drivers/i2c/busses/i2c-s6000.c - maze/linux - Git at Google

 /*
  * drivers/i2c/busses/i2c-s6000.c
  *
  * Description: Driver for S6000 Family I2C Interface
  * Copyright (c) 2008 emlix GmbH
  * Author:	Oskar Schirmer <oskar@scara.com>
  *
  * Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
  * Copyright (c) 2005-2007 Analog Devices, Inc.
  *
  * 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., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
  */

 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/i2c/s6000.h>
 #include <linux/timer.h>
 #include <linux/spinlock.h>
 #include <linux/completion.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>

 #include "i2c-s6000.h"

 #define DRV_NAME "i2c-s6000"

 #define POLL_TIMEOUT	(2 * HZ)

 struct s6i2c_if {
 	u8 __iomem		*reg; /* memory mapped registers */
 	int			irq;
 	spinlock_t		lock;
 	struct i2c_msg		*msgs; /* messages currently handled */
 	int			msgs_num; /* nb of msgs to do */
 	int			msgs_push; /* nb of msgs read/written */
 	int			msgs_done; /* nb of msgs finally handled */
 	unsigned		push; /* nb of bytes read/written in msg */
 	unsigned		done; /* nb of bytes finally handled */
 	int			timeout_count; /* timeout retries left */
 	struct timer_list	timeout_timer;
 	struct i2c_adapter	adap;
 	struct completion	complete;
 	struct clk		*clk;
 	struct resource		*res;
 };

 static inline u16 i2c_rd16(struct s6i2c_if *iface, unsigned n)
 {
 	return readw(iface->reg + (n));
 }

 static inline void i2c_wr16(struct s6i2c_if *iface, unsigned n, u16 v)
 {
 	writew(v, iface->reg + (n));
 }

 static inline u32 i2c_rd32(struct s6i2c_if *iface, unsigned n)
 {
 	return readl(iface->reg + (n));
 }

 static inline void i2c_wr32(struct s6i2c_if *iface, unsigned n, u32 v)
 {
 	writel(v, iface->reg + (n));
 }

 static struct s6i2c_if s6i2c_if;

 static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
 {
 	if (i2c_rd16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
 		i2c_rd16(iface, S6_I2C_CLRTXABRT);
 		i2c_wr16(iface, S6_I2C_INTRMASK, 0);
 		complete(&iface->complete);
 		return;
 	}
 	if (iface->msgs_done >= iface->msgs_num) {
 		dev_err(&iface->adap.dev, "s6i2c: spurious I2C irq: %04x\n",
 			i2c_rd16(iface, S6_I2C_INTRSTAT));
 		i2c_wr16(iface, S6_I2C_INTRMASK, 0);
 		return;
 	}
 	while ((iface->msgs_push < iface->msgs_num)
 	    && (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
 		struct i2c_msg *m = &iface->msgs[iface->msgs_push];
 		if (!(m->flags & I2C_M_RD))
 			i2c_wr16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
 		else
 			i2c_wr16(iface, S6_I2C_DATACMD,
 				 1 << S6_I2C_DATACMD_READ);
 		if (++iface->push >= m->len) {
 			iface->push = 0;
 			iface->msgs_push += 1;
 		}
 	}
 	do {
 		struct i2c_msg *m = &iface->msgs[iface->msgs_done];
 		if (!(m->flags & I2C_M_RD)) {
 			if (iface->msgs_done < iface->msgs_push)
 				iface->msgs_done += 1;
 			else
 				break;
 		} else if (i2c_rd16(iface, S6_I2C_STATUS)
 				& (1 << S6_I2C_STATUS_RFNE)) {
 			m->buf[iface->done] = i2c_rd16(iface, S6_I2C_DATACMD);
 			if (++iface->done >= m->len) {
 				iface->done = 0;
 				iface->msgs_done += 1;
 			}
 		} else{
 			break;
 		}
 	} while (iface->msgs_done < iface->msgs_num);
 	if (iface->msgs_done >= iface->msgs_num) {
 		i2c_wr16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
 		complete(&iface->complete);
 	} else if (iface->msgs_push >= iface->msgs_num) {
 		i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
 						 (1 << S6_I2C_INTR_RXFULL));
 	} else {
 		i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
 						 (1 << S6_I2C_INTR_TXEMPTY) |
 						 (1 << S6_I2C_INTR_RXFULL));
 	}
 }

