/*
 * Driver for the PN544 NFC chip.
 *
 * Copyright (C) Nokia Corporation
 *
 * Author: Jari Vanhala <ext-jari.vanhala@nokia.com>
 * Contact: Matti Aaltonen <matti.j.aaltonen@nokia.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms 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/completion.h>
#include <linux/crc-ccitt.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/nfc/pn544.h>
#include <linux/poll.h>
#include <linux/regulator/consumer.h>
#include <linux/serial_core.h> /* for TCGETS */
#include <linux/slab.h>

#define DRIVER_CARD     "PN544 NFC"
#define DRIVER_DESC     "NFC driver for PN544"

static struct i2c_device_id pn544_id_table[] = {
        { PN544_DRIVER_NAME, 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, pn544_id_table);

#define HCI_MODE        0
#define FW_MODE         1

enum pn544_state {
        PN544_ST_COLD,
        PN544_ST_FW_READY,
        PN544_ST_READY,
};

enum pn544_irq {
        PN544_NONE,
        PN544_INT,
};

struct pn544_info {
        struct miscdevice miscdev;
        struct i2c_client *i2c_dev;
        struct regulator_bulk_data regs[3];

        enum pn544_state state;
        wait_queue_head_t read_wait;
        loff_t read_offset;
        enum pn544_irq read_irq;
        struct mutex read_mutex; /* Serialize read_irq access */
        struct mutex mutex; /* Serialize info struct access */
        u8 *buf;
        size_t buflen;
};

static const char reg_vdd_io[]  = "Vdd_IO";
static const char reg_vbat[]    = "VBat";
static const char reg_vsim[]    = "VSim";

/* sysfs interface */
static ssize_t pn544_test(struct device *dev,
                          struct device_attribute *attr, char *buf)
{
        struct pn544_info *info = dev_get_drvdata(dev);
        struct i2c_client *client = info->i2c_dev;
        struct pn544_nfc_platform_data *pdata = client->dev.platform_data;

        return snprintf(buf, PAGE_SIZE, "%d\n", pdata->test());
}

static int pn544_enable(struct pn544_info *info, int mode)
{
        struct pn544_nfc_platform_data *pdata;
        struct i2c_client *client = info->i2c_dev;

        int r;

        r = regulator_bulk_enable(ARRAY_SIZE(info->regs), info->regs);
        if (r < 0)
                return r;

        pdata = client->dev.platform_data;
        info->read_irq = PN544_NONE;
        if (pdata->enable)
                pdata->enable(mode);

        if (mode) {
                info->state = PN544_ST_FW_READY;
                dev_dbg(&client->dev, "now in FW-mode\n");
        } else {
                info->state = PN544_ST_READY;
                dev_dbg(&client->dev, "now in HCI-mode\n");
        }

        usleep_range(10000, 15000);

        return 0;
}

static void pn544_disable(struct pn544_info *info)
{
        struct pn544_nfc_platform_data *pdata;
        struct i2c_client *client = info->i2c_dev;

        pdata = client->dev.platform_data;
        if (pdata->disable)
                pdata->disable();

        info->state = PN544_ST_COLD;

        dev_dbg(&client->dev, "Now in OFF-mode\n");

        msleep(PN544_RESETVEN_TIME);

        info->read_irq = PN544_NONE;
        regulator_bulk_disable(ARRAY_SIZE(info->regs), info->regs);
}

static int check_crc(u8 *buf, int buflen)
{
        u8 len;
        u16 crc;

        len = buf[0] + 1;
        if (len < 4 || len != buflen || len > PN544_MSG_MAX_SIZE) {
                pr_err(PN544_DRIVER_NAME
                       ": CRC; corrupt packet len %u (%d)\n", len, buflen);
                print_hex_dump(KERN_DEBUG, "crc: ", DUMP_PREFIX_NONE,
                               16, 2, buf, buflen, false);
                return -EPERM;
        }
        crc = crc_ccitt(0xffff, buf, len - 2);
        crc = ~crc;

        if (buf[len-2] != (crc & 0xff) || buf[len-1] != (crc >> 8)) {
                pr_err(PN544_DRIVER_NAME ": CRC error 0x%x != 0x%x 0x%x\n",
                       crc, buf[len-1], buf[len-2]);

