hgpk.c

Go to the documentation of this file.

/*
 * OLPC HGPK (XO-1) touchpad PS/2 mouse driver
 *
 * Copyright (c) 2006-2008 One Laptop Per Child
 * Authors:
 *   Zephaniah E. Hull
 *   Andres Salomon <[email protected]>
 *
 * This driver is partly based on the ALPS driver, which is:
 *
 * Copyright (c) 2003 Neil Brown <[email protected]>
 * Copyright (c) 2003-2005 Peter Osterlund <[email protected]>
 * Copyright (c) 2004 Dmitry Torokhov <[email protected]>
 * Copyright (c) 2005 Vojtech Pavlik <[email protected]>
 *
 * 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.
 */

/*
 * The spec from ALPS is available from
 * <http://wiki.laptop.org/go/Touch_Pad/Tablet>.  It refers to this
 * device as HGPK (Hybrid GS, PT, and Keymatrix).
 *
 * The earliest versions of the device had simultaneous reporting; that
 * was removed.  After that, the device used the Advanced Mode GS/PT streaming
 * stuff.  That turned out to be too buggy to support, so we've finally
 * switched to Mouse Mode (which utilizes only the center 1/3 of the touchpad).
 */

#define DEBUG
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/libps2.h>
#include <linux/delay.h>
#include <asm/olpc.h>

#include "psmouse.h"
#include "hgpk.h"

#define ILLEGAL_XY 999999

static bool tpdebug;
module_param(tpdebug, bool, 0644);
MODULE_PARM_DESC(tpdebug, "enable debugging, dumping packets to KERN_DEBUG.");

static int recalib_delta = 100;
module_param(recalib_delta, int, 0644);
MODULE_PARM_DESC(recalib_delta,
    "packets containing a delta this large will be discarded, and a "
    "recalibration may be scheduled.");

static int jumpy_delay = 20;
module_param(jumpy_delay, int, 0644);
MODULE_PARM_DESC(jumpy_delay,
    "delay (ms) before recal after jumpiness detected");

static int spew_delay = 1;
module_param(spew_delay, int, 0644);
MODULE_PARM_DESC(spew_delay,
    "delay (ms) before recal after packet spew detected");

static int recal_guard_time;
module_param(recal_guard_time, int, 0644);
MODULE_PARM_DESC(recal_guard_time,
    "interval (ms) during which recal will be restarted if packet received");

static int post_interrupt_delay = 40;
module_param(post_interrupt_delay, int, 0644);
MODULE_PARM_DESC(post_interrupt_delay,
    "delay (ms) before recal after recal interrupt detected");

static bool autorecal = true;
module_param(autorecal, bool, 0644);
MODULE_PARM_DESC(autorecal, "enable recalibration in the driver");

static char hgpk_mode_name[16];
module_param_string(hgpk_mode, hgpk_mode_name, sizeof(hgpk_mode_name), 0644);
MODULE_PARM_DESC(hgpk_mode,
    "default hgpk mode: mouse, glidesensor or pentablet");

static int hgpk_default_mode = HGPK_MODE_MOUSE;

static const char * const hgpk_mode_names[] = {
    [HGPK_MODE_MOUSE] = "Mouse",
    [HGPK_MODE_GLIDESENSOR] = "GlideSensor",
    [HGPK_MODE_PENTABLET] = "PenTablet",
};

static int hgpk_mode_from_name(const char *buf, int len)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(hgpk_mode_names); i++) {
        const char *name = hgpk_mode_names[i];
        if (strlen(name) == len && !strncasecmp(name, buf, len))
            return i;
    }

    return HGPK_MODE_INVALID;
}

/*
 * see if new value is within 20% of half of old value
 */
static int approx_half(int curr, int prev)
{
    int belowhalf, abovehalf;

    if (curr < 5 || prev < 5)
        return 0;

    belowhalf = (prev * 8) / 20;
    abovehalf = (prev * 12) / 20;

    return belowhalf < curr && curr <= abovehalf;
}

/*
 * Throw out oddly large delta packets, and any that immediately follow whose
 * values are each approximately half of the previous.  It seems that the ALPS
 * firmware emits errant packets, and they get averaged out slowly.
 */
static int hgpk_discard_decay_hack(struct psmouse *psmouse, int x, int y)
{
    struct hgpk_data *priv = psmouse->private;
    int avx, avy;
    bool do_recal = false;

    avx = abs(x);
    avy = abs(y);