 static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
 {
 	struct s6i2c_if *iface = dev_id;
 	if (!(i2c_rd16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
 					      | (1 << S6_I2C_INTR_RXOVER)
 					      | (1 << S6_I2C_INTR_RXFULL)
 					      | (1 << S6_I2C_INTR_TXOVER)
 					      | (1 << S6_I2C_INTR_TXEMPTY)
 					      | (1 << S6_I2C_INTR_RDREQ)
 					      | (1 << S6_I2C_INTR_TXABRT)
 					      | (1 << S6_I2C_INTR_RXDONE)
 					      | (1 << S6_I2C_INTR_ACTIVITY)
 					      | (1 << S6_I2C_INTR_STOPDET)
 					      | (1 << S6_I2C_INTR_STARTDET)
 					      | (1 << S6_I2C_INTR_GENCALL))))
 		return IRQ_NONE;

 	spin_lock(&iface->lock);
 	del_timer(&iface->timeout_timer);
 	s6i2c_handle_interrupt(iface);
 	spin_unlock(&iface->lock);
 	return IRQ_HANDLED;
 }

 static void s6i2c_timeout(unsigned long data)
 {
 	struct s6i2c_if *iface = (struct s6i2c_if *)data;
 	unsigned long flags;

 	spin_lock_irqsave(&iface->lock, flags);
 	s6i2c_handle_interrupt(iface);
 	if (--iface->timeout_count > 0) {
 		iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
 		add_timer(&iface->timeout_timer);
 	} else {
 		complete(&iface->complete);
 		i2c_wr16(iface, S6_I2C_INTRMASK, 0);
 	}
 	spin_unlock_irqrestore(&iface->lock, flags);
 }

 static int s6i2c_master_xfer(struct i2c_adapter *adap,
 				struct i2c_msg *msgs, int num)
 {
 	struct s6i2c_if *iface = adap->algo_data;
 	int i;
 	if (num == 0)
 		return 0;
 	if (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
 		yield();
 	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
 	i2c_rd16(iface, S6_I2C_CLRINTR);
 	for (i = 0; i < num; i++) {
 		if (msgs[i].flags & I2C_M_TEN) {
 			dev_err(&adap->dev,
 				"s6i2c: 10 bits addr not supported\n");
 			return -EINVAL;
 		}
 		if (msgs[i].len == 0) {
 			dev_err(&adap->dev,
 				"s6i2c: zero length message not supported\n");
 			return -EINVAL;
 		}
 		if (msgs[i].addr != msgs[0].addr) {
 			dev_err(&adap->dev,
 				"s6i2c: multiple xfer cannot change target\n");
 			return -EINVAL;
 		}
 	}

 	iface->msgs = msgs;
 	iface->msgs_num = num;
 	iface->msgs_push = 0;
 	iface->msgs_done = 0;
 	iface->push = 0;
 	iface->done = 0;
 	iface->timeout_count = 10;
 	i2c_wr16(iface, S6_I2C_TAR, msgs[0].addr);
 	i2c_wr16(iface, S6_I2C_ENABLE, 1);
 	i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
 					 (1 << S6_I2C_INTR_TXABRT));

 	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
 	add_timer(&iface->timeout_timer);
 	wait_for_completion(&iface->complete);
 	del_timer_sync(&iface->timeout_timer);
 	while (i2c_rd32(iface, S6_I2C_TXFLR) > 0)
 		schedule();
 	while (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
 		schedule();

 	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
 	i2c_wr16(iface, S6_I2C_ENABLE, 0);
 	return iface->msgs_done;
 }

 static u32 s6i2c_functionality(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }

 static struct i2c_algorithm s6i2c_algorithm = {
 	.master_xfer   = s6i2c_master_xfer,
 	.functionality = s6i2c_functionality,
 };

 static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
 {
 	u32 dividend = ((clk_get_rate(iface->clk) / 1000) * ns) / 1000000;
 	if (dividend > 0xffff)
 		return 0xffff;
 	return dividend;
 }

