lirc_sasem.c

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/*
 * lirc_sasem.c - USB remote support for LIRC
 * Version 0.5
 *
 * Copyright (C) 2004-2005 Oliver Stabel <[email protected]>
 *           Tim Davies <[email protected]>
 *
 * This driver was derived from:
 *   Venky Raju <[email protected]>
 *      "lirc_imon - "LIRC/VFD driver for Ahanix/Soundgraph IMON IR/VFD"
 *   Paul Miller <[email protected]>'s 2003-2004
 *      "lirc_atiusb - USB remote support for LIRC"
 *   Culver Consulting Services <[email protected]>'s 2003
 *      "Sasem OnAir VFD/IR USB driver"
 *
 *
 * NOTE - The LCDproc iMon driver should work with this module.  More info at
 *  http://www.frogstorm.info/sasem
 */

/*
 *  This program 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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  "Oliver Stabel <[email protected]>, " \
            "Tim Davies <[email protected]>"
#define MOD_DESC    "USB Driver for Sasem Remote Controller V1.1"
#define MOD_NAME    "lirc_sasem"
#define MOD_VERSION "0.5"

#define VFD_MINOR_BASE  144 /* Same as LCD */
#define DEVICE_NAME "lcd%d"

#define BUF_CHUNK_SIZE  8
#define BUF_SIZE    128

#define IOCTL_LCD_CONTRAST 1

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

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

/* VFD file_operations function prototypes */
static int vfd_open(struct inode *inode, struct file *file);
static long vfd_ioctl(struct file *file, unsigned cmd, unsigned long arg);
static int vfd_close(struct inode *inode, struct file *file);
static ssize_t vfd_write(struct file *file, const char *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 SASEM_DATA_BUF_SZ   32

struct sasem_context {

    struct usb_device *dev;
    int vfd_isopen;         /* VFD port has been opened */
    unsigned int vfd_contrast;  /* VFD contrast */
    int ir_isopen;          /* IR port has been opened */
    int dev_present;        /* USB device presence */
    struct mutex ctx_lock;      /* to lock this object */
    wait_queue_head_t remove_ok;    /* For unexpected USB disconnects */

    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 tx_t {
        unsigned char data_buf[SASEM_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;

    /* for dealing with repeat codes (wish there was a toggle bit!) */
    struct timeval presstime;
    char lastcode[8];
    int codesaved;
};

/* VFD file operations */
static const struct file_operations vfd_fops = {
    .owner      = THIS_MODULE,
    .open       = &vfd_open,
    .write      = &vfd_write,
    .unlocked_ioctl = &vfd_ioctl,
    .release    = &vfd_close,
    .llseek     = noop_llseek,
};

/* USB Device ID for Sasem USB Control Board */
static struct usb_device_id sasem_usb_id_table[] = {
    /* Sasem USB Control Board */
    { USB_DEVICE(0x11ba, 0x0101) },
    /* Terminating entry */
    {}
};

/* USB Device data */
static struct usb_driver sasem_driver = {
    .name       = MOD_NAME,
    .probe      = sasem_probe,
    .disconnect = sasem_disconnect,
    .id_table   = sasem_usb_id_table,
};

static struct usb_class_driver sasem_class = {
    .name       = DEVICE_NAME,
    .fops       = &vfd_fops,
    .minor_base = VFD_MINOR_BASE,
};

/* to prevent races between open() and disconnect() */
static DEFINE_MUTEX(disconnect_lock);

static int debug;


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

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

static void delete_context(struct sasem_context *context)
{
    usb_free_urb(context->tx_urb);  /* VFD */
    usb_free_urb(context->rx_urb);  /* IR */
    lirc_buffer_free(context->driver->rbuf);
    kfree(context->driver->rbuf);
    kfree(context->driver);
    kfree(context);

    if (debug)
        printk(KERN_INFO "%s: context deleted\n", __func__);
}

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

    retval = lirc_unregister_driver(minor);
    if (retval)
        printk(KERN_ERR "%s: unable to deregister from lirc (%d)\n",
            __func__, retval);
    else
        printk(KERN_INFO "Deregistered Sasem driver (minor:%d)\n",
               minor);

}

static int vfd_open(struct inode *inode, struct file *file)
{
    struct usb_interface *interface;
    struct sasem_context *context = NULL;
    int subminor;
    int retval = 0;

