lirc_imon.c

Go to the documentation of this file.

/*
 *   lirc_imon.c:  LIRC/VFD/LCD driver for SoundGraph iMON IR/VFD/LCD
 *         including the iMON PAD model
 *
 *   Copyright(C) 2004  Venky Raju([email protected])
 *   Copyright(C) 2009  Jarod Wilson <[email protected]>
 *
 *   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.
 */

#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 <[email protected]>"
#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)
        printk(KERN_ERR KBUILD_MODNAME
               ": %s: unable to deregister from lirc(%d)",
               __func__, retval);
    else
        printk(KERN_INFO MOD_NAME ": Deregistered iMON driver "
               "(minor:%d)\n", minor);

}

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) {
        printk(KERN_ERR KBUILD_MODNAME
               ": %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;
}

static int display_close(struct inode *inode, struct file *file)
{
    struct imon_context *context = NULL;
    int retval = 0;

    context = file->private_data;

    if (!context) {
        printk(KERN_ERR KBUILD_MODNAME
               "%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;
}

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;
}

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) {
        printk(KERN_ERR KBUILD_MODNAME
               "%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;
}

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;
}

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;
}

static void ir_close(void *data)
{
    struct imon_context *context;

    context = (struct imon_context *)data;
    if (!context) {
        printk(KERN_ERR KBUILD_MODNAME
               "%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;
}

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;
}

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;
    }
}

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;
}

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) {
        dev_err(dev, "%s: kzalloc failed for context\n", __func__);
        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) {
        dev_err(dev, "%s: kzalloc failed for lirc_driver\n", __func__);
        alloc_status = 2;
        goto alloc_status_switch;
    }
    rbuf = kmalloc(sizeof(struct lirc_buffer), GFP_KERNEL);
    if (!rbuf) {
        dev_err(dev, "%s: kmalloc failed for lirc_buffer\n", __func__);
        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;
}

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);

    printk(KERN_INFO "%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);