 static int __devinit s6i2c_probe(struct platform_device *dev)
 {
 	struct s6i2c_if *iface = &s6i2c_if;
 	struct i2c_adapter *p_adap;
 	const char *clock;
 	int bus_num, rc;
 	spin_lock_init(&iface->lock);
 	init_completion(&iface->complete);
 	iface->irq = platform_get_irq(dev, 0);
 	if (iface->irq < 0) {
 		rc = iface->irq;
 		goto err_out;
 	}
 	iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 	if (!iface->res) {
 		rc = -ENXIO;
 		goto err_out;
 	}
 	iface->res = request_mem_region(iface->res->start,
 					resource_size(iface->res),
 					dev->dev.bus_id);
 	if (!iface->res) {
 		rc = -EBUSY;
 		goto err_out;
 	}
 	iface->reg = ioremap_nocache(iface->res->start,
 				     resource_size(iface->res));
 	if (!iface->reg) {
 		rc = -ENOMEM;
 		goto err_reg;
 	}

 	clock = 0;
 	bus_num = -1;
 	if (dev->dev.platform_data) {
 		struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
 		bus_num = pdata->bus_num;
 		clock = pdata->clock;
 	}
 	iface->clk = clk_get(&dev->dev, clock);
 	if (IS_ERR(iface->clk)) {
 		rc = PTR_ERR(iface->clk);
 		goto err_map;
 	}
 	rc = clk_enable(iface->clk);
 	if (rc < 0)
 		goto err_clk_put;
 	init_timer(&iface->timeout_timer);
 	iface->timeout_timer.function = s6i2c_timeout;
 	iface->timeout_timer.data = (unsigned long)iface;

 	p_adap = &iface->adap;
 	strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
 	p_adap->algo = &s6i2c_algorithm;
 	p_adap->algo_data = iface;
 	p_adap->nr = bus_num;
 	p_adap->class = 0;
 	p_adap->dev.parent = &dev->dev;
 	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
 	rc = request_irq(iface->irq, s6i2c_interrupt_entry,
 			 IRQF_SHARED, dev->name, iface);
 	if (rc) {
 		dev_err(&p_adap->dev, "s6i2c: can't get IRQ %d\n", iface->irq);
 		goto err_clk_dis;
 	}

 	i2c_wr16(iface, S6_I2C_ENABLE, 0);
 	udelay(1);
 	i2c_wr32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
 	i2c_wr16(iface, S6_I2C_CLRTXABRT, 1);
 	i2c_wr16(iface, S6_I2C_CON,
 			(1 << S6_I2C_CON_MASTER) |
 			(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
 			(0 << S6_I2C_CON_10BITSLAVE) |
 			(0 << S6_I2C_CON_10BITMASTER) |
 			(1 << S6_I2C_CON_RESTARTENA) |
 			(1 << S6_I2C_CON_SLAVEDISABLE));
 	i2c_wr16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
 	i2c_wr16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
 	i2c_wr16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
 	i2c_wr16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
 	i2c_wr16(iface, S6_I2C_RXTL, 0);
 	i2c_wr16(iface, S6_I2C_TXTL, 0);

 	platform_set_drvdata(dev, iface);
 	rc = i2c_add_numbered_adapter(p_adap);
 	if (rc)
 		goto err_irq_free;
 	return 0;

 err_irq_free:
 	free_irq(iface->irq, iface);
 err_clk_dis:
 	clk_disable(iface->clk);
 err_clk_put:
 	clk_put(iface->clk);
 err_map:
 	iounmap(iface->reg);
 err_reg:
 	release_mem_region(iface->res->start,
 			   resource_size(iface->res));
 err_out:
 	return rc;
 }

 static int __devexit s6i2c_remove(struct platform_device *pdev)
 {
 	struct s6i2c_if *iface = platform_get_drvdata(pdev);
 	i2c_wr16(iface, S6_I2C_ENABLE, 0);
 	platform_set_drvdata(pdev, NULL);
 	i2c_del_adapter(&iface->adap);
 	free_irq(iface->irq, iface);
 	clk_disable(iface->clk);
 	clk_put(iface->clk);
 	iounmap(iface->reg);
 	release_mem_region(iface->res->start,
 			   resource_size(iface->res));
 	return 0;
 }

 static struct platform_driver s6i2c_driver = {
 	.probe		= s6i2c_probe,
 	.remove		= __devexit_p(s6i2c_remove),
 	.driver		= {
 		.name	= DRV_NAME,
 		.owner	= THIS_MODULE,
 	},
 };

 static int __init s6i2c_init(void)
 {
 	pr_info("I2C: S6000 I2C driver\n");
 	return platform_driver_register(&s6i2c_driver);
 }

 static void __exit s6i2c_exit(void)
 {
 	platform_driver_unregister(&s6i2c_driver);
 }

 MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:" DRV_NAME);

 subsys_initcall(s6i2c_init);
 module_exit(s6i2c_exit);
	/*
	* drivers/i2c/busses/i2c-s6000.c
	*
	* Description: Driver for S6000 Family I2C Interface
	* Copyright (c) 2008 emlix GmbH
	* Author: Oskar Schirmer <oskar@scara.com>
	*
	* Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
	* Copyright (c) 2005-2007 Analog Devices, Inc.
	*
	* 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., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
	*/

	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/delay.h>
	#include <linux/i2c.h>
	#include <linux/i2c/s6000.h>
	#include <linux/timer.h>
	#include <linux/spinlock.h>
	#include <linux/completion.h>
	#include <linux/interrupt.h>
	#include <linux/platform_device.h>
	#include <linux/io.h>

	#include "i2c-s6000.h"

	#define DRV_NAME "i2c-s6000"

	#define POLL_TIMEOUT (2 * HZ)

	struct s6i2c_if {
	u8 __iomem reg; / memory mapped registers */
	int irq;
	spinlock_t lock;
	struct i2c_msg msgs; / messages currently handled */
	int msgs_num; /* nb of msgs to do */
	int msgs_push; /* nb of msgs read/written */
	int msgs_done; /* nb of msgs finally handled */
	unsigned push; /* nb of bytes read/written in msg */
	unsigned done; /* nb of bytes finally handled */
	int timeout_count; /* timeout retries left */
	struct timer_list timeout_timer;
	struct i2c_adapter adap;
	struct completion complete;
	struct clk *clk;
	struct resource *res;
	};

	static inline u16 i2c_rd16(struct s6i2c_if *iface, unsigned n)
	{
	return readw(iface->reg + (n));
	}

	static inline void i2c_wr16(struct s6i2c_if *iface, unsigned n, u16 v)
	{
	writew(v, iface->reg + (n));
	}

	static inline u32 i2c_rd32(struct s6i2c_if *iface, unsigned n)
	{
	return readl(iface->reg + (n));
	}

	static inline void i2c_wr32(struct s6i2c_if *iface, unsigned n, u32 v)
	{
	writel(v, iface->reg + (n));
	}

	static struct s6i2c_if s6i2c_if;

	static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
	{
	if (i2c_rd16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
	i2c_rd16(iface, S6_I2C_CLRTXABRT);
	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
	complete(&iface->complete);
	return;
	}
	if (iface->msgs_done >= iface->msgs_num) {
	dev_err(&iface->adap.dev, "s6i2c: spurious I2C irq: %04x\n",
	i2c_rd16(iface, S6_I2C_INTRSTAT));
	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
	return;
	}
	while ((iface->msgs_push < iface->msgs_num)
	&& (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
	struct i2c_msg *m = &iface->msgs[iface->msgs_push];
	if (!(m->flags & I2C_M_RD))
	i2c_wr16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
	else
	i2c_wr16(iface, S6_I2C_DATACMD,
	1 << S6_I2C_DATACMD_READ);
	if (++iface->push >= m->len) {
	iface->push = 0;
	iface->msgs_push += 1;
	}
	}
	do {
	struct i2c_msg *m = &iface->msgs[iface->msgs_done];
	if (!(m->flags & I2C_M_RD)) {
	if (iface->msgs_done < iface->msgs_push)
	iface->msgs_done += 1;
	else
	break;
	} else if (i2c_rd16(iface, S6_I2C_STATUS)
	& (1 << S6_I2C_STATUS_RFNE)) {
	m->buf[iface->done] = i2c_rd16(iface, S6_I2C_DATACMD);
	if (++iface->done >= m->len) {
	iface->done = 0;
	iface->msgs_done += 1;
	}
	} else{
	break;
	}
	} while (iface->msgs_done < iface->msgs_num);
	if (iface->msgs_done >= iface->msgs_num) {
	i2c_wr16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
	complete(&iface->complete);
	} else if (iface->msgs_push >= iface->msgs_num) {
	i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) \|
	(1 << S6_I2C_INTR_RXFULL));
	} else {
	i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) \|
	(1 << S6_I2C_INTR_TXEMPTY) \|
	(1 << S6_I2C_INTR_RXFULL));
	}
	}