                print_hex_dump(KERN_DEBUG, "crc: ", DUMP_PREFIX_NONE,
                               16, 2, buf, buflen, false);
                return -EPERM;
        }
        return 0;
}

static int pn544_i2c_write(struct i2c_client *client, u8 *buf, int len)
{
        int r;

        if (len < 4 || len != (buf[0] + 1)) {
                dev_err(&client->dev, "%s: Illegal message length: %d\n",
                        __func__, len);
                return -EINVAL;
        }

        if (check_crc(buf, len))
                return -EINVAL;

        usleep_range(3000, 6000);

        r = i2c_master_send(client, buf, len);
        dev_dbg(&client->dev, "send: %d\n", r);

        if (r == -EREMOTEIO) { /* Retry, chip was in standby */
                usleep_range(6000, 10000);
                r = i2c_master_send(client, buf, len);
                dev_dbg(&client->dev, "send2: %d\n", r);
        }

        if (r != len)
                return -EREMOTEIO;

        return r;
}

static int pn544_i2c_read(struct i2c_client *client, u8 *buf, int buflen)
{
        int r;
        u8 len;

        /*
         * You could read a packet in one go, but then you'd need to read
         * max size and rest would be 0xff fill, so we do split reads.
         */
        r = i2c_master_recv(client, &len, 1);
        dev_dbg(&client->dev, "recv1: %d\n", r);

        if (r != 1)
                return -EREMOTEIO;

        if (len < PN544_LLC_HCI_OVERHEAD)
                len = PN544_LLC_HCI_OVERHEAD;
        else if (len > (PN544_MSG_MAX_SIZE - 1))
                len = PN544_MSG_MAX_SIZE - 1;

        if (1 + len > buflen) /* len+(data+crc16) */
                return -EMSGSIZE;

        buf[0] = len;

        r = i2c_master_recv(client, buf + 1, len);
        dev_dbg(&client->dev, "recv2: %d\n", r);

        if (r != len)
                return -EREMOTEIO;

        usleep_range(3000, 6000);

        return r + 1;
}

static int pn544_fw_write(struct i2c_client *client, u8 *buf, int len)
{
        int r;

        dev_dbg(&client->dev, "%s\n", __func__);

        if (len < PN544_FW_HEADER_SIZE ||
            (PN544_FW_HEADER_SIZE + (buf[1] << 8) + buf[2]) != len)
                return -EINVAL;

        r = i2c_master_send(client, buf, len);
        dev_dbg(&client->dev, "fw send: %d\n", r);

        if (r == -EREMOTEIO) { /* Retry, chip was in standby */
                usleep_range(6000, 10000);
                r = i2c_master_send(client, buf, len);
                dev_dbg(&client->dev, "fw send2: %d\n", r);
        }

        if (r != len)
                return -EREMOTEIO;

        return r;
}

static int pn544_fw_read(struct i2c_client *client, u8 *buf, int buflen)
{
        int r, len;

        if (buflen < PN544_FW_HEADER_SIZE)
                return -EINVAL;

        r = i2c_master_recv(client, buf, PN544_FW_HEADER_SIZE);
        dev_dbg(&client->dev, "FW recv1: %d\n", r);

        if (r < 0)
                return r;

        if (r < PN544_FW_HEADER_SIZE)
                return -EINVAL;

        len = (buf[1] << 8) + buf[2];
        if (len == 0) /* just header, no additional data */
                return r;

        if (len > buflen - PN544_FW_HEADER_SIZE)
                return -EMSGSIZE;

        r = i2c_master_recv(client, buf + PN544_FW_HEADER_SIZE, len);
        dev_dbg(&client->dev, "fw recv2: %d\n", r);

        if (r != len)
                return -EINVAL;

        return r + PN544_FW_HEADER_SIZE;
}

static irqreturn_t pn544_irq_thread_fn(int irq, void *dev_id)
{
        struct pn544_info *info = dev_id;
        struct i2c_client *client = info->i2c_dev;