    /* discard if too big, or half that but > 4 times the prev delta */
    if (avx > recalib_delta ||
        (avx > recalib_delta / 2 && ((avx / 4) > priv->xlast))) {
        psmouse_warn(psmouse, "detected %dpx jump in x\n", x);
        priv->xbigj = avx;
    } else if (approx_half(avx, priv->xbigj)) {
        psmouse_warn(psmouse, "detected secondary %dpx jump in x\n", x);
        priv->xbigj = avx;
        priv->xsaw_secondary++;
    } else {
        if (priv->xbigj && priv->xsaw_secondary > 1)
            do_recal = true;
        priv->xbigj = 0;
        priv->xsaw_secondary = 0;
    }

    if (avy > recalib_delta ||
        (avy > recalib_delta / 2 && ((avy / 4) > priv->ylast))) {
        psmouse_warn(psmouse, "detected %dpx jump in y\n", y);
        priv->ybigj = avy;
    } else if (approx_half(avy, priv->ybigj)) {
        psmouse_warn(psmouse, "detected secondary %dpx jump in y\n", y);
        priv->ybigj = avy;
        priv->ysaw_secondary++;
    } else {
        if (priv->ybigj && priv->ysaw_secondary > 1)
            do_recal = true;
        priv->ybigj = 0;
        priv->ysaw_secondary = 0;
    }

    priv->xlast = avx;
    priv->ylast = avy;

    if (do_recal && jumpy_delay) {
        psmouse_warn(psmouse, "scheduling recalibration\n");
        psmouse_queue_work(psmouse, &priv->recalib_wq,
                msecs_to_jiffies(jumpy_delay));
    }

    return priv->xbigj || priv->ybigj;
}

static void hgpk_reset_spew_detection(struct hgpk_data *priv)
{
    priv->spew_count = 0;
    priv->dupe_count = 0;
    priv->x_tally = 0;
    priv->y_tally = 0;
    priv->spew_flag = NO_SPEW;
}

static void hgpk_reset_hack_state(struct psmouse *psmouse)
{
    struct hgpk_data *priv = psmouse->private;

    priv->abs_x = priv->abs_y = -1;
    priv->xlast = priv->ylast = ILLEGAL_XY;
    priv->xbigj = priv->ybigj = 0;
    priv->xsaw_secondary = priv->ysaw_secondary = 0;
    hgpk_reset_spew_detection(priv);
}

/*
 * We have no idea why this particular hardware bug occurs.  The touchpad
 * will randomly start spewing packets without anything touching the
 * pad.  This wouldn't necessarily be bad, but it's indicative of a
 * severely miscalibrated pad; attempting to use the touchpad while it's
 * spewing means the cursor will jump all over the place, and act "drunk".
 *
 * The packets that are spewed tend to all have deltas between -2 and 2, and
 * the cursor will move around without really going very far.  It will
 * tend to end up in the same location; if we tally up the changes over
 * 100 packets, we end up w/ a final delta of close to 0.  This happens
 * pretty regularly when the touchpad is spewing, and is pretty hard to
 * manually trigger (at least for *my* fingers).  So, it makes a perfect
 * scheme for detecting spews.
 */
static void hgpk_spewing_hack(struct psmouse *psmouse,
                  int l, int r, int x, int y)
{
    struct hgpk_data *priv = psmouse->private;

    /* ignore button press packets; many in a row could trigger
     * a false-positive! */
    if (l || r)
        return;

    /* don't track spew if the workaround feature has been turned off */
    if (!spew_delay)
        return;

    if (abs(x) > 3 || abs(y) > 3) {
        /* no spew, or spew ended */
        hgpk_reset_spew_detection(priv);
        return;
    }

    /* Keep a tally of the overall delta to the cursor position caused by
     * the spew */
    priv->x_tally += x;
    priv->y_tally += y;

    switch (priv->spew_flag) {
    case NO_SPEW:
        /* we're not spewing, but this packet might be the start */
        priv->spew_flag = MAYBE_SPEWING;

        /* fall-through */

    case MAYBE_SPEWING:
        priv->spew_count++;

        if (priv->spew_count < SPEW_WATCH_COUNT)
            break;

        /* excessive spew detected, request recalibration */
        priv->spew_flag = SPEW_DETECTED;

