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i2c-elv.c

/* ------------------------------------------------------------------------- */
/* i2c-elv.c i2c-hw access for philips style parallel port adapters          */
/* ------------------------------------------------------------------------- */
/*   Copyright (C) 1995-2000 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.                */
/* ------------------------------------------------------------------------- */

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

/* $Id: i2c-elv.c,v 1.30 2004/11/25 21:43:45 khali Exp $ */

#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    */


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


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

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

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

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

static int bit_elv_init(void)
{
      if (!request_region(base, (base == 0x3bc) ? 3 : 8,
                        "i2c (ELV adapter)"))
            return -ENODEV;

      if (inb(base+1) & 0x80) {     /* BUSY should be high  */
            DEBINIT(printk(KERN_DEBUG "i2c-elv.o: Busy was low.\n"));
            goto fail;
      } 

      outb(0x0c,base+2);      /* SLCT auf low         */
      udelay(400);
      if (!(inb(base+1) && 0x10)) {
            outb(0x04,base+2);
            DEBINIT(printk(KERN_DEBUG "i2c-elv.o: Select was high.\n"));
            goto fail;
      }

      PortData = 0;
      bit_elv_setsda((void*)base,1);
      bit_elv_setscl((void*)base,1);
      return 0;

fail:
      release_region(base , (base == 0x3bc) ? 3 : 8);
      return -ENODEV;
}

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

static void bit_elv_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_elv_data = {
      .setsda           = bit_elv_setsda,
      .setscl           = bit_elv_setscl,
      .getsda           = bit_elv_getsda,
      .getscl           = bit_elv_getscl,
      .udelay           = 80,
      .mdelay           = 80,
      .timeout    = HZ
};

static struct i2c_adapter bit_elv_ops = {
      .name       = "ELV Parallel port adaptor",
      .id         = I2C_HW_B_ELV,
      .algo_data  = &bit_elv_data,
      .inc_use    = bit_elv_inc_use,
      .dec_use    = bit_elv_dec_use,
};

static int __init i2c_bitelv_init(void)
{
      printk(KERN_INFO "i2c-elv.o: i2c ELV parallel port adapter module version %s (%s)\n", I2C_VERSION, I2C_DATE);
      if (base==0) {
            /* probe some values */
            base=DEFAULT_BASE;
            bit_elv_data.data=(void*)DEFAULT_BASE;
            if (bit_elv_init()==0) {
                  if(i2c_bit_add_bus(&bit_elv_ops) < 0)
                        return -ENODEV;
            } else {
                  return -ENODEV;
            }
      } else {
            bit_elv_ops.data=(void*)base;
            if (bit_elv_init()==0) {
                  if(i2c_bit_add_bus(&bit_elv_ops) < 0)
                        return -ENODEV;
            } else {
                  return -ENODEV;
            }
      }
      printk(KERN_DEBUG "i2c-elv.o: found device at %#x.\n",base);
      return 0;
}

static void __exit i2c_bitelv_exit(void)
{
      i2c_bit_del_bus(&bit_elv_ops);
      release_region(base, (base == 0x3bc) ? 3 : 8);
}

EXPORT_NO_SYMBOLS;

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

MODULE_PARM(base, "i");

module_init(i2c_bitelv_init);
module_exit(i2c_bitelv_exit);

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