/*
 *   lirc_imon.c:  LIRC/VFD/LCD driver for SoundGraph iMON IR/VFD/LCD
 *                 including the iMON PAD model
 *
 *   Copyright(C) 2004  Venky Raju(dev@venky.ws)
 *   Copyright(C) 2009  Jarod Wilson <jarod@wilsonet.com>
 *
 *   lirc_imon is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/usb.h>

#include <media/lirc.h>
#include <media/lirc_dev.h>


#define MOD_AUTHOR      "Venky Raju <dev@venky.ws>"
#define MOD_DESC        "Driver for SoundGraph iMON MultiMedia IR/Display"
#define MOD_NAME        "lirc_imon"
#define MOD_VERSION     "0.8"

#define DISPLAY_MINOR_BASE      144
#define DEVICE_NAME     "lcd%d"

#define BUF_CHUNK_SIZE  4
#define BUF_SIZE        128

#define BIT_DURATION    250     /* each bit received is 250us */

/*** P R O T O T Y P E S ***/

/* USB Callback prototypes */
static int imon_probe(struct usb_interface *interface,
                      const struct usb_device_id *id);
static void imon_disconnect(struct usb_interface *interface);
static void usb_rx_callback(struct urb *urb);
static void usb_tx_callback(struct urb *urb);

/* suspend/resume support */
static int imon_resume(struct usb_interface *intf);
static int imon_suspend(struct usb_interface *intf, pm_message_t message);

/* Display file_operations function prototypes */
static int display_open(struct inode *inode, struct file *file);
static int display_close(struct inode *inode, struct file *file);

/* VFD write operation */
static ssize_t vfd_write(struct file *file, const char __user *buf,
                         size_t n_bytes, loff_t *pos);

/* LIRC driver function prototypes */
static int ir_open(void *data);
static void ir_close(void *data);

/*** G L O B A L S ***/
#define IMON_DATA_BUF_SZ        35

struct imon_context {
        struct usb_device *usbdev;
        /* Newer devices have two interfaces */
        int display;                    /* not all controllers do */
        int display_isopen;             /* display port has been opened */
        int ir_isopen;                  /* IR port open */
        int dev_present;                /* USB device presence */
        struct mutex ctx_lock;          /* to lock this object */
        wait_queue_head_t remove_ok;    /* For unexpected USB disconnects */

        int vfd_proto_6p;               /* some VFD require a 6th packet */

        struct lirc_driver *driver;
        struct usb_endpoint_descriptor *rx_endpoint;
        struct usb_endpoint_descriptor *tx_endpoint;
        struct urb *rx_urb;
        struct urb *tx_urb;
        unsigned char usb_rx_buf[8];
        unsigned char usb_tx_buf[8];

        struct rx_data {
                int count;              /* length of 0 or 1 sequence */
                int prev_bit;           /* logic level of sequence */
                int initial_space;      /* initial space flag */
        } rx;

        struct tx_t {
                unsigned char data_buf[IMON_DATA_BUF_SZ]; /* user data buffer */
                struct completion finished;     /* wait for write to finish */
                atomic_t busy;                  /* write in progress */
                int status;                     /* status of tx completion */
        } tx;
};

static const struct file_operations display_fops = {
        .owner          = THIS_MODULE,
        .open           = &display_open,
        .write          = &vfd_write,
        .release        = &display_close,
        .llseek         = noop_llseek,
};

/*
 * USB Device ID for iMON USB Control Boards
 *
 * The Windows drivers contain 6 different inf files, more or less one for
 * each new device until the 0x0034-0x0046 devices, which all use the same
 * driver. Some of the devices in the 34-46 range haven't been definitively
 * identified yet. Early devices have either a TriGem Computer, Inc. or a
 * Samsung vendor ID (0x0aa8 and 0x04e8 respectively), while all later
 * devices use the SoundGraph vendor ID (0x15c2).
 */
static struct usb_device_id imon_usb_id_table[] = {
        /* TriGem iMON (IR only) -- TG_iMON.inf */
        { USB_DEVICE(0x0aa8, 0x8001) },

        /* SoundGraph iMON (IR only) -- sg_imon.inf */
        { USB_DEVICE(0x04e8, 0xff30) },

        /* SoundGraph iMON VFD (IR & VFD) -- iMON_VFD.inf */
        { USB_DEVICE(0x0aa8, 0xffda) },

