Revert "[PATCH] paravirt: Add startup infrastructure for paravirtualization"

[pv_ops_mirror.git] / drivers / input / mouse / appletouch.c

/*
 * Apple USB Touchpad (for post-February 2005 PowerBooks and MacBooks) driver
 *
 * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
 * Copyright (C) 2005      Johannes Berg (johannes@sipsolutions.net)
 * Copyright (C) 2005      Stelian Pop (stelian@popies.net)
 * Copyright (C) 2005      Frank Arnold (frank@scirocco-5v-turbo.de)
 * Copyright (C) 2005      Peter Osterlund (petero2@telia.com)
 * Copyright (C) 2005      Michael Hanselmann (linux-kernel@hansmi.ch)
 * Copyright (C) 2006      Nicolas Boichat (nicolas@boichat.ch)
 *
 * Thanks to Alex Harper <basilisk@foobox.net> for his inputs.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

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

/* Apple has powerbooks which have the keyboard with different Product IDs */
#define APPLE_VENDOR_ID         0x05AC

/* These names come from Info.plist in AppleUSBTrackpad.kext */
#define FOUNTAIN_ANSI_PRODUCT_ID        0x020E
#define FOUNTAIN_ISO_PRODUCT_ID         0x020F

#define FOUNTAIN_TP_ONLY_PRODUCT_ID     0x030A

#define GEYSER1_TP_ONLY_PRODUCT_ID      0x030B

#define GEYSER_ANSI_PRODUCT_ID          0x0214
#define GEYSER_ISO_PRODUCT_ID           0x0215
#define GEYSER_JIS_PRODUCT_ID           0x0216

/* MacBook devices */
#define GEYSER3_ANSI_PRODUCT_ID         0x0217
#define GEYSER3_ISO_PRODUCT_ID          0x0218
#define GEYSER3_JIS_PRODUCT_ID          0x0219

/*
 * Geyser IV: same as Geyser III according to Info.plist in AppleUSBTrackpad.kext
 * -> same IOClass (AppleUSBGrIIITrackpad), same acceleration tables
 */
#define GEYSER4_ANSI_PRODUCT_ID 0x021A
#define GEYSER4_ISO_PRODUCT_ID  0x021B
#define GEYSER4_JIS_PRODUCT_ID  0x021C

#define ATP_DEVICE(prod)                                        \
        .match_flags = USB_DEVICE_ID_MATCH_DEVICE |             \
                       USB_DEVICE_ID_MATCH_INT_CLASS |          \
                       USB_DEVICE_ID_MATCH_INT_PROTOCOL,        \
        .idVendor = APPLE_VENDOR_ID,                            \
        .idProduct = (prod),                                    \
        .bInterfaceClass = 0x03,                                \
        .bInterfaceProtocol = 0x02

/* table of devices that work with this driver */
static struct usb_device_id atp_table [] = {
        { ATP_DEVICE(FOUNTAIN_ANSI_PRODUCT_ID) },
        { ATP_DEVICE(FOUNTAIN_ISO_PRODUCT_ID) },
        { ATP_DEVICE(FOUNTAIN_TP_ONLY_PRODUCT_ID) },
        { ATP_DEVICE(GEYSER1_TP_ONLY_PRODUCT_ID) },

        /* PowerBooks Oct 2005 */
        { ATP_DEVICE(GEYSER_ANSI_PRODUCT_ID) },
        { ATP_DEVICE(GEYSER_ISO_PRODUCT_ID) },
        { ATP_DEVICE(GEYSER_JIS_PRODUCT_ID) },

        /* Core Duo MacBook & MacBook Pro */
        { ATP_DEVICE(GEYSER3_ANSI_PRODUCT_ID) },
        { ATP_DEVICE(GEYSER3_ISO_PRODUCT_ID) },
        { ATP_DEVICE(GEYSER3_JIS_PRODUCT_ID) },

        /* Core2 Duo MacBook & MacBook Pro */
        { ATP_DEVICE(GEYSER4_ANSI_PRODUCT_ID) },
        { ATP_DEVICE(GEYSER4_ISO_PRODUCT_ID) },
        { ATP_DEVICE(GEYSER4_JIS_PRODUCT_ID) },

        /* Terminating entry */
        { }
};
MODULE_DEVICE_TABLE (usb, atp_table);

