/*
 * ALPS touchpad PS/2 mouse driver
 *
 * Copyright (c) 2003 Neil Brown <neilb@cse.unsw.edu.au>
 * Copyright (c) 2003-2005 Peter Osterlund <petero2@telia.com>
 * Copyright (c) 2004 Dmitry Torokhov <dtor@mail.ru>
 * Copyright (c) 2005 Vojtech Pavlik <vojtech@suse.cz>
 * Copyright (c) 2009 Sebastian Kapfer <sebastian_kapfer@gmx.net>
 *
 * ALPS detection, tap switching and status querying info is taken from
 * tpconfig utility (by C. Scott Ananian and Bruce Kall).
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/input.h>
#include <linux/serio.h>
#include <linux/libps2.h>

#include "psmouse.h"
#include "alps.h"

#undef DEBUG
#ifdef DEBUG
#define dbg(format, arg...) printk(KERN_INFO "alps.c: " format "\n", ## arg)
#else
#define dbg(format, arg...) do {} while (0)
#endif

#define ALPS_OLDPROTO           0x01    /* old style input */
#define ALPS_DUALPOINT          0x02    /* touchpad has trackstick */
#define ALPS_PASS               0x04    /* device has a pass-through port */

#define ALPS_WHEEL              0x08    /* hardware wheel present */
#define ALPS_FW_BK_1            0x10    /* front & back buttons present */
#define ALPS_FW_BK_2            0x20    /* front & back buttons present */
#define ALPS_FOUR_BUTTONS       0x40    /* 4 direction button present */
#define ALPS_PS2_INTERLEAVED    0x80    /* 3-byte PS/2 packet interleaved with
                                           6-byte ALPS packet */

static const struct alps_model_info alps_model_data[] = {
        { { 0x32, 0x02, 0x14 }, 0xf8, 0xf8, ALPS_PASS | ALPS_DUALPOINT }, /* Toshiba Salellite Pro M10 */
        { { 0x33, 0x02, 0x0a }, 0x88, 0xf8, ALPS_OLDPROTO },              /* UMAX-530T */
        { { 0x53, 0x02, 0x0a }, 0xf8, 0xf8, 0 },
        { { 0x53, 0x02, 0x14 }, 0xf8, 0xf8, 0 },
        { { 0x60, 0x03, 0xc8 }, 0xf8, 0xf8, 0 },                          /* HP ze1115 */
        { { 0x63, 0x02, 0x0a }, 0xf8, 0xf8, 0 },
        { { 0x63, 0x02, 0x14 }, 0xf8, 0xf8, 0 },
        { { 0x63, 0x02, 0x28 }, 0xf8, 0xf8, ALPS_FW_BK_2 },               /* Fujitsu Siemens S6010 */
        { { 0x63, 0x02, 0x3c }, 0x8f, 0x8f, ALPS_WHEEL },                 /* Toshiba Satellite S2400-103 */
        { { 0x63, 0x02, 0x50 }, 0xef, 0xef, ALPS_FW_BK_1 },               /* NEC Versa L320 */
        { { 0x63, 0x02, 0x64 }, 0xf8, 0xf8, 0 },
        { { 0x63, 0x03, 0xc8 }, 0xf8, 0xf8, ALPS_PASS | ALPS_DUALPOINT }, /* Dell Latitude D800 */
        { { 0x73, 0x00, 0x0a }, 0xf8, 0xf8, ALPS_DUALPOINT },             /* ThinkPad R61 8918-5QG */
        { { 0x73, 0x02, 0x0a }, 0xf8, 0xf8, 0 },
        { { 0x73, 0x02, 0x14 }, 0xf8, 0xf8, ALPS_FW_BK_2 },               /* Ahtec Laptop */
        { { 0x20, 0x02, 0x0e }, 0xf8, 0xf8, ALPS_PASS | ALPS_DUALPOINT }, /* XXX */
        { { 0x22, 0x02, 0x0a }, 0xf8, 0xf8, ALPS_PASS | ALPS_DUALPOINT },
        { { 0x22, 0x02, 0x14 }, 0xff, 0xff, ALPS_PASS | ALPS_DUALPOINT }, /* Dell Latitude D600 */
        /* Dell Latitude E5500, E6400, E6500, Precision M4400 */
        { { 0x62, 0x02, 0x14 }, 0xcf, 0xcf,
                ALPS_PASS | ALPS_DUALPOINT | ALPS_PS2_INTERLEAVED },
        { { 0x73, 0x02, 0x50 }, 0xcf, 0xcf, ALPS_FOUR_BUTTONS },          /* Dell Vostro 1400 */
};

