/*
 *  Native support for the Aiptek HyperPen USB Tablets
 *  (4000U/5000U/6000U/8000U/12000U)
 *
 *  Copyright (c) 2001      Chris Atenasio   <chris@crud.net>
 *  Copyright (c) 2002-2004 Bryan W. Headley <bwheadley@earthlink.net>
 *
 *  based on wacom.c by
 *     Vojtech Pavlik      <vojtech@suse.cz>
 *     Andreas Bach Aaen   <abach@stofanet.dk>
 *     Clifford Wolf       <clifford@clifford.at>
 *     Sam Mosel           <sam.mosel@computer.org>
 *     James E. Blair      <corvus@gnu.org>
 *     Daniel Egger        <egger@suse.de>
 *
 *  Many thanks to Oliver Kuechemann for his support.
 *
 *  ChangeLog:
 *      v0.1 - Initial release
 *      v0.2 - Hack to get around fake event 28's. (Bryan W. Headley)
 *      v0.3 - Make URB dynamic (Bryan W. Headley, Jun-8-2002)
 *             Released to Linux 2.4.19 and 2.5.x
 *      v0.4 - Rewrote substantial portions of the code to deal with
 *             corrected control sequences, timing, dynamic configuration,
 *             support of 6000U - 12000U, procfs, and macro key support
 *             (Jan-1-2003 - Feb-5-2003, Bryan W. Headley)
 *      v1.0 - Added support for diagnostic messages, count of messages
 *             received from URB - Mar-8-2003, Bryan W. Headley
 *      v1.1 - added support for tablet resolution, changed DV and proximity
 *             some corrections - Jun-22-2003, martin schneebacher
 *           - Added support for the sysfs interface, deprecating the
 *             procfs interface for 2.5.x kernel. Also added support for
 *             Wheel command. Bryan W. Headley July-15-2003.
 *      v1.2 - Reworked jitter timer as a kernel thread.
 *             Bryan W. Headley November-28-2003/Jan-10-2004.
 *      v1.3 - Repaired issue of kernel thread going nuts on single-processor
 *             machines, introduced programmableDelay as a command line
 *             parameter. Feb 7 2004, Bryan W. Headley.
 *      v1.4 - Re-wire jitter so it does not require a thread. Courtesy of
 *             Rene van Paassen. Added reporting of physical pointer device
 *             (e.g., stylus, mouse in reports 2, 3, 4, 5. We don't know
 *             for reports 1, 6.)
 *             what physical device reports for reports 1, 6.) Also enabled
 *             MOUSE and LENS tool button modes. Renamed "rubber" to "eraser".
 *             Feb 20, 2004, Bryan W. Headley.
 *      v1.5 - Added previousJitterable, so we don't do jitter delay when the
 *             user is holding a button down for periods of time.
 *
 * NOTE:
 *      This kernel driver is augmented by the "Aiptek" XFree86 input
 *      driver for your X server, as well as the Gaiptek GUI Front-end
 *      "Tablet Manager".
 *      These three products are highly interactive with one another,
 *      so therefore it's easier to document them all as one subsystem.
 *      Please visit the project's "home page", located at,
 *      http://aiptektablet.sourceforge.net.
 *
 * 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/jiffies.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/usb/input.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>

/*
 * Version Information
 */
#define DRIVER_VERSION "v2.3 (May 2, 2007)"
#define DRIVER_AUTHOR  "Bryan W. Headley/Chris Atenasio/Cedric Brun/Rene van Paassen"
#define DRIVER_DESC    "Aiptek HyperPen USB Tablet Driver (Linux 2.6.x)"

/*
 * Aiptek status packet:
 *
 * (returned as Report 1 - relative coordinates from mouse and stylus)
 *
 *        bit7  bit6  bit5  bit4  bit3  bit2  bit1  bit0
 * byte0   0     0     0     0     0     0     0     1
 * byte1   0     0     0     0     0    BS2   BS    Tip
 * byte2  X7    X6    X5    X4    X3    X2    X1    X0
 * byte3  Y7    Y6    Y5    Y4    Y3    Y2    Y1    Y0
 *
 * (returned as Report 2 - absolute coordinates from the stylus)
 *
 *        bit7  bit6  bit5  bit4  bit3  bit2  bit1  bit0
 * byte0   0     0     0     0     0     0     1     0
 * byte1  X7    X6    X5    X4    X3    X2    X1    X0
 * byte2  X15   X14   X13   X12   X11   X10   X9    X8
 * byte3  Y7    Y6    Y5    Y4    Y3    Y2    Y1    Y0
 * byte4  Y15   Y14   Y13   Y12   Y11   Y10   Y9    Y8
 * byte5   *     *     *    BS2   BS1   Tip   IR    DV
 * byte6  P7    P6    P5    P4    P3    P2    P1    P0
 * byte7  P15   P14   P13   P12   P11   P10   P9    P8
 *
 * (returned as Report 3 - absolute coordinates from the mouse)
 *
 *        bit7  bit6  bit5  bit4  bit3  bit2  bit1  bit0
 * byte0   0     0     0     0     0     0     1     1
 * byte1  X7    X6    X5    X4    X3    X2    X1    X0
 * byte2  X15   X14   X13   X12   X11   X10   X9    X8
 * byte3  Y7    Y6    Y5    Y4    Y3    Y2    Y1    Y0
 * byte4  Y15   Y14   Y13   Y12   Y11   Y10   Y9    Y8
 * byte5   *     *     *    BS2   BS1   Tip   IR    DV
 * byte6  P7    P6    P5    P4    P3    P2    P1    P0
 * byte7  P15   P14   P13   P12   P11   P10   P9    P8
 *
 * (returned as Report 4 - macrokeys from the stylus)
 *
 *        bit7  bit6  bit5  bit4  bit3  bit2  bit1  bit0
 * byte0   0     0     0     0     0     1     0     0
 * byte1   0     0     0    BS2   BS    Tip   IR    DV
 * byte2   0     0     0     0     0     0     1     0
 * byte3   0     0     0    K4    K3    K2    K1    K0
 * byte4  P7    P6    P5    P4    P3    P2    P1    P0
 * byte5  P15   P14   P13   P12   P11   P10   P9    P8
 *
 * (returned as Report 5 - macrokeys from the mouse)
 *
 *        bit7  bit6  bit5  bit4  bit3  bit2  bit1  bit0
 * byte0   0     0     0     0     0     1     0     1
 * byte1   0     0     0    BS2   BS    Tip   IR    DV
 * byte2   0     0     0     0     0     0     1     0
 * byte3   0     0     0    K4    K3    K2    K1    K0
 * byte4  P7    P6    P5    P4    P3    P2    P1    P0
 * byte5  P15   P14   P13   P12   P11   P10   P9    P8
 *
 * IR: In Range = Proximity on
 * DV = Data Valid
 * BS = Barrel Switch (as in, macro keys)
 * BS2 also referred to as Tablet Pick
 *
 * Command Summary:
 *
 * Use report_type CONTROL (3)
 * Use report_id   2
 *
 * Command/Data    Description     Return Bytes    Return Value
 * 0x10/0x00       SwitchToMouse       0
 * 0x10/0x01       SwitchToTablet      0
 * 0x18/0x04       SetResolution       0
 * 0x12/0xFF       AutoGainOn          0
 * 0x17/0x00       FilterOn            0
 * 0x01/0x00       GetXExtension       2           MaxX
 * 0x01/0x01       GetYExtension       2           MaxY
 * 0x02/0x00       GetModelCode        2           ModelCode = LOBYTE
 * 0x03/0x00       GetODMCode          2           ODMCode
 * 0x08/0x00       GetPressureLevels   2           =512
 * 0x04/0x00       GetFirmwareVersion  2           Firmware Version
 * 0x11/0x02       EnableMacroKeys     0
 *
 * To initialize the tablet:
 *
 * (1) Send Resolution500LPI (Command)
 * (2) Query for Model code (Option Report)
 * (3) Query for ODM code (Option Report)
 * (4) Query for firmware (Option Report)
 * (5) Query for GetXExtension (Option Report)
 * (6) Query for GetYExtension (Option Report)
 * (7) Query for GetPressureLevels (Option Report)
 * (8) SwitchToTablet for Absolute coordinates, or
 *     SwitchToMouse for Relative coordinates (Command)
 * (9) EnableMacroKeys (Command)
 * (10) FilterOn (Command)
 * (11) AutoGainOn (Command)
 *
 * (Step 9 can be omitted, but you'll then have no function keys.)
 */

#define USB_VENDOR_ID_AIPTEK                            0x08ca
#define USB_VENDOR_ID_KYE                               0x0458
#define USB_REQ_GET_REPORT                              0x01
#define USB_REQ_SET_REPORT                              0x09

        /* PointerMode codes
         */
#define AIPTEK_POINTER_ONLY_MOUSE_MODE                  0
#define AIPTEK_POINTER_ONLY_STYLUS_MODE                 1
#define AIPTEK_POINTER_EITHER_MODE                      2