/*
 * number of sensors. Note that only 16 instead of 26 X (horizontal)
 * sensors exist on 12" and 15" PowerBooks. All models have 16 Y
 * (vertical) sensors.
 */
#define ATP_XSENSORS    26
#define ATP_YSENSORS    16

/* amount of fuzz this touchpad generates */
#define ATP_FUZZ        16

/* maximum pressure this driver will report */
#define ATP_PRESSURE    300
/*
 * multiplication factor for the X and Y coordinates.
 * We try to keep the touchpad aspect ratio while still doing only simple
 * arithmetics.
 * The factors below give coordinates like:
 *      0 <= x <  960 on 12" and 15" Powerbooks
 *      0 <= x < 1600 on 17" Powerbooks
 *      0 <= y <  646
 */
#define ATP_XFACT       64
#define ATP_YFACT       43

/*
 * Threshold for the touchpad sensors. Any change less than ATP_THRESHOLD is
 * ignored.
 */
#define ATP_THRESHOLD    5

/* MacBook Pro (Geyser 3 & 4) initialization constants */
#define ATP_GEYSER3_MODE_READ_REQUEST_ID 1
#define ATP_GEYSER3_MODE_WRITE_REQUEST_ID 9
#define ATP_GEYSER3_MODE_REQUEST_VALUE 0x300
#define ATP_GEYSER3_MODE_REQUEST_INDEX 0
#define ATP_GEYSER3_MODE_VENDOR_VALUE 0x04

/* Structure to hold all of our device specific stuff */
struct atp {
        char                    phys[64];
        struct usb_device *     udev;           /* usb device */
        struct urb *            urb;            /* usb request block */
        signed char *           data;           /* transferred data */
        int                     open;           /* non-zero if opened */
        struct input_dev        *input;         /* input dev */
        int                     valid;          /* are the sensors valid ? */
        int                     x_old;          /* last reported x/y, */
        int                     y_old;          /* used for smoothing */
                                                /* current value of the sensors */
        signed char             xy_cur[ATP_XSENSORS + ATP_YSENSORS];
                                                /* last value of the sensors */
        signed char             xy_old[ATP_XSENSORS + ATP_YSENSORS];
                                                /* accumulated sensors */
        int                     xy_acc[ATP_XSENSORS + ATP_YSENSORS];
        int                     overflowwarn;   /* overflow warning printed? */
        int                     datalen;        /* size of an USB urb transfer */
};

#define dbg_dump(msg, tab) \
        if (debug > 1) {                                                \
                int i;                                                  \
                printk("appletouch: %s %lld", msg, (long long)jiffies); \
                for (i = 0; i < ATP_XSENSORS + ATP_YSENSORS; i++)       \
                        printk(" %02x", tab[i]);                        \
                printk("\n");                                           \
        }

#define dprintk(format, a...)                                           \
        do {                                                            \
                if (debug) printk(format, ##a);                         \
        } while (0)

MODULE_AUTHOR("Johannes Berg, Stelian Pop, Frank Arnold, Michael Hanselmann");
MODULE_DESCRIPTION("Apple PowerBooks USB touchpad driver");
MODULE_LICENSE("GPL");

/*
 * Make the threshold a module parameter
 */
static int threshold = ATP_THRESHOLD;
module_param(threshold, int, 0644);
MODULE_PARM_DESC(threshold, "Discards any change in data from a sensor (trackpad has hundreds of these sensors) less than this value");

static int debug = 1;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Activate debugging output");

/* Checks if the device a Geyser 2 (ANSI, ISO, JIS) */
static inline int atp_is_geyser_2(struct atp *dev)
{
        u16 productId = le16_to_cpu(dev->udev->descriptor.idProduct);

        return (productId == GEYSER_ANSI_PRODUCT_ID) ||
                (productId == GEYSER_ISO_PRODUCT_ID) ||
                (productId == GEYSER_JIS_PRODUCT_ID);
}

static inline int atp_is_geyser_3(struct atp *dev)
{
        u16 productId = le16_to_cpu(dev->udev->descriptor.idProduct);

        return (productId == GEYSER3_ANSI_PRODUCT_ID) ||
                (productId == GEYSER3_ISO_PRODUCT_ID) ||
                (productId == GEYSER3_JIS_PRODUCT_ID) ||
                (productId == GEYSER4_ANSI_PRODUCT_ID) ||
                (productId == GEYSER4_ISO_PRODUCT_ID) ||
                (productId == GEYSER4_JIS_PRODUCT_ID);
}

static int atp_calculate_abs(int *xy_sensors, int nb_sensors, int fact,
                             int *z, int *fingers)
{
        int i;
        /* values to calculate mean */
        int pcum = 0, psum = 0;
        int is_increasing = 0;