/*
 * XXX - this entry is suspicious. First byte has zero lower nibble,
 * which is what a normal mouse would report. Also, the value 0x0e
 * isn't valid per PS/2 spec.
 */

/*
 * PS/2 packet format
 *
 * byte 0:  0    0 YSGN XSGN    1    M    R    L
 * byte 1: X7   X6   X5   X4   X3   X2   X1   X0
 * byte 2: Y7   Y6   Y5   Y4   Y3   Y2   Y1   Y0
 *
 * Note that the device never signals overflow condition.
 *
 * ALPS absolute Mode - new format
 *
 * byte 0:  1    ?    ?    ?    1    ?    ?    ?
 * byte 1:  0   x6   x5   x4   x3   x2   x1   x0
 * byte 2:  0  x10   x9   x8   x7    ?  fin  ges
 * byte 3:  0   y9   y8   y7    1    M    R    L
 * byte 4:  0   y6   y5   y4   y3   y2   y1   y0
 * byte 5:  0   z6   z5   z4   z3   z2   z1   z0
 *
 * Dualpoint device -- interleaved packet format
 *
 * byte 0:    1    1    0    0    1    1    1    1
 * byte 1:    0   x6   x5   x4   x3   x2   x1   x0
 * byte 2:    0  x10   x9   x8   x7    0  fin  ges
 * byte 3:    0    0 YSGN XSGN    1    1    1    1
 * byte 4:   X7   X6   X5   X4   X3   X2   X1   X0
 * byte 5:   Y7   Y6   Y5   Y4   Y3   Y2   Y1   Y0
 * byte 6:    0   y9   y8   y7    1    m    r    l
 * byte 7:    0   y6   y5   y4   y3   y2   y1   y0
 * byte 8:    0   z6   z5   z4   z3   z2   z1   z0
 *
 * CAPITALS = stick, miniscules = touchpad
 *
 * ?'s can have different meanings on different models,
 * such as wheel rotation, extra buttons, stick buttons
 * on a dualpoint, etc.
 */

static bool alps_is_valid_first_byte(const struct alps_model_info *model,
                                     unsigned char data)
{
        return (data & model->mask0) == model->byte0;
}

static void alps_report_buttons(struct psmouse *psmouse,
                                struct input_dev *dev1, struct input_dev *dev2,
                                int left, int right, int middle)
{
        struct alps_data *priv = psmouse->private;
        const struct alps_model_info *model = priv->i;

        if (model->flags & ALPS_PS2_INTERLEAVED) {
                struct input_dev *dev;

                /*
                 * If shared button has already been reported on the
                 * other device (dev2) then this event should be also
                 * sent through that device.
                 */
                dev = test_bit(BTN_LEFT, dev2->key) ? dev2 : dev1;
                input_report_key(dev, BTN_LEFT, left);

                dev = test_bit(BTN_RIGHT, dev2->key) ? dev2 : dev1;
                input_report_key(dev, BTN_RIGHT, right);

                dev = test_bit(BTN_MIDDLE, dev2->key) ? dev2 : dev1;
                input_report_key(dev, BTN_MIDDLE, middle);

                /*
                 * Sync the _other_ device now, we'll do the first
                 * device later once we report the rest of the events.
                 */
                input_sync(dev2);
        } else {
                /*
                 * For devices with non-interleaved packets we know what
                 * device buttons belong to so we can simply report them.
                 */
                input_report_key(dev1, BTN_LEFT, left);
                input_report_key(dev1, BTN_RIGHT, right);
                input_report_key(dev1, BTN_MIDDLE, middle);
        }
}

static void alps_process_packet(struct psmouse *psmouse)
{
        struct alps_data *priv = psmouse->private;
        const struct alps_model_info *model = priv->i;
        unsigned char *packet = psmouse->packet;
        struct input_dev *dev = psmouse->dev;
        struct input_dev *dev2 = priv->dev2;
        int x, y, z, ges, fin, left, right, middle;
        int back = 0, forward = 0;