        /* SoundGraph iMON SS (IR & VFD) -- iMON_SS.inf */
        { USB_DEVICE(0x15c2, 0xffda) },

        {}
};

/* Some iMON VFD models requires a 6th packet for VFD writes */
static struct usb_device_id vfd_proto_6p_list[] = {
        { USB_DEVICE(0x15c2, 0xffda) },
        {}
};

/* Some iMON devices have no lcd/vfd, don't set one up */
static struct usb_device_id ir_only_list[] = {
        { USB_DEVICE(0x0aa8, 0x8001) },
        { USB_DEVICE(0x04e8, 0xff30) },
        {}
};

/* USB Device data */
static struct usb_driver imon_driver = {
        .name           = MOD_NAME,
        .probe          = imon_probe,
        .disconnect     = imon_disconnect,
        .suspend        = imon_suspend,
        .resume         = imon_resume,
        .id_table       = imon_usb_id_table,
};

static struct usb_class_driver imon_class = {
        .name           = DEVICE_NAME,
        .fops           = &display_fops,
        .minor_base     = DISPLAY_MINOR_BASE,
};

/* to prevent races between open() and disconnect(), probing, etc */
static DEFINE_MUTEX(driver_lock);

static int debug;

/***  M O D U L E   C O D E ***/

MODULE_AUTHOR(MOD_AUTHOR);
MODULE_DESCRIPTION(MOD_DESC);
MODULE_VERSION(MOD_VERSION);
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(usb, imon_usb_id_table);
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug messages: 0=no, 1=yes(default: no)");

static void free_imon_context(struct imon_context *context)
{
        struct device *dev = context->driver->dev;
        usb_free_urb(context->tx_urb);
        usb_free_urb(context->rx_urb);
        lirc_buffer_free(context->driver->rbuf);
        kfree(context->driver->rbuf);
        kfree(context->driver);
        kfree(context);

        dev_dbg(dev, "%s: iMON context freed\n", __func__);
}

static void deregister_from_lirc(struct imon_context *context)
{
        int retval;
        int minor = context->driver->minor;

        retval = lirc_unregister_driver(minor);
        if (retval)
                dev_err(&context->usbdev->dev,
                        ": %s: unable to deregister from lirc(%d)",
                        __func__, retval);
        else
                dev_info(&context->usbdev->dev,
                         "Deregistered iMON driver (minor:%d)\n", minor);

}

/**
 * Called when the Display device (e.g. /dev/lcd0)
 * is opened by the application.
 */
static int display_open(struct inode *inode, struct file *file)
{
        struct usb_interface *interface;
        struct imon_context *context = NULL;
        int subminor;
        int retval = 0;

        /* prevent races with disconnect */
        mutex_lock(&driver_lock);

        subminor = iminor(inode);
        interface = usb_find_interface(&imon_driver, subminor);
        if (!interface) {
                pr_err("%s: could not find interface for minor %d\n",
                       __func__, subminor);
                retval = -ENODEV;
                goto exit;
        }
        context = usb_get_intfdata(interface);

        if (!context) {
                dev_err(&interface->dev,
                        "%s: no context found for minor %d\n",
                        __func__, subminor);
                retval = -ENODEV;
                goto exit;
        }

        mutex_lock(&context->ctx_lock);

        if (!context->display) {
                dev_err(&interface->dev,
                        "%s: display not supported by device\n", __func__);
                retval = -ENODEV;
        } else if (context->display_isopen) {
                dev_err(&interface->dev,
                        "%s: display port is already open\n", __func__);
                retval = -EBUSY;
        } else {
                context->display_isopen = 1;
                file->private_data = context;
                dev_info(context->driver->dev, "display port opened\n");
        }

        mutex_unlock(&context->ctx_lock);

exit:
        mutex_unlock(&driver_lock);
        return retval;
}

/**
 * Called when the display device (e.g. /dev/lcd0)
 * is closed by the application.
 */
static int display_close(struct inode *inode, struct file *file)
{
        struct imon_context *context = NULL;
        int retval = 0;

        context = file->private_data;

        if (!context) {
                pr_err("%s: no context for device\n", __func__);
                return -ENODEV;
        }

        mutex_lock(&context->ctx_lock);