        *fingers = 0;

        for (i = 0; i < nb_sensors; i++) {
                if (xy_sensors[i] < threshold) {
                        if (is_increasing)
                                is_increasing = 0;

                        continue;
                }

                /*
                 * Makes the finger detection more versatile.  For example,
                 * two fingers with no gap will be detected.  Also, my
                 * tests show it less likely to have intermittent loss
                 * of multiple finger readings while moving around (scrolling).
                 *
                 * Changes the multiple finger detection to counting humps on
                 * sensors (transitions from nonincreasing to increasing)
                 * instead of counting transitions from low sensors (no
                 * finger reading) to high sensors (finger above
                 * sensor)
                 *
                 * - Jason Parekh <jasonparekh@gmail.com>
                 */
                if (i < 1 || (!is_increasing && xy_sensors[i - 1] < xy_sensors[i])) {
                        (*fingers)++;
                        is_increasing = 1;
                } else if (i > 0 && xy_sensors[i - 1] >= xy_sensors[i]) {
                        is_increasing = 0;
                }

                /*
                 * Subtracts threshold so a high sensor that just passes the threshold
                 * won't skew the calculated absolute coordinate.  Fixes an issue
                 * where slowly moving the mouse would occassionaly jump a number of
                 * pixels (let me restate--slowly moving the mouse makes this issue
                 * most apparent).
                 */
                pcum += (xy_sensors[i] - threshold) * i;
                psum += (xy_sensors[i] - threshold);
        }

        if (psum > 0) {
                *z = psum;
                return pcum * fact / psum;
        }

        return 0;
}

static inline void atp_report_fingers(struct input_dev *input, int fingers)
{
        input_report_key(input, BTN_TOOL_FINGER, fingers == 1);
        input_report_key(input, BTN_TOOL_DOUBLETAP, fingers == 2);
        input_report_key(input, BTN_TOOL_TRIPLETAP, fingers > 2);
}

static void atp_complete(struct urb* urb)
{
        int x, y, x_z, y_z, x_f, y_f;
        int retval, i, j;
        struct atp *dev = urb->context;

        switch (urb->status) {
        case 0:
                /* success */
                break;
        case -EOVERFLOW:
                if(!dev->overflowwarn) {
                        printk("appletouch: OVERFLOW with data "
                                "length %d, actual length is %d\n",
                                dev->datalen, dev->urb->actual_length);
                        dev->overflowwarn = 1;
                }
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                /* This urb is terminated, clean up */
                dbg("%s - urb shutting down with status: %d",
                    __FUNCTION__, urb->status);
                return;
        default:
                dbg("%s - nonzero urb status received: %d",
                    __FUNCTION__, urb->status);
                goto exit;
        }

        /* drop incomplete datasets */
        if (dev->urb->actual_length != dev->datalen) {
                dprintk("appletouch: incomplete data package"
                        " (first byte: %d, length: %d).\n",
                        dev->data[0], dev->urb->actual_length);
                goto exit;
        }

        /* reorder the sensors values */
        if (atp_is_geyser_3(dev)) {
                memset(dev->xy_cur, 0, sizeof(dev->xy_cur));

                /*
                 * The values are laid out like this:
                 * -, Y1, Y2, -, Y3, Y4, -, ..., -, X1, X2, -, X3, X4, ...
                 * '-' is an unused value.
                 */

                /* read X values */
                for (i = 0, j = 19; i < 20; i += 2, j += 3) {
                        dev->xy_cur[i] = dev->data[j + 1];
                        dev->xy_cur[i + 1] = dev->data[j + 2];
                }
                /* read Y values */
                for (i = 0, j = 1; i < 9; i += 2, j += 3) {
                        dev->xy_cur[ATP_XSENSORS + i] = dev->data[j + 1];
                        dev->xy_cur[ATP_XSENSORS + i + 1] = dev->data[j + 2];
                }
        } else if (atp_is_geyser_2(dev)) {
                memset(dev->xy_cur, 0, sizeof(dev->xy_cur));