        if (model->flags & ALPS_OLDPROTO) {
                left = packet[2] & 0x10;
                right = packet[2] & 0x08;
                middle = 0;
                x = packet[1] | ((packet[0] & 0x07) << 7);
                y = packet[4] | ((packet[3] & 0x07) << 7);
                z = packet[5];
        } else {
                left = packet[3] & 1;
                right = packet[3] & 2;
                middle = packet[3] & 4;
                x = packet[1] | ((packet[2] & 0x78) << (7 - 3));
                y = packet[4] | ((packet[3] & 0x70) << (7 - 4));
                z = packet[5];
        }

        if (model->flags & ALPS_FW_BK_1) {
                back = packet[0] & 0x10;
                forward = packet[2] & 4;
        }

        if (model->flags & ALPS_FW_BK_2) {
                back = packet[3] & 4;
                forward = packet[2] & 4;
                if ((middle = forward && back))
                        forward = back = 0;
        }

        ges = packet[2] & 1;
        fin = packet[2] & 2;

        if ((model->flags & ALPS_DUALPOINT) && z == 127) {
                input_report_rel(dev2, REL_X,  (x > 383 ? (x - 768) : x));
                input_report_rel(dev2, REL_Y, -(y > 255 ? (y - 512) : y));

                alps_report_buttons(psmouse, dev2, dev, left, right, middle);

                input_sync(dev2);
                return;
        }

        alps_report_buttons(psmouse, dev, dev2, left, right, middle);

        /* Convert hardware tap to a reasonable Z value */
        if (ges && !fin)
                z = 40;

        /*
         * A "tap and drag" operation is reported by the hardware as a transition
         * from (!fin && ges) to (fin && ges). This should be translated to the
         * sequence Z>0, Z==0, Z>0, so the Z==0 event has to be generated manually.
         */
        if (ges && fin && !priv->prev_fin) {
                input_report_abs(dev, ABS_X, x);
                input_report_abs(dev, ABS_Y, y);
                input_report_abs(dev, ABS_PRESSURE, 0);
                input_report_key(dev, BTN_TOOL_FINGER, 0);
                input_sync(dev);
        }
        priv->prev_fin = fin;

        if (z > 30)
                input_report_key(dev, BTN_TOUCH, 1);
        if (z < 25)
                input_report_key(dev, BTN_TOUCH, 0);

        if (z > 0) {
                input_report_abs(dev, ABS_X, x);
                input_report_abs(dev, ABS_Y, y);
        }

        input_report_abs(dev, ABS_PRESSURE, z);
        input_report_key(dev, BTN_TOOL_FINGER, z > 0);

        if (model->flags & ALPS_WHEEL)
                input_report_rel(dev, REL_WHEEL, ((packet[2] << 1) & 0x08) - ((packet[0] >> 4) & 0x07));

        if (model->flags & (ALPS_FW_BK_1 | ALPS_FW_BK_2)) {
                input_report_key(dev, BTN_FORWARD, forward);
                input_report_key(dev, BTN_BACK, back);
        }

        if (model->flags & ALPS_FOUR_BUTTONS) {
                input_report_key(dev, BTN_0, packet[2] & 4);
                input_report_key(dev, BTN_1, packet[0] & 0x10);
                input_report_key(dev, BTN_2, packet[3] & 4);
                input_report_key(dev, BTN_3, packet[0] & 0x20);
        }

        input_sync(dev);
}

static void alps_report_bare_ps2_packet(struct psmouse *psmouse,
                                        unsigned char packet[],
                                        bool report_buttons)
{
        struct alps_data *priv = psmouse->private;
        struct input_dev *dev2 = priv->dev2;

        if (report_buttons)
                alps_report_buttons(psmouse, dev2, psmouse->dev,
                                packet[0] & 1, packet[0] & 2, packet[0] & 4);

        input_report_rel(dev2, REL_X,
                packet[1] ? packet[1] - ((packet[0] << 4) & 0x100) : 0);
        input_report_rel(dev2, REL_Y,
                packet[2] ? ((packet[0] << 3) & 0x100) - packet[2] : 0);

