root/i2c/trunk/kernel/i2c-philips-par.c @ 3317

/* ------------------------------------------------------------------------- */
/* bit-lp.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/ioport.h>
#include <linux/module.h>
#if LINUX_VERSION_CODE >= 0x020135
#include <linux/init.h>
#else
#define __init 
#endif
#include <asm/io.h>
#include <linux/stddef.h>

#include "i2c.h"
#include "i2c-algo-bit.h"

#define DEFAULT_BASE 0x378
static int base=0;

/* Note: all we need to know is the base address of the parallel port, so
 * instead of having a dedicated struct to store this value, we store this
 * int in the pointer field (=bit_lp_ops.data) itself.
 */

/* Note2: as the hw that implements the i2c bus on the parallel port is 
 * incompatible with other epp stuff etc., we access the port exclusively
 * and don't cooperate with parport functions.
 */

/* ----- 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                               */

/* ----- printer port defines ------------------------------------------*/
                                        /* Pin Port  Inverted   name    */
#define I2C_ON          0x20            /* 12 status N  paper           */
                                        /* ... only for phil. not used  */
#define I2C_SDA         0x80            /*  9 data   N  data7           */
#define I2C_SCL         0x08            /* 17 ctrl   N  dsel            */

#define I2C_SDAIN       0x80            /* 11 stat   Y  busy            */
#define I2C_SCLIN       0x08            /* 15 stat   Y  enable          */

#define I2C_DMASK       0x7f
#define I2C_CMASK       0xf7

/* --- 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_lp_setscl(void *data, int state)
{
        /*be cautious about state of the control register - 
                touch only the one bit needed*/
        if (state) {
                outb(inb(CTRL)|I2C_SCL,   CTRL);
        } else {
                outb(inb(CTRL)&I2C_CMASK, CTRL);
        }
}

void bit_lp_setsda(void *data, int state)
{
        if (state) {
                outb(I2C_DMASK , DATA);
        } else {
                outb(I2C_SDA , DATA);
        }
}

int bit_lp_getscl(void *data)
{
        return ( 0 != ( (inb(STAT)) & I2C_SCLIN ) );
}

int bit_lp_getsda(void *data)
{
        return ( 0 != ( (inb(STAT)) & I2C_SDAIN ) );
}

int bit_lp_init(void)
{
        if (check_region(base,(base == 0x3bc)? 3 : 8) < 0 ) {
                return -ENODEV;
        } else {
                request_region(base,(base == 0x3bc)? 3 : 8,
                        "i2c (parallel port adapter)");
                /* reset hardware to sane state */
                bit_lp_setsda((void*)base,1);
                bit_lp_setscl((void*)base,1);
        }
        return 0;
}

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

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

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

static void bit_lp_inc_use(struct bit_adapter *adap)
{
  MOD_INC_USE_COUNT;
}

static void bit_lp_dec_use(struct bit_adapter *adap)
{
  MOD_DEC_USE_COUNT;
}

/* ------------------------------------------------------------------------
 * 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_lp_ops = {
        "Philips Parallel port adapter",
        HW_B_LP,
        NULL,
        bit_lp_setsda,
        bit_lp_setscl,
        bit_lp_getsda,
        bit_lp_getscl,
        bit_lp_reg,
        bit_lp_unreg,
        bit_lp_inc_use,
        bit_lp_dec_use,
        80, 80, 100,            /*      waits, timeout */
};


int __init bitlp_init(void)
{
        if (base==0) {
                /* probe some values */
                base=DEFAULT_BASE;
                bit_lp_ops.data=(void*)DEFAULT_BASE;
                if (bit_lp_init()==0) {
                        i2c_bit_add_bus(&bit_lp_ops);
                } else {
                        return -ENODEV;
                }
        } else {
                bit_lp_ops.data=(void*)base;
                if (bit_lp_init()==0) {
                        i2c_bit_add_bus(&bit_lp_ops);
                } else {
                        return -ENODEV;
                }
        }
        printk("bit_lp: 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 Philips parallel port adapter");

MODULE_PARM(base, "i");

EXPORT_NO_SYMBOLS;

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

void cleanup_module(void) 
{
        i2c_bit_del_bus(&bit_lp_ops);
        bit_lp_exit();
}

#endif