                /*
                 * The values are laid out like this:
                 * Y1, Y2, -, Y3, Y4, -, ..., X1, X2, -, X3, X4, -, ...
                 * '-' is an unused value.
                 */

                /* read X values */
                for (i = 0, j = 19; i < 20; i += 2, j += 3) {
                        dev->xy_cur[i] = dev->data[j];
                        dev->xy_cur[i + 1] = dev->data[j + 1];
                }

                /* read Y values */
                for (i = 0, j = 1; i < 9; i += 2, j += 3) {
                        dev->xy_cur[ATP_XSENSORS + i] = dev->data[j];
                        dev->xy_cur[ATP_XSENSORS + i + 1] = dev->data[j + 1];
                }
        } else {
                for (i = 0; i < 8; i++) {
                        /* X values */
                        dev->xy_cur[i     ] = dev->data[5 * i +  2];
                        dev->xy_cur[i +  8] = dev->data[5 * i +  4];
                        dev->xy_cur[i + 16] = dev->data[5 * i + 42];
                        if (i < 2)
                                dev->xy_cur[i + 24] = dev->data[5 * i + 44];

                        /* Y values */
                        dev->xy_cur[i + 26] = dev->data[5 * i +  1];
                        dev->xy_cur[i + 34] = dev->data[5 * i +  3];
                }
        }

        dbg_dump("sample", dev->xy_cur);

        if (!dev->valid) {
                /* first sample */
                dev->valid = 1;
                dev->x_old = dev->y_old = -1;
                memcpy(dev->xy_old, dev->xy_cur, sizeof(dev->xy_old));

                if (atp_is_geyser_3(dev)) /* No 17" Macbooks (yet) */
                        goto exit;

                /* 17" Powerbooks have extra X sensors */
                for (i = (atp_is_geyser_2(dev)?15:16); i < ATP_XSENSORS; i++) {
                        if (!dev->xy_cur[i]) continue;

                        printk("appletouch: 17\" model detected.\n");
                        if(atp_is_geyser_2(dev))
                                input_set_abs_params(dev->input, ABS_X, 0,
                                                     (20 - 1) *
                                                     ATP_XFACT - 1,
                                                     ATP_FUZZ, 0);
                        else
                                input_set_abs_params(dev->input, ABS_X, 0,
                                                     (ATP_XSENSORS - 1) *
                                                     ATP_XFACT - 1,
                                                     ATP_FUZZ, 0);

                        break;
                }

                goto exit;
        }

        for (i = 0; i < ATP_XSENSORS + ATP_YSENSORS; i++) {
                /* accumulate the change */
                signed char change = dev->xy_old[i] - dev->xy_cur[i];
                dev->xy_acc[i] -= change;

                /* prevent down drifting */
                if (dev->xy_acc[i] < 0)
                        dev->xy_acc[i] = 0;
        }

        memcpy(dev->xy_old, dev->xy_cur, sizeof(dev->xy_old));

        dbg_dump("accumulator", dev->xy_acc);

        x = atp_calculate_abs(dev->xy_acc, ATP_XSENSORS,
                              ATP_XFACT, &x_z, &x_f);
        y = atp_calculate_abs(dev->xy_acc + ATP_XSENSORS, ATP_YSENSORS,
                              ATP_YFACT, &y_z, &y_f);

        if (x && y) {
                if (dev->x_old != -1) {
                        x = (dev->x_old * 3 + x) >> 2;
                        y = (dev->y_old * 3 + y) >> 2;
                        dev->x_old = x;
                        dev->y_old = y;

                        if (debug > 1)
                                printk("appletouch: X: %3d Y: %3d "
                                       "Xz: %3d Yz: %3d\n",
                                       x, y, x_z, y_z);

                        input_report_key(dev->input, BTN_TOUCH, 1);
                        input_report_abs(dev->input, ABS_X, x);
                        input_report_abs(dev->input, ABS_Y, y);
                        input_report_abs(dev->input, ABS_PRESSURE,
                                         min(ATP_PRESSURE, x_z + y_z));
                        atp_report_fingers(dev->input, max(x_f, y_f));
                }
                dev->x_old = x;
                dev->y_old = y;
        }
        else if (!x && !y) {

                dev->x_old = dev->y_old = -1;
                input_report_key(dev->input, BTN_TOUCH, 0);
                input_report_abs(dev->input, ABS_PRESSURE, 0);
                atp_report_fingers(dev->input, 0);