        BUG_ON(!info);
        BUG_ON(irq != info->i2c_dev->irq);

        dev_dbg(&client->dev, "IRQ\n");

        mutex_lock(&info->read_mutex);
        info->read_irq = PN544_INT;
        mutex_unlock(&info->read_mutex);

        wake_up_interruptible(&info->read_wait);

        return IRQ_HANDLED;
}

static enum pn544_irq pn544_irq_state(struct pn544_info *info)
{
        enum pn544_irq irq;

        mutex_lock(&info->read_mutex);
        irq = info->read_irq;
        mutex_unlock(&info->read_mutex);
        /*
         * XXX: should we check GPIO-line status directly?
         * return pdata->irq_status() ? PN544_INT : PN544_NONE;
         */

        return irq;
}

static ssize_t pn544_read(struct file *file, char __user *buf,
                          size_t count, loff_t *offset)
{
        struct pn544_info *info = container_of(file->private_data,
                                               struct pn544_info, miscdev);
        struct i2c_client *client = info->i2c_dev;
        enum pn544_irq irq;
        size_t len;
        int r = 0;

        dev_dbg(&client->dev, "%s: info: %p, count: %zu\n", __func__,
                info, count);

        mutex_lock(&info->mutex);

        if (info->state == PN544_ST_COLD) {
                r = -ENODEV;
                goto out;
        }

        irq = pn544_irq_state(info);
        if (irq == PN544_NONE) {
                if (file->f_flags & O_NONBLOCK) {
                        r = -EAGAIN;
                        goto out;
                }

                if (wait_event_interruptible(info->read_wait,
                                             (info->read_irq == PN544_INT))) {
                        r = -ERESTARTSYS;
                        goto out;
                }
        }

        if (info->state == PN544_ST_FW_READY) {
                len = min(count, info->buflen);

                mutex_lock(&info->read_mutex);
                r = pn544_fw_read(info->i2c_dev, info->buf, len);
                info->read_irq = PN544_NONE;
                mutex_unlock(&info->read_mutex);

                if (r < 0) {
                        dev_err(&info->i2c_dev->dev, "FW read failed: %d\n", r);
                        goto out;
                }

                print_hex_dump(KERN_DEBUG, "FW read: ", DUMP_PREFIX_NONE,
                               16, 2, info->buf, r, false);

                *offset += r;
                if (copy_to_user(buf, info->buf, r)) {
                        r = -EFAULT;
                        goto out;
                }
        } else {
                len = min(count, info->buflen);

                mutex_lock(&info->read_mutex);
                r = pn544_i2c_read(info->i2c_dev, info->buf, len);
                info->read_irq = PN544_NONE;
                mutex_unlock(&info->read_mutex);

                if (r < 0) {
                        dev_err(&info->i2c_dev->dev, "read failed (%d)\n", r);
                        goto out;
                }
                print_hex_dump(KERN_DEBUG, "read: ", DUMP_PREFIX_NONE,
                               16, 2, info->buf, r, false);

                *offset += r;
                if (copy_to_user(buf, info->buf, r)) {
                        r = -EFAULT;
                        goto out;
                }
        }

out:
        mutex_unlock(&info->mutex);

        return r;
}

static unsigned int pn544_poll(struct file *file, poll_table *wait)
{
        struct pn544_info *info = container_of(file->private_data,
                                               struct pn544_info, miscdev);
        struct i2c_client *client = info->i2c_dev;
        int r = 0;

        dev_dbg(&client->dev, "%s: info: %p\n", __func__, info);

        mutex_lock(&info->mutex);

        if (info->state == PN544_ST_COLD) {
                r = -ENODEV;
                goto out;
        }

        poll_wait(file, &info->read_wait, wait);

        if (pn544_irq_state(info) == PN544_INT) {
                r = POLLIN | POLLRDNORM;
                goto out;
        }
out:
        mutex_unlock(&info->mutex);

        return r;
}

static ssize_t pn544_write(struct file *file, const char __user *buf,
                           size_t count, loff_t *ppos)
{
        struct pn544_info *info = container_of(file->private_data,
                                               struct pn544_info, miscdev);
        struct i2c_client *client = info->i2c_dev;
        ssize_t len;
        int r;

        dev_dbg(&client->dev, "%s: info: %p, count %zu\n", __func__,
                info, count);

        mutex_lock(&info->mutex);

        if (info->state == PN544_ST_COLD) {
                r = -ENODEV;
                goto out;
        }

