source: mainline/uspace/srv/hid/char_mouse/proto/ps2.c@ a70bda4

/*
 * Copyright (c) 2006 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 */

/** @addtogroup mouse
 * @{
 */
/**
 * @file
 * @brief PS/2 mouse protocol driver.
 */

#include <stdio.h>
#include <mouse_proto.h>
#include <char_mouse.h>

#define BUFSIZE 3

typedef struct {
        union {
                unsigned char data[BUFSIZE];
                struct {
                        unsigned leftbtn : 1;
                        unsigned rightbtn : 1;
                        unsigned middlebtn : 1;
                        unsigned isone : 1; /* Always one */
                        unsigned xsign : 1;
                        unsigned ysign : 1;
                        unsigned xovfl : 1;
                        unsigned yovfl : 1;
                        unsigned char x;
                        unsigned char y;
                } val;
        } u;
} ps2packet_t;

static ps2packet_t buf;
static int bufpos = 0;
static int leftbtn = 0;
static int rightbtn = 0;
static int middlebtn = 0;

int mouse_proto_init(void)
{
        return 0;
}

/** Convert 9-bit 2-complement signed number to integer */
static int bit9toint(int sign, unsigned char data)
{
        int tmp;

        if (!sign)
                return data;

        tmp = ((unsigned char)~data) + 1;
        return -tmp;
}

/** Process mouse data */
void mouse_proto_parse_byte(int data)
{
        int x, y;

        /* Check that we have not lost synchronization */
        if (bufpos == 0 && !(data & 0x8))
                return; /* Synchro lost, ignore byte */

        buf.u.data[bufpos++] = data;
        if (bufpos == BUFSIZE) {
                bufpos = 0;

                if (buf.u.val.leftbtn ^ leftbtn) {
                        leftbtn = buf.u.val.leftbtn;
                        mouse_ev_btn(1, leftbtn);
                }

                if (buf.u.val.rightbtn ^ rightbtn) {
                        rightbtn = buf.u.val.rightbtn;
                        mouse_ev_btn(2, rightbtn);
                }

                if (buf.u.val.middlebtn ^ middlebtn) {
                        middlebtn = buf.u.val.middlebtn;
                        mouse_ev_btn(3, middlebtn);
                }

                x =   bit9toint(buf.u.val.xsign, buf.u.val.x);
                y = - bit9toint(buf.u.val.ysign, buf.u.val.y);

                if (x != 0 || y != 0) {
                        mouse_ev_move(x, y);
                }
        }

        return;
}

/**
 * @}
 */