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i2c-philips-par.c

/* ------------------------------------------------------------------------- */
/* i2c-philips-par.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-philips-par.c,v 1.34 2004/11/25 21:43:45 khali Exp $ */

#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/stddef.h>
#include <linux/parport.h>
#include <linux/slab.h>
#include "i2c.h"
#include "i2c-algo-bit.h"

static int type;

struct i2c_par
{
      struct pardevice *pdev;
      struct i2c_adapter adapter;
      struct i2c_algo_bit_data bit_lp_data;
      struct i2c_par *next;
};

static struct i2c_par *adapter_list;


/* ----- 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

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

static void bit_lp_setscl(void *data, int state)
{
      /*be cautious about state of the control register - 
            touch only the one bit needed*/
      if (state) {
            parport_write_control((struct parport *) data,
                  parport_read_control((struct parport *) data)|I2C_SCL);
      } else {
            parport_write_control((struct parport *) data,
                  parport_read_control((struct parport *) data)&I2C_CMASK);
      }
}

static void bit_lp_setsda(void *data, int state)
{
      if (state) {
            parport_write_data((struct parport *) data, I2C_DMASK);
      } else {
            parport_write_data((struct parport *) data, I2C_SDA);
      }
}

static int bit_lp_getscl(void *data)
{
      return parport_read_status((struct parport *) data) & I2C_SCLIN;
}

static int bit_lp_getsda(void *data)
{
      return parport_read_status((struct parport *) data) & I2C_SDAIN;
}

static void bit_lp_setscl2(void *data, int state)
{
      if (state) {
            parport_write_data((struct parport *) data,
                  parport_read_data((struct parport *) data)|0x1);
      } else {
            parport_write_data((struct parport *) data,
                  parport_read_data((struct parport *) data)&0xfe);
      }
}

static void bit_lp_setsda2(void *data, int state)
{
      if (state) {
            parport_write_data((struct parport *) data,
                  parport_read_data((struct parport *) data)|0x2);
      } else {
            parport_write_data((struct parport *) data,
                  parport_read_data((struct parport *) data)&0xfd);
      }
}

static int bit_lp_getsda2(void *data)
{
      return (parport_read_status((struct parport *) data) & 
                               PARPORT_STATUS_BUSY) ? 0 : 1;
}

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

static void bit_lp_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_lp_data = {
      .setsda           = bit_lp_setsda,
      .setscl           = bit_lp_setscl,
      .getsda           = bit_lp_getsda,
      .getscl           = bit_lp_getscl,
      .udelay           = 80,
      .mdelay           = 80,
      .timeout    = HZ
}; 

static struct i2c_algo_bit_data bit_lp_data2 = {
      .setsda           = bit_lp_setsda2,
      .setscl           = bit_lp_setscl2,
      .getsda           = bit_lp_getsda2,
      .udelay           = 80,
      .mdelay           = 80,
      .timeout    = HZ
}; 

static struct i2c_adapter bit_lp_ops = {
      .name       = "Philips Parallel port adapter",
      .id         = I2C_HW_B_LP,
      .inc_use    = bit_lp_inc_use,
      .dec_use    = bit_lp_dec_use,
};

static void i2c_parport_attach (struct parport *port)
{
      struct i2c_par *adapter = kmalloc(sizeof(struct i2c_par),
                                GFP_KERNEL);
      if (!adapter) {
            printk(KERN_ERR "i2c-philips-par: Unable to malloc.\n");
            return;
      }

      printk(KERN_DEBUG "i2c-philips-par.o: attaching to %s\n", port->name);

      adapter->pdev = parport_register_device(port, "i2c-philips-par",
                                    NULL, NULL, NULL, 
                                    PARPORT_FLAG_EXCL,
                                    NULL);
      if (!adapter->pdev) {
            printk(KERN_ERR "i2c-philips-par: Unable to register with parport.\n");
            kfree(adapter);
            return;
      }

      adapter->adapter = bit_lp_ops;
      adapter->adapter.algo_data = &adapter->bit_lp_data;
      adapter->bit_lp_data = type ? bit_lp_data2 : bit_lp_data;
      adapter->bit_lp_data.data = port;

      if (parport_claim_or_block(adapter->pdev) < 0 ) {
            printk(KERN_ERR "i2c-philips-par: Could not claim parallel port.\n");
            kfree(adapter);
            return;
      }
      /* reset hardware to sane state */
      adapter->bit_lp_data.setsda(port, 1);
      adapter->bit_lp_data.setscl(port, 1);
      parport_release(adapter->pdev);

      if (i2c_bit_add_bus(&adapter->adapter) < 0)
      {
            printk(KERN_ERR "i2c-philips-par: Unable to register with I2C.\n");
            parport_unregister_device(adapter->pdev);
            kfree(adapter);
            return;           /* No good */
      }

      adapter->next = adapter_list;
      adapter_list = adapter;
}

static void i2c_parport_detach (struct parport *port)
{
      struct i2c_par *adapter, *prev = NULL;

      for (adapter = adapter_list; adapter; adapter = adapter->next)
      {
            if (adapter->pdev->port == port)
            {
                  parport_unregister_device(adapter->pdev);
                  i2c_bit_del_bus(&adapter->adapter);
                  if (prev)
                        prev->next = adapter->next;
                  else
                        adapter_list = adapter->next;
                  kfree(adapter);
                  return;
            }
            prev = adapter;
      }
}


static struct parport_driver i2c_driver = {
      "i2c-philips-par",
      i2c_parport_attach,
      i2c_parport_detach,
      NULL
};

static int __init i2c_bitlp_init(void)
{
      printk(KERN_INFO "i2c-philips-par.o: i2c Philips parallel port adapter module version %s (%s)\n", I2C_VERSION, I2C_DATE);

      parport_register_driver(&i2c_driver);
      
      return 0;
}

static void __exit i2c_bitlp_exit(void)
{
      parport_unregister_driver(&i2c_driver);
}

EXPORT_NO_SYMBOLS;

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

MODULE_PARM(type, "i");

module_init(i2c_bitlp_init);
module_exit(i2c_bitlp_exit);

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