#define AIPTEK_POINTER_ALLOW_MOUSE_MODE(a)              \
        (a == AIPTEK_POINTER_ONLY_MOUSE_MODE ||         \
         a == AIPTEK_POINTER_EITHER_MODE)
#define AIPTEK_POINTER_ALLOW_STYLUS_MODE(a)             \
        (a == AIPTEK_POINTER_ONLY_STYLUS_MODE ||        \
         a == AIPTEK_POINTER_EITHER_MODE)

        /* CoordinateMode code
         */
#define AIPTEK_COORDINATE_RELATIVE_MODE                 0
#define AIPTEK_COORDINATE_ABSOLUTE_MODE                 1

       /* XTilt and YTilt values
        */
#define AIPTEK_TILT_MIN                                 (-128)
#define AIPTEK_TILT_MAX                                 127
#define AIPTEK_TILT_DISABLE                             (-10101)

        /* Wheel values
         */
#define AIPTEK_WHEEL_MIN                                0
#define AIPTEK_WHEEL_MAX                                1024
#define AIPTEK_WHEEL_DISABLE                            (-10101)

        /* ToolCode values, which BTW are 0x140 .. 0x14f
         * We have things set up such that if the tool button has changed,
         * the tools get reset.
         */
        /* toolMode codes
         */
#define AIPTEK_TOOL_BUTTON_PEN_MODE                     BTN_TOOL_PEN
#define AIPTEK_TOOL_BUTTON_PENCIL_MODE                  BTN_TOOL_PENCIL
#define AIPTEK_TOOL_BUTTON_BRUSH_MODE                   BTN_TOOL_BRUSH
#define AIPTEK_TOOL_BUTTON_AIRBRUSH_MODE                BTN_TOOL_AIRBRUSH
#define AIPTEK_TOOL_BUTTON_ERASER_MODE                  BTN_TOOL_RUBBER
#define AIPTEK_TOOL_BUTTON_MOUSE_MODE                   BTN_TOOL_MOUSE
#define AIPTEK_TOOL_BUTTON_LENS_MODE                    BTN_TOOL_LENS

        /* Diagnostic message codes
         */
#define AIPTEK_DIAGNOSTIC_NA                            0
#define AIPTEK_DIAGNOSTIC_SENDING_RELATIVE_IN_ABSOLUTE  1
#define AIPTEK_DIAGNOSTIC_SENDING_ABSOLUTE_IN_RELATIVE  2
#define AIPTEK_DIAGNOSTIC_TOOL_DISALLOWED               3

        /* Time to wait (in ms) to help mask hand jittering
         * when pressing the stylus buttons.
         */
#define AIPTEK_JITTER_DELAY_DEFAULT                     50

        /* Time to wait (in ms) in-between sending the tablet
         * a command and beginning the process of reading the return
         * sequence from the tablet.
         */
#define AIPTEK_PROGRAMMABLE_DELAY_25            25
#define AIPTEK_PROGRAMMABLE_DELAY_50            50
#define AIPTEK_PROGRAMMABLE_DELAY_100           100
#define AIPTEK_PROGRAMMABLE_DELAY_200           200
#define AIPTEK_PROGRAMMABLE_DELAY_300           300
#define AIPTEK_PROGRAMMABLE_DELAY_400           400
#define AIPTEK_PROGRAMMABLE_DELAY_DEFAULT       AIPTEK_PROGRAMMABLE_DELAY_400

        /* Mouse button programming
         */
#define AIPTEK_MOUSE_LEFT_BUTTON                0x04
#define AIPTEK_MOUSE_RIGHT_BUTTON               0x08
#define AIPTEK_MOUSE_MIDDLE_BUTTON              0x10

        /* Stylus button programming
         */
#define AIPTEK_STYLUS_LOWER_BUTTON              0x08
#define AIPTEK_STYLUS_UPPER_BUTTON              0x10

        /* Length of incoming packet from the tablet
         */
#define AIPTEK_PACKET_LENGTH                    8

        /* We report in EV_MISC both the proximity and
         * whether the report came from the stylus, tablet mouse
         * or "unknown" -- Unknown when the tablet is in relative
         * mode, because we only get report 1's.
         */
#define AIPTEK_REPORT_TOOL_UNKNOWN              0x10
#define AIPTEK_REPORT_TOOL_STYLUS               0x20
#define AIPTEK_REPORT_TOOL_MOUSE                0x40

static int programmableDelay = AIPTEK_PROGRAMMABLE_DELAY_DEFAULT;
static int jitterDelay = AIPTEK_JITTER_DELAY_DEFAULT;

struct aiptek_features {
        int odmCode;            /* Tablet manufacturer code       */
        int modelCode;          /* Tablet model code (not unique) */
        int firmwareCode;       /* prom/eeprom version            */
        char usbPath[64 + 1];   /* device's physical usb path     */
};

struct aiptek_settings {
        int pointerMode;        /* stylus-, mouse-only or either */
        int coordinateMode;     /* absolute/relative coords      */
        int toolMode;           /* pen, pencil, brush, etc. tool */
        int xTilt;              /* synthetic xTilt amount        */
        int yTilt;              /* synthetic yTilt amount        */
        int wheel;              /* synthetic wheel amount        */
        int stylusButtonUpper;  /* stylus upper btn delivers...  */
        int stylusButtonLower;  /* stylus lower btn delivers...  */
        int mouseButtonLeft;    /* mouse left btn delivers...    */
        int mouseButtonMiddle;  /* mouse middle btn delivers...  */
        int mouseButtonRight;   /* mouse right btn delivers...   */
        int programmableDelay;  /* delay for tablet programming  */
        int jitterDelay;        /* delay for hand jittering      */
};

struct aiptek {
        struct input_dev *inputdev;             /* input device struct           */
        struct usb_device *usbdev;              /* usb device struct             */
        struct urb *urb;                        /* urb for incoming reports      */
        dma_addr_t data_dma;                    /* our dma stuffage              */
        struct aiptek_features features;        /* tablet's array of features    */
        struct aiptek_settings curSetting;      /* tablet's current programmable */
        struct aiptek_settings newSetting;      /* ... and new param settings    */
        unsigned int ifnum;                     /* interface number for IO       */
        int diagnostic;                         /* tablet diagnostic codes       */
        unsigned long eventCount;               /* event count                   */
        int inDelay;                            /* jitter: in jitter delay?      */
        unsigned long endDelay;                 /* jitter: time when delay ends  */
        int previousJitterable;                 /* jitterable prev value     */

        int lastMacro;                          /* macro key to reset            */
        int previousToolMode;                   /* pen, pencil, brush, etc. tool */
        unsigned char *data;                    /* incoming packet data          */
};

static const int eventTypes[] = {
        EV_KEY, EV_ABS, EV_REL, EV_MSC,
};

static const int absEvents[] = {
        ABS_X, ABS_Y, ABS_PRESSURE, ABS_TILT_X, ABS_TILT_Y,
        ABS_WHEEL, ABS_MISC,
};

static const int relEvents[] = {
        REL_X, REL_Y, REL_WHEEL,
};

static const int buttonEvents[] = {
        BTN_LEFT, BTN_RIGHT, BTN_MIDDLE,
        BTN_TOOL_PEN, BTN_TOOL_RUBBER, BTN_TOOL_PENCIL, BTN_TOOL_AIRBRUSH,
        BTN_TOOL_BRUSH, BTN_TOOL_MOUSE, BTN_TOOL_LENS, BTN_TOUCH,
        BTN_STYLUS, BTN_STYLUS2,
};

/*
 * Permit easy lookup of keyboard events to send, versus
 * the bitmap which comes from the tablet. This hides the
 * issue that the F_keys are not sequentially numbered.
 */
static const int macroKeyEvents[] = {
        KEY_ESC, KEY_F1, KEY_F2, KEY_F3, KEY_F4, KEY_F5,
        KEY_F6, KEY_F7, KEY_F8, KEY_F9, KEY_F10, KEY_F11,
        KEY_F12, KEY_F13, KEY_F14, KEY_F15, KEY_F16, KEY_F17,
        KEY_F18, KEY_F19, KEY_F20, KEY_F21, KEY_F22, KEY_F23,
        KEY_F24, KEY_STOP, KEY_AGAIN, KEY_PROPS, KEY_UNDO,
        KEY_FRONT, KEY_COPY, KEY_OPEN, KEY_PASTE, 0
};

