/* ------------------------------------------------------------------------- */
/* i2c-mcselec.c i2c-hw access for MCS Electronics style adapter	     */
/* ------------------------------------------------------------------------- */
/*   Copyright (C) 1995-2000 Simon G. Vogl
     Copyright (C) 2004 Sebastian Zagrodzki <s.zagrodzki@net.icm.edu.pl>

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

/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and even
   Frodo Looijaard <frodol@dds.nl> */

/* $Id: i2c-elv.c,v 1.17 2001/07/29 02:44:25 mds Exp $ */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>

#include <asm/uaccess.h>

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

#define DEFAULT_BASE 0x378
static int base=0;
static unsigned char PortData = 0;
static unsigned char PortStatus = 0;
static unsigned char PortCtl = 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 ----------------------------------------------	*/


static void bit_mcselec_setscl(void *data, int state)
{
	if (state) {
		PortCtl |= 0x08;
	} else {
		PortCtl &= 0xf7;
	}
	outb_p(PortCtl, CTRL);
}

static void bit_mcselec_setsda(void *data, int state)
{
	if (state) {
		PortData &= 0x7f;
	} else {
		PortData |= 0x80;
	}
	outb(PortData, DATA);
} 

static int bit_mcselec_getscl(void *data)
{
	return (inb_p(STAT) & 0x08);
}

static int bit_mcselec_getsda(void *data)
{
	return (inb_p(STAT) & 0x80);
}

static int bit_mcselec_init(void)
{
	if (check_region(base,(base == 0x3bc)? 3 : 8) < 0 ) {
		return -ENODEV;	
	} else { 
		/* test for adapter 	*/
		bit_mcselec_setscl((void*)base, 1);
		udelay(400);
		if (!bit_mcselec_getscl((void*)base)) {	/* SCL should be high	*/
			DEBINIT(printk(KERN_DEBUG "i2c-mcselec.o: SCL (Error) was low after SCL (Select) set high.\n"));
			return -ENODEV;
		} else {
			bit_mcselec_setscl((void*)base, 0);	/* SCL to low		*/
			udelay(400);
			if (bit_mcselec_getscl((void*)base)) {
				bit_mcselec_setscl((void*)base, 1);
				DEBINIT(printk(KERN_DEBUG "i2c-mcselec.o: SCL (Error) was high after SCL (Select) set low.\n"));
				return -ENODEV;
			}
		}
		request_region(base,(base == 0x3bc)? 3 : 8,
			"i2c (MCS Electronics adapter)");
		PortData = 0;
		PortStatus = 0;
		PortCtl = 0;
		bit_mcselec_setsda((void*)base,1);
		bit_mcselec_setscl((void*)base,1);
	}
	return 0;
}

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

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

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

static void bit_mcselec_inc_use(struct i2c_adapter *adap)
{
#ifdef MODULE
	MOD_INC_USE_COUNT;
#endif
}

static void bit_mcselec_dec_use(struct i2c_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.
 */
static struct i2c_algo_bit_data bit_mcselec_data = {
	NULL,
	bit_mcselec_setsda,
	bit_mcselec_setscl,
	bit_mcselec_getsda,
	bit_mcselec_getscl,
	40, 40, 50,		/*	waits, timeout */
};

static struct i2c_adapter bit_mcselec_ops = {
	"MCS Electronics parport adapter",
	I2C_HW_B_MCSELEC,
	NULL,
	&bit_mcselec_data,
	bit_mcselec_inc_use,
	bit_mcselec_dec_use,
	bit_mcselec_reg,
	bit_mcselec_unreg,	
};

int __init i2c_bitmcselec_init(void)
{
	printk(KERN_INFO "i2c-mcselec.o: i2c MCS Electronics parallel port adapter module version %s (%s)\n", I2C_VERSION, I2C_DATE);
	if (base==0) {
		/* probe some values */
		base=DEFAULT_BASE;
		bit_mcselec_data.data=(void*)DEFAULT_BASE;
		if (bit_mcselec_init()==0) {
			if(i2c_bit_add_bus(&bit_mcselec_ops) < 0)
				return -ENODEV;
		} else {
			return -ENODEV;
		}
	} else {
		bit_mcselec_ops.data=(void*)base;
		if (bit_mcselec_init()==0) {
			if(i2c_bit_add_bus(&bit_mcselec_ops) < 0)
				return -ENODEV;
		} else {
			return -ENODEV;
		}
	}
	printk(KERN_DEBUG "i2c-mcselec.o: found device at %#x.\n",base);
	return 0;
}


EXPORT_NO_SYMBOLS;

#ifdef MODULE
MODULE_AUTHOR("Sebastian Zagrodzki <s.zagrodzki@net.icm.edu.pl>");
MODULE_DESCRIPTION("I2C-Bus adapter routines for MCS Electronics parallel port adapter");
MODULE_LICENSE("GPL");

MODULE_PARM(base, "i");

int init_module(void)
{
	return i2c_bitmcselec_init();
}

void cleanup_module(void)
{
	i2c_bit_del_bus(&bit_mcselec_ops);
	bit_mcselec_exit();
}

#endif