/*
 * lirc_sasem.c - USB remote support for LIRC
 * Version 0.5
 *
 * Copyright (C) 2004-2005 Oliver Stabel <oliver.stabel@gmx.de>
 *                       Tim Davies <tim@opensystems.net.au>
 *
 * This driver was derived from:
 *   Venky Raju <dev@venky.ws>
 *      "lirc_imon - "LIRC/VFD driver for Ahanix/Soundgraph IMON IR/VFD"
 *   Paul Miller <pmiller9@users.sourceforge.net>'s 2003-2004
 *      "lirc_atiusb - USB remote support for LIRC"
 *   Culver Consulting Services <henry@culcon.com>'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
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

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


#define MOD_AUTHOR      "Oliver Stabel <oliver.stabel@gmx.de>, " \
                        "Tim Davies <tim@opensystems.net.au>"
#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 __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 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!) */
        ktime_t 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);
}

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

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

}

/**
 * Called when the VFD device (e.g. /dev/usb/lcd)
 * is opened by the application.
 */
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) {
                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, "no context found for minor %d\n",
                        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;
}

/**
 * Called when the VFD device (e.g. /dev/usb/lcd)
 * is closed by the application.
 */
static long vfd_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
        struct sasem_context *context;

        context = (struct sasem_context *) file->private_data;

        if (!context) {
                pr_err("%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:
                pr_info("Unknown IOCTL command\n");
                mutex_unlock(&context->ctx_lock);
                return -ENOIOCTLCMD;  /* not supported */
        }

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

/**
 * Called when the VFD device (e.g. /dev/usb/lcd)
 * is closed by the application.
 */
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) {
                pr_err("%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;
                dev_info(&context->dev->dev, "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;
}

/**
 * Sends a packet to the VFD.
 */
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, "error submitting urb (%d)\n",
                        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,
                                "packet tx failed (%d)\n", retval);
        }

        return retval;
}

/**
 * Writes data to the VFD.  The Sasem VFD is 2x16 characters
 * and requires data in 9 consecutive USB interrupt packets,
 * each packet carrying 8 bytes.
 */
static ssize_t vfd_write(struct file *file, const char __user *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) {
                pr_err("%s: no context for device\n", __func__);
                return -ENODEV;
        }

        mutex_lock(&context->ctx_lock);

        if (!context->dev_present) {
                pr_err("%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);
                data_buf = NULL;
                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,
                                "send packet failed for packet #%d\n", i);
                        goto exit;
                }
        }
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 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);
}

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

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

        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,
                        "usb_submit_urb failed for ir_open (%d)\n", retval);
        else {
                context->ir_isopen = 1;
                dev_info(&context->dev->dev, "IR port opened\n");
        }

exit:
        mutex_unlock(&context->ctx_lock);

        mutex_unlock(&disconnect_lock);
        return retval;
}

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

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

        mutex_lock(&context->ctx_lock);

        usb_kill_urb(context->rx_urb);
        context->ir_isopen = 0;
        pr_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);
}

/**
 * Process the incoming packet
 */
static void incoming_packet(struct sasem_context *context,
                                   struct urb *urb)
{
        int len = urb->actual_length;
        unsigned char *buf = urb->transfer_buffer;
        u64 ns;
        ktime_t kt;

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

        if (debug)
                dev_info(&context->dev->dev, "Incoming data: %*ph\n", len, buf);
        /*
         * 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 */
        kt = ktime_get();
        ns = ktime_to_ns(ktime_sub(kt, context->presstime));

        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 ((ns < 250 * NSEC_PER_MSEC) && (context->codesaved != 0)) {
                        memcpy(buf, &context->lastcode, 8);
                        context->presstime = kt;
                }
        } 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 = kt;
        }

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

/**
 * Callback function for USB core API: receive data
 */
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:
                dev_warn(&urb->dev->dev, "%s: status (%d): ignored",
                         __func__, urb->status);
                break;
        }

        usb_submit_urb(context->rx_urb, GFP_ATOMIC);
}



/**
 * Callback function for USB core API: Probe
 */
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;

                ep = &iface_desc->endpoint [i].desc;

                if (!ir_ep_found &&
                        usb_endpoint_is_int_in(ep)) {

                        rx_endpoint = ep;
                        ir_ep_found = 1;
                        if (debug)
                                dev_info(&interface->dev,
                                        "%s: found IR endpoint\n", __func__);

                } else if (!vfd_ep_found &&
                        usb_endpoint_is_int_out(ep)) {

                        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) {
                alloc_status = 1;
                goto alloc_status_switch;
        }
        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(&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
                dev_info(&interface->dev,
                         "%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)
                        dev_info(&interface->dev,
                                 "Registering VFD with sysfs\n");
                if (usb_register_dev(interface, &sasem_class))
                        /* Not a fatal error, so ignore */
                        dev_info(&interface->dev,
                                 "%s: could not get a minor number for VFD\n",
                                 __func__);
        }

        dev_info(&interface->dev,
                 "%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);
                /* fall-through */
        case 5:
                lirc_buffer_free(rbuf);
                /* fall-through */
        case 4:
                kfree(rbuf);
                /* fall-through */
        case 3:
                kfree(driver);
                /* fall-through */
        case 2:
                kfree(context);
                context = NULL;
                /* fall-through */
        case 1:
                if (retval == 0)
                        retval = -ENOMEM;
        }

exit:
        return retval;
}

/**
 * Callback function for USB core API: disconnect
 */
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);

        dev_info(&interface->dev, "%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);