/***********************************************************************
 * Map values to strings and back. Every map should have the following
 * as its last element: { NULL, AIPTEK_INVALID_VALUE }.
 */
#define AIPTEK_INVALID_VALUE    -1

struct aiptek_map {
        const char *string;
        int value;
};

static int map_str_to_val(const struct aiptek_map *map, const char *str, size_t count)
{
        const struct aiptek_map *p;

        if (str[count - 1] == '\n')
                count--;

        for (p = map; p->string; p++)
                if (!strncmp(str, p->string, count))
                        return p->value;

        return AIPTEK_INVALID_VALUE;
}

static const char *map_val_to_str(const struct aiptek_map *map, int val)
{
        const struct aiptek_map *p;

        for (p = map; p->value != AIPTEK_INVALID_VALUE; p++)
                if (val == p->value)
                        return p->string;

        return "unknown";
}

/***********************************************************************
 * aiptek_irq can receive one of six potential reports.
 * The documentation for each is in the body of the function.
 *
 * The tablet reports on several attributes per invocation of
 * aiptek_irq. Because the Linux Input Event system allows the
 * transmission of ONE attribute per input_report_xxx() call,
 * collation has to be done on the other end to reconstitute
 * a complete tablet report. Further, the number of Input Event reports
 * submitted varies, depending on what USB report type, and circumstance.
 * To deal with this, EV_MSC is used to indicate an 'end-of-report'
 * message. This has been an undocumented convention understood by the kernel
 * tablet driver and clients such as gpm and XFree86's tablet drivers.
 *
 * Of the information received from the tablet, the one piece I
 * cannot transmit is the proximity bit (without resorting to an EV_MSC
 * convention above.) I therefore have taken over REL_MISC and ABS_MISC
 * (for relative and absolute reports, respectively) for communicating
 * Proximity. Why two events? I thought it interesting to know if the
 * Proximity event occurred while the tablet was in absolute or relative
 * mode.
 * Update: REL_MISC proved not to be such a good idea. With REL_MISC you
 * get an event transmitted each time. ABS_MISC works better, since it
 * can be set and re-set. Thus, only using ABS_MISC from now on.
 *
 * Other tablets use the notion of a certain minimum stylus pressure
 * to infer proximity. While that could have been done, that is yet
 * another 'by convention' behavior, the documentation for which
 * would be spread between two (or more) pieces of software.
 *
 * EV_MSC usage was terminated for this purpose in Linux 2.5.x, and
 * replaced with the input_sync() method (which emits EV_SYN.)
 */

static void aiptek_irq(struct urb *urb)
{
        struct aiptek *aiptek = urb->context;
        unsigned char *data = aiptek->data;
        struct input_dev *inputdev = aiptek->inputdev;
        int jitterable = 0;
        int retval, macro, x, y, z, left, right, middle, p, dv, tip, bs, pck;

        switch (urb->status) {
        case 0:
                /* Success */
                break;

        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                /* This urb is terminated, clean up */
                dbg("%s - urb shutting down with status: %d",
                    __func__, urb->status);
                return;

        default:
                dbg("%s - nonzero urb status received: %d",
                    __func__, urb->status);
                goto exit;
        }

        /* See if we are in a delay loop -- throw out report if true.
         */
        if (aiptek->inDelay == 1 && time_after(aiptek->endDelay, jiffies)) {
                goto exit;
        }

        aiptek->inDelay = 0;
        aiptek->eventCount++;

        /* Report 1 delivers relative coordinates with either a stylus
         * or the mouse. You do not know, however, which input
         * tool generated the event.
         */
        if (data[0] == 1) {
                if (aiptek->curSetting.coordinateMode ==
                    AIPTEK_COORDINATE_ABSOLUTE_MODE) {
                        aiptek->diagnostic =
                            AIPTEK_DIAGNOSTIC_SENDING_RELATIVE_IN_ABSOLUTE;
                } else {
                        x = (signed char) data[2];
                        y = (signed char) data[3];

                        /* jitterable keeps track of whether any button has been pressed.
                         * We're also using it to remap the physical mouse button mask
                         * to pseudo-settings. (We don't specifically care about it's
                         * value after moving/transposing mouse button bitmasks, except
                         * that a non-zero value indicates that one or more
                         * mouse button was pressed.)
                         */
                        jitterable = data[1] & 0x07;

                        left = (data[1] & aiptek->curSetting.mouseButtonLeft >> 2) != 0 ? 1 : 0;
                        right = (data[1] & aiptek->curSetting.mouseButtonRight >> 2) != 0 ? 1 : 0;
                        middle = (data[1] & aiptek->curSetting.mouseButtonMiddle >> 2) != 0 ? 1 : 0;

                        input_report_key(inputdev, BTN_LEFT, left);
                        input_report_key(inputdev, BTN_MIDDLE, middle);
                        input_report_key(inputdev, BTN_RIGHT, right);

                        input_report_abs(inputdev, ABS_MISC,
                                         1 | AIPTEK_REPORT_TOOL_UNKNOWN);
                        input_report_rel(inputdev, REL_X, x);
                        input_report_rel(inputdev, REL_Y, y);

                        /* Wheel support is in the form of a single-event
                         * firing.
                         */
                        if (aiptek->curSetting.wheel != AIPTEK_WHEEL_DISABLE) {
                                input_report_rel(inputdev, REL_WHEEL,
                                                 aiptek->curSetting.wheel);
                                aiptek->curSetting.wheel = AIPTEK_WHEEL_DISABLE;
                        }
                        if (aiptek->lastMacro != -1) {
                                input_report_key(inputdev,
                                                 macroKeyEvents[aiptek->lastMacro], 0);
                                aiptek->lastMacro = -1;
                        }
                        input_sync(inputdev);
                }
        }
        /* Report 2 is delivered only by the stylus, and delivers
         * absolute coordinates.
         */
        else if (data[0] == 2) {
                if (aiptek->curSetting.coordinateMode == AIPTEK_COORDINATE_RELATIVE_MODE) {
                        aiptek->diagnostic = AIPTEK_DIAGNOSTIC_SENDING_ABSOLUTE_IN_RELATIVE;
                } else if (!AIPTEK_POINTER_ALLOW_STYLUS_MODE
                            (aiptek->curSetting.pointerMode)) {
                                aiptek->diagnostic = AIPTEK_DIAGNOSTIC_TOOL_DISALLOWED;
                } else {
                        x = get_unaligned_le16(data + 1);
                        y = get_unaligned_le16(data + 3);
                        z = get_unaligned_le16(data + 6);

                        dv = (data[5] & 0x01) != 0 ? 1 : 0;
                        p = (data[5] & 0x02) != 0 ? 1 : 0;
                        tip = (data[5] & 0x04) != 0 ? 1 : 0;

                        /* Use jitterable to re-arrange button masks
                         */
                        jitterable = data[5] & 0x18;

                        bs = (data[5] & aiptek->curSetting.stylusButtonLower) != 0 ? 1 : 0;
                        pck = (data[5] & aiptek->curSetting.stylusButtonUpper) != 0 ? 1 : 0;

                        /* dv indicates 'data valid' (e.g., the tablet is in sync
                         * and has delivered a "correct" report) We will ignore
                         * all 'bad' reports...
                         */
                        if (dv != 0) {
                                /* If the selected tool changed, reset the old
                                 * tool key, and set the new one.
                                 */
                                if (aiptek->previousToolMode !=
                                    aiptek->curSetting.toolMode) {
                                        input_report_key(inputdev,
                                                         aiptek->previousToolMode, 0);
                                        input_report_key(inputdev,
                                                         aiptek->curSetting.toolMode,
                                                         1);
                                        aiptek->previousToolMode =
                                                  aiptek->curSetting.toolMode;
                                }

                                if (p != 0) {
                                        input_report_abs(inputdev, ABS_X, x);
                                        input_report_abs(inputdev, ABS_Y, y);
                                        input_report_abs(inputdev, ABS_PRESSURE, z);

                                        input_report_key(inputdev, BTN_TOUCH, tip);
                                        input_report_key(inputdev, BTN_STYLUS, bs);
                                        input_report_key(inputdev, BTN_STYLUS2, pck);

                                        if (aiptek->curSetting.xTilt !=
                                            AIPTEK_TILT_DISABLE) {
                                                input_report_abs(inputdev,
                                                                 ABS_TILT_X,
                                                                 aiptek->curSetting.xTilt);
                                        }
                                        if (aiptek->curSetting.yTilt != AIPTEK_TILT_DISABLE) {
                                                input_report_abs(inputdev,
                                                                 ABS_TILT_Y,
                                                                 aiptek->curSetting.yTilt);
                                        }

                                        /* Wheel support is in the form of a single-event
                                         * firing.
                                         */
                                        if (aiptek->curSetting.wheel !=
                                            AIPTEK_WHEEL_DISABLE) {
                                                input_report_abs(inputdev,
                                                                 ABS_WHEEL,
                                                                 aiptek->curSetting.wheel);
                                                aiptek->curSetting.wheel = AIPTEK_WHEEL_DISABLE;
                                        }
                                }
                                input_report_abs(inputdev, ABS_MISC, p | AIPTEK_REPORT_TOOL_STYLUS);
                                if (aiptek->lastMacro != -1) {
                                        input_report_key(inputdev,
                                                         macroKeyEvents[aiptek->lastMacro], 0);
                                        aiptek->lastMacro = -1;
                                }
                                input_sync(inputdev);
                        }
                }
        }
        /* Report 3's come from the mouse in absolute mode.
         */
        else if (data[0] == 3) {
                if (aiptek->curSetting.coordinateMode == AIPTEK_COORDINATE_RELATIVE_MODE) {
                        aiptek->diagnostic = AIPTEK_DIAGNOSTIC_SENDING_ABSOLUTE_IN_RELATIVE;
                } else if (!AIPTEK_POINTER_ALLOW_MOUSE_MODE
                        (aiptek->curSetting.pointerMode)) {
                        aiptek->diagnostic = AIPTEK_DIAGNOSTIC_TOOL_DISALLOWED;
                } else {
                        x = get_unaligned_le16(data + 1);
                        y = get_unaligned_le16(data + 3);

