/*
 * Copyright (c) 2005 Jesse Off.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *
 * The matrix keypad is a primitive type of keying device
 * commonly used in systems as a small, cheap, easy-to-build and rugged
 * way to get user input in a variety of embedded environments.  This
 * driver can work for any size of keypad.  A one key keypad (aka
 * button) can also be used.  The theory of operation is described
 * thusly:
 *
 *      1) The keypad is connected to the NetBSD embedded system
 *      with digital I/O (DIO) pins connected to each column of
 *      the keypad and also to each row of the keypad.
 *
 *      2) When a button is pressed, a short is made between a
 *      column line and the intersecting row line.
 *
 *      3) Software is responsible to poll each row/column individually
 *      and also to debounce any key presses.
 *
 * To correctly wire up such a thing requires the input DIO
 * lines to have pull-up resistors, otherwise an input may be read as a random
 * value if not currently being shorted by a button press.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: matrixkp_subr.c,v 1.7 2007/10/19 11:59:55 ad Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/callout.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/types.h>

#include <machine/autoconf.h>
#include <sys/intr.h>
#include <sys/bus.h>

#include <dev/wscons/wsconsio.h>
#include <dev/wscons/wskbdvar.h>
#include <dev/wscons/wsksymdef.h>
#include <dev/wscons/wsksymvar.h>

#include <dev/ic/matrixkpvar.h>

#define TV_ELAPSED_US(x, y)     (((x).tv_sec - (y).tv_sec) * 1000000 + \
        ((x).tv_usec - (y).tv_usec))

const struct wskbd_accessops mxkp_accessops = {
        mxkp_enable,
        mxkp_set_leds,
        mxkp_ioctl,
};

void
mxkp_attach(struct matrixkp_softc *sc)
{
        u_int32_t i;

        callout_init(&sc->sc_callout, 0);
        callout_setfunc(&sc->sc_callout, mxkp_poll, sc);
        if (sc->poll_freq > hz || sc->poll_freq == 0)
                sc->poll_freq = hz;
        sc->sc_enabled = 0;
        if (sc->debounce_stable_ms == 0)
                sc->sc_flags |= MXKP_NODEBOUNCE;
        if (sc->mxkp_event == NULL)
                sc->mxkp_event = mxkp_wskbd_event;
        FOR_KEYS(i, sc->mxkp_pressed[i] = 0);
}

void
mxkp_poll(void *arg)
{
        struct matrixkp_softc *sc = (struct matrixkp_softc *)arg;
        u_int32_t i, anychanged;
        u_int32_t scanned[(MAXNKEYS + 31) / 32];
        u_int32_t changed[(MAXNKEYS + 31) / 32];
        u_int32_t set[(MAXNKEYS + 31) / 32];
        u_int32_t cleared[(MAXNKEYS + 31) / 32];

rescan:
        anychanged = 0;
        FOR_KEYS(i, scanned[i] = 0);
        sc->mxkp_scankeys(sc, scanned);
        FOR_KEYS(i, changed[i] = sc->mxkp_pressed[i] ^ scanned[i]);
        FOR_KEYS(i, anychanged |= changed[i]);

        if (!(sc->sc_flags & MXKP_NODEBOUNCE) && anychanged) {
                mxkp_debounce(sc, changed, scanned);
                anychanged = 0;
                FOR_KEYS(i, changed[i] &= sc->mxkp_pressed[i] ^ scanned[i]);
                FOR_KEYS(i, anychanged |= changed[i]);
        }
        if (anychanged) {
                FOR_KEYS(i, set[i] = changed[i] & scanned[i]);
                FOR_KEYS(i, cleared[i] = changed[i] & sc->mxkp_pressed[i]);
                sc->mxkp_event(sc, set, cleared);
                FOR_KEYS(i, sc->mxkp_pressed[i] &= ~cleared[i]);
                FOR_KEYS(i, sc->mxkp_pressed[i] |= set[i]);
                goto rescan;
        }
        if (sc->sc_enabled)
                callout_schedule(&sc->sc_callout, hz / sc->poll_freq);
}

/*
 * debounce will return when masked keys have been stable
 * for sc->debounce_stable_ms
 */
void
mxkp_debounce(struct matrixkp_softc *sc, u_int32_t *mask, u_int32_t *scan) {
        struct timeval verystart, start, now;
        u_int32_t last_val[(MAXNKEYS + 31) / 32];
        u_int32_t anyset, i;

        FOR_KEYS(i, last_val[i] = scan[i]);
        microtime(&verystart);
        start = verystart;
        do {
                FOR_KEYS(i, scan[i] = 0);
                sc->mxkp_scankeys(sc, scan);
                microtime(&now);
                anyset = 0;
                FOR_KEYS(i, anyset |= (scan[i] ^ last_val[i]) & mask[i]);
                if (anyset) /* bounce detected */
                        start = now;
                FOR_KEYS(i, last_val[i] = scan[i]);
        } while (TV_ELAPSED_US(now, start) <= (sc->debounce_stable_ms * 1000));
}

void
mxkp_wskbd_event(struct matrixkp_softc *sc, u_int32_t *on, u_int32_t *off)
{
        unsigned int i;

        for(i = 0; i < sc->mxkp_nkeys; i++) {
                if (off[i / 32] & (1 << (i % 32))) {
                        wskbd_input(sc->sc_wskbddev, WSCONS_EVENT_KEY_UP, i);
                }
        }
        for(i = 0; i < sc->mxkp_nkeys; i++) {
                if (on[i / 32] & (1 << (i % 32))) {
                        wskbd_input(sc->sc_wskbddev, WSCONS_EVENT_KEY_DOWN, i);
                }
        }
}

int
mxkp_enable(void *v, int on)
{
        struct matrixkp_softc *sc = v;

        if (on) {
                if (sc->sc_enabled)
                        return EBUSY;

                sc->sc_enabled = 1;
                callout_schedule(&sc->sc_callout, hz / sc->poll_freq);
        } else {
                sc->sc_enabled = 0;
        }

        return 0;
}

void
mxkp_set_leds(void *v, int leds)
{
}

int
mxkp_ioctl(void *v, u_long cmd, void *data, int flag, struct lwp *l)
{
        switch (cmd) {
        case WSKBDIO_GTYPE:
                *(int *)data = WSKBD_TYPE_MATRIXKP;
                return 0;
        case WSKBDIO_SETLEDS:
                return 0;
        case WSKBDIO_GETLEDS:
                *(int *)data = 0;
                return 0;
        case WSKBDIO_COMPLEXBELL:
                return 0;
        }
        return EPASSTHROUGH;
}