->kbuf);
err_free_dev:
	kfree(nqx_dev);
err_free_data:
	if (client->dev.of_node)
		devm_kfree(&client->dev, platform_data);
err_platform_data:
	dev_err(&client->dev,
	"%s: probing nqxx failed, check hardware\n",
		 __func__);
	return r;
}

static int nqx_remove(struct i2c_client *client)
{
	int ret = 0;
	struct nqx_dev *nqx_dev;

	nqx_dev = i2c_get_clientdata(client);
	if (!nqx_dev) {
		dev_err(&client->dev,
		"%s: device doesn't exist anymore\n", __func__);
		ret = -ENODEV;
		goto err;
	}

	gpio_set_value(nqx_dev->en_gpio, 0);
	// HW dependent delay before LDO goes into LPM mode
	usleep_range(10000, 10100);
	if (nqx_dev->reg) {
		ret = nfc_ldo_unvote(nqx_dev);
		regulator_put(nqx_dev->reg);
	}
	unregister_reboot_notifier(&nfcc_notifier);
	free_irq(client->irq, nqx_dev);
	cdev_del(&nqx_dev->c_dev);
	device_destroy(nqx_dev->nqx_class, nqx_dev->devno);
	class_destroy(nqx_dev->nqx_class);
	unregister_chrdev_region(nqx_dev->devno, DEV_COUNT);
	mutex_destroy(&nqx_dev->read_mutex);
	mutex_destroy(&nqx_dev->dev_ref_mutex);
	gpio_free(nqx_dev->clkreq_gpio);
	/* optional gpio, not sure was configured in probe */
	if (nqx_dev->ese_gpio > 0)
		gpio_free(nqx_dev->ese_gpio);
	gpio_free(nqx_dev->firm_gpio);
	gpio_free(nqx_dev->irq_gpio);
	gpio_free(nqx_dev->en_gpio);
	kfree(nqx_dev->kbuf);
	if (client->dev.of_node)
		devm_kfree(&client->dev, nqx_dev->pdata);

	kfree(nqx_dev);
err:
	return ret;
}

static int nqx_suspend(struct device *device)
{
	struct i2c_client *client = to_i2c_client(device);
	struct nqx_dev *nqx_dev = i2c_get_clientdata(client);

	if (device_may_wakeup(&client->dev) && nqx_dev->irq_enabled) {
		if (!enable_irq_wake(client->irq))
			nqx_dev->irq_wake_up = true;
	}
	return 0;
}

static int nqx_resume(struct device *device)
{
	struct i2c_client *client = to_i2c_client(device);
	struct nqx_dev *nqx_dev = i2c_get_clientdata(client);

	if (device_may_wakeup(&client->dev) && nqx_dev->irq_wake_up) {
		if (!disable_irq_wake(client->irq))
			nqx_dev->irq_wake_up = false;
	}
	return 0;
}

static const struct i2c_device_id nqx_id[] = {
	{"nqx-i2c", 0},
	{}
};

static const struct dev_pm_ops nfc_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(nqx_suspend, nqx_resume)
};

static struct i2c_driver nqx = {
	.id_table = nqx_id,
	.probe = nqx_probe,
	.remove = nqx_remove,
	.driver = {
		.name = "nq-nci",
		.of_match_table = msm_match_table,
		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
		.pm = &nfc_pm_ops,
	},
};

static int nfcc_reboot(struct notifier_block *notifier, unsigned long val,
			  void *v)
{
	gpio_set_value(disable_ctrl, 1);
	return NOTIFY_OK;
}

/*
 * module load/unload record keeping
 */
static int __init nqx_dev_init(void)
{
	return i2c_add_driver(&nqx);
}
module_init(nqx_dev_init);

static void __exit nqx_dev_exit(void)
{
	unregister_reboot_notifier(&nfcc_notifier);
	i2c_del_driver(&nqx);
}
module_exit(nqx_dev_exit);

MODULE_DESCRIPTION("NFC nqx");
MODULE_LICENSE("GPL v2");