        /* fall-through */

    case SPEW_DETECTED:
        /* only recalibrate when the overall delta to the cursor
         * is really small. if the spew is causing significant cursor
         * movement, it is probably a case of the user moving the
         * cursor very slowly across the screen. */
        if (abs(priv->x_tally) < 3 && abs(priv->y_tally) < 3) {
            psmouse_warn(psmouse, "packet spew detected (%d,%d)\n",
                     priv->x_tally, priv->y_tally);
            priv->spew_flag = RECALIBRATING;
            psmouse_queue_work(psmouse, &priv->recalib_wq,
                       msecs_to_jiffies(spew_delay));
        }

        break;
    case RECALIBRATING:
        /* we already detected a spew and requested a recalibration,
         * just wait for the queue to kick into action. */
        break;
    }
}

/*
 * HGPK Mouse Mode format (standard mouse format, sans middle button)
 *
 * byte 0:  y-over  x-over  y-neg   x-neg   1   0   swr swl
 * byte 1:  x7  x6  x5  x4  x3  x2  x1  x0
 * byte 2:  y7  y6  y5  y4  y3  y2  y1  y0
 *
 * swr/swl are the left/right buttons.
 * x-neg/y-neg are the x and y delta negative bits
 * x-over/y-over are the x and y overflow bits
 *
 * ---
 *
 * HGPK Advanced Mode - single-mode format
 *
 * byte 0(PT):  1    1    0    0    1    1     1     1
 * byte 0(GS):  1    1    1    1    1    1     1     1
 * byte 1:      0   x6   x5   x4   x3   x2    x1    x0
 * byte 2(PT):  0    0   x9   x8   x7    ? pt-dsw    0
 * byte 2(GS):  0  x10   x9   x8   x7    ? gs-dsw pt-dsw
 * byte 3:      0   y9   y8   y7    1    0   swr   swl
 * byte 4:      0   y6   y5   y4   y3   y2    y1    y0
 * byte 5:      0   z6   z5   z4   z3   z2    z1    z0
 *
 * ?'s are not defined in the protocol spec, may vary between models.
 *
 * swr/swl are the left/right buttons.
 *
 * pt-dsw/gs-dsw indicate that the pt/gs sensor is detecting a
 * pen/finger
 */
static bool hgpk_is_byte_valid(struct psmouse *psmouse, unsigned char *packet)
{
    struct hgpk_data *priv = psmouse->private;
    int pktcnt = psmouse->pktcnt;
    bool valid;

    switch (priv->mode) {
    case HGPK_MODE_MOUSE:
        valid = (packet[0] & 0x0C) == 0x08;
        break;

    case HGPK_MODE_GLIDESENSOR:
        valid = pktcnt == 1 ?
            packet[0] == HGPK_GS : !(packet[pktcnt - 1] & 0x80);
        break;

    case HGPK_MODE_PENTABLET:
        valid = pktcnt == 1 ?
            packet[0] == HGPK_PT : !(packet[pktcnt - 1] & 0x80);
        break;

    default:
        valid = false;
        break;
    }

    if (!valid)
        psmouse_dbg(psmouse,
                "bad data, mode %d (%d) %*ph\n",
                priv->mode, pktcnt, 6, psmouse->packet);

    return valid;
}

static void hgpk_process_advanced_packet(struct psmouse *psmouse)
{
    struct hgpk_data *priv = psmouse->private;
    struct input_dev *idev = psmouse->dev;
    unsigned char *packet = psmouse->packet;
    int down = !!(packet[2] & 2);
    int left = !!(packet[3] & 1);
    int right = !!(packet[3] & 2);
    int x = packet[1] | ((packet[2] & 0x78) << 4);
    int y = packet[4] | ((packet[3] & 0x70) << 3);

    if (priv->mode == HGPK_MODE_GLIDESENSOR) {
        int pt_down = !!(packet[2] & 1);
        int finger_down = !!(packet[2] & 2);
        int z = packet[5];

        input_report_abs(idev, ABS_PRESSURE, z);
        if (tpdebug)
            psmouse_dbg(psmouse, "pd=%d fd=%d z=%d",
                    pt_down, finger_down, z);
    } else {
        /*
         * PenTablet mode does not report pressure, so we don't
         * report it here
         */
        if (tpdebug)
            psmouse_dbg(psmouse, "pd=%d ", down);
    }

    if (tpdebug)
        psmouse_dbg(psmouse, "l=%d r=%d x=%d y=%d\n",
                left, right, x, y);

    input_report_key(idev, BTN_TOUCH, down);
    input_report_key(idev, BTN_LEFT, left);
    input_report_key(idev, BTN_RIGHT, right);