                /* reset the accumulator on release */
                memset(dev->xy_acc, 0, sizeof(dev->xy_acc));
        }

        input_report_key(dev->input, BTN_LEFT,
                         !!dev->data[dev->datalen - 1]);

        input_sync(dev->input);

exit:
        retval = usb_submit_urb(dev->urb, GFP_ATOMIC);
        if (retval) {
                err("%s - usb_submit_urb failed with result %d",
                    __FUNCTION__, retval);
        }
}

static int atp_open(struct input_dev *input)
{
        struct atp *dev = input_get_drvdata(input);

        if (usb_submit_urb(dev->urb, GFP_ATOMIC))
                return -EIO;

        dev->open = 1;
        return 0;
}

static void atp_close(struct input_dev *input)
{
        struct atp *dev = input_get_drvdata(input);

        usb_kill_urb(dev->urb);
        dev->open = 0;
}

static int atp_probe(struct usb_interface *iface, const struct usb_device_id *id)
{
        struct atp *dev;
        struct input_dev *input_dev;
        struct usb_device *udev = interface_to_usbdev(iface);
        struct usb_host_interface *iface_desc;
        struct usb_endpoint_descriptor *endpoint;
        int int_in_endpointAddr = 0;
        int i, error = -ENOMEM;

        /* set up the endpoint information */
        /* use only the first interrupt-in endpoint */
        iface_desc = iface->cur_altsetting;
        for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
                endpoint = &iface_desc->endpoint[i].desc;
                if (!int_in_endpointAddr && usb_endpoint_is_int_in(endpoint)) {
                        /* we found an interrupt in endpoint */
                        int_in_endpointAddr = endpoint->bEndpointAddress;
                        break;
                }
        }
        if (!int_in_endpointAddr) {
                err("Could not find int-in endpoint");
                return -EIO;
        }

        /* allocate memory for our device state and initialize it */
        dev = kzalloc(sizeof(struct atp), GFP_KERNEL);
        input_dev = input_allocate_device();
        if (!dev || !input_dev) {
                err("Out of memory");
                goto err_free_devs;
        }

        dev->udev = udev;
        dev->input = input_dev;
        dev->overflowwarn = 0;
        if (atp_is_geyser_3(dev))
                dev->datalen = 64;
        else if (atp_is_geyser_2(dev))
                dev->datalen = 64;
        else
                dev->datalen = 81;

        if (atp_is_geyser_3(dev)) {
                /*
                 * By default Geyser 3 device sends standard USB HID mouse
                 * packets (Report ID 2). This code changes device mode, so it
                 * sends raw sensor reports (Report ID 5).
                 */
                char data[8];
                int size;

                size = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
                        ATP_GEYSER3_MODE_READ_REQUEST_ID,
                        USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
                        ATP_GEYSER3_MODE_REQUEST_VALUE,
                        ATP_GEYSER3_MODE_REQUEST_INDEX, &data, 8, 5000);

                if (size != 8) {
                        err("Could not do mode read request from device"
                                                        " (Geyser 3 mode)");
                        goto err_free_devs;
                }

                /* Apply the mode switch */
                data[0] = ATP_GEYSER3_MODE_VENDOR_VALUE;

                size = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
                        ATP_GEYSER3_MODE_WRITE_REQUEST_ID,
                        USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
                        ATP_GEYSER3_MODE_REQUEST_VALUE,
                        ATP_GEYSER3_MODE_REQUEST_INDEX, &data, 8, 5000);

                if (size != 8) {
                        err("Could not do mode write request to device"
                                                        " (Geyser 3 mode)");
                        goto err_free_devs;
                }
                printk("appletouch Geyser 3 inited.\n");
        }

        dev->urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!dev->urb)
                goto err_free_devs;

        dev->data = usb_buffer_alloc(dev->udev, dev->datalen, GFP_KERNEL,
                                     &dev->urb->transfer_dma);
        if (!dev->data)
                goto err_free_urb;

        usb_fill_int_urb(dev->urb, udev,
                         usb_rcvintpipe(udev, int_in_endpointAddr),
                         dev->data, dev->datalen, atp_complete, dev, 1);

        usb_make_path(udev, dev->phys, sizeof(dev->phys));
        strlcat(dev->phys, "/input0", sizeof(dev->phys));