        if (!context->display) {
                dev_err(&context->usbdev->dev,
                        "%s: display not supported by device\n", __func__);
                retval = -ENODEV;
        } else if (!context->display_isopen) {
                dev_err(&context->usbdev->dev,
                        "%s: display is not open\n", __func__);
                retval = -EIO;
        } else {
                context->display_isopen = 0;
                dev_info(context->driver->dev, "display port closed\n");
                if (!context->dev_present && !context->ir_isopen) {
                        /*
                         * Device disconnected before close and IR port is not
                         * open. If IR port is open, context will be deleted by
                         * ir_close.
                         */
                        mutex_unlock(&context->ctx_lock);
                        free_imon_context(context);
                        return retval;
                }
        }

        mutex_unlock(&context->ctx_lock);
        return retval;
}

/**
 * Sends a packet to the device -- this function must be called
 * with context->ctx_lock held.
 */
static int send_packet(struct imon_context *context)
{
        unsigned int pipe;
        int interval = 0;
        int retval = 0;

        /* Check if we need to use control or interrupt urb */
        pipe = usb_sndintpipe(context->usbdev,
                              context->tx_endpoint->bEndpointAddress);
        interval = context->tx_endpoint->bInterval;

        usb_fill_int_urb(context->tx_urb, context->usbdev, pipe,
                         context->usb_tx_buf,
                         sizeof(context->usb_tx_buf),
                         usb_tx_callback, context, interval);

        context->tx_urb->actual_length = 0;

        init_completion(&context->tx.finished);
        atomic_set(&(context->tx.busy), 1);

        retval = usb_submit_urb(context->tx_urb, GFP_KERNEL);
        if (retval) {
                atomic_set(&(context->tx.busy), 0);
                dev_err(&context->usbdev->dev,
                        "%s: error submitting urb(%d)\n", __func__, retval);
        } else {
                /* Wait for transmission to complete (or abort) */
                mutex_unlock(&context->ctx_lock);
                retval = wait_for_completion_interruptible(
                                &context->tx.finished);
                if (retval)
                        dev_err(&context->usbdev->dev,
                                "%s: task interrupted\n", __func__);
                mutex_lock(&context->ctx_lock);

                retval = context->tx.status;
                if (retval)
                        dev_err(&context->usbdev->dev,
                                "%s: packet tx failed (%d)\n",
                                __func__, retval);
        }

        return retval;
}

/**
 * Writes data to the VFD.  The iMON VFD is 2x16 characters
 * and requires data in 5 consecutive USB interrupt packets,
 * each packet but the last carrying 7 bytes.
 *
 * I don't know if the VFD board supports features such as
 * scrolling, clearing rows, blanking, etc. so at
 * the caller must provide a full screen of data.  If fewer
 * than 32 bytes are provided spaces will be appended to
 * generate a full screen.
 */
static ssize_t vfd_write(struct file *file, const char __user *buf,
                         size_t n_bytes, loff_t *pos)
{
        int i;
        int offset;
        int seq;
        int retval = 0;
        struct imon_context *context;
        const unsigned char vfd_packet6[] = {
                0x01, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF };
        int *data_buf = NULL;

        context = file->private_data;
        if (!context) {
                pr_err("%s: no context for device\n", __func__);
                return -ENODEV;
        }

        mutex_lock(&context->ctx_lock);

        if (!context->dev_present) {
                dev_err(&context->usbdev->dev,
                        "%s: no iMON device present\n", __func__);
                retval = -ENODEV;
                goto exit;
        }

        if (n_bytes <= 0 || n_bytes > IMON_DATA_BUF_SZ - 3) {
                dev_err(&context->usbdev->dev,
                        "%s: invalid payload size\n", __func__);
                retval = -EINVAL;
                goto exit;
        }

        data_buf = memdup_user(buf, n_bytes);
        if (IS_ERR(data_buf)) {
                retval = PTR_ERR(data_buf);
                goto exit;
        }

        memcpy(context->tx.data_buf, data_buf, n_bytes);