                        jitterable = data[5] & 0x1c;

                        dv = (data[5] & 0x01) != 0 ? 1 : 0;
                        p = (data[5] & 0x02) != 0 ? 1 : 0;
                        left = (data[5] & aiptek->curSetting.mouseButtonLeft) != 0 ? 1 : 0;
                        right = (data[5] & aiptek->curSetting.mouseButtonRight) != 0 ? 1 : 0;
                        middle = (data[5] & aiptek->curSetting.mouseButtonMiddle) != 0 ? 1 : 0;

                        if (dv != 0) {
                                /* If the selected tool changed, reset the old
                                 * tool key, and set the new one.
                                 */
                                if (aiptek->previousToolMode !=
                                    aiptek->curSetting.toolMode) {
                                        input_report_key(inputdev,
                                                         aiptek->previousToolMode, 0);
                                        input_report_key(inputdev,
                                                         aiptek->curSetting.toolMode,
                                                         1);
                                        aiptek->previousToolMode =
                                                  aiptek->curSetting.toolMode;
                                }

                                if (p != 0) {
                                        input_report_abs(inputdev, ABS_X, x);
                                        input_report_abs(inputdev, ABS_Y, y);

                                        input_report_key(inputdev, BTN_LEFT, left);
                                        input_report_key(inputdev, BTN_MIDDLE, middle);
                                        input_report_key(inputdev, BTN_RIGHT, right);

                                        /* Wheel support is in the form of a single-event
                                         * firing.
                                         */
                                        if (aiptek->curSetting.wheel != AIPTEK_WHEEL_DISABLE) {
                                                input_report_abs(inputdev,
                                                                 ABS_WHEEL,
                                                                 aiptek->curSetting.wheel);
                                                aiptek->curSetting.wheel = AIPTEK_WHEEL_DISABLE;
                                        }
                                }
                                input_report_abs(inputdev, ABS_MISC, p | AIPTEK_REPORT_TOOL_MOUSE);
                                if (aiptek->lastMacro != -1) {
                                        input_report_key(inputdev,
                                                         macroKeyEvents[aiptek->lastMacro], 0);
                                        aiptek->lastMacro = -1;
                                }
                                input_sync(inputdev);
                        }
                }
        }
        /* Report 4s come from the macro keys when pressed by stylus
         */
        else if (data[0] == 4) {
                jitterable = data[1] & 0x18;

                dv = (data[1] & 0x01) != 0 ? 1 : 0;
                p = (data[1] & 0x02) != 0 ? 1 : 0;
                tip = (data[1] & 0x04) != 0 ? 1 : 0;
                bs = (data[1] & aiptek->curSetting.stylusButtonLower) != 0 ? 1 : 0;
                pck = (data[1] & aiptek->curSetting.stylusButtonUpper) != 0 ? 1 : 0;

                macro = dv && p && tip && !(data[3] & 1) ? (data[3] >> 1) : -1;
                z = get_unaligned_le16(data + 4);

                if (dv) {
                        /* If the selected tool changed, reset the old
                         * tool key, and set the new one.
                         */
                        if (aiptek->previousToolMode !=
                            aiptek->curSetting.toolMode) {
                                input_report_key(inputdev,
                                                 aiptek->previousToolMode, 0);
                                input_report_key(inputdev,
                                                 aiptek->curSetting.toolMode,
                                                 1);
                                aiptek->previousToolMode =
                                        aiptek->curSetting.toolMode;
                        }
                }

                if (aiptek->lastMacro != -1 && aiptek->lastMacro != macro) {
                        input_report_key(inputdev, macroKeyEvents[aiptek->lastMacro], 0);
                        aiptek->lastMacro = -1;
                }

                if (macro != -1 && macro != aiptek->lastMacro) {
                        input_report_key(inputdev, macroKeyEvents[macro], 1);
                        aiptek->lastMacro = macro;
                }
                input_report_abs(inputdev, ABS_MISC,
                                 p | AIPTEK_REPORT_TOOL_STYLUS);
                input_sync(inputdev);
        }
        /* Report 5s come from the macro keys when pressed by mouse
         */
        else if (data[0] == 5) {
                jitterable = data[1] & 0x1c;

                dv = (data[1] & 0x01) != 0 ? 1 : 0;
                p = (data[1] & 0x02) != 0 ? 1 : 0;
                left = (data[1]& aiptek->curSetting.mouseButtonLeft) != 0 ? 1 : 0;
                right = (data[1] & aiptek->curSetting.mouseButtonRight) != 0 ? 1 : 0;
                middle = (data[1] & aiptek->curSetting.mouseButtonMiddle) != 0 ? 1 : 0;
                macro = dv && p && left && !(data[3] & 1) ? (data[3] >> 1) : 0;

                if (dv) {
                        /* If the selected tool changed, reset the old
                         * tool key, and set the new one.
                         */
                        if (aiptek->previousToolMode !=
                            aiptek->curSetting.toolMode) {
                                input_report_key(inputdev,
                                                 aiptek->previousToolMode, 0);
                                input_report_key(inputdev,
                                                 aiptek->curSetting.toolMode, 1);
                                aiptek->previousToolMode = aiptek->curSetting.toolMode;
                        }
                }

                if (aiptek->lastMacro != -1 && aiptek->lastMacro != macro) {
                        input_report_key(inputdev, macroKeyEvents[aiptek->lastMacro], 0);
                        aiptek->lastMacro = -1;
                }

                if (macro != -1 && macro != aiptek->lastMacro) {
                        input_report_key(inputdev, macroKeyEvents[macro], 1);
                        aiptek->lastMacro = macro;
                }

                input_report_abs(inputdev, ABS_MISC,
                                 p | AIPTEK_REPORT_TOOL_MOUSE);
                input_sync(inputdev);
        }
        /* We have no idea which tool can generate a report 6. Theoretically,
         * neither need to, having been given reports 4 & 5 for such use.
         * However, report 6 is the 'official-looking' report for macroKeys;
         * reports 4 & 5 supposively are used to support unnamed, unknown
         * hat switches (which just so happen to be the macroKeys.)
         */
        else if (data[0] == 6) {
                macro = get_unaligned_le16(data + 1);
                if (macro > 0) {
                        input_report_key(inputdev, macroKeyEvents[macro - 1],
                                         0);
                }
                if (macro < 25) {
                        input_report_key(inputdev, macroKeyEvents[macro + 1],
                                         0);
                }

                /* If the selected tool changed, reset the old
                   tool key, and set the new one.
                */
                if (aiptek->previousToolMode !=
                    aiptek->curSetting.toolMode) {
                        input_report_key(inputdev,
                                         aiptek->previousToolMode, 0);
                        input_report_key(inputdev,
                                         aiptek->curSetting.toolMode,
                                         1);
                        aiptek->previousToolMode =
                                aiptek->curSetting.toolMode;
                }

                input_report_key(inputdev, macroKeyEvents[macro], 1);
                input_report_abs(inputdev, ABS_MISC,
                                 1 | AIPTEK_REPORT_TOOL_UNKNOWN);
                input_sync(inputdev);
        } else {
                dbg("Unknown report %d", data[0]);
        }

        /* Jitter may occur when the user presses a button on the stlyus
         * or the mouse. What we do to prevent that is wait 'x' milliseconds
         * following a 'jitterable' event, which should give the hand some time
         * stabilize itself.
         *
         * We just introduced aiptek->previousJitterable to carry forth the
         * notion that jitter occurs when the button state changes from on to off:
         * a person drawing, holding a button down is not subject to jittering.
         * With that in mind, changing from upper button depressed to lower button
         * WILL transition through a jitter delay.
         */

        if (aiptek->previousJitterable != jitterable &&
            aiptek->curSetting.jitterDelay != 0 && aiptek->inDelay != 1) {
                aiptek->endDelay = jiffies +
                    ((aiptek->curSetting.jitterDelay * HZ) / 1000);
                aiptek->inDelay = 1;
        }
        aiptek->previousJitterable = jitterable;

exit:
        retval = usb_submit_urb(urb, GFP_ATOMIC);
        if (retval != 0) {
                err("%s - usb_submit_urb failed with result %d",
                    __func__, retval);
        }
}