    /*
     * If this packet says that the finger was removed, reset our position
     * tracking so that we don't erroneously detect a jump on next press.
     */
    if (!down) {
        hgpk_reset_hack_state(psmouse);
        goto done;
    }

    /*
     * Weed out duplicate packets (we get quite a few, and they mess up
     * our jump detection)
     */
    if (x == priv->abs_x && y == priv->abs_y) {
        if (++priv->dupe_count > SPEW_WATCH_COUNT) {
            if (tpdebug)
                psmouse_dbg(psmouse, "hard spew detected\n");
            priv->spew_flag = RECALIBRATING;
            psmouse_queue_work(psmouse, &priv->recalib_wq,
                       msecs_to_jiffies(spew_delay));
        }
        goto done;
    }

    /* not a duplicate, continue with position reporting */
    priv->dupe_count = 0;

    /* Don't apply hacks in PT mode, it seems reliable */
    if (priv->mode != HGPK_MODE_PENTABLET && priv->abs_x != -1) {
        int x_diff = priv->abs_x - x;
        int y_diff = priv->abs_y - y;
        if (hgpk_discard_decay_hack(psmouse, x_diff, y_diff)) {
            if (tpdebug)
                psmouse_dbg(psmouse, "discarding\n");
            goto done;
        }
        hgpk_spewing_hack(psmouse, left, right, x_diff, y_diff);
    }

    input_report_abs(idev, ABS_X, x);
    input_report_abs(idev, ABS_Y, y);
    priv->abs_x = x;
    priv->abs_y = y;

done:
    input_sync(idev);
}

static void hgpk_process_simple_packet(struct psmouse *psmouse)
{
    struct input_dev *dev = psmouse->dev;
    unsigned char *packet = psmouse->packet;
    int left = packet[0] & 1;
    int right = (packet[0] >> 1) & 1;
    int x = packet[1] - ((packet[0] << 4) & 0x100);
    int y = ((packet[0] << 3) & 0x100) - packet[2];

    if (packet[0] & 0xc0)
        psmouse_dbg(psmouse,
                "overflow -- 0x%02x 0x%02x 0x%02x\n",
                packet[0], packet[1], packet[2]);

    if (hgpk_discard_decay_hack(psmouse, x, y)) {
        if (tpdebug)
            psmouse_dbg(psmouse, "discarding\n");
        return;
    }

    hgpk_spewing_hack(psmouse, left, right, x, y);

    if (tpdebug)
        psmouse_dbg(psmouse, "l=%d r=%d x=%d y=%d\n",
                left, right, x, y);

    input_report_key(dev, BTN_LEFT, left);
    input_report_key(dev, BTN_RIGHT, right);

    input_report_rel(dev, REL_X, x);
    input_report_rel(dev, REL_Y, y);

    input_sync(dev);
}

static psmouse_ret_t hgpk_process_byte(struct psmouse *psmouse)
{
    struct hgpk_data *priv = psmouse->private;

    if (!hgpk_is_byte_valid(psmouse, psmouse->packet))
        return PSMOUSE_BAD_DATA;

    if (psmouse->pktcnt >= psmouse->pktsize) {
        if (priv->mode == HGPK_MODE_MOUSE)
            hgpk_process_simple_packet(psmouse);
        else
            hgpk_process_advanced_packet(psmouse);
        return PSMOUSE_FULL_PACKET;
    }

    if (priv->recalib_window) {
        if (time_before(jiffies, priv->recalib_window)) {
            /*
             * ugh, got a packet inside our recalibration
             * window, schedule another recalibration.
             */
            psmouse_dbg(psmouse,
                    "packet inside calibration window, queueing another recalibration\n");
            psmouse_queue_work(psmouse, &priv->recalib_wq,
                    msecs_to_jiffies(post_interrupt_delay));
        }
        priv->recalib_window = 0;
    }

    return PSMOUSE_GOOD_DATA;
}

static int hgpk_select_mode(struct psmouse *psmouse)
{
    struct ps2dev *ps2dev = &psmouse->ps2dev;
    struct hgpk_data *priv = psmouse->private;
    int i;
    int cmd;