        /* Pad with spaces */
        for (i = n_bytes; i < IMON_DATA_BUF_SZ - 3; ++i)
                context->tx.data_buf[i] = ' ';

        for (i = IMON_DATA_BUF_SZ - 3; i < IMON_DATA_BUF_SZ; ++i)
                context->tx.data_buf[i] = 0xFF;

        offset = 0;
        seq = 0;

        do {
                memcpy(context->usb_tx_buf, context->tx.data_buf + offset, 7);
                context->usb_tx_buf[7] = (unsigned char) seq;

                retval = send_packet(context);
                if (retval) {
                        dev_err(&context->usbdev->dev,
                                "%s: send packet failed for packet #%d\n",
                                __func__, seq/2);
                        goto exit;
                } else {
                        seq += 2;
                        offset += 7;
                }

        } while (offset < IMON_DATA_BUF_SZ);

        if (context->vfd_proto_6p) {
                /* Send packet #6 */
                memcpy(context->usb_tx_buf, &vfd_packet6, sizeof(vfd_packet6));
                context->usb_tx_buf[7] = (unsigned char) seq;
                retval = send_packet(context);
                if (retval)
                        dev_err(&context->usbdev->dev,
                                "%s: send packet failed for packet #%d\n",
                                        __func__, seq/2);
        }

exit:
        mutex_unlock(&context->ctx_lock);
        kfree(data_buf);

        return (!retval) ? n_bytes : retval;
}

/**
 * Callback function for USB core API: transmit data
 */
static void usb_tx_callback(struct urb *urb)
{
        struct imon_context *context;

        if (!urb)
                return;
        context = (struct imon_context *)urb->context;
        if (!context)
                return;

        context->tx.status = urb->status;

        /* notify waiters that write has finished */
        atomic_set(&context->tx.busy, 0);
        complete(&context->tx.finished);

        return;
}

/**
 * Called by lirc_dev when the application opens /dev/lirc
 */
static int ir_open(void *data)
{
        int retval = 0;
        struct imon_context *context;

        /* prevent races with disconnect */
        mutex_lock(&driver_lock);

        context = (struct imon_context *)data;

        /* initial IR protocol decode variables */
        context->rx.count = 0;
        context->rx.initial_space = 1;
        context->rx.prev_bit = 0;

        context->ir_isopen = 1;
        dev_info(context->driver->dev, "IR port opened\n");

        mutex_unlock(&driver_lock);
        return retval;
}

/**
 * Called by lirc_dev when the application closes /dev/lirc
 */
static void ir_close(void *data)
{
        struct imon_context *context;

        context = (struct imon_context *)data;
        if (!context) {
                pr_err("%s: no context for device\n", __func__);
                return;
        }

        mutex_lock(&context->ctx_lock);

        context->ir_isopen = 0;
        dev_info(context->driver->dev, "IR port closed\n");

        if (!context->dev_present) {
                /*
                 * Device disconnected while IR port was still open. Driver
                 * was not deregistered at disconnect time, so do it now.
                 */
                deregister_from_lirc(context);

                if (!context->display_isopen) {
                        mutex_unlock(&context->ctx_lock);
                        free_imon_context(context);
                        return;
                }
                /*
                 * If display port is open, context will be deleted by
                 * display_close
                 */
        }

        mutex_unlock(&context->ctx_lock);
        return;
}

/**
 * Convert bit count to time duration (in us) and submit
 * the value to lirc_dev.
 */
static void submit_data(struct imon_context *context)
{
        unsigned char buf[4];
        int value = context->rx.count;
        int i;

        dev_dbg(context->driver->dev, "submitting data to LIRC\n");

        value *= BIT_DURATION;
        value &= PULSE_MASK;
        if (context->rx.prev_bit)
                value |= PULSE_BIT;

        for (i = 0; i < 4; ++i)
                buf[i] = value>>(i*8);

        lirc_buffer_write(context->driver->rbuf, buf);
        wake_up(&context->driver->rbuf->wait_poll);
        return;
}

static inline int tv2int(const struct timeval *a, const struct timeval *b)
{
        int usecs = 0;
        int sec   = 0;

        if (b->tv_usec > a->tv_usec) {
                usecs = 1000000;
                sec--;
        }

        usecs += a->tv_usec - b->tv_usec;

        sec += a->tv_sec - b->tv_sec;
        sec *= 1000;
        usecs /= 1000;
        sec += usecs;

        if (sec < 0)
                sec = 1000;

        return sec;
}

/**
 * Process the incoming packet
 */
static void imon_incoming_packet(struct imon_context *context,
                                 struct urb *urb, int intf)
{
        int len = urb->actual_length;
        unsigned char *buf = urb->transfer_buffer;
        struct device *dev = context->driver->dev;
        int octet, bit;
        unsigned char mask;
        int i;