        /*
         * XXX: should we detect rset-writes and clean possible
         * read_irq state
         */
        if (info->state == PN544_ST_FW_READY) {
                size_t fw_len;

                if (count < PN544_FW_HEADER_SIZE) {
                        r = -EINVAL;
                        goto out;
                }

                len = min(count, info->buflen);
                if (copy_from_user(info->buf, buf, len)) {
                        r = -EFAULT;
                        goto out;
                }

                print_hex_dump(KERN_DEBUG, "FW write: ", DUMP_PREFIX_NONE,
                               16, 2, info->buf, len, false);

                fw_len = PN544_FW_HEADER_SIZE + (info->buf[1] << 8) +
                        info->buf[2];

                if (len > fw_len) /* 1 msg at a time */
                        len = fw_len;

                r = pn544_fw_write(info->i2c_dev, info->buf, len);
        } else {
                if (count < PN544_LLC_MIN_SIZE) {
                        r = -EINVAL;
                        goto out;
                }

                len = min(count, info->buflen);
                if (copy_from_user(info->buf, buf, len)) {
                        r = -EFAULT;
                        goto out;
                }

                print_hex_dump(KERN_DEBUG, "write: ", DUMP_PREFIX_NONE,
                               16, 2, info->buf, len, false);

                if (len > (info->buf[0] + 1)) /* 1 msg at a time */
                        len  = info->buf[0] + 1;

                r = pn544_i2c_write(info->i2c_dev, info->buf, len);
        }
out:
        mutex_unlock(&info->mutex);

        return r;

}

static long pn544_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        struct pn544_info *info = container_of(file->private_data,
                                               struct pn544_info, miscdev);
        struct i2c_client *client = info->i2c_dev;
        struct pn544_nfc_platform_data *pdata;
        unsigned int val;
        int r = 0;

        dev_dbg(&client->dev, "%s: info: %p, cmd: 0x%x\n", __func__, info, cmd);

        mutex_lock(&info->mutex);

        if (info->state == PN544_ST_COLD) {
                r = -ENODEV;
                goto out;
        }

        pdata = info->i2c_dev->dev.platform_data;
        switch (cmd) {
        case PN544_GET_FW_MODE:
                dev_dbg(&client->dev, "%s:  PN544_GET_FW_MODE\n", __func__);

                val = (info->state == PN544_ST_FW_READY);
                if (copy_to_user((void __user *)arg, &val, sizeof(val))) {
                        r = -EFAULT;
                        goto out;
                }

                break;

        case PN544_SET_FW_MODE:
                dev_dbg(&client->dev, "%s:  PN544_SET_FW_MODE\n", __func__);

                if (copy_from_user(&val, (void __user *)arg, sizeof(val))) {
                        r = -EFAULT;
                        goto out;
                }

                if (val) {
                        if (info->state == PN544_ST_FW_READY)
                                break;

                        pn544_disable(info);
                        r = pn544_enable(info, FW_MODE);
                        if (r < 0)
                                goto out;
                } else {
                        if (info->state == PN544_ST_READY)
                                break;
                        pn544_disable(info);
                        r = pn544_enable(info, HCI_MODE);
                        if (r < 0)
                                goto out;
                }
                file->f_pos = info->read_offset;
                break;

        case TCGETS:
                dev_dbg(&client->dev, "%s:  TCGETS\n", __func__);

                r = -ENOIOCTLCMD;
                break;

        default:
                dev_err(&client->dev, "Unknown ioctl 0x%x\n", cmd);
                r = -ENOIOCTLCMD;
                break;
        }

out:
        mutex_unlock(&info->mutex);

        return r;
}

static int pn544_open(struct inode *inode, struct file *file)
{
        struct pn544_info *info = container_of(file->private_data,
                                               struct pn544_info, miscdev);
        struct i2c_client *client = info->i2c_dev;
        int r = 0;

        dev_dbg(&client->dev, "%s: info: %p, client %p\n", __func__,
                info, info->i2c_dev);

        mutex_lock(&info->mutex);