    /*
     * 4 disables to enable advanced mode
     * then 3 0xf2 bytes as the preamble for GS/PT selection
     */
    const int advanced_init[] = {
        PSMOUSE_CMD_DISABLE, PSMOUSE_CMD_DISABLE,
        PSMOUSE_CMD_DISABLE, PSMOUSE_CMD_DISABLE,
        0xf2, 0xf2, 0xf2,
    };

    switch (priv->mode) {
    case HGPK_MODE_MOUSE:
        psmouse->pktsize = 3;
        break;

    case HGPK_MODE_GLIDESENSOR:
    case HGPK_MODE_PENTABLET:
        psmouse->pktsize = 6;

        /* Switch to 'Advanced mode.', four disables in a row. */
        for (i = 0; i < ARRAY_SIZE(advanced_init); i++)
            if (ps2_command(ps2dev, NULL, advanced_init[i]))
                return -EIO;

        /* select between GlideSensor (mouse) or PenTablet */
        cmd = priv->mode == HGPK_MODE_GLIDESENSOR ?
            PSMOUSE_CMD_SETSCALE11 : PSMOUSE_CMD_SETSCALE21;

        if (ps2_command(ps2dev, NULL, cmd))
            return -EIO;
        break;

    default:
        return -EINVAL;
    }

    return 0;
}

static void hgpk_setup_input_device(struct input_dev *input,
                    struct input_dev *old_input,
                    enum hgpk_mode mode)
{
    if (old_input) {
        input->name = old_input->name;
        input->phys = old_input->phys;
        input->id = old_input->id;
        input->dev.parent = old_input->dev.parent;
    }

    memset(input->evbit, 0, sizeof(input->evbit));
    memset(input->relbit, 0, sizeof(input->relbit));
    memset(input->keybit, 0, sizeof(input->keybit));

    /* All modes report left and right buttons */
    __set_bit(EV_KEY, input->evbit);
    __set_bit(BTN_LEFT, input->keybit);
    __set_bit(BTN_RIGHT, input->keybit);

    switch (mode) {
    case HGPK_MODE_MOUSE:
        __set_bit(EV_REL, input->evbit);
        __set_bit(REL_X, input->relbit);
        __set_bit(REL_Y, input->relbit);
        break;

    case HGPK_MODE_GLIDESENSOR:
        __set_bit(BTN_TOUCH, input->keybit);
        __set_bit(BTN_TOOL_FINGER, input->keybit);

        __set_bit(EV_ABS, input->evbit);

        /* GlideSensor has pressure sensor, PenTablet does not */
        input_set_abs_params(input, ABS_PRESSURE, 0, 15, 0, 0);

        /* From device specs */
        input_set_abs_params(input, ABS_X, 0, 399, 0, 0);
        input_set_abs_params(input, ABS_Y, 0, 290, 0, 0);

        /* Calculated by hand based on usable size (52mm x 38mm) */
        input_abs_set_res(input, ABS_X, 8);
        input_abs_set_res(input, ABS_Y, 8);
        break;

    case HGPK_MODE_PENTABLET:
        __set_bit(BTN_TOUCH, input->keybit);
        __set_bit(BTN_TOOL_FINGER, input->keybit);

        __set_bit(EV_ABS, input->evbit);

        /* From device specs */
        input_set_abs_params(input, ABS_X, 0, 999, 0, 0);
        input_set_abs_params(input, ABS_Y, 5, 239, 0, 0);

        /* Calculated by hand based on usable size (156mm x 38mm) */
        input_abs_set_res(input, ABS_X, 6);
        input_abs_set_res(input, ABS_Y, 8);
        break;

    default:
        BUG();
    }
}

static int hgpk_reset_device(struct psmouse *psmouse, bool recalibrate)
{
    int err;

    psmouse_reset(psmouse);

    if (recalibrate) {
        struct ps2dev *ps2dev = &psmouse->ps2dev;

        /* send the recalibrate request */
        if (ps2_command(ps2dev, NULL, 0xf5) ||
            ps2_command(ps2dev, NULL, 0xf5) ||
            ps2_command(ps2dev, NULL, 0xe6) ||
            ps2_command(ps2dev, NULL, 0xf5)) {
            return -1;
        }

        /* according to ALPS, 150mS is required for recalibration */
        msleep(150);
    }

    err = hgpk_select_mode(psmouse);
    if (err) {
        psmouse_err(psmouse, "failed to select mode\n");
        return err;
    }

    hgpk_reset_hack_state(psmouse);

    return 0;
}

static int hgpk_force_recalibrate(struct psmouse *psmouse)
{
    struct hgpk_data *priv = psmouse->private;
    int err;