        input_dev->name = "appletouch";
        input_dev->phys = dev->phys;
        usb_to_input_id(dev->udev, &input_dev->id);
        input_dev->dev.parent = &iface->dev;

        input_set_drvdata(input_dev, dev);

        input_dev->open = atp_open;
        input_dev->close = atp_close;

        set_bit(EV_ABS, input_dev->evbit);

        if (atp_is_geyser_3(dev)) {
                /*
                 * MacBook have 20 X sensors, 10 Y sensors
                 */
                input_set_abs_params(input_dev, ABS_X, 0,
                                     ((20 - 1) * ATP_XFACT) - 1, ATP_FUZZ, 0);
                input_set_abs_params(input_dev, ABS_Y, 0,
                                     ((10 - 1) * ATP_YFACT) - 1, ATP_FUZZ, 0);
        } else if (atp_is_geyser_2(dev)) {
                /*
                 * Oct 2005 15" PowerBooks have 15 X sensors, 17" are detected
                 * later.
                 */
                input_set_abs_params(input_dev, ABS_X, 0,
                                     ((15 - 1) * ATP_XFACT) - 1, ATP_FUZZ, 0);
                input_set_abs_params(input_dev, ABS_Y, 0,
                                     ((9 - 1) * ATP_YFACT) - 1, ATP_FUZZ, 0);
        } else {
                /*
                 * 12" and 15" Powerbooks only have 16 x sensors,
                 * 17" models are detected later.
                 */
                input_set_abs_params(input_dev, ABS_X, 0,
                                     (16 - 1) * ATP_XFACT - 1, ATP_FUZZ, 0);
                input_set_abs_params(input_dev, ABS_Y, 0,
                                     (ATP_YSENSORS - 1) * ATP_YFACT - 1, ATP_FUZZ, 0);
        }
        input_set_abs_params(input_dev, ABS_PRESSURE, 0, ATP_PRESSURE, 0, 0);

        set_bit(EV_KEY, input_dev->evbit);
        set_bit(BTN_TOUCH, input_dev->keybit);
        set_bit(BTN_TOOL_FINGER, input_dev->keybit);
        set_bit(BTN_TOOL_DOUBLETAP, input_dev->keybit);
        set_bit(BTN_TOOL_TRIPLETAP, input_dev->keybit);
        set_bit(BTN_LEFT, input_dev->keybit);

        error = input_register_device(dev->input);
        if (error)
                goto err_free_buffer;

        /* save our data pointer in this interface device */
        usb_set_intfdata(iface, dev);

        return 0;

 err_free_buffer:
        usb_buffer_free(dev->udev, dev->datalen,
                        dev->data, dev->urb->transfer_dma);
 err_free_urb:
        usb_free_urb(dev->urb);
 err_free_devs:
        usb_set_intfdata(iface, NULL);
        kfree(dev);
        input_free_device(input_dev);
        return error;
}

static void atp_disconnect(struct usb_interface *iface)
{
        struct atp *dev = usb_get_intfdata(iface);

        usb_set_intfdata(iface, NULL);
        if (dev) {
                usb_kill_urb(dev->urb);
                input_unregister_device(dev->input);
                usb_buffer_free(dev->udev, dev->datalen,
                                dev->data, dev->urb->transfer_dma);
                usb_free_urb(dev->urb);
                kfree(dev);
        }
        printk(KERN_INFO "input: appletouch disconnected\n");
}

static int atp_suspend(struct usb_interface *iface, pm_message_t message)
{
        struct atp *dev = usb_get_intfdata(iface);
        usb_kill_urb(dev->urb);
        dev->valid = 0;
        return 0;
}

static int atp_resume(struct usb_interface *iface)
{
        struct atp *dev = usb_get_intfdata(iface);
        if (dev->open && usb_submit_urb(dev->urb, GFP_ATOMIC))
                return -EIO;

        return 0;
}

static struct usb_driver atp_driver = {
        .name           = "appletouch",
        .probe          = atp_probe,
        .disconnect     = atp_disconnect,
        .suspend        = atp_suspend,
        .resume         = atp_resume,
        .id_table       = atp_table,
};

static int __init atp_init(void)
{
        return usb_register(&atp_driver);
}

static void __exit atp_exit(void)
{
        usb_deregister(&atp_driver);
}

module_init(atp_init);
module_exit(atp_exit);