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/*

   -------------------------------------------------------------------------

   i2c-adap-ite.c i2c-hw access for the IIC peripheral on the ITE MIPS system

   -------------------------------------------------------------------------

   Hai-Pao Fan, MontaVista Software, Inc.

   hpfan@mvista.com or source@mvista.com

   Copyright 2001 MontaVista Software Inc.

   ----------------------------------------------------------------------------

   This file was highly leveraged from i2c-elektor.c, which was created

   by Simon G. Vogl and Hans Berglund:

     Copyright (C) 1995-97 Simon G. Vogl

                   1998-99 Hans Berglund

    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> */

#include <linux/kernel.h>

#include <linux/ioport.h>

#include <linux/module.h>

#include <linux/delay.h>

#include <linux/slab.h>

#include <linux/init.h>

#include <asm/irq.h>

#include <asm/io.h>

#include <linux/i2c.h>

#include <linux/i2c-algo-ite.h>

#include <linux/i2c-adap-ite.h>

#include "i2c-ite.h"

#define DEFAULT_BASE  0x14014030

#define ITE_IIC_IO_SIZE 0x40

#define DEFAULT_IRQ   0

#define DEFAULT_CLOCK 0x1b0e    /* default 16MHz/(27+14) = 400KHz */

#define DEFAULT_OWN   0x55

static int base  = 0;

static int irq   = 0;

static int clock = 0;

static int own   = 0;

static int i2c_debug=0;

static struct iic_ite gpi;

static wait_queue_head_t iic_wait;

static int iic_pending;

/* ----- global defines ----------------------------------------------- */

#define DEB(x)  if (i2c_debug>=1) x

#define DEB2(x) if (i2c_debug>=2) x

#define DEB3(x) if (i2c_debug>=3) x

#define DEBE(x) x       /* error messages                               */

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

static void iic_ite_setiic(void *data, int ctl, short val)

{

        unsigned long j = jiffies + 10;

        DEB3(printk(" Write 0x%02x to 0x%x\n",(unsigned short)val, ctl&0xff));

        DEB3({while (jiffies < j) schedule();})

        outw(val,ctl);

}

static short iic_ite_getiic(void *data, int ctl)

{

        short val;

        val = inw(ctl);

        DEB3(printk("Read 0x%02x from 0x%x\n",(unsigned short)val, ctl&0xff));

        return (val);

}

/* Return our slave address.  This is the address

 * put on the I2C bus when another master on the bus wants to address us

 * as a slave

 */

static int iic_ite_getown(void *data)

{

        return (gpi.iic_own);

}

static int iic_ite_getclock(void *data)

{

        return (gpi.iic_clock);

}

#if 0

static void iic_ite_sleep(unsigned long timeout)

{

        schedule_timeout( timeout * HZ);

}

#endif

/* Put this process to sleep.  We will wake up when the

 * IIC controller interrupts.

 */

static void iic_ite_waitforpin(void) {

   int timeout = 2;

   /* If interrupts are enabled (which they are), then put the process to

    * sleep.  This process will be awakened by two events -- either the

    * the IIC peripheral interrupts or the timeout expires.

    * If interrupts are not enabled then delay for a reasonable amount

    * of time and return.

    */

   if (gpi.iic_irq > 0) {

        cli();

        if (iic_pending == 0) {

                interruptible_sleep_on_timeout(&iic_wait, timeout*HZ );

        } else

                iic_pending = 0;

        sti();

   } else {

      udelay(100);

   }

}

static void iic_ite_handler(int this_irq, void *dev_id, struct pt_regs *regs)

{

   iic_pending = 1;

   DEB2(printk("iic_ite_handler: in interrupt handler\n"));

   wake_up_interruptible(&iic_wait);

}

/* Lock the region of memory where I/O registers exist.  Request our

 * interrupt line and register its associated handler.