    /* C-series touchpads added the recalibrate command */
    if (psmouse->model < HGPK_MODEL_C)
        return 0;

    if (!autorecal) {
        psmouse_dbg(psmouse, "recalibration disabled, ignoring\n");
        return 0;
    }

    psmouse_dbg(psmouse, "recalibrating touchpad..\n");

    /* we don't want to race with the irq handler, nor with resyncs */
    psmouse_set_state(psmouse, PSMOUSE_INITIALIZING);

    /* start by resetting the device */
    err = hgpk_reset_device(psmouse, true);
    if (err)
        return err;

    /*
     * XXX: If a finger is down during this delay, recalibration will
     * detect capacitance incorrectly.  This is a hardware bug, and
     * we don't have a good way to deal with it.  The 2s window stuff
     * (below) is our best option for now.
     */
    if (psmouse_activate(psmouse))
        return -1;

    if (tpdebug)
        psmouse_dbg(psmouse, "touchpad reactivated\n");

    /*
     * If we get packets right away after recalibrating, it's likely
     * that a finger was on the touchpad.  If so, it's probably
     * miscalibrated, so we optionally schedule another.
     */
    if (recal_guard_time)
        priv->recalib_window = jiffies +
            msecs_to_jiffies(recal_guard_time);

    return 0;
}

/*
 * This puts the touchpad in a power saving mode; according to ALPS, current
 * consumption goes down to 50uA after running this.  To turn power back on,
 * we drive MS-DAT low.  Measuring with a 1mA resolution ammeter says that
 * the current on the SUS_3.3V rail drops from 3mA or 4mA to 0 when we do this.
 *
 * We have no formal spec that details this operation -- the low-power
 * sequence came from a long-lost email trail.
 */
static int hgpk_toggle_powersave(struct psmouse *psmouse, int enable)
{
    struct ps2dev *ps2dev = &psmouse->ps2dev;
    int timeo;
    int err;

    /* Added on D-series touchpads */
    if (psmouse->model < HGPK_MODEL_D)
        return 0;

    if (enable) {
        psmouse_set_state(psmouse, PSMOUSE_INITIALIZING);

        /*
         * Sending a byte will drive MS-DAT low; this will wake up
         * the controller.  Once we get an ACK back from it, it
         * means we can continue with the touchpad re-init.  ALPS
         * tells us that 1s should be long enough, so set that as
         * the upper bound. (in practice, it takes about 3 loops.)
         */
        for (timeo = 20; timeo > 0; timeo--) {
            if (!ps2_sendbyte(&psmouse->ps2dev,
                    PSMOUSE_CMD_DISABLE, 20))
                break;
            msleep(25);
        }

        err = hgpk_reset_device(psmouse, false);
        if (err) {
            psmouse_err(psmouse, "Failed to reset device!\n");
            return err;
        }

        /* should be all set, enable the touchpad */
        psmouse_activate(psmouse);
        psmouse_dbg(psmouse, "Touchpad powered up.\n");
    } else {
        psmouse_dbg(psmouse, "Powering off touchpad.\n");

        if (ps2_command(ps2dev, NULL, 0xec) ||
            ps2_command(ps2dev, NULL, 0xec) ||
            ps2_command(ps2dev, NULL, 0xea)) {
            return -1;
        }

        psmouse_set_state(psmouse, PSMOUSE_IGNORE);

        /* probably won't see an ACK, the touchpad will be off */
        ps2_sendbyte(&psmouse->ps2dev, 0xec, 20);
    }

    return 0;
}

static int hgpk_poll(struct psmouse *psmouse)
{
    /* We can't poll, so always return failure. */
    return -1;
}

static int hgpk_reconnect(struct psmouse *psmouse)
{
    struct hgpk_data *priv = psmouse->private;