	static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
	{
	struct s6i2c_if *iface = dev_id;
	if (!(i2c_rd16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
	\| (1 << S6_I2C_INTR_RXOVER)
	\| (1 << S6_I2C_INTR_RXFULL)
	\| (1 << S6_I2C_INTR_TXOVER)
	\| (1 << S6_I2C_INTR_TXEMPTY)
	\| (1 << S6_I2C_INTR_RDREQ)
	\| (1 << S6_I2C_INTR_TXABRT)
	\| (1 << S6_I2C_INTR_RXDONE)
	\| (1 << S6_I2C_INTR_ACTIVITY)
	\| (1 << S6_I2C_INTR_STOPDET)
	\| (1 << S6_I2C_INTR_STARTDET)
	\| (1 << S6_I2C_INTR_GENCALL))))
	return IRQ_NONE;

	spin_lock(&iface->lock);
	del_timer(&iface->timeout_timer);
	s6i2c_handle_interrupt(iface);
	spin_unlock(&iface->lock);
	return IRQ_HANDLED;
	}

	static void s6i2c_timeout(unsigned long data)
	{
	struct s6i2c_if iface = (struct s6i2c_if )data;
	unsigned long flags;

	spin_lock_irqsave(&iface->lock, flags);
	s6i2c_handle_interrupt(iface);
	if (--iface->timeout_count > 0) {
	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
	add_timer(&iface->timeout_timer);
	} else {
	complete(&iface->complete);
	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
	}
	spin_unlock_irqrestore(&iface->lock, flags);
	}

	static int s6i2c_master_xfer(struct i2c_adapter *adap,
	struct i2c_msg *msgs, int num)
	{
	struct s6i2c_if *iface = adap->algo_data;
	int i;
	if (num == 0)
	return 0;
	if (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
	yield();
	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
	i2c_rd16(iface, S6_I2C_CLRINTR);
	for (i = 0; i < num; i++) {
	if (msgs[i].flags & I2C_M_TEN) {
	dev_err(&adap->dev,
	"s6i2c: 10 bits addr not supported\n");
	return -EINVAL;
	}
	if (msgs[i].len == 0) {
	dev_err(&adap->dev,
	"s6i2c: zero length message not supported\n");
	return -EINVAL;
	}
	if (msgs[i].addr != msgs[0].addr) {
	dev_err(&adap->dev,
	"s6i2c: multiple xfer cannot change target\n");
	return -EINVAL;
	}
	}

	iface->msgs = msgs;
	iface->msgs_num = num;
	iface->msgs_push = 0;
	iface->msgs_done = 0;
	iface->push = 0;
	iface->done = 0;
	iface->timeout_count = 10;
	i2c_wr16(iface, S6_I2C_TAR, msgs[0].addr);
	i2c_wr16(iface, S6_I2C_ENABLE, 1);
	i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) \|
	(1 << S6_I2C_INTR_TXABRT));

	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
	add_timer(&iface->timeout_timer);
	wait_for_completion(&iface->complete);
	del_timer_sync(&iface->timeout_timer);
	while (i2c_rd32(iface, S6_I2C_TXFLR) > 0)
	schedule();
	while (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
	schedule();

	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
	i2c_wr16(iface, S6_I2C_ENABLE, 0);
	return iface->msgs_done;
	}

	static u32 s6i2c_functionality(struct i2c_adapter *adap)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	}

	static struct i2c_algorithm s6i2c_algorithm = {
	.master_xfer = s6i2c_master_xfer,
	.functionality = s6i2c_functionality,
	};

	static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
	{
	u32 dividend = ((clk_get_rate(iface->clk) / 1000) * ns) / 1000000;
	if (dividend > 0xffff)
	return 0xffff;
	return dividend;
	}