 */

static int iic_hw_resrc_init(void)

{

        if (check_region(gpi.iic_base, ITE_IIC_IO_SIZE) < 0 ) {

           return -ENODEV;

        } else {

           request_region(gpi.iic_base, ITE_IIC_IO_SIZE,

                "i2c (i2c bus adapter)");

        }

        if (gpi.iic_irq > 0) {

           if (request_irq(gpi.iic_irq, iic_ite_handler, 0, "ITE IIC", 0) < 0) {

              gpi.iic_irq = 0;

           } else

              DEB3(printk("Enabled IIC IRQ %d\n", gpi.iic_irq));

              enable_irq(gpi.iic_irq);

        }

        return 0;

}

static void iic_ite_release(void)

{

        if (gpi.iic_irq > 0) {

                disable_irq(gpi.iic_irq);

                free_irq(gpi.iic_irq, 0);

        }

        release_region(gpi.iic_base , 2);

}

static int iic_ite_reg(struct i2c_client *client)

{

        return 0;

}

static int iic_ite_unreg(struct i2c_client *client)

{

        return 0;

}

static void iic_ite_inc_use(struct i2c_adapter *adap)

{

#ifdef MODULE

        MOD_INC_USE_COUNT;

#endif

}

static void iic_ite_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_iic_data iic_ite_data = {

        NULL,

        iic_ite_setiic,

        iic_ite_getiic,

        iic_ite_getown,

        iic_ite_getclock,

        iic_ite_waitforpin,

        80, 80, 100,            /*      waits, timeout */

};

static struct i2c_adapter iic_ite_ops = {

        "ITE IIC adapter",

        I2C_HW_I_IIC,

        NULL,

        &iic_ite_data,

        iic_ite_inc_use,

        iic_ite_dec_use,

        iic_ite_reg,

        iic_ite_unreg,

};

/* Called when the module is loaded.  This function starts the

 * cascade of calls up through the hierarchy of i2c modules (i.e. up to the

 *  algorithm layer and into to the core layer)

 */

static int __init iic_ite_init(void)

{

        struct iic_ite *piic = &gpi;

        printk(KERN_INFO "Initialize ITE IIC adapter module\n");

        if (base == 0)

                piic->iic_base = DEFAULT_BASE;

        else

                piic->iic_base = base;

        if (irq == 0)

                piic->iic_irq = DEFAULT_IRQ;

        else

                piic->iic_irq = irq;

        if (clock == 0)

                piic->iic_clock = DEFAULT_CLOCK;

        else

                piic->iic_clock = clock;

        if (own == 0)

                piic->iic_own = DEFAULT_OWN;

        else

                piic->iic_own = own;

        iic_ite_data.data = (void *)piic;

        if (iic_hw_resrc_init() == 0) {

                if (i2c_iic_add_bus(&iic_ite_ops) < 0)

                        return -ENODEV;

        } else {

                return -ENODEV;

        }

        printk(KERN_INFO " found device at %#x irq %d.\n",

                piic->iic_base, piic->iic_irq);

        return 0;

}

static void iic_ite_exit(void)

{

        i2c_iic_del_bus(&iic_ite_ops);

        iic_ite_release();

}

EXPORT_NO_SYMBOLS;

/* If modules is NOT defined when this file is compiled, then the MODULE_*

 * macros will resolve to nothing

 */

MODULE_AUTHOR("MontaVista Software <www.mvista.com>");

MODULE_DESCRIPTION("I2C-Bus adapter routines for ITE IIC bus adapter");

MODULE_LICENSE("GPL");

MODULE_PARM(base, "i");

MODULE_PARM(irq, "i");

MODULE_PARM(clock, "i");

MODULE_PARM(own, "i");

MODULE_PARM(i2c_debug,"i");

/* Called when module is loaded or when kernel is intialized.

 * If MODULES is defined when this file is compiled, then this function will

 * resolve to init_module (the function called when insmod is invoked for a

 * module).  Otherwise, this function is called early in the boot, when the

 * kernel is intialized.  Check out /include/init.h to see how this works.

 */

module_init(iic_ite_init);

/* Resolves to module_cleanup when MODULES is defined. */

module_exit(iic_ite_exit);