        input_sync(dev2);
}

static psmouse_ret_t alps_handle_interleaved_ps2(struct psmouse *psmouse)
{
        struct alps_data *priv = psmouse->private;

        if (psmouse->pktcnt < 6)
                return PSMOUSE_GOOD_DATA;

        if (psmouse->pktcnt == 6) {
                /*
                 * Start a timer to flush the packet if it ends up last
                 * 6-byte packet in the stream. Timer needs to fire
                 * psmouse core times out itself. 20 ms should be enough
                 * to decide if we are getting more data or not.
                 */
                mod_timer(&priv->timer, jiffies + msecs_to_jiffies(20));
                return PSMOUSE_GOOD_DATA;
        }

        del_timer(&priv->timer);

        if (psmouse->packet[6] & 0x80) {

                /*
                 * Highest bit is set - that means we either had
                 * complete ALPS packet and this is start of the
                 * next packet or we got garbage.
                 */

                if (((psmouse->packet[3] |
                      psmouse->packet[4] |
                      psmouse->packet[5]) & 0x80) ||
                    (!alps_is_valid_first_byte(priv->i, psmouse->packet[6]))) {
                        dbg("refusing packet %x %x %x %x "
                            "(suspected interleaved ps/2)\n",
                            psmouse->packet[3], psmouse->packet[4],
                            psmouse->packet[5], psmouse->packet[6]);
                        return PSMOUSE_BAD_DATA;
                }

                alps_process_packet(psmouse);

                /* Continue with the next packet */
                psmouse->packet[0] = psmouse->packet[6];
                psmouse->pktcnt = 1;

        } else {

                /*
                 * High bit is 0 - that means that we indeed got a PS/2
                 * packet in the middle of ALPS packet.
                 *
                 * There is also possibility that we got 6-byte ALPS
                 * packet followed  by 3-byte packet from trackpoint. We
                 * can not distinguish between these 2 scenarios but
                 * becase the latter is unlikely to happen in course of
                 * normal operation (user would need to press all
                 * buttons on the pad and start moving trackpoint
                 * without touching the pad surface) we assume former.
                 * Even if we are wrong the wost thing that would happen
                 * the cursor would jump but we should not get protocol
                 * desynchronization.
                 */

                alps_report_bare_ps2_packet(psmouse, &psmouse->packet[3],
                                            false);

                /*
                 * Continue with the standard ALPS protocol handling,
                 * but make sure we won't process it as an interleaved
                 * packet again, which may happen if all buttons are
                 * pressed. To avoid this let's reset the 4th bit which
                 * is normally 1.
                 */
                psmouse->packet[3] = psmouse->packet[6] & 0xf7;
                psmouse->pktcnt = 4;
        }

        return PSMOUSE_GOOD_DATA;
}

static void alps_flush_packet(unsigned long data)
{
        struct psmouse *psmouse = (struct psmouse *)data;

        serio_pause_rx(psmouse->ps2dev.serio);

        if (psmouse->pktcnt == 6) {

                /*
                 * We did not any more data in reasonable amount of time.
                 * Validate the last 3 bytes and process as a standard
                 * ALPS packet.
                 */
                if ((psmouse->packet[3] |
                     psmouse->packet[4] |
                     psmouse->packet[5]) & 0x80) {
                        dbg("refusing packet %x %x %x "
                            "(suspected interleaved ps/2)\n",
                            psmouse->packet[3], psmouse->packet[4],
                            psmouse->packet[5]);
                } else {
                        alps_process_packet(psmouse);
                }
                psmouse->pktcnt = 0;
        }

        serio_continue_rx(psmouse->ps2dev.serio);
}

static psmouse_ret_t alps_process_byte(struct psmouse *psmouse)
{
        struct alps_data *priv = psmouse->private;
        const struct alps_model_info *model = priv->i;

        if ((psmouse->packet[0] & 0xc8) == 0x08) { /* PS/2 packet */
                if (psmouse->pktcnt == 3) {
                        alps_report_bare_ps2_packet(psmouse, psmouse->packet,
                                                    true);
                        return PSMOUSE_FULL_PACKET;
                }
                return PSMOUSE_GOOD_DATA;
        }

