root/i2c/trunk/kernel/i2c-pport.c @ 3765

/* ------------------------------------------------------------------------- */
/* i2c-pport.c i2c-hw access  for primitive i2c par. port adapter            */
/* ------------------------------------------------------------------------- */
/*   Copyright (C) 2001    Daniel Smolik

    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.                */
/* ------------------------------------------------------------------------- */

/*
        See doc/i2c-pport for instructions on wiring to the
        parallel port connector.

        Cut & paste :-)  based on Velleman K9000 driver by Simon G. Vogl
*/


#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include "i2c.h"
#include "i2c-algo-bit.h"
#include <asm/io.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      */

/* we will use SDA  - Auto Linefeed(14)   bit 1  POUT   */
/* we will use SCL - Initialize printer(16)    BUSY bit 2*/

#define  SET_SCL    | 0x04
#define  CLR_SCL    & 0xFB




#define  SET_SDA    & 0x04
#define  CLR_SDA    | 0x02


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


static void bit_pport_setscl(void *data, int state)
{
        if (state) {
                //high
                PortData = PortData SET_SCL;
        } else {
                //low
                PortData = PortData CLR_SCL; 
        }
        outb(PortData, CTRL);
}

static void bit_pport_setsda(void *data, int state)
{
        if (state) {
                
                PortData = PortData SET_SDA;
        } else {

                PortData = PortData CLR_SDA;
        }
        outb(PortData, CTRL);
} 

static int bit_pport_getscl(void *data)
{

        return ( 4 == ( (inb_p(CTRL)) & 0x04 ) );
}

static int bit_pport_getsda(void *data)
{
        return ( 0 == ( (inb_p(CTRL)) & 0x02 ) );
}

static int bit_pport_init(void)
{
        if (!request_region((base+2),1, "i2c (PPORT adapter)")) {
                return -ENODEV; 
        } else {
                /* test for PPORT adap.         */
        

                PortData=inb(base+2);
                PortData= (PortData SET_SDA) SET_SCL;
                outb(PortData,base+2);                          

                if (!(inb(base+2) | 0x06)) {    /* SDA and SCL will be high     */
                        DEBINIT(printk("i2c-pport.o: SDA and SCL was low.\n"));
                        return -ENODEV;
                } else {
                
                        /*SCL high and SDA low*/
                        PortData = PortData SET_SCL CLR_SDA;
                        outb(PortData,base+2);  
                        schedule_timeout(400);
                        if ( !(inb(base+2) | 0x4) ) {
                                //outb(0x04,base+2);
                                DEBINIT(printk("i2c-port.o: SDA was high.\n"));
                                return -ENODEV;
                        }
                }
                bit_pport_setsda((void*)base,1);
                bit_pport_setscl((void*)base,1);
        }
        return 0;
}


/* ------------------------------------------------------------------------
 * Encapsulate the above functions in the correct operations structure.
 * This is only done when more than one hardware adapter is supported.
 */
static struct i2c_algo_bit_data bit_pport_data = {
        .setsda         = bit_pport_setsda,
        .setscl         = bit_pport_setscl,
        .getsda         = bit_pport_getsda,
        .getscl         = bit_pport_getscl,
        .udelay         = 40,
        .mdelay         = 80,
        .timeout        = HZ
};

static struct i2c_adapter bit_pport_ops = {
        .owner          = THIS_MODULE,
        .name           = "Primitive Parallel port adaptor",
        .id             = I2C_HW_B_PPORT,
        .algo_data      = &bit_pport_data,
};

int __init i2c_bitpport_init(void)
{
        printk("i2c-pport.o: i2c Primitive parallel port adapter module version %s (%s)\n", I2C_VERSION, I2C_DATE);

        if (base==0) {
                /* probe some values */
                base=DEFAULT_BASE;
                bit_pport_data.data=(void*)DEFAULT_BASE;
                if (bit_pport_init()==0) {
                        if(i2c_bit_add_bus(&bit_pport_ops) < 0)
                                return -ENODEV;
                } else {
                        return -ENODEV;
                }
        } else {
                bit_pport_data.data=(void*)base;
                if (bit_pport_init()==0) {
                        if(i2c_bit_add_bus(&bit_pport_ops) < 0)
                                return -ENODEV;
                } else {
                        return -ENODEV;
                }
        }
        printk("i2c-pport.o: found device at %#x.\n",base);
        return 0;
}

static void __exit i2c_bitpport_exit(void)
{
        i2c_bit_del_bus(&bit_pport_ops);
        release_region((base+2),1);
}

EXPORT_NO_SYMBOLS;

MODULE_AUTHOR("Daniel Smolik <marvin@sitour.cz>");
MODULE_DESCRIPTION("I2C-Bus adapter routines for Primitive parallel port adapter");
MODULE_LICENSE("GPL");

MODULE_PARM(base, "i");

module_init(i2c_bitpport_init);
module_exit(i2c_bitpport_exit);