/***********************************************************************
 * These are the USB id's known so far. We do not identify them to
 * specific Aiptek model numbers, because there has been overlaps,
 * use, and reuse of id's in existing models. Certain models have
 * been known to use more than one ID, indicative perhaps of
 * manufacturing revisions. In any event, we consider these
 * IDs to not be model-specific nor unique.
 */
static const struct usb_device_id aiptek_ids[] = {
        {USB_DEVICE(USB_VENDOR_ID_AIPTEK, 0x01)},
        {USB_DEVICE(USB_VENDOR_ID_AIPTEK, 0x10)},
        {USB_DEVICE(USB_VENDOR_ID_AIPTEK, 0x20)},
        {USB_DEVICE(USB_VENDOR_ID_AIPTEK, 0x21)},
        {USB_DEVICE(USB_VENDOR_ID_AIPTEK, 0x22)},
        {USB_DEVICE(USB_VENDOR_ID_AIPTEK, 0x23)},
        {USB_DEVICE(USB_VENDOR_ID_AIPTEK, 0x24)},
        {USB_DEVICE(USB_VENDOR_ID_KYE, 0x5003)},
        {}
};

MODULE_DEVICE_TABLE(usb, aiptek_ids);

/***********************************************************************
 * Open an instance of the tablet driver.
 */
static int aiptek_open(struct input_dev *inputdev)
{
        struct aiptek *aiptek = input_get_drvdata(inputdev);

        aiptek->urb->dev = aiptek->usbdev;
        if (usb_submit_urb(aiptek->urb, GFP_KERNEL) != 0)
                return -EIO;

        return 0;
}

/***********************************************************************
 * Close an instance of the tablet driver.
 */
static void aiptek_close(struct input_dev *inputdev)
{
        struct aiptek *aiptek = input_get_drvdata(inputdev);

        usb_kill_urb(aiptek->urb);
}

/***********************************************************************
 * aiptek_set_report and aiptek_get_report() are borrowed from Linux 2.4.x,
 * where they were known as usb_set_report and usb_get_report.
 */
static int
aiptek_set_report(struct aiptek *aiptek,
                  unsigned char report_type,
                  unsigned char report_id, void *buffer, int size)
{
        return usb_control_msg(aiptek->usbdev,
                               usb_sndctrlpipe(aiptek->usbdev, 0),
                               USB_REQ_SET_REPORT,
                               USB_TYPE_CLASS | USB_RECIP_INTERFACE |
                               USB_DIR_OUT, (report_type << 8) + report_id,
                               aiptek->ifnum, buffer, size, 5000);
}

static int
aiptek_get_report(struct aiptek *aiptek,
                  unsigned char report_type,
                  unsigned char report_id, void *buffer, int size)
{
        return usb_control_msg(aiptek->usbdev,
                               usb_rcvctrlpipe(aiptek->usbdev, 0),
                               USB_REQ_GET_REPORT,
                               USB_TYPE_CLASS | USB_RECIP_INTERFACE |
                               USB_DIR_IN, (report_type << 8) + report_id,
                               aiptek->ifnum, buffer, size, 5000);
}

/***********************************************************************
 * Send a command to the tablet.
 */
static int
aiptek_command(struct aiptek *aiptek, unsigned char command, unsigned char data)
{
        const int sizeof_buf = 3 * sizeof(u8);
        int ret;
        u8 *buf;

        buf = kmalloc(sizeof_buf, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        buf[0] = 2;
        buf[1] = command;
        buf[2] = data;

        if ((ret =
             aiptek_set_report(aiptek, 3, 2, buf, sizeof_buf)) != sizeof_buf) {
                dbg("aiptek_program: failed, tried to send: 0x%02x 0x%02x",
                    command, data);
        }
        kfree(buf);
        return ret < 0 ? ret : 0;
}

/***********************************************************************
 * Retrieve information from the tablet. Querying info is defined as first
 * sending the {command,data} sequence as a command, followed by a wait
 * (aka, "programmaticDelay") and then a "read" request.
 */
static int
aiptek_query(struct aiptek *aiptek, unsigned char command, unsigned char data)
{
        const int sizeof_buf = 3 * sizeof(u8);
        int ret;
        u8 *buf;

        buf = kmalloc(sizeof_buf, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        buf[0] = 2;
        buf[1] = command;
        buf[2] = data;

        if (aiptek_command(aiptek, command, data) != 0) {
                kfree(buf);
                return -EIO;
        }
        msleep(aiptek->curSetting.programmableDelay);

        if ((ret =
             aiptek_get_report(aiptek, 3, 2, buf, sizeof_buf)) != sizeof_buf) {
                dbg("aiptek_query failed: returned 0x%02x 0x%02x 0x%02x",
                    buf[0], buf[1], buf[2]);
                ret = -EIO;
        } else {
                ret = get_unaligned_le16(buf + 1);
        }
        kfree(buf);
        return ret;
}

/***********************************************************************
 * Program the tablet into either absolute or relative mode.
 * We also get information about the tablet's size.
 */
static int aiptek_program_tablet(struct aiptek *aiptek)
{
        int ret;
        /* Execute Resolution500LPI */
        if ((ret = aiptek_command(aiptek, 0x18, 0x04)) < 0)
                return ret;

        /* Query getModelCode */
        if ((ret = aiptek_query(aiptek, 0x02, 0x00)) < 0)
                return ret;
        aiptek->features.modelCode = ret & 0xff;

        /* Query getODMCode */
        if ((ret = aiptek_query(aiptek, 0x03, 0x00)) < 0)
                return ret;
        aiptek->features.odmCode = ret;

        /* Query getFirmwareCode */
        if ((ret = aiptek_query(aiptek, 0x04, 0x00)) < 0)
                return ret;
        aiptek->features.firmwareCode = ret;

        /* Query getXextension */
        if ((ret = aiptek_query(aiptek, 0x01, 0x00)) < 0)
                return ret;
        input_set_abs_params(aiptek->inputdev, ABS_X, 0, ret - 1, 0, 0);

        /* Query getYextension */
        if ((ret = aiptek_query(aiptek, 0x01, 0x01)) < 0)
                return ret;
        input_set_abs_params(aiptek->inputdev, ABS_Y, 0, ret - 1, 0, 0);

        /* Query getPressureLevels */
        if ((ret = aiptek_query(aiptek, 0x08, 0x00)) < 0)
                return ret;
        input_set_abs_params(aiptek->inputdev, ABS_PRESSURE, 0, ret - 1, 0, 0);

        /* Depending on whether we are in absolute or relative mode, we will
         * do a switchToTablet(absolute) or switchToMouse(relative) command.
         */
        if (aiptek->curSetting.coordinateMode ==
            AIPTEK_COORDINATE_ABSOLUTE_MODE) {
                /* Execute switchToTablet */
                if ((ret = aiptek_command(aiptek, 0x10, 0x01)) < 0) {
                        return ret;
                }
        } else {
                /* Execute switchToMouse */
                if ((ret = aiptek_command(aiptek, 0x10, 0x00)) < 0) {
                        return ret;
                }
        }

        /* Enable the macro keys */
        if ((ret = aiptek_command(aiptek, 0x11, 0x02)) < 0)
                return ret;
#if 0
        /* Execute FilterOn */
        if ((ret = aiptek_command(aiptek, 0x17, 0x00)) < 0)
                return ret;
#endif

        /* Execute AutoGainOn */
        if ((ret = aiptek_command(aiptek, 0x12, 0xff)) < 0)
                return ret;

        /* Reset the eventCount, so we track events from last (re)programming
         */
        aiptek->diagnostic = AIPTEK_DIAGNOSTIC_NA;
        aiptek->eventCount = 0;

        return 0;
}

/***********************************************************************
 * Sysfs functions. Sysfs prefers that individually-tunable parameters
 * exist in their separate pseudo-files. Summary data that is immutable
 * may exist in a singular file so long as you don't define a writeable
 * interface.
 */

/***********************************************************************
 * support the 'size' file -- display support
 */
static ssize_t show_tabletSize(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%dx%d\n",
                        input_abs_get_max(aiptek->inputdev, ABS_X) + 1,
                        input_abs_get_max(aiptek->inputdev, ABS_Y) + 1);
}

/* These structs define the sysfs files, param #1 is the name of the
 * file, param 2 is the file permissions, param 3 & 4 are to the
 * output generator and input parser routines. Absence of a routine is
 * permitted -- it only means can't either 'cat' the file, or send data
 * to it.
 */
static DEVICE_ATTR(size, S_IRUGO, show_tabletSize, NULL);

/***********************************************************************
 * support routines for the 'pointer_mode' file. Note that this file
 * both displays current setting and allows reprogramming.
 */
static struct aiptek_map pointer_mode_map[] = {
        { "stylus",     AIPTEK_POINTER_ONLY_STYLUS_MODE },
        { "mouse",      AIPTEK_POINTER_ONLY_MOUSE_MODE },
        { "either",     AIPTEK_POINTER_EITHER_MODE },
        { NULL,         AIPTEK_INVALID_VALUE }
};

static ssize_t show_tabletPointerMode(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%s\n",
                        map_val_to_str(pointer_mode_map,
                                        aiptek->curSetting.pointerMode));
}

static ssize_t
store_tabletPointerMode(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        int new_mode = map_str_to_val(pointer_mode_map, buf, count);

        if (new_mode == AIPTEK_INVALID_VALUE)
                return -EINVAL;

        aiptek->newSetting.pointerMode = new_mode;
        return count;
}

static DEVICE_ATTR(pointer_mode,
                   S_IRUGO | S_IWUSR,
                   show_tabletPointerMode, store_tabletPointerMode);