        /*
         * just bail out if no listening IR client
         */
        if (!context->ir_isopen)
                return;

        if (len != 8) {
                dev_warn(dev, "imon %s: invalid incoming packet "
                         "size (len = %d, intf%d)\n", __func__, len, intf);
                return;
        }

        if (debug) {
                printk(KERN_INFO "raw packet: ");
                for (i = 0; i < len; ++i)
                        printk("%02x ", buf[i]);
                printk("\n");
        }

        /*
         * Translate received data to pulse and space lengths.
         * Received data is active low, i.e. pulses are 0 and
         * spaces are 1.
         *
         * My original algorithm was essentially similar to
         * Changwoo Ryu's with the exception that he switched
         * the incoming bits to active high and also fed an
         * initial space to LIRC at the start of a new sequence
         * if the previous bit was a pulse.
         *
         * I've decided to adopt his algorithm.
         */

        if (buf[7] == 1 && context->rx.initial_space) {
                /* LIRC requires a leading space */
                context->rx.prev_bit = 0;
                context->rx.count = 4;
                submit_data(context);
                context->rx.count = 0;
        }

        for (octet = 0; octet < 5; ++octet) {
                mask = 0x80;
                for (bit = 0; bit < 8; ++bit) {
                        int curr_bit = !(buf[octet] & mask);
                        if (curr_bit != context->rx.prev_bit) {
                                if (context->rx.count) {
                                        submit_data(context);
                                        context->rx.count = 0;
                                }
                                context->rx.prev_bit = curr_bit;
                        }
                        ++context->rx.count;
                        mask >>= 1;
                }
        }

        if (buf[7] == 10) {
                if (context->rx.count) {
                        submit_data(context);
                        context->rx.count = 0;
                }
                context->rx.initial_space = context->rx.prev_bit;
        }
}

/**
 * Callback function for USB core API: receive data
 */
static void usb_rx_callback(struct urb *urb)
{
        struct imon_context *context;
        int intfnum = 0;

        if (!urb)
                return;

        context = (struct imon_context *)urb->context;
        if (!context)
                return;

        switch (urb->status) {
        case -ENOENT:           /* usbcore unlink successful! */
                return;

        case 0:
                imon_incoming_packet(context, urb, intfnum);
                break;

        default:
                dev_warn(context->driver->dev, "imon %s: status(%d): ignored\n",
                         __func__, urb->status);
                break;
        }

        usb_submit_urb(context->rx_urb, GFP_ATOMIC);

        return;
}

/**
 * Callback function for USB core API: Probe
 */
static int imon_probe(struct usb_interface *interface,
                      const struct usb_device_id *id)
{
        struct usb_device *usbdev = NULL;
        struct usb_host_interface *iface_desc = NULL;
        struct usb_endpoint_descriptor *rx_endpoint = NULL;
        struct usb_endpoint_descriptor *tx_endpoint = NULL;
        struct urb *rx_urb = NULL;
        struct urb *tx_urb = NULL;
        struct lirc_driver *driver = NULL;
        struct lirc_buffer *rbuf = NULL;
        struct device *dev = &interface->dev;
        int ifnum;
        int lirc_minor = 0;
        int num_endpts;
        int retval = 0;
        int display_ep_found = 0;
        int ir_ep_found = 0;
        int alloc_status = 0;
        int vfd_proto_6p = 0;
        struct imon_context *context = NULL;
        int i;
        u16 vendor, product;

        /* prevent races probing devices w/multiple interfaces */
        mutex_lock(&driver_lock);

        context = kzalloc(sizeof(struct imon_context), GFP_KERNEL);
        if (!context) {
                alloc_status = 1;
                goto alloc_status_switch;
        }

        /*
         * Try to auto-detect the type of display if the user hasn't set
         * it by hand via the display_type modparam. Default is VFD.
         */
        if (usb_match_id(interface, ir_only_list))
                context->display = 0;
        else
                context->display = 1;

        usbdev     = usb_get_dev(interface_to_usbdev(interface));
        iface_desc = interface->cur_altsetting;
        num_endpts = iface_desc->desc.bNumEndpoints;
        ifnum      = iface_desc->desc.bInterfaceNumber;
        vendor     = le16_to_cpu(usbdev->descriptor.idVendor);
        product    = le16_to_cpu(usbdev->descriptor.idProduct);

        dev_dbg(dev, "%s: found iMON device (%04x:%04x, intf%d)\n",
                __func__, vendor, product, ifnum);