        /* Check for PS/2 packet stuffed in the middle of ALPS packet. */

        if ((model->flags & ALPS_PS2_INTERLEAVED) &&
            psmouse->pktcnt >= 4 && (psmouse->packet[3] & 0x0f) == 0x0f) {
                return alps_handle_interleaved_ps2(psmouse);
        }

        if (!alps_is_valid_first_byte(model, psmouse->packet[0])) {
                dbg("refusing packet[0] = %x (mask0 = %x, byte0 = %x)\n",
                    psmouse->packet[0], model->mask0, model->byte0);
                return PSMOUSE_BAD_DATA;
        }

        /* Bytes 2 - 6 should have 0 in the highest bit */
        if (psmouse->pktcnt >= 2 && psmouse->pktcnt <= 6 &&
            (psmouse->packet[psmouse->pktcnt - 1] & 0x80)) {
                dbg("refusing packet[%i] = %x\n",
                    psmouse->pktcnt - 1, psmouse->packet[psmouse->pktcnt - 1]);
                return PSMOUSE_BAD_DATA;
        }

        if (psmouse->pktcnt == 6) {
                alps_process_packet(psmouse);
                return PSMOUSE_FULL_PACKET;
        }

        return PSMOUSE_GOOD_DATA;
}

static const struct alps_model_info *alps_get_model(struct psmouse *psmouse, int *version)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        static const unsigned char rates[] = { 0, 10, 20, 40, 60, 80, 100, 200 };
        unsigned char param[4];
        int i;

        /*
         * First try "E6 report".
         * ALPS should return 0,0,10 or 0,0,100
         */
        param[0] = 0;
        if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES) ||
            ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
            ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
            ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11))
                return NULL;

        param[0] = param[1] = param[2] = 0xff;
        if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
                return NULL;

        dbg("E6 report: %2.2x %2.2x %2.2x", param[0], param[1], param[2]);

        if (param[0] != 0 || param[1] != 0 || (param[2] != 10 && param[2] != 100))
                return NULL;

        /*
         * Now try "E7 report". Allowed responses are in
         * alps_model_data[].signature
         */
        param[0] = 0;
        if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES) ||
            ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE21) ||
            ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE21) ||
            ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE21))
                return NULL;

        param[0] = param[1] = param[2] = 0xff;
        if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
                return NULL;

        dbg("E7 report: %2.2x %2.2x %2.2x", param[0], param[1], param[2]);

        if (version) {
                for (i = 0; i < ARRAY_SIZE(rates) && param[2] != rates[i]; i++)
                        /* empty */;
                *version = (param[0] << 8) | (param[1] << 4) | i;
        }

        for (i = 0; i < ARRAY_SIZE(alps_model_data); i++)
                if (!memcmp(param, alps_model_data[i].signature,
                            sizeof(alps_model_data[i].signature)))
                        return alps_model_data + i;

        return NULL;
}

/*
 * For DualPoint devices select the device that should respond to
 * subsequent commands. It looks like glidepad is behind stickpointer,
 * I'd thought it would be other way around...
 */
static int alps_passthrough_mode(struct psmouse *psmouse, bool enable)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        int cmd = enable ? PSMOUSE_CMD_SETSCALE21 : PSMOUSE_CMD_SETSCALE11;

        if (ps2_command(ps2dev, NULL, cmd) ||
            ps2_command(ps2dev, NULL, cmd) ||
            ps2_command(ps2dev, NULL, cmd) ||
            ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE))
                return -1;

        /* we may get 3 more bytes, just ignore them */
        ps2_drain(ps2dev, 3, 100);

        return 0;
}

static int alps_absolute_mode(struct psmouse *psmouse)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;

        /* Try ALPS magic knock - 4 disable before enable */
        if (ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev, NULL, PSMOUSE_CMD_ENABLE))
                return -1;

        /*
         * Switch mouse to poll (remote) mode so motion data will not
         * get in our way
         */
        return ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETPOLL);
}

static int alps_get_status(struct psmouse *psmouse, char *param)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;