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

    subminor = iminor(inode);
    interface = usb_find_interface(&sasem_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->vfd_isopen) {
        dev_err(&interface->dev,
            "%s: VFD port is already open", __func__);
        retval = -EBUSY;
    } else {
        context->vfd_isopen = 1;
        file->private_data = context;
        dev_info(&interface->dev, "VFD port opened\n");
    }

    mutex_unlock(&context->ctx_lock);

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

static long vfd_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
    struct sasem_context *context = NULL;

    context = (struct sasem_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);

    switch (cmd) {
    case IOCTL_LCD_CONTRAST:
        if (arg > 1000)
            arg = 1000;
        context->vfd_contrast = (unsigned int)arg;
        break;
    default:
        printk(KERN_INFO "Unknown IOCTL command\n");
        mutex_unlock(&context->ctx_lock);
        return -ENOIOCTLCMD;  /* not supported */
    }

    mutex_unlock(&context->ctx_lock);
    return 0;
}

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

    context = (struct sasem_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->vfd_isopen) {
        dev_err(&context->dev->dev, "%s: VFD is not open\n", __func__);
        retval = -EIO;
    } else {
        context->vfd_isopen = 0;
        printk(KERN_INFO "VFD 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);
            delete_context(context);
            return retval;
        }
    }

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

static int send_packet(struct sasem_context *context)
{
    unsigned int pipe;
    int interval = 0;
    int retval = 0;

    pipe = usb_sndintpipe(context->dev,
            context->tx_endpoint->bEndpointAddress);
    interval = context->tx_endpoint->bInterval;

    usb_fill_int_urb(context->tx_urb, context->dev, 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->dev->dev, "%s: error submitting urb (%d)\n",
            __func__, retval);
    } else {
        /* Wait for transmission to complete (or abort) */
        mutex_unlock(&context->ctx_lock);
        wait_for_completion(&context->tx.finished);
        mutex_lock(&context->ctx_lock);

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

    return retval;
}

static ssize_t vfd_write(struct file *file, const char *buf,
                size_t n_bytes, loff_t *pos)
{
    int i;
    int retval = 0;
    struct sasem_context *context;
    int *data_buf = NULL;

    context = (struct sasem_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) {
        printk(KERN_ERR KBUILD_MODNAME
               ": %s: no Sasem device present\n", __func__);
        retval = -ENODEV;
        goto exit;
    }

    if (n_bytes <= 0 || n_bytes > SASEM_DATA_BUF_SZ) {
        dev_err(&context->dev->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 < SASEM_DATA_BUF_SZ; ++i)
        context->tx.data_buf[i] = ' ';

    /* Nine 8 byte packets to be sent */
    /* NOTE: "\x07\x01\0\0\0\0\0\0" or "\x0c\0\0\0\0\0\0\0"
     *       will clear the VFD */
    for (i = 0; i < 9; i++) {
        switch (i) {
        case 0:
            memcpy(context->usb_tx_buf, "\x07\0\0\0\0\0\0\0", 8);
            context->usb_tx_buf[1] = (context->vfd_contrast) ?
                (0x2B - (context->vfd_contrast - 1) / 250)
                : 0x2B;
            break;
        case 1:
            memcpy(context->usb_tx_buf, "\x09\x01\0\0\0\0\0\0", 8);
            break;
        case 2:
            memcpy(context->usb_tx_buf, "\x0b\x01\0\0\0\0\0\0", 8);
            break;
        case 3:
            memcpy(context->usb_tx_buf, context->tx.data_buf, 8);
            break;
        case 4:
            memcpy(context->usb_tx_buf,
                   context->tx.data_buf + 8, 8);
            break;
        case 5:
            memcpy(context->usb_tx_buf, "\x09\x01\0\0\0\0\0\0", 8);
            break;
        case 6:
            memcpy(context->usb_tx_buf, "\x0b\x02\0\0\0\0\0\0", 8);
            break;
        case 7:
            memcpy(context->usb_tx_buf,
                   context->tx.data_buf + 16, 8);
            break;
        case 8:
            memcpy(context->usb_tx_buf,
                   context->tx.data_buf + 24, 8);
            break;
        }
        retval = send_packet(context);
        if (retval) {
            dev_err(&context->dev->dev,
                "%s: send packet failed for packet #%d\n",
                __func__, i);
            goto exit;
        }
    }
exit:

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

    return (!retval) ? n_bytes : retval;
}

static void usb_tx_callback(struct urb *urb)
{
    struct sasem_context *context;

    if (!urb)
        return;
    context = (struct sasem_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 sasem_context *context;

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

    context = (struct sasem_context *) data;

    mutex_lock(&context->ctx_lock);

    if (context->ir_isopen) {
        dev_err(&context->dev->dev, "%s: IR port is already open\n",
            __func__);
        retval = -EBUSY;
        goto exit;
    }

    usb_fill_int_urb(context->rx_urb, context->dev,
        usb_rcvintpipe(context->dev,
                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(&context->dev->dev,
            "%s: usb_submit_urb failed for ir_open (%d)\n",
            __func__, retval);
    else {
        context->ir_isopen = 1;
        printk(KERN_INFO "IR port opened\n");
    }

exit:
    mutex_unlock(&context->ctx_lock);

    mutex_unlock(&disconnect_lock);
    return retval;
}

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

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

    mutex_lock(&context->ctx_lock);

    usb_kill_urb(context->rx_urb);
    context->ir_isopen = 0;
    printk(KERN_INFO "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->vfd_isopen) {

            mutex_unlock(&context->ctx_lock);
            delete_context(context);
            return;
        }
        /* If VFD port is open, context will be deleted by vfd_close */
    }

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

static void incoming_packet(struct sasem_context *context,
                   struct urb *urb)
{
    int len = urb->actual_length;
    unsigned char *buf = urb->transfer_buffer;
    long ms;
    struct timeval tv;
    int i;

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

    if (debug) {
        printk(KERN_INFO "Incoming data: ");
        for (i = 0; i < 8; ++i)
            printk(KERN_CONT "%02x ", buf[i]);
        printk(KERN_CONT "\n");
    }

    /*
     * Lirc could deal with the repeat code, but we really need to block it
     * if it arrives too late.  Otherwise we could repeat the wrong code.
     */

    /* get the time since the last button press */
    do_gettimeofday(&tv);
    ms = (tv.tv_sec - context->presstime.tv_sec) * 1000 +
         (tv.tv_usec - context->presstime.tv_usec) / 1000;

    if (memcmp(buf, "\x08\0\0\0\0\0\0\0", 8) == 0) {
        /*
         * the repeat code is being sent, so we copy
         * the old code to LIRC
         */

        /*
         * NOTE: Only if the last code was less than 250ms ago
         * - no one should be able to push another (undetected) button
         *   in that time and then get a false repeat of the previous
         *   press but it is long enough for a genuine repeat
         */
        if ((ms < 250) && (context->codesaved != 0)) {
            memcpy(buf, &context->lastcode, 8);
            context->presstime.tv_sec = tv.tv_sec;
            context->presstime.tv_usec = tv.tv_usec;
        }
    } else {
        /* save the current valid code for repeats */
        memcpy(&context->lastcode, buf, 8);
        /*
         * set flag to signal a valid code was save;
         * just for safety reasons
         */
        context->codesaved = 1;
        context->presstime.tv_sec = tv.tv_sec;
        context->presstime.tv_usec = tv.tv_usec;
    }

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

static void usb_rx_callback(struct urb *urb)
{
    struct sasem_context *context;

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

    switch (urb->status) {

    case -ENOENT:       /* usbcore unlink successful! */
        return;

    case 0:
        if (context->ir_isopen)
            incoming_packet(context, urb);
        break;

    default:
        printk(KERN_WARNING "%s: status (%d): ignored",
             __func__, urb->status);
        break;
    }

    usb_submit_urb(context->rx_urb, GFP_ATOMIC);
    return;
}



static int sasem_probe(struct usb_interface *interface,
            const struct usb_device_id *id)
{
    struct usb_device *dev = 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;
    int lirc_minor = 0;
    int num_endpoints;
    int retval = 0;
    int vfd_ep_found;
    int ir_ep_found;
    int alloc_status;
    struct sasem_context *context = NULL;
    int i;

    dev_info(&interface->dev, "%s: found Sasem device\n", __func__);


    dev = usb_get_dev(interface_to_usbdev(interface));
    iface_desc = interface->cur_altsetting;
    num_endpoints = iface_desc->desc.bNumEndpoints;

    /*
     * Scan the endpoint list and set:
     *  first input endpoint = IR endpoint
     *  first output endpoint = VFD endpoint
     */

    ir_ep_found = 0;
    vfd_ep_found = 0;

    for (i = 0; i < num_endpoints && !(ir_ep_found && vfd_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;
            if (debug)
                dev_info(&interface->dev,
                    "%s: found IR endpoint\n", __func__);

