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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 <linux/wait.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;
static int irq;
static int clock;
static int own;
static struct iic_ite gpi;
static wait_queue_head_t iic_wait;
static int iic_pending;
static spinlock_t lock;
/* ----- local functions ---------------------------------------------- */
static void iic_ite_setiic(void *data, int ctl, short val)
{
unsigned long j = jiffies + 10;
pr_debug(" Write 0x%02x to 0x%x\n",(unsigned short)val, ctl&0xff);
#ifdef DEBUG
while (time_before(jiffies, j))
schedule();
#endif
outw(val,ctl);
}
static short iic_ite_getiic(void *data, int ctl)
{
short val;
val = inw(ctl);
pr_debug("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);
}
/* Put this process to sleep. We will wake up when the
* IIC controller interrupts.
*/
static void iic_ite_waitforpin(void) {
DEFINE_WAIT(wait);
int timeout = 2;
unsigned long flags;
/* 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) {
spin_lock_irqsave(&lock, flags);
if (iic_pending == 0) {
spin_unlock_irqrestore(&lock, flags);
prepare_to_wait(&iic_wait, &wait, TASK_INTERRUPTIBLE);
if (schedule_timeout(timeout*HZ)) {
spin_lock_irqsave(&lock, flags);
if (iic_pending == 1) {
iic_pending = 0;
}
spin_unlock_irqrestore(&lock, flags);
}
finish_wait(&iic_wait, &wait);
} else {
iic_pending = 0;
spin_unlock_irqrestore(&lock, flags);
}
} else {
udelay(100);
}
}
static irqreturn_t iic_ite_handler(int this_irq, void *dev_id,
struct pt_regs *regs)
{
spin_lock(&lock);
iic_pending = 1;
spin_unlock(&lock);
wake_up_interruptible(&iic_wait);
return IRQ_HANDLED;
}
/* 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 (!request_region(gpi.iic_base, ITE_IIC_IO_SIZE, "i2c"))
return -ENODEV;
if (gpi.iic_irq <= 0)
return 0;
if (request_irq(gpi.iic_irq, iic_ite_handler, 0, "ITE IIC", 0) < 0)
gpi.iic_irq = 0;
else
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);
}
/* ------------------------------------------------------------------------
* 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 = {
.owner = THIS_MODULE,
.id = I2C_HW_I_IIC,
.algo_data = &iic_ite_data,
.name = "ITE IIC adapter",
};
/* 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;
init_waitqueue_head(&iic_wait);
spin_lock_init(&lock);
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();
}
/* 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_param(base, int, 0);
module_param(irq, int, 0);
module_param(clock, int, 0);
module_param(own, int, 0);
/* Called when module is loaded or when kernel is initialized.
* 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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