/***********************************************************************
 * support routines for the 'coordinate_mode' file. Note that this file
 * both displays current setting and allows reprogramming.
 */

static struct aiptek_map coordinate_mode_map[] = {
        { "absolute",   AIPTEK_COORDINATE_ABSOLUTE_MODE },
        { "relative",   AIPTEK_COORDINATE_RELATIVE_MODE },
        { NULL,         AIPTEK_INVALID_VALUE }
};

static ssize_t show_tabletCoordinateMode(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%s\n",
                        map_val_to_str(coordinate_mode_map,
                                        aiptek->curSetting.coordinateMode));
}

static ssize_t
store_tabletCoordinateMode(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        int new_mode = map_str_to_val(coordinate_mode_map, buf, count);

        if (new_mode == AIPTEK_INVALID_VALUE)
                return -EINVAL;

        aiptek->newSetting.coordinateMode = new_mode;
        return count;
}

static DEVICE_ATTR(coordinate_mode,
                   S_IRUGO | S_IWUSR,
                   show_tabletCoordinateMode, store_tabletCoordinateMode);

/***********************************************************************
 * support routines for the 'tool_mode' file. Note that this file
 * both displays current setting and allows reprogramming.
 */

static struct aiptek_map tool_mode_map[] = {
        { "mouse",      AIPTEK_TOOL_BUTTON_MOUSE_MODE },
        { "eraser",     AIPTEK_TOOL_BUTTON_ERASER_MODE },
        { "pencil",     AIPTEK_TOOL_BUTTON_PENCIL_MODE },
        { "pen",        AIPTEK_TOOL_BUTTON_PEN_MODE },
        { "brush",      AIPTEK_TOOL_BUTTON_BRUSH_MODE },
        { "airbrush",   AIPTEK_TOOL_BUTTON_AIRBRUSH_MODE },
        { "lens",       AIPTEK_TOOL_BUTTON_LENS_MODE },
        { NULL,         AIPTEK_INVALID_VALUE }
};

static ssize_t show_tabletToolMode(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%s\n",
                        map_val_to_str(tool_mode_map,
                                        aiptek->curSetting.toolMode));
}

static ssize_t
store_tabletToolMode(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        int new_mode = map_str_to_val(tool_mode_map, buf, count);

        if (new_mode == AIPTEK_INVALID_VALUE)
                return -EINVAL;

        aiptek->newSetting.toolMode = new_mode;
        return count;
}

static DEVICE_ATTR(tool_mode,
                   S_IRUGO | S_IWUSR,
                   show_tabletToolMode, store_tabletToolMode);

/***********************************************************************
 * support routines for the 'xtilt' file. Note that this file
 * both displays current setting and allows reprogramming.
 */
static ssize_t show_tabletXtilt(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        if (aiptek->curSetting.xTilt == AIPTEK_TILT_DISABLE) {
                return snprintf(buf, PAGE_SIZE, "disable\n");
        } else {
                return snprintf(buf, PAGE_SIZE, "%d\n",
                                aiptek->curSetting.xTilt);
        }
}

static ssize_t
store_tabletXtilt(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        long x;

        if (strict_strtol(buf, 10, &x)) {
                size_t len = buf[count - 1] == '\n' ? count - 1 : count;

                if (strncmp(buf, "disable", len))
                        return -EINVAL;

                aiptek->newSetting.xTilt = AIPTEK_TILT_DISABLE;
        } else {
                if (x < AIPTEK_TILT_MIN || x > AIPTEK_TILT_MAX)
                        return -EINVAL;

                aiptek->newSetting.xTilt = x;
        }

        return count;
}

static DEVICE_ATTR(xtilt,
                   S_IRUGO | S_IWUSR, show_tabletXtilt, store_tabletXtilt);

/***********************************************************************
 * support routines for the 'ytilt' file. Note that this file
 * both displays current setting and allows reprogramming.
 */
static ssize_t show_tabletYtilt(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        if (aiptek->curSetting.yTilt == AIPTEK_TILT_DISABLE) {
                return snprintf(buf, PAGE_SIZE, "disable\n");
        } else {
                return snprintf(buf, PAGE_SIZE, "%d\n",
                                aiptek->curSetting.yTilt);
        }
}

static ssize_t
store_tabletYtilt(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        long y;

        if (strict_strtol(buf, 10, &y)) {
                size_t len = buf[count - 1] == '\n' ? count - 1 : count;

                if (strncmp(buf, "disable", len))
                        return -EINVAL;

                aiptek->newSetting.yTilt = AIPTEK_TILT_DISABLE;
        } else {
                if (y < AIPTEK_TILT_MIN || y > AIPTEK_TILT_MAX)
                        return -EINVAL;

                aiptek->newSetting.yTilt = y;
        }

        return count;
}

static DEVICE_ATTR(ytilt,
                   S_IRUGO | S_IWUSR, show_tabletYtilt, store_tabletYtilt);

/***********************************************************************
 * support routines for the 'jitter' file. Note that this file
 * both displays current setting and allows reprogramming.
 */
static ssize_t show_tabletJitterDelay(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%d\n", aiptek->curSetting.jitterDelay);
}

static ssize_t
store_tabletJitterDelay(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        long j;

        if (strict_strtol(buf, 10, &j))
                return -EINVAL;

        aiptek->newSetting.jitterDelay = (int)j;
        return count;
}

static DEVICE_ATTR(jitter,
                   S_IRUGO | S_IWUSR,
                   show_tabletJitterDelay, store_tabletJitterDelay);

/***********************************************************************
 * support routines for the 'delay' file. Note that this file
 * both displays current setting and allows reprogramming.
 */
static ssize_t show_tabletProgrammableDelay(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%d\n",
                        aiptek->curSetting.programmableDelay);
}

static ssize_t
store_tabletProgrammableDelay(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        long d;

        if (strict_strtol(buf, 10, &d))
                return -EINVAL;

        aiptek->newSetting.programmableDelay = (int)d;
        return count;
}

static DEVICE_ATTR(delay,
                   S_IRUGO | S_IWUSR,
                   show_tabletProgrammableDelay, store_tabletProgrammableDelay);

/***********************************************************************
 * support routines for the 'event_count' file. Note that this file
 * only displays current setting.
 */
static ssize_t show_tabletEventsReceived(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%ld\n", aiptek->eventCount);
}

static DEVICE_ATTR(event_count, S_IRUGO, show_tabletEventsReceived, NULL);

/***********************************************************************
 * support routines for the 'diagnostic' file. Note that this file
 * only displays current setting.
 */
static ssize_t show_tabletDiagnosticMessage(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        char *retMsg;

        switch (aiptek->diagnostic) {
        case AIPTEK_DIAGNOSTIC_NA:
                retMsg = "no errors\n";
                break;

        case AIPTEK_DIAGNOSTIC_SENDING_RELATIVE_IN_ABSOLUTE:
                retMsg = "Error: receiving relative reports\n";
                break;

        case AIPTEK_DIAGNOSTIC_SENDING_ABSOLUTE_IN_RELATIVE:
                retMsg = "Error: receiving absolute reports\n";
                break;

        case AIPTEK_DIAGNOSTIC_TOOL_DISALLOWED:
                if (aiptek->curSetting.pointerMode ==
                    AIPTEK_POINTER_ONLY_MOUSE_MODE) {
                        retMsg = "Error: receiving stylus reports\n";
                } else {
                        retMsg = "Error: receiving mouse reports\n";
                }
                break;

        default:
                return 0;
        }
        return snprintf(buf, PAGE_SIZE, retMsg);
}

static DEVICE_ATTR(diagnostic, S_IRUGO, show_tabletDiagnosticMessage, NULL);

/***********************************************************************
 * support routines for the 'stylus_upper' file. Note that this file
 * both displays current setting and allows for setting changing.
 */

static struct aiptek_map stylus_button_map[] = {
        { "upper",      AIPTEK_STYLUS_UPPER_BUTTON },
        { "lower",      AIPTEK_STYLUS_LOWER_BUTTON },
        { NULL,         AIPTEK_INVALID_VALUE }
};

static ssize_t show_tabletStylusUpper(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%s\n",
                        map_val_to_str(stylus_button_map,
                                        aiptek->curSetting.stylusButtonUpper));
}

static ssize_t
store_tabletStylusUpper(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        int new_button = map_str_to_val(stylus_button_map, buf, count);

        if (new_button == AIPTEK_INVALID_VALUE)
                return -EINVAL;

        aiptek->newSetting.stylusButtonUpper = new_button;
        return count;
}

static DEVICE_ATTR(stylus_upper,
                   S_IRUGO | S_IWUSR,
                   show_tabletStylusUpper, store_tabletStylusUpper);