        /* Get status: 0xF5 0xF5 0xF5 0xE9 */
        if (ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
                return -1;

        dbg("Status: %2.2x %2.2x %2.2x", param[0], param[1], param[2]);

        return 0;
}

/*
 * Turn touchpad tapping on or off. The sequences are:
 * 0xE9 0xF5 0xF5 0xF3 0x0A to enable,
 * 0xE9 0xF5 0xF5 0xE8 0x00 to disable.
 * My guess that 0xE9 (GetInfo) is here as a sync point.
 * For models that also have stickpointer (DualPoints) its tapping
 * is controlled separately (0xE6 0xE6 0xE6 0xF3 0x14|0x0A) but
 * we don't fiddle with it.
 */
static int alps_tap_mode(struct psmouse *psmouse, int enable)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        int cmd = enable ? PSMOUSE_CMD_SETRATE : PSMOUSE_CMD_SETRES;
        unsigned char tap_arg = enable ? 0x0A : 0x00;
        unsigned char param[4];

        if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO) ||
            ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev, NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev, &tap_arg, cmd))
                return -1;

        if (alps_get_status(psmouse, param))
                return -1;

        return 0;
}

/*
 * alps_poll() - poll the touchpad for current motion packet.
 * Used in resync.
 */
static int alps_poll(struct psmouse *psmouse)
{
        struct alps_data *priv = psmouse->private;
        unsigned char buf[6];
        bool poll_failed;

        if (priv->i->flags & ALPS_PASS)
                alps_passthrough_mode(psmouse, true);

        poll_failed = ps2_command(&psmouse->ps2dev, buf,
                                  PSMOUSE_CMD_POLL | (psmouse->pktsize << 8)) < 0;

        if (priv->i->flags & ALPS_PASS)
                alps_passthrough_mode(psmouse, false);

        if (poll_failed || (buf[0] & priv->i->mask0) != priv->i->byte0)
                return -1;

        if ((psmouse->badbyte & 0xc8) == 0x08) {
/*
 * Poll the track stick ...
 */
                if (ps2_command(&psmouse->ps2dev, buf, PSMOUSE_CMD_POLL | (3 << 8)))
                        return -1;
        }

        memcpy(psmouse->packet, buf, sizeof(buf));
        return 0;
}

static int alps_hw_init(struct psmouse *psmouse)
{
        struct alps_data *priv = psmouse->private;
        const struct alps_model_info *model = priv->i;

        if ((model->flags & ALPS_PASS) &&
            alps_passthrough_mode(psmouse, true)) {
                return -1;
        }

        if (alps_tap_mode(psmouse, true)) {
                printk(KERN_WARNING "alps.c: Failed to enable hardware tapping\n");
                return -1;
        }

        if (alps_absolute_mode(psmouse)) {
                printk(KERN_ERR "alps.c: Failed to enable absolute mode\n");
                return -1;
        }

        if ((model->flags & ALPS_PASS) &&
            alps_passthrough_mode(psmouse, false)) {
                return -1;
        }

        /* ALPS needs stream mode, otherwise it won't report any data */
        if (ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSTREAM)) {
                printk(KERN_ERR "alps.c: Failed to enable stream mode\n");
                return -1;
        }

        return 0;
}

static int alps_reconnect(struct psmouse *psmouse)
{
        const struct alps_model_info *model;

        psmouse_reset(psmouse);

        model = alps_get_model(psmouse, NULL);
        if (!model)
                return -1;

        return alps_hw_init(psmouse);
}

static void alps_disconnect(struct psmouse *psmouse)
{
        struct alps_data *priv = psmouse->private;

        psmouse_reset(psmouse);
        del_timer_sync(&priv->timer);
        input_unregister_device(priv->dev2);
        kfree(priv);
}

int alps_init(struct psmouse *psmouse)
{
        struct alps_data *priv;
        const struct alps_model_info *model;
        struct input_dev *dev1 = psmouse->dev, *dev2;
        int version;

        priv = kzalloc(sizeof(struct alps_data), GFP_KERNEL);
        dev2 = input_allocate_device();
        if (!priv || !dev2)
                goto init_fail;

        priv->dev2 = dev2;
        setup_timer(&priv->timer, alps_flush_packet, (unsigned long)psmouse);

        psmouse->private = priv;

        model = alps_get_model(psmouse, &version);
        if (!model)
                goto init_fail;

        priv->i = model;

        if (alps_hw_init(psmouse))
                goto init_fail;

