root/i2c/trunk/kernel/i2c-elv.c @ 3317

/* ------------------------------------------------------------------------- */
/* bit-elv.c i2c-hw access for philips style parallel port adapters          */
/* ------------------------------------------------------------------------- */
/*   Copyright (C) 1995-97 Simon G. Vogl

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                */
/* ------------------------------------------------------------------------- 
static char rcsid[] = "$Id$";
   ------------------------------------------------------------------------- */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/malloc.h>
#include <linux/version.h>
#if LINUX_VERSION_CODE >= 0x020135
#include <linux/init.h>
#else
#define __init 
#endif

#if LINUX_VERSION_CODE >= 0x020100
#  include <asm/uaccess.h>
#else
#  include <asm/segment.h>
#endif

#include <linux/ioport.h>
#include <asm/io.h>
#include <linux/errno.h>
#include "i2c.h"
#include "i2c-algo-bit.h"

#define DEFAULT_BASE 0x378
static int base=0;
static unsigned char PortData = 0;

/* ----- global defines ----------------------------------------------- */
#define DEB(x)          /* should be reasonable open, close &c.         */
#define DEB2(x)         /* low level debugging - very slow              */
#define DEBE(x) x       /* error messages                               */
#define DEBINIT(x) x    /* detection status messages                    */

/* --- Convenience defines for the parallel port:                       */
#define BASE    (unsigned int)(data)
#define DATA    BASE                    /* Centronics data port         */
#define STAT    (BASE+1)                /* Centronics status port       */
#define CTRL    (BASE+2)                /* Centronics control port      */


/* ----- local functions ---------------------------------------------- */


void bit_elv_setscl(void *data, int state)
{
        if (state) {
                PortData &= 0xfe;
        } else {
                PortData |=1;
        }
        outb(PortData, DATA);
}

void bit_elv_setsda(void *data, int state)
{
        if (state) {
                PortData &=0xfd;
        } else {
                PortData |=2;
        }
        outb(PortData, DATA);
} 

int bit_elv_getscl(void *data)
{
        return ( 0 == ( (inb_p(STAT)) & 0x08 ) );
}

int bit_elv_getsda(void *data)
{
        return ( 0 == ( (inb_p(STAT)) & 0x40 ) );
}

int bit_elv_init(void)
{
        if (check_region(base,(base == 0x3bc)? 3 : 8) < 0 ) {
                return -ENODEV; 
        } else {
                                                /* test for ELV adap.   */
                if (inb(base+1) & 0x80) {       /* BUSY should be high  */
                        DEBINIT(printk("i2c ELV: Busy was low.\n"));
                        return -ENODEV;
                } else {
                        outb(0x0c,base+2);      /* SLCT auf low         */
                        udelay(400);
                        if ( !(inb(base+1) && 0x10) ) {
                                outb(0x04,base+2);
                                DEBINIT(printk("i2c ELV: Select was high.\n"));
                                return -ENODEV;
                        }
                }
                request_region(base,(base == 0x3bc)? 3 : 8,
                        "i2c (ELV adapter)");
                PortData = 0;
                bit_elv_setsda((void*)base,1);
                bit_elv_setscl((void*)base,1);
        }
        return 0;
}

void bit_elv_exit(void)
{
        release_region( base , (base == 0x3bc)? 3 : 8 );
}

int bit_elv_reg(struct i2c_client *client)
{
        return 0;
}

int bit_elv_unreg(struct i2c_client *client)
{
        return 0;
}

static void bit_elv_inc_use(struct bit_adapter *adap)
{
#ifdef MODULE
  MOD_INC_USE_COUNT;
#endif
}

static void bit_elv_dec_use(struct bit_adapter *adap)
{
#ifdef MODULE
  MOD_DEC_USE_COUNT;
#endif
}

/* ------------------------------------------------------------------------
 * Encapsulate the above functions in the correct operations structure.
 * This is only done when more than one hardware adapter is supported.
 */
struct bit_adapter bit_elv_ops = {
        "ELV Parallel port adaptor",
        HW_B_ELV,
        NULL,
        bit_elv_setsda,
        bit_elv_setscl,
        bit_elv_getsda,
        bit_elv_getscl,
        bit_elv_reg,
        bit_elv_unreg,  
        bit_elv_inc_use,
        bit_elv_dec_use,
        80, 80, 100,            /*      waits, timeout */
};


int  __init bitelv_init(void)
{
        if (base==0) {
                /* probe some values */
                base=DEFAULT_BASE;
                bit_elv_ops.data=(void*)DEFAULT_BASE;
                if (bit_elv_init()==0) {
                        i2c_bit_add_bus(&bit_elv_ops);
                } else {
                        return -ENODEV;
                }
        } else {
                bit_elv_ops.data=(void*)base;
                if (bit_elv_init()==0) {
                        i2c_bit_add_bus(&bit_elv_ops);
                } else {
                        return -ENODEV;
                }
        }
        printk("bit_elv: found device at %#x.\n",base);
        return 0;
}


#ifdef MODULE
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
MODULE_DESCRIPTION("I2C-Bus adapter routines for ELV parallel port adapter")
;

MODULE_PARM(base, "i");

EXPORT_NO_SYMBOLS;

int init_module(void)
{
        return bitelv_init();
}

void cleanup_module(void)
{
        i2c_bit_del_bus(&bit_elv_ops);
        bit_elv_exit();
}

#endif