        /*
         * Scan the endpoint list and set:
         *      first input endpoint = IR endpoint
         *      first output endpoint = display endpoint
         */
        for (i = 0; i < num_endpts && !(ir_ep_found && display_ep_found); ++i) {
                struct usb_endpoint_descriptor *ep;
                int ep_dir;
                int ep_type;
                ep = &iface_desc->endpoint[i].desc;
                ep_dir = ep->bEndpointAddress & USB_ENDPOINT_DIR_MASK;
                ep_type = ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;

                if (!ir_ep_found &&
                        ep_dir == USB_DIR_IN &&
                        ep_type == USB_ENDPOINT_XFER_INT) {

                        rx_endpoint = ep;
                        ir_ep_found = 1;
                        dev_dbg(dev, "%s: found IR endpoint\n", __func__);

                } else if (!display_ep_found && ep_dir == USB_DIR_OUT &&
                           ep_type == USB_ENDPOINT_XFER_INT) {
                        tx_endpoint = ep;
                        display_ep_found = 1;
                        dev_dbg(dev, "%s: found display endpoint\n", __func__);
                }
        }

        /*
         * Some iMON receivers have no display. Unfortunately, it seems
         * that SoundGraph recycles device IDs between devices both with
         * and without... :\
         */
        if (context->display == 0) {
                display_ep_found = 0;
                dev_dbg(dev, "%s: device has no display\n", __func__);
        }

        /* Input endpoint is mandatory */
        if (!ir_ep_found) {
                dev_err(dev, "%s: no valid input (IR) endpoint found.\n", __func__);
                retval = -ENODEV;
                alloc_status = 2;
                goto alloc_status_switch;
        }

        /* Determine if display requires 6 packets */
        if (display_ep_found) {
                if (usb_match_id(interface, vfd_proto_6p_list))
                        vfd_proto_6p = 1;

                dev_dbg(dev, "%s: vfd_proto_6p: %d\n",
                        __func__, vfd_proto_6p);
        }

        driver = kzalloc(sizeof(struct lirc_driver), GFP_KERNEL);
        if (!driver) {
                alloc_status = 2;
                goto alloc_status_switch;
        }
        rbuf = kmalloc(sizeof(struct lirc_buffer), GFP_KERNEL);
        if (!rbuf) {
                alloc_status = 3;
                goto alloc_status_switch;
        }
        if (lirc_buffer_init(rbuf, BUF_CHUNK_SIZE, BUF_SIZE)) {
                dev_err(dev, "%s: lirc_buffer_init failed\n", __func__);
                alloc_status = 4;
                goto alloc_status_switch;
        }
        rx_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!rx_urb) {
                dev_err(dev, "%s: usb_alloc_urb failed for IR urb\n", __func__);
                alloc_status = 5;
                goto alloc_status_switch;
        }
        tx_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!tx_urb) {
                dev_err(dev, "%s: usb_alloc_urb failed for display urb\n",
                    __func__);
                alloc_status = 6;
                goto alloc_status_switch;
        }

        mutex_init(&context->ctx_lock);
        context->vfd_proto_6p = vfd_proto_6p;

        strcpy(driver->name, MOD_NAME);
        driver->minor = -1;
        driver->code_length = BUF_CHUNK_SIZE * 8;
        driver->sample_rate = 0;
        driver->features = LIRC_CAN_REC_MODE2;
        driver->data = context;
        driver->rbuf = rbuf;
        driver->set_use_inc = ir_open;
        driver->set_use_dec = ir_close;
        driver->dev = &interface->dev;
        driver->owner = THIS_MODULE;

        mutex_lock(&context->ctx_lock);

        context->driver = driver;
        /* start out in keyboard mode */

        lirc_minor = lirc_register_driver(driver);
        if (lirc_minor < 0) {
                dev_err(dev, "%s: lirc_register_driver failed\n", __func__);
                alloc_status = 7;
                goto unlock;
        } else
                dev_info(dev, "Registered iMON driver "
                         "(lirc minor: %d)\n", lirc_minor);

