FreeBSD/Linux Kernel Cross Reference
sys/dev/ic/matrixkp_subr.c

     /*
      * 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 1.4 2005/12/12 01:20:26 christos 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 <machine/intr.h>
    #include <machine/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);
            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, caddr_t 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;
   }

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