	static int __devinit s6i2c_probe(struct platform_device *dev)
	{
	struct s6i2c_if *iface = &s6i2c_if;
	struct i2c_adapter *p_adap;
	const char *clock;
	int bus_num, rc;
	spin_lock_init(&iface->lock);
	init_completion(&iface->complete);
	iface->irq = platform_get_irq(dev, 0);
	if (iface->irq < 0) {
	rc = iface->irq;
	goto err_out;
	}
	iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
	if (!iface->res) {
	rc = -ENXIO;
	goto err_out;
	}
	iface->res = request_mem_region(iface->res->start,
	resource_size(iface->res),
	dev->dev.bus_id);
	if (!iface->res) {
	rc = -EBUSY;
	goto err_out;
	}
	iface->reg = ioremap_nocache(iface->res->start,
	resource_size(iface->res));
	if (!iface->reg) {
	rc = -ENOMEM;
	goto err_reg;
	}

	clock = 0;
	bus_num = -1;
	if (dev->dev.platform_data) {
	struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
	bus_num = pdata->bus_num;
	clock = pdata->clock;
	}
	iface->clk = clk_get(&dev->dev, clock);
	if (IS_ERR(iface->clk)) {
	rc = PTR_ERR(iface->clk);
	goto err_map;
	}
	rc = clk_enable(iface->clk);
	if (rc < 0)
	goto err_clk_put;
	init_timer(&iface->timeout_timer);
	iface->timeout_timer.function = s6i2c_timeout;
	iface->timeout_timer.data = (unsigned long)iface;

	p_adap = &iface->adap;
	strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
	p_adap->algo = &s6i2c_algorithm;
	p_adap->algo_data = iface;
	p_adap->nr = bus_num;
	p_adap->class = 0;
	p_adap->dev.parent = &dev->dev;
	i2c_wr16(iface, S6_I2C_INTRMASK, 0);
	rc = request_irq(iface->irq, s6i2c_interrupt_entry,
	IRQF_SHARED, dev->name, iface);
	if (rc) {
	dev_err(&p_adap->dev, "s6i2c: can't get IRQ %d\n", iface->irq);
	goto err_clk_dis;
	}

	i2c_wr16(iface, S6_I2C_ENABLE, 0);
	udelay(1);
	i2c_wr32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
	i2c_wr16(iface, S6_I2C_CLRTXABRT, 1);
	i2c_wr16(iface, S6_I2C_CON,
	(1 << S6_I2C_CON_MASTER) \|
	(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) \|
	(0 << S6_I2C_CON_10BITSLAVE) \|
	(0 << S6_I2C_CON_10BITMASTER) \|
	(1 << S6_I2C_CON_RESTARTENA) \|
	(1 << S6_I2C_CON_SLAVEDISABLE));
	i2c_wr16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
	i2c_wr16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
	i2c_wr16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
	i2c_wr16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
	i2c_wr16(iface, S6_I2C_RXTL, 0);
	i2c_wr16(iface, S6_I2C_TXTL, 0);

	platform_set_drvdata(dev, iface);
	rc = i2c_add_numbered_adapter(p_adap);
	if (rc)
	goto err_irq_free;
	return 0;

	err_irq_free:
	free_irq(iface->irq, iface);
	err_clk_dis:
	clk_disable(iface->clk);
	err_clk_put:
	clk_put(iface->clk);
	err_map:
	iounmap(iface->reg);
	err_reg:
	release_mem_region(iface->res->start,
	resource_size(iface->res));
	err_out:
	return rc;
	}

	static int __devexit s6i2c_remove(struct platform_device *pdev)
	{
	struct s6i2c_if *iface = platform_get_drvdata(pdev);
	i2c_wr16(iface, S6_I2C_ENABLE, 0);
	platform_set_drvdata(pdev, NULL);
	i2c_del_adapter(&iface->adap);
	free_irq(iface->irq, iface);
	clk_disable(iface->clk);
	clk_put(iface->clk);
	iounmap(iface->reg);
	release_mem_region(iface->res->start,
	resource_size(iface->res));
	return 0;
	}

	static struct platform_driver s6i2c_driver = {
	.probe = s6i2c_probe,
	.remove = __devexit_p(s6i2c_remove),
	.driver = {
	.name = DRV_NAME,
	.owner = THIS_MODULE,
	},
	};

	static int __init s6i2c_init(void)
	{
	pr_info("I2C: S6000 I2C driver\n");
	return platform_driver_register(&s6i2c_driver);
	}

	static void __exit s6i2c_exit(void)
	{
	platform_driver_unregister(&s6i2c_driver);
	}

	MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:" DRV_NAME);

	subsys_initcall(s6i2c_init);
	module_exit(s6i2c_exit);