        /* Needed while unregistering! */
        driver->minor = lirc_minor;

        context->usbdev = usbdev;
        context->dev_present = 1;
        context->rx_endpoint = rx_endpoint;
        context->rx_urb = rx_urb;

        /*
         * tx is used to send characters to lcd/vfd, associate RF
         * remotes, set IR protocol, and maybe more...
         */
        context->tx_endpoint = tx_endpoint;
        context->tx_urb = tx_urb;

        if (display_ep_found)
                context->display = 1;

        usb_fill_int_urb(context->rx_urb, context->usbdev,
                usb_rcvintpipe(context->usbdev,
                        context->rx_endpoint->bEndpointAddress),
                context->usb_rx_buf, sizeof(context->usb_rx_buf),
                usb_rx_callback, context,
                context->rx_endpoint->bInterval);

        retval = usb_submit_urb(context->rx_urb, GFP_KERNEL);

        if (retval) {
                dev_err(dev, "%s: usb_submit_urb failed for intf0 (%d)\n",
                        __func__, retval);
                mutex_unlock(&context->ctx_lock);
                goto exit;
        }

        usb_set_intfdata(interface, context);

        if (context->display && ifnum == 0) {
                dev_dbg(dev, "%s: Registering iMON display with sysfs\n",
                        __func__);

                if (usb_register_dev(interface, &imon_class)) {
                        /* Not a fatal error, so ignore */
                        dev_info(dev, "%s: could not get a minor number for "
                                 "display\n", __func__);
                }
        }

        dev_info(dev, "iMON device (%04x:%04x, intf%d) on "
                 "usb<%d:%d> initialized\n", vendor, product, ifnum,
                 usbdev->bus->busnum, usbdev->devnum);

unlock:
        mutex_unlock(&context->ctx_lock);
alloc_status_switch:

        switch (alloc_status) {
        case 7:
                usb_free_urb(tx_urb);
        case 6:
                usb_free_urb(rx_urb);
        case 5:
                if (rbuf)
                        lirc_buffer_free(rbuf);
        case 4:
                kfree(rbuf);
        case 3:
                kfree(driver);
        case 2:
                kfree(context);
                context = NULL;
        case 1:
                if (retval != -ENODEV)
                        retval = -ENOMEM;
                break;
        case 0:
                retval = 0;
        }

exit:
        mutex_unlock(&driver_lock);

        return retval;
}

/**
 * Callback function for USB core API: disconnect
 */
static void imon_disconnect(struct usb_interface *interface)
{
        struct imon_context *context;
        int ifnum;

        /* prevent races with ir_open()/display_open() */
        mutex_lock(&driver_lock);

        context = usb_get_intfdata(interface);
        ifnum = interface->cur_altsetting->desc.bInterfaceNumber;

        mutex_lock(&context->ctx_lock);

        usb_set_intfdata(interface, NULL);

        /* Abort ongoing write */
        if (atomic_read(&context->tx.busy)) {
                usb_kill_urb(context->tx_urb);
                complete_all(&context->tx.finished);
        }

        context->dev_present = 0;
        usb_kill_urb(context->rx_urb);
        if (context->display)
                usb_deregister_dev(interface, &imon_class);

        if (!context->ir_isopen && !context->dev_present) {
                deregister_from_lirc(context);
                mutex_unlock(&context->ctx_lock);
                if (!context->display_isopen)

                        free_imon_context(context);
        } else
                mutex_unlock(&context->ctx_lock);

        mutex_unlock(&driver_lock);

        dev_info(&interface->dev, "%s: iMON device (intf%d) disconnected\n",
                 __func__, ifnum);
}

static int imon_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct imon_context *context = usb_get_intfdata(intf);

        usb_kill_urb(context->rx_urb);

        return 0;
}

static int imon_resume(struct usb_interface *intf)
{
        int rc = 0;
        struct imon_context *context = usb_get_intfdata(intf);

        usb_fill_int_urb(context->rx_urb, context->usbdev,
                usb_rcvintpipe(context->usbdev,
                        context->rx_endpoint->bEndpointAddress),
                context->usb_rx_buf, sizeof(context->usb_rx_buf),
                usb_rx_callback, context,
                context->rx_endpoint->bInterval);

        rc = usb_submit_urb(context->rx_urb, GFP_ATOMIC);

        return rc;
}

module_usb_driver(imon_driver);