        } else if (!vfd_ep_found &&
            ep_dir == USB_DIR_OUT &&
            ep_type == USB_ENDPOINT_XFER_INT) {

            tx_endpoint = ep;
            vfd_ep_found = 1;
            if (debug)
                dev_info(&interface->dev,
                    "%s: found VFD endpoint\n", __func__);
        }
    }

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

    if (!vfd_ep_found)
        dev_info(&interface->dev,
            "%s: no valid output (VFD) endpoint found.\n",
            __func__);


    /* Allocate memory */
    alloc_status = 0;

    context = kzalloc(sizeof(struct sasem_context), GFP_KERNEL);
    if (!context) {
        dev_err(&interface->dev,
            "%s: kzalloc failed for context\n", __func__);
        alloc_status = 1;
        goto alloc_status_switch;
    }
    driver = kzalloc(sizeof(struct lirc_driver), GFP_KERNEL);
    if (!driver) {
        dev_err(&interface->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(&interface->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(&interface->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(&interface->dev,
            "%s: usb_alloc_urb failed for IR urb\n", __func__);
        alloc_status = 5;
        goto alloc_status_switch;
    }
    if (vfd_ep_found) {
        tx_urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!tx_urb) {
            dev_err(&interface->dev,
                "%s: usb_alloc_urb failed for VFD urb",
                __func__);
            alloc_status = 6;
            goto alloc_status_switch;
        }
    }

    mutex_init(&context->ctx_lock);

    strcpy(driver->name, MOD_NAME);
    driver->minor = -1;
    driver->code_length = 64;
    driver->sample_rate = 0;
    driver->features = LIRC_CAN_REC_LIRCCODE;
    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);

    lirc_minor = lirc_register_driver(driver);
    if (lirc_minor < 0) {
        dev_err(&interface->dev,
            "%s: lirc_register_driver failed\n", __func__);
        alloc_status = 7;
        retval = lirc_minor;
        goto unlock;
    } else
        printk(KERN_INFO "%s: Registered Sasem driver (minor:%d)\n",
            __func__, lirc_minor);

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

    context->dev = dev;
    context->dev_present = 1;
    context->rx_endpoint = rx_endpoint;
    context->rx_urb = rx_urb;
    if (vfd_ep_found) {
        context->tx_endpoint = tx_endpoint;
        context->tx_urb = tx_urb;
        context->vfd_contrast = 1000;   /* range 0 - 1000 */
    }
    context->driver = driver;

    usb_set_intfdata(interface, context);

    if (vfd_ep_found) {

        if (debug)
            printk(KERN_INFO "Registering VFD with sysfs\n");
        if (usb_register_dev(interface, &sasem_class))
            /* Not a fatal error, so ignore */
            printk(KERN_INFO "%s: could not get a minor number "
                   "for VFD\n", __func__);
    }

    printk(KERN_INFO "%s: Sasem device on usb<%d:%d> initialized\n",
            __func__, dev->bus->busnum, dev->devnum);
unlock:
    mutex_unlock(&context->ctx_lock);

alloc_status_switch:
    switch (alloc_status) {

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

exit:
    return retval;
}

static void sasem_disconnect(struct usb_interface *interface)
{
    struct sasem_context *context;

    /* prevent races with ir_open()/vfd_open() */
    mutex_lock(&disconnect_lock);

    context = usb_get_intfdata(interface);
    mutex_lock(&context->ctx_lock);

    printk(KERN_INFO "%s: Sasem device disconnected\n", __func__);

    usb_set_intfdata(interface, NULL);
    context->dev_present = 0;

    /* Stop reception */
    usb_kill_urb(context->rx_urb);

    /* Abort ongoing write */
    if (atomic_read(&context->tx.busy)) {

        usb_kill_urb(context->tx_urb);
        wait_for_completion(&context->tx.finished);
    }

    /* De-register from lirc_dev if IR port is not open */
    if (!context->ir_isopen)
        deregister_from_lirc(context);

    usb_deregister_dev(interface, &sasem_class);

    mutex_unlock(&context->ctx_lock);

    if (!context->ir_isopen && !context->vfd_isopen)
        delete_context(context);

    mutex_unlock(&disconnect_lock);
}

module_usb_driver(sasem_driver);