/***********************************************************************
 * support routines for the 'stylus_lower' file. Note that this file
 * both displays current setting and allows for setting changing.
 */

static ssize_t show_tabletStylusLower(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%s\n",
                        map_val_to_str(stylus_button_map,
                                        aiptek->curSetting.stylusButtonLower));
}

static ssize_t
store_tabletStylusLower(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        int new_button = map_str_to_val(stylus_button_map, buf, count);

        if (new_button == AIPTEK_INVALID_VALUE)
                return -EINVAL;

        aiptek->newSetting.stylusButtonLower = new_button;
        return count;
}

static DEVICE_ATTR(stylus_lower,
                   S_IRUGO | S_IWUSR,
                   show_tabletStylusLower, store_tabletStylusLower);

/***********************************************************************
 * support routines for the 'mouse_left' file. Note that this file
 * both displays current setting and allows for setting changing.
 */

static struct aiptek_map mouse_button_map[] = {
        { "left",       AIPTEK_MOUSE_LEFT_BUTTON },
        { "middle",     AIPTEK_MOUSE_MIDDLE_BUTTON },
        { "right",      AIPTEK_MOUSE_RIGHT_BUTTON },
        { NULL,         AIPTEK_INVALID_VALUE }
};

static ssize_t show_tabletMouseLeft(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%s\n",
                        map_val_to_str(mouse_button_map,
                                        aiptek->curSetting.mouseButtonLeft));
}

static ssize_t
store_tabletMouseLeft(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        int new_button = map_str_to_val(mouse_button_map, buf, count);

        if (new_button == AIPTEK_INVALID_VALUE)
                return -EINVAL;

        aiptek->newSetting.mouseButtonLeft = new_button;
        return count;
}

static DEVICE_ATTR(mouse_left,
                   S_IRUGO | S_IWUSR,
                   show_tabletMouseLeft, store_tabletMouseLeft);

/***********************************************************************
 * support routines for the 'mouse_middle' file. Note that this file
 * both displays current setting and allows for setting changing.
 */
static ssize_t show_tabletMouseMiddle(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%s\n",
                        map_val_to_str(mouse_button_map,
                                        aiptek->curSetting.mouseButtonMiddle));
}

static ssize_t
store_tabletMouseMiddle(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        int new_button = map_str_to_val(mouse_button_map, buf, count);

        if (new_button == AIPTEK_INVALID_VALUE)
                return -EINVAL;

        aiptek->newSetting.mouseButtonMiddle = new_button;
        return count;
}

static DEVICE_ATTR(mouse_middle,
                   S_IRUGO | S_IWUSR,
                   show_tabletMouseMiddle, store_tabletMouseMiddle);

/***********************************************************************
 * support routines for the 'mouse_right' file. Note that this file
 * both displays current setting and allows for setting changing.
 */
static ssize_t show_tabletMouseRight(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%s\n",
                        map_val_to_str(mouse_button_map,
                                        aiptek->curSetting.mouseButtonRight));
}

static ssize_t
store_tabletMouseRight(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        int new_button = map_str_to_val(mouse_button_map, buf, count);

        if (new_button == AIPTEK_INVALID_VALUE)
                return -EINVAL;

        aiptek->newSetting.mouseButtonRight = new_button;
        return count;
}

static DEVICE_ATTR(mouse_right,
                   S_IRUGO | S_IWUSR,
                   show_tabletMouseRight, store_tabletMouseRight);

/***********************************************************************
 * support routines for the 'wheel' file. Note that this file
 * both displays current setting and allows for setting changing.
 */
static ssize_t show_tabletWheel(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        if (aiptek->curSetting.wheel == AIPTEK_WHEEL_DISABLE) {
                return snprintf(buf, PAGE_SIZE, "disable\n");
        } else {
                return snprintf(buf, PAGE_SIZE, "%d\n",
                                aiptek->curSetting.wheel);
        }
}

static ssize_t
store_tabletWheel(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);
        long w;

        if (strict_strtol(buf, 10, &w)) return -EINVAL;

        aiptek->newSetting.wheel = (int)w;
        return count;
}

static DEVICE_ATTR(wheel,
                   S_IRUGO | S_IWUSR, show_tabletWheel, store_tabletWheel);

/***********************************************************************
 * support routines for the 'execute' file. Note that this file
 * both displays current setting and allows for setting changing.
 */
static ssize_t show_tabletExecute(struct device *dev, struct device_attribute *attr, char *buf)
{
        /* There is nothing useful to display, so a one-line manual
         * is in order...
         */
        return snprintf(buf, PAGE_SIZE,
                        "Write anything to this file to program your tablet.\n");
}

static ssize_t
store_tabletExecute(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        /* We do not care what you write to this file. Merely the action
         * of writing to this file triggers a tablet reprogramming.
         */
        memcpy(&aiptek->curSetting, &aiptek->newSetting,
               sizeof(struct aiptek_settings));

        if (aiptek_program_tablet(aiptek) < 0)
                return -EIO;

        return count;
}

static DEVICE_ATTR(execute,
                   S_IRUGO | S_IWUSR, show_tabletExecute, store_tabletExecute);

/***********************************************************************
 * support routines for the 'odm_code' file. Note that this file
 * only displays current setting.
 */
static ssize_t show_tabletODMCode(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "0x%04x\n", aiptek->features.odmCode);
}

static DEVICE_ATTR(odm_code, S_IRUGO, show_tabletODMCode, NULL);

/***********************************************************************
 * support routines for the 'model_code' file. Note that this file
 * only displays current setting.
 */
static ssize_t show_tabletModelCode(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "0x%04x\n", aiptek->features.modelCode);
}

static DEVICE_ATTR(model_code, S_IRUGO, show_tabletModelCode, NULL);

/***********************************************************************
 * support routines for the 'firmware_code' file. Note that this file
 * only displays current setting.
 */
static ssize_t show_firmwareCode(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct aiptek *aiptek = dev_get_drvdata(dev);

        return snprintf(buf, PAGE_SIZE, "%04x\n",
                        aiptek->features.firmwareCode);
}

static DEVICE_ATTR(firmware_code, S_IRUGO, show_firmwareCode, NULL);

static struct attribute *aiptek_attributes[] = {
        &dev_attr_size.attr,
        &dev_attr_pointer_mode.attr,
        &dev_attr_coordinate_mode.attr,
        &dev_attr_tool_mode.attr,
        &dev_attr_xtilt.attr,
        &dev_attr_ytilt.attr,
        &dev_attr_jitter.attr,
        &dev_attr_delay.attr,
        &dev_attr_event_count.attr,
        &dev_attr_diagnostic.attr,
        &dev_attr_odm_code.attr,
        &dev_attr_model_code.attr,
        &dev_attr_firmware_code.attr,
        &dev_attr_stylus_lower.attr,
        &dev_attr_stylus_upper.attr,
        &dev_attr_mouse_left.attr,
        &dev_attr_mouse_middle.attr,
        &dev_attr_mouse_right.attr,
        &dev_attr_wheel.attr,
        &dev_attr_execute.attr,
        NULL
};

static struct attribute_group aiptek_attribute_group = {
        .attrs  = aiptek_attributes,
};

/***********************************************************************
 * This routine is called when a tablet has been identified. It basically
 * sets up the tablet and the driver's internal structures.
 */
static int
aiptek_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
        struct usb_device *usbdev = interface_to_usbdev(intf);
        struct usb_endpoint_descriptor *endpoint;
        struct aiptek *aiptek;
        struct input_dev *inputdev;
        int i;
        int speeds[] = { 0,
                AIPTEK_PROGRAMMABLE_DELAY_50,
                AIPTEK_PROGRAMMABLE_DELAY_400,
                AIPTEK_PROGRAMMABLE_DELAY_25,
                AIPTEK_PROGRAMMABLE_DELAY_100,
                AIPTEK_PROGRAMMABLE_DELAY_200,
                AIPTEK_PROGRAMMABLE_DELAY_300
        };
        int err = -ENOMEM;

        /* programmableDelay is where the command-line specified
         * delay is kept. We make it the first element of speeds[],
         * so therefore, your override speed is tried first, then the
         * remainder. Note that the default value of 400ms will be tried
         * if you do not specify any command line parameter.
         */
        speeds[0] = programmableDelay;

        aiptek = kzalloc(sizeof(struct aiptek), GFP_KERNEL);
        inputdev = input_allocate_device();
        if (!aiptek || !inputdev) {
                dev_warn(&intf->dev,
                         "cannot allocate memory or input device\n");
                goto fail1;
        }

        aiptek->data = usb_alloc_coherent(usbdev, AIPTEK_PACKET_LENGTH,
                                          GFP_ATOMIC, &aiptek->data_dma);
        if (!aiptek->data) {
                dev_warn(&intf->dev, "cannot allocate usb buffer\n");
                goto fail1;
        }

        aiptek->urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!aiptek->urb) {
                dev_warn(&intf->dev, "cannot allocate urb\n");
                goto fail2;
        }

        aiptek->inputdev = inputdev;
        aiptek->usbdev = usbdev;
        aiptek->ifnum = intf->altsetting[0].desc.bInterfaceNumber;
        aiptek->inDelay = 0;
        aiptek->endDelay = 0;
        aiptek->previousJitterable = 0;
        aiptek->lastMacro = -1;