        /*
         * Only 1 at a time.
         * XXX: maybe user (counter) would work better
         */
        if (info->state != PN544_ST_COLD) {
                r = -EBUSY;
                goto out;
        }

        file->f_pos = info->read_offset;
        r = pn544_enable(info, HCI_MODE);

out:
        mutex_unlock(&info->mutex);
        return r;
}

static int pn544_close(struct inode *inode, struct file *file)
{
        struct pn544_info *info = container_of(file->private_data,
                                               struct pn544_info, miscdev);
        struct i2c_client *client = info->i2c_dev;

        dev_dbg(&client->dev, "%s: info: %p, client %p\n",
                __func__, info, info->i2c_dev);

        mutex_lock(&info->mutex);
        pn544_disable(info);
        mutex_unlock(&info->mutex);

        return 0;
}

static const struct file_operations pn544_fops = {
        .owner          = THIS_MODULE,
        .llseek         = no_llseek,
        .read           = pn544_read,
        .write          = pn544_write,
        .poll           = pn544_poll,
        .open           = pn544_open,
        .release        = pn544_close,
        .unlocked_ioctl = pn544_ioctl,
};

#ifdef CONFIG_PM
static int pn544_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct pn544_info *info;
        int r = 0;

        dev_info(&client->dev, "***\n%s: client %p\n***\n", __func__, client);

        info = i2c_get_clientdata(client);
        dev_info(&client->dev, "%s: info: %p, client %p\n", __func__,
                 info, client);

        mutex_lock(&info->mutex);

        switch (info->state) {
        case PN544_ST_FW_READY:
                /* Do not suspend while upgrading FW, please! */
                r = -EPERM;
                break;

        case PN544_ST_READY:
                /*
                 * CHECK: Device should be in standby-mode. No way to check?
                 * Allowing low power mode for the regulator is potentially
                 * dangerous if pn544 does not go to suspension.
                 */
                break;

        case PN544_ST_COLD:
                break;
        };

        mutex_unlock(&info->mutex);
        return r;
}

static int pn544_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct pn544_info *info = i2c_get_clientdata(client);
        int r = 0;

        dev_dbg(&client->dev, "%s: info: %p, client %p\n", __func__,
                info, client);

        mutex_lock(&info->mutex);

        switch (info->state) {
        case PN544_ST_READY:
                /*
                 * CHECK: If regulator low power mode is allowed in
                 * pn544_suspend, we should go back to normal mode
                 * here.
                 */
                break;

        case PN544_ST_COLD:
                break;

        case PN544_ST_FW_READY:
                break;
        };

        mutex_unlock(&info->mutex);

        return r;
}

static SIMPLE_DEV_PM_OPS(pn544_pm_ops, pn544_suspend, pn544_resume);
#endif

static struct device_attribute pn544_attr =
        __ATTR(nfc_test, S_IRUGO, pn544_test, NULL);

static int __devinit pn544_probe(struct i2c_client *client,
                                 const struct i2c_device_id *id)
{
        struct pn544_info *info;
        struct pn544_nfc_platform_data *pdata;
        int r = 0;

        dev_dbg(&client->dev, "%s\n", __func__);
        dev_dbg(&client->dev, "IRQ: %d\n", client->irq);

        /* private data allocation */
        info = kzalloc(sizeof(struct pn544_info), GFP_KERNEL);
        if (!info) {
                dev_err(&client->dev,
                        "Cannot allocate memory for pn544_info.\n");
                r = -ENOMEM;
                goto err_info_alloc;
        }

        info->buflen = max(PN544_MSG_MAX_SIZE, PN544_MAX_I2C_TRANSFER);
        info->buf = kzalloc(info->buflen, GFP_KERNEL);
        if (!info->buf) {
                dev_err(&client->dev,
                        "Cannot allocate memory for pn544_info->buf.\n");
                r = -ENOMEM;
                goto err_buf_alloc;
        }

        info->regs[0].supply = reg_vdd_io;
        info->regs[1].supply = reg_vbat;
        info->regs[2].supply = reg_vsim;
        r = regulator_bulk_get(&client->dev, ARRAY_SIZE(info->regs),
                                 info->regs);
        if (r < 0)
                goto err_kmalloc;