        /*
         * Undo part of setup done for us by psmouse core since touchpad
         * is not a relative device.
         */
        __clear_bit(EV_REL, dev1->evbit);
        __clear_bit(REL_X, dev1->relbit);
        __clear_bit(REL_Y, dev1->relbit);

        /*
         * Now set up our capabilities.
         */
        dev1->evbit[BIT_WORD(EV_KEY)] |= BIT_MASK(EV_KEY);
        dev1->keybit[BIT_WORD(BTN_TOUCH)] |= BIT_MASK(BTN_TOUCH);
        dev1->keybit[BIT_WORD(BTN_TOOL_FINGER)] |= BIT_MASK(BTN_TOOL_FINGER);
        dev1->keybit[BIT_WORD(BTN_LEFT)] |=
                BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_RIGHT);

        dev1->evbit[BIT_WORD(EV_ABS)] |= BIT_MASK(EV_ABS);
        input_set_abs_params(dev1, ABS_X, 0, 1023, 0, 0);
        input_set_abs_params(dev1, ABS_Y, 0, 767, 0, 0);
        input_set_abs_params(dev1, ABS_PRESSURE, 0, 127, 0, 0);

        if (model->flags & ALPS_WHEEL) {
                dev1->evbit[BIT_WORD(EV_REL)] |= BIT_MASK(EV_REL);
                dev1->relbit[BIT_WORD(REL_WHEEL)] |= BIT_MASK(REL_WHEEL);
        }

        if (model->flags & (ALPS_FW_BK_1 | ALPS_FW_BK_2)) {
                dev1->keybit[BIT_WORD(BTN_FORWARD)] |= BIT_MASK(BTN_FORWARD);
                dev1->keybit[BIT_WORD(BTN_BACK)] |= BIT_MASK(BTN_BACK);
        }

        if (model->flags & ALPS_FOUR_BUTTONS) {
                dev1->keybit[BIT_WORD(BTN_0)] |= BIT_MASK(BTN_0);
                dev1->keybit[BIT_WORD(BTN_1)] |= BIT_MASK(BTN_1);
                dev1->keybit[BIT_WORD(BTN_2)] |= BIT_MASK(BTN_2);
                dev1->keybit[BIT_WORD(BTN_3)] |= BIT_MASK(BTN_3);
        } else {
                dev1->keybit[BIT_WORD(BTN_MIDDLE)] |= BIT_MASK(BTN_MIDDLE);
        }

        snprintf(priv->phys, sizeof(priv->phys), "%s/input1", psmouse->ps2dev.serio->phys);
        dev2->phys = priv->phys;
        dev2->name = (model->flags & ALPS_DUALPOINT) ? "DualPoint Stick" : "PS/2 Mouse";
        dev2->id.bustype = BUS_I8042;
        dev2->id.vendor  = 0x0002;
        dev2->id.product = PSMOUSE_ALPS;
        dev2->id.version = 0x0000;
        dev2->dev.parent = &psmouse->ps2dev.serio->dev;

        dev2->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);
        dev2->relbit[BIT_WORD(REL_X)] = BIT_MASK(REL_X) | BIT_MASK(REL_Y);
        dev2->keybit[BIT_WORD(BTN_LEFT)] =
                BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT);

        if (input_register_device(priv->dev2))
                goto init_fail;

        psmouse->protocol_handler = alps_process_byte;
        psmouse->poll = alps_poll;
        psmouse->disconnect = alps_disconnect;
        psmouse->reconnect = alps_reconnect;
        psmouse->pktsize = 6;

        /* We are having trouble resyncing ALPS touchpads so disable it for now */
        psmouse->resync_time = 0;

        return 0;

init_fail:
        psmouse_reset(psmouse);
        input_free_device(dev2);
        kfree(priv);
        psmouse->private = NULL;
        return -1;
}

int alps_detect(struct psmouse *psmouse, bool set_properties)
{
        int version;
        const struct alps_model_info *model;

        model = alps_get_model(psmouse, &version);
        if (!model)
                return -1;

        if (set_properties) {
                psmouse->vendor = "ALPS";
                psmouse->name = model->flags & ALPS_DUALPOINT ?
                                "DualPoint TouchPad" : "GlidePoint";
                psmouse->model = version;
        }
        return 0;
}