        /* Set up the curSettings struct. Said struct contains the current
         * programmable parameters. The newSetting struct contains changes
         * the user makes to the settings via the sysfs interface. Those
         * changes are not "committed" to curSettings until the user
         * writes to the sysfs/.../execute file.
         */
        aiptek->curSetting.pointerMode = AIPTEK_POINTER_EITHER_MODE;
        aiptek->curSetting.coordinateMode = AIPTEK_COORDINATE_ABSOLUTE_MODE;
        aiptek->curSetting.toolMode = AIPTEK_TOOL_BUTTON_PEN_MODE;
        aiptek->curSetting.xTilt = AIPTEK_TILT_DISABLE;
        aiptek->curSetting.yTilt = AIPTEK_TILT_DISABLE;
        aiptek->curSetting.mouseButtonLeft = AIPTEK_MOUSE_LEFT_BUTTON;
        aiptek->curSetting.mouseButtonMiddle = AIPTEK_MOUSE_MIDDLE_BUTTON;
        aiptek->curSetting.mouseButtonRight = AIPTEK_MOUSE_RIGHT_BUTTON;
        aiptek->curSetting.stylusButtonUpper = AIPTEK_STYLUS_UPPER_BUTTON;
        aiptek->curSetting.stylusButtonLower = AIPTEK_STYLUS_LOWER_BUTTON;
        aiptek->curSetting.jitterDelay = jitterDelay;
        aiptek->curSetting.programmableDelay = programmableDelay;

        /* Both structs should have equivalent settings
         */
        aiptek->newSetting = aiptek->curSetting;

        /* Determine the usb devices' physical path.
         * Asketh not why we always pretend we're using "../input0",
         * but I suspect this will have to be refactored one
         * day if a single USB device can be a keyboard & a mouse
         * & a tablet, and the inputX number actually will tell
         * us something...
         */
        usb_make_path(usbdev, aiptek->features.usbPath,
                        sizeof(aiptek->features.usbPath));
        strlcat(aiptek->features.usbPath, "/input0",
                sizeof(aiptek->features.usbPath));

        /* Set up client data, pointers to open and close routines
         * for the input device.
         */
        inputdev->name = "Aiptek";
        inputdev->phys = aiptek->features.usbPath;
        usb_to_input_id(usbdev, &inputdev->id);
        inputdev->dev.parent = &intf->dev;

        input_set_drvdata(inputdev, aiptek);

        inputdev->open = aiptek_open;
        inputdev->close = aiptek_close;

        /* Now program the capacities of the tablet, in terms of being
         * an input device.
         */
        for (i = 0; i < ARRAY_SIZE(eventTypes); ++i)
                __set_bit(eventTypes[i], inputdev->evbit);

        for (i = 0; i < ARRAY_SIZE(absEvents); ++i)
                __set_bit(absEvents[i], inputdev->absbit);

        for (i = 0; i < ARRAY_SIZE(relEvents); ++i)
                __set_bit(relEvents[i], inputdev->relbit);

        __set_bit(MSC_SERIAL, inputdev->mscbit);

        /* Set up key and button codes */
        for (i = 0; i < ARRAY_SIZE(buttonEvents); ++i)
                __set_bit(buttonEvents[i], inputdev->keybit);

        for (i = 0; i < ARRAY_SIZE(macroKeyEvents); ++i)
                __set_bit(macroKeyEvents[i], inputdev->keybit);

        /*
         * Program the input device coordinate capacities. We do not yet
         * know what maximum X, Y, and Z values are, so we're putting fake
         * values in. Later, we'll ask the tablet to put in the correct
         * values.
         */
        input_set_abs_params(inputdev, ABS_X, 0, 2999, 0, 0);
        input_set_abs_params(inputdev, ABS_Y, 0, 2249, 0, 0);
        input_set_abs_params(inputdev, ABS_PRESSURE, 0, 511, 0, 0);
        input_set_abs_params(inputdev, ABS_TILT_X, AIPTEK_TILT_MIN, AIPTEK_TILT_MAX, 0, 0);
        input_set_abs_params(inputdev, ABS_TILT_Y, AIPTEK_TILT_MIN, AIPTEK_TILT_MAX, 0, 0);
        input_set_abs_params(inputdev, ABS_WHEEL, AIPTEK_WHEEL_MIN, AIPTEK_WHEEL_MAX - 1, 0, 0);

        endpoint = &intf->altsetting[0].endpoint[0].desc;

        /* Go set up our URB, which is called when the tablet receives
         * input.
         */
        usb_fill_int_urb(aiptek->urb,
                         aiptek->usbdev,
                         usb_rcvintpipe(aiptek->usbdev,
                                        endpoint->bEndpointAddress),
                         aiptek->data, 8, aiptek_irq, aiptek,
                         endpoint->bInterval);

        aiptek->urb->transfer_dma = aiptek->data_dma;
        aiptek->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

        /* Program the tablet. This sets the tablet up in the mode
         * specified in newSetting, and also queries the tablet's
         * physical capacities.
         *
         * Sanity check: if a tablet doesn't like the slow programmatic
         * delay, we often get sizes of 0x0. Let's use that as an indicator
         * to try faster delays, up to 25 ms. If that logic fails, well, you'll
         * have to explain to us how your tablet thinks it's 0x0, and yet that's
         * not an error :-)
         */

        for (i = 0; i < ARRAY_SIZE(speeds); ++i) {
                aiptek->curSetting.programmableDelay = speeds[i];
                (void)aiptek_program_tablet(aiptek);
                if (input_abs_get_max(aiptek->inputdev, ABS_X) > 0) {
                        dev_info(&intf->dev,
                                 "Aiptek using %d ms programming speed\n",
                                 aiptek->curSetting.programmableDelay);
                        break;
                }
        }

        /* Murphy says that some day someone will have a tablet that fails the
           above test. That's you, Frederic Rodrigo */
        if (i == ARRAY_SIZE(speeds)) {
                dev_info(&intf->dev,
                         "Aiptek tried all speeds, no sane response\n");
                goto fail2;
        }

        /* Associate this driver's struct with the usb interface.
         */
        usb_set_intfdata(intf, aiptek);

        /* Set up the sysfs files
         */
        err = sysfs_create_group(&intf->dev.kobj, &aiptek_attribute_group);
        if (err) {
                dev_warn(&intf->dev, "cannot create sysfs group err: %d\n",
                         err);
                goto fail3;
        }

        /* Register the tablet as an Input Device
         */
        err = input_register_device(aiptek->inputdev);
        if (err) {
                dev_warn(&intf->dev,
                         "input_register_device returned err: %d\n", err);
                goto fail4;
        }
        return 0;

 fail4: sysfs_remove_group(&intf->dev.kobj, &aiptek_attribute_group);
 fail3: usb_free_urb(aiptek->urb);
 fail2: usb_free_coherent(usbdev, AIPTEK_PACKET_LENGTH, aiptek->data,
                          aiptek->data_dma);
 fail1: usb_set_intfdata(intf, NULL);
        input_free_device(inputdev);
        kfree(aiptek);
        return err;
}

/***********************************************************************
 * Deal with tablet disconnecting from the system.
 */
static void aiptek_disconnect(struct usb_interface *intf)
{
        struct aiptek *aiptek = usb_get_intfdata(intf);

        /* Disassociate driver's struct with usb interface
         */
        usb_set_intfdata(intf, NULL);
        if (aiptek != NULL) {
                /* Free & unhook everything from the system.
                 */
                usb_kill_urb(aiptek->urb);
                input_unregister_device(aiptek->inputdev);
                sysfs_remove_group(&intf->dev.kobj, &aiptek_attribute_group);
                usb_free_urb(aiptek->urb);
                usb_free_coherent(interface_to_usbdev(intf),
                                  AIPTEK_PACKET_LENGTH,
                                  aiptek->data, aiptek->data_dma);
                kfree(aiptek);
        }
}

static struct usb_driver aiptek_driver = {
        .name = "aiptek",
        .probe = aiptek_probe,
        .disconnect = aiptek_disconnect,
        .id_table = aiptek_ids,
};

static int __init aiptek_init(void)
{
        int result = usb_register(&aiptek_driver);
        if (result == 0) {
                printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
                       DRIVER_DESC "\n");
                printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_AUTHOR "\n");
        }
        return result;
}

static void __exit aiptek_exit(void)
{
        usb_deregister(&aiptek_driver);
}

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

module_param(programmableDelay, int, 0);
MODULE_PARM_DESC(programmableDelay, "delay used during tablet programming");
module_param(jitterDelay, int, 0);
MODULE_PARM_DESC(jitterDelay, "stylus/mouse settlement delay");

module_init(aiptek_init);
module_exit(aiptek_exit);