    /*
     * During suspend/resume the ps2 rails remain powered.  We don't want
     * to do a reset because it's flush data out of buffers; however,
     * earlier prototypes (B1) had some brokenness that required a reset.
     */
    if (olpc_board_at_least(olpc_board(0xb2)))
        if (psmouse->ps2dev.serio->dev.power.power_state.event !=
                PM_EVENT_ON)
            return 0;

    priv->powered = 1;
    return hgpk_reset_device(psmouse, false);
}

static ssize_t hgpk_show_powered(struct psmouse *psmouse, void *data, char *buf)
{
    struct hgpk_data *priv = psmouse->private;

    return sprintf(buf, "%d\n", priv->powered);
}

static ssize_t hgpk_set_powered(struct psmouse *psmouse, void *data,
                const char *buf, size_t count)
{
    struct hgpk_data *priv = psmouse->private;
    unsigned int value;
    int err;

    err = kstrtouint(buf, 10, &value);
    if (err)
        return err;

    if (value > 1)
        return -EINVAL;

    if (value != priv->powered) {
        /*
         * hgpk_toggle_power will deal w/ state so
         * we're not racing w/ irq
         */
        err = hgpk_toggle_powersave(psmouse, value);
        if (!err)
            priv->powered = value;
    }

    return err ? err : count;
}

__PSMOUSE_DEFINE_ATTR(powered, S_IWUSR | S_IRUGO, NULL,
              hgpk_show_powered, hgpk_set_powered, false);

static ssize_t attr_show_mode(struct psmouse *psmouse, void *data, char *buf)
{
    struct hgpk_data *priv = psmouse->private;

    return sprintf(buf, "%s\n", hgpk_mode_names[priv->mode]);
}

static ssize_t attr_set_mode(struct psmouse *psmouse, void *data,
                 const char *buf, size_t len)
{
    struct hgpk_data *priv = psmouse->private;
    enum hgpk_mode old_mode = priv->mode;
    enum hgpk_mode new_mode = hgpk_mode_from_name(buf, len);
    struct input_dev *old_dev = psmouse->dev;
    struct input_dev *new_dev;
    int err;

    if (new_mode == HGPK_MODE_INVALID)
        return -EINVAL;

    if (old_mode == new_mode)
        return len;

    new_dev = input_allocate_device();
    if (!new_dev)
        return -ENOMEM;

    psmouse_set_state(psmouse, PSMOUSE_INITIALIZING);

    /* Switch device into the new mode */
    priv->mode = new_mode;
    err = hgpk_reset_device(psmouse, false);
    if (err)
        goto err_try_restore;

    hgpk_setup_input_device(new_dev, old_dev, new_mode);

    psmouse_set_state(psmouse, PSMOUSE_CMD_MODE);

    err = input_register_device(new_dev);
    if (err)
        goto err_try_restore;

    psmouse->dev = new_dev;
    input_unregister_device(old_dev);

    return len;

err_try_restore:
    input_free_device(new_dev);
    priv->mode = old_mode;
    hgpk_reset_device(psmouse, false);

    return err;
}

PSMOUSE_DEFINE_ATTR(hgpk_mode, S_IWUSR | S_IRUGO, NULL,
            attr_show_mode, attr_set_mode);

static ssize_t hgpk_trigger_recal_show(struct psmouse *psmouse,
        void *data, char *buf)
{
    return -EINVAL;
}

static ssize_t hgpk_trigger_recal(struct psmouse *psmouse, void *data,
                const char *buf, size_t count)
{
    struct hgpk_data *priv = psmouse->private;
    unsigned int value;
    int err;

    err = kstrtouint(buf, 10, &value);
    if (err)
        return err;

    if (value != 1)
        return -EINVAL;

    /*
     * We queue work instead of doing recalibration right here
     * to avoid adding locking to to hgpk_force_recalibrate()
     * since workqueue provides serialization.
     */
    psmouse_queue_work(psmouse, &priv->recalib_wq, 0);
    return count;
}

__PSMOUSE_DEFINE_ATTR(recalibrate, S_IWUSR | S_IRUGO, NULL,
              hgpk_trigger_recal_show, hgpk_trigger_recal, false);

static void hgpk_disconnect(struct psmouse *psmouse)
{
    struct hgpk_data *priv = psmouse->private;

    device_remove_file(&psmouse->ps2dev.serio->dev,
               &psmouse_attr_powered.dattr);
    device_remove_file(&psmouse->ps2dev.serio->dev,
               &psmouse_attr_hgpk_mode.dattr);

    if (psmouse->model >= HGPK_MODEL_C)
        device_remove_file(&psmouse->ps2dev.serio->dev,
                   &psmouse_attr_recalibrate.dattr);

    psmouse_reset(psmouse);
    kfree(priv);
}

static void hgpk_recalib_work(struct work_struct *work)
{
    struct delayed_work *w = to_delayed_work(work);
    struct hgpk_data *priv = container_of(w, struct hgpk_data, recalib_wq);
    struct psmouse *psmouse = priv->psmouse;

    if (hgpk_force_recalibrate(psmouse))
        psmouse_err(psmouse, "recalibration failed!\n");
}

static int hgpk_register(struct psmouse *psmouse)
{
    struct hgpk_data *priv = psmouse->private;
    int err;