        info->i2c_dev = client;
        info->state = PN544_ST_COLD;
        info->read_irq = PN544_NONE;
        mutex_init(&info->read_mutex);
        mutex_init(&info->mutex);
        init_waitqueue_head(&info->read_wait);
        i2c_set_clientdata(client, info);
        pdata = client->dev.platform_data;
        if (!pdata) {
                dev_err(&client->dev, "No platform data\n");
                r = -EINVAL;
                goto err_reg;
        }

        if (!pdata->request_resources) {
                dev_err(&client->dev, "request_resources() missing\n");
                r = -EINVAL;
                goto err_reg;
        }

        r = pdata->request_resources(client);
        if (r) {
                dev_err(&client->dev, "Cannot get platform resources\n");
                goto err_reg;
        }

        r = request_threaded_irq(client->irq, NULL, pn544_irq_thread_fn,
                                 IRQF_TRIGGER_RISING, PN544_DRIVER_NAME,
                                 info);
        if (r < 0) {
                dev_err(&client->dev, "Unable to register IRQ handler\n");
                goto err_res;
        }

        /* If we don't have the test we don't need the sysfs file */
        if (pdata->test) {
                r = device_create_file(&client->dev, &pn544_attr);
                if (r) {
                        dev_err(&client->dev,
                                "sysfs registration failed, error %d\n", r);
                        goto err_irq;
                }
        }

        info->miscdev.minor = MISC_DYNAMIC_MINOR;
        info->miscdev.name = PN544_DRIVER_NAME;
        info->miscdev.fops = &pn544_fops;
        info->miscdev.parent = &client->dev;
        r = misc_register(&info->miscdev);
        if (r < 0) {
                dev_err(&client->dev, "Device registration failed\n");
                goto err_sysfs;
        }

        dev_dbg(&client->dev, "%s: info: %p, pdata %p, client %p\n",
                __func__, info, pdata, client);

        return 0;

err_sysfs:
        if (pdata->test)
                device_remove_file(&client->dev, &pn544_attr);
err_irq:
        free_irq(client->irq, info);
err_res:
        if (pdata->free_resources)
                pdata->free_resources();
err_reg:
        regulator_bulk_free(ARRAY_SIZE(info->regs), info->regs);
err_kmalloc:
        kfree(info->buf);
err_buf_alloc:
        kfree(info);
err_info_alloc:
        return r;
}

static __devexit int pn544_remove(struct i2c_client *client)
{
        struct pn544_info *info = i2c_get_clientdata(client);
        struct pn544_nfc_platform_data *pdata = client->dev.platform_data;

        dev_dbg(&client->dev, "%s\n", __func__);

        misc_deregister(&info->miscdev);
        if (pdata->test)
                device_remove_file(&client->dev, &pn544_attr);

        if (info->state != PN544_ST_COLD) {
                if (pdata->disable)
                        pdata->disable();

                info->read_irq = PN544_NONE;
        }

        free_irq(client->irq, info);
        if (pdata->free_resources)
                pdata->free_resources();

        regulator_bulk_free(ARRAY_SIZE(info->regs), info->regs);
        kfree(info->buf);
        kfree(info);

        return 0;
}

static struct i2c_driver pn544_driver = {
        .driver = {
                .name = PN544_DRIVER_NAME,
#ifdef CONFIG_PM
                .pm = &pn544_pm_ops,
#endif
        },
        .probe = pn544_probe,
        .id_table = pn544_id_table,
        .remove = __devexit_p(pn544_remove),
};

static int __init pn544_init(void)
{
        int r;

        pr_debug(DRIVER_DESC ": %s\n", __func__);

        r = i2c_add_driver(&pn544_driver);
        if (r) {
                pr_err(PN544_DRIVER_NAME ": driver registration failed\n");
                return r;
        }

        return 0;
}

static void __exit pn544_exit(void)
{
        i2c_del_driver(&pn544_driver);
        pr_info(DRIVER_DESC ", Exiting.\n");
}

module_init(pn544_init);
module_exit(pn544_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(DRIVER_DESC);