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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/malloc.h>
#include <linux/version.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;
#if (LINUX_VERSION_CODE < 0x020301)
static struct wait_queue *iic_wait = NULL;
#else
static wait_queue_head_t iic_wait;
#endif
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 heirarchy 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 (LINUX_VERSION_CODE >= 0x020301)
init_waitqueue_head(&iic_wait);
#endif
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_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);
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