    /* register handlers */
    psmouse->protocol_handler = hgpk_process_byte;
    psmouse->poll = hgpk_poll;
    psmouse->disconnect = hgpk_disconnect;
    psmouse->reconnect = hgpk_reconnect;

    /* Disable the idle resync. */
    psmouse->resync_time = 0;
    /* Reset after a lot of bad bytes. */
    psmouse->resetafter = 1024;

    hgpk_setup_input_device(psmouse->dev, NULL, priv->mode);

    err = device_create_file(&psmouse->ps2dev.serio->dev,
                 &psmouse_attr_powered.dattr);
    if (err) {
        psmouse_err(psmouse, "Failed creating 'powered' sysfs node\n");
        return err;
    }

    err = device_create_file(&psmouse->ps2dev.serio->dev,
                 &psmouse_attr_hgpk_mode.dattr);
    if (err) {
        psmouse_err(psmouse,
                "Failed creating 'hgpk_mode' sysfs node\n");
        goto err_remove_powered;
    }

    /* C-series touchpads added the recalibrate command */
    if (psmouse->model >= HGPK_MODEL_C) {
        err = device_create_file(&psmouse->ps2dev.serio->dev,
                     &psmouse_attr_recalibrate.dattr);
        if (err) {
            psmouse_err(psmouse,
                    "Failed creating 'recalibrate' sysfs node\n");
            goto err_remove_mode;
        }
    }

    return 0;

err_remove_mode:
    device_remove_file(&psmouse->ps2dev.serio->dev,
               &psmouse_attr_hgpk_mode.dattr);
err_remove_powered:
    device_remove_file(&psmouse->ps2dev.serio->dev,
               &psmouse_attr_powered.dattr);
    return err;
}

int hgpk_init(struct psmouse *psmouse)
{
    struct hgpk_data *priv;
    int err;

    priv = kzalloc(sizeof(struct hgpk_data), GFP_KERNEL);
    if (!priv) {
        err = -ENOMEM;
        goto alloc_fail;
    }

    psmouse->private = priv;

    priv->psmouse = psmouse;
    priv->powered = true;
    priv->mode = hgpk_default_mode;
    INIT_DELAYED_WORK(&priv->recalib_wq, hgpk_recalib_work);

    err = hgpk_reset_device(psmouse, false);
    if (err)
        goto init_fail;

    err = hgpk_register(psmouse);
    if (err)
        goto init_fail;

    return 0;

init_fail:
    kfree(priv);
alloc_fail:
    return err;
}

static enum hgpk_model_t hgpk_get_model(struct psmouse *psmouse)
{
    struct ps2dev *ps2dev = &psmouse->ps2dev;
    unsigned char param[3];

    /* E7, E7, E7, E9 gets us a 3 byte identifier */
    if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE21) ||
        ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE21) ||
        ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE21) ||
        ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
        return -EIO;
    }

    psmouse_dbg(psmouse, "ID: %*ph\n", 3, param);

    /* HGPK signature: 0x67, 0x00, 0x<model> */
    if (param[0] != 0x67 || param[1] != 0x00)
        return -ENODEV;

    psmouse_info(psmouse, "OLPC touchpad revision 0x%x\n", param[2]);

    return param[2];
}

int hgpk_detect(struct psmouse *psmouse, bool set_properties)
{
    int version;

    version = hgpk_get_model(psmouse);
    if (version < 0)
        return version;

    if (set_properties) {
        psmouse->vendor = "ALPS";
        psmouse->name = "HGPK";
        psmouse->model = version;
    }

    return 0;
}

void hgpk_module_init(void)
{
    hgpk_default_mode = hgpk_mode_from_name(hgpk_mode_name,
                        strlen(hgpk_mode_name));
    if (hgpk_default_mode == HGPK_MODE_INVALID) {
        hgpk_default_mode = HGPK_MODE_MOUSE;
        strlcpy(hgpk_mode_name, hgpk_mode_names[HGPK_MODE_MOUSE],
            sizeof(hgpk_mode_name));
    }
}