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

 /*
  * SuperH Mobile I2C Controller
  *
  * Copyright (C) 2008 Magnus Damm
  *
  * Portions of the code based on out-of-tree driver i2c-sh7343.c
  * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>
  *
  * 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
  *
  * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */

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

 enum sh_mobile_i2c_op {
 	OP_START = 0,
 	OP_TX_ONLY,
 	OP_TX_STOP,
 	OP_TX_TO_RX,
 	OP_RX_ONLY,
 	OP_RX_STOP,
 };

 struct sh_mobile_i2c_data {
 	struct device *dev;
 	void __iomem *reg;
 	struct i2c_adapter adap;

 	struct clk *clk;
 	u_int8_t iccl;
 	u_int8_t icch;

 	spinlock_t lock;
 	wait_queue_head_t wait;
 	struct i2c_msg *msg;
 	int pos;
 	int sr;
 };

 #define NORMAL_SPEED		100000 /* FAST_SPEED 400000 */

 /* Register offsets */
 #define ICDR(pd)		(pd->reg + 0x00)
 #define ICCR(pd)		(pd->reg + 0x04)
 #define ICSR(pd)		(pd->reg + 0x08)
 #define ICIC(pd)		(pd->reg + 0x0c)
 #define ICCL(pd)		(pd->reg + 0x10)
 #define ICCH(pd)		(pd->reg + 0x14)

 /* Register bits */
 #define ICCR_ICE		0x80
 #define ICCR_RACK		0x40
 #define ICCR_TRS		0x10
 #define ICCR_BBSY		0x04
 #define ICCR_SCP		0x01

 #define ICSR_SCLM		0x80
 #define ICSR_SDAM		0x40
 #define SW_DONE			0x20
 #define ICSR_BUSY		0x10
 #define ICSR_AL			0x08
 #define ICSR_TACK		0x04
 #define ICSR_WAIT		0x02
 #define ICSR_DTE		0x01

 #define ICIC_ALE		0x08
 #define ICIC_TACKE		0x04
 #define ICIC_WAITE		0x02
 #define ICIC_DTEE		0x01

 static void activate_ch(struct sh_mobile_i2c_data *pd)
 {
 	/* Make sure the clock is enabled */
 	clk_enable(pd->clk);

 	/* Enable channel and configure rx ack */
 	iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));

 	/* Mask all interrupts */
 	iowrite8(0, ICIC(pd));

 	/* Set the clock */
 	iowrite8(pd->iccl, ICCL(pd));
 	iowrite8(pd->icch, ICCH(pd));
 }

 static void deactivate_ch(struct sh_mobile_i2c_data *pd)
 {
 	/* Clear/disable interrupts */
 	iowrite8(0, ICSR(pd));
 	iowrite8(0, ICIC(pd));

 	/* Disable channel */
 	iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));

 	/* Disable clock */
 	clk_disable(pd->clk);
 }

 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
 			    enum sh_mobile_i2c_op op, unsigned char data)
 {
 	unsigned char ret = 0;
 	unsigned long flags;

 	dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);

 	spin_lock_irqsave(&pd->lock, flags);

 	switch (op) {
 	case OP_START:
 		iowrite8(0x94, ICCR(pd));
 		break;
 	case OP_TX_ONLY:
 		iowrite8(data, ICDR(pd));
 		break;
 	case OP_TX_STOP:
 		iowrite8(data, ICDR(pd));
 		iowrite8(0x90, ICCR(pd));
 		iowrite8(ICIC_ALE | ICIC_TACKE, ICIC(pd));
 		break;
 	case OP_TX_TO_RX:
 		iowrite8(data, ICDR(pd));
 		iowrite8(0x81, ICCR(pd));
 		break;
 	case OP_RX_ONLY:
 		ret = ioread8(ICDR(pd));
 		break;
 	case OP_RX_STOP:
 		ret = ioread8(ICDR(pd));
 		iowrite8(0xc0, ICCR(pd));
 		break;
 	}

 	spin_unlock_irqrestore(&pd->lock, flags);

 	dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
 	return ret;
 }

 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
 {
 	struct platform_device *dev = dev_id;
 	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
 	struct i2c_msg *msg = pd->msg;
 	unsigned char data, sr;
 	int wakeup = 0;

 	sr = ioread8(ICSR(pd));
 	pd->sr |= sr;

 	dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
 	       (msg->flags & I2C_M_RD) ? "read" : "write",
 	       pd->pos, msg->len);

 	if (sr & (ICSR_AL | ICSR_TACK)) {
 		iowrite8(0, ICIC(pd)); /* disable interrupts */
 		wakeup = 1;
 		goto do_wakeup;
 	}

 	if (pd->pos == msg->len) {
 		i2c_op(pd, OP_RX_ONLY, 0);
 		wakeup = 1;
 		goto do_wakeup;
 	}

 	if (pd->pos == -1) {
 		data = (msg->addr & 0x7f) << 1;
 		data |= (msg->flags & I2C_M_RD) ? 1 : 0;
 	} else
 		data = msg->buf[pd->pos];

 	if ((pd->pos == -1) || !(msg->flags & I2C_M_RD)) {
 		if (msg->flags & I2C_M_RD)
 			i2c_op(pd, OP_TX_TO_RX, data);
 		else if (pd->pos == (msg->len - 1)) {
 			i2c_op(pd, OP_TX_STOP, data);
 			wakeup = 1;
 		} else
 			i2c_op(pd, OP_TX_ONLY, data);
 	} else {
 		if (pd->pos == (msg->len - 1))
 			data = i2c_op(pd, OP_RX_STOP, 0);
 		else
 			data = i2c_op(pd, OP_RX_ONLY, 0);

 		msg->buf[pd->pos] = data;
 	}
 	pd->pos++;

  do_wakeup:
 	if (wakeup) {
 		pd->sr |= SW_DONE;
 		wake_up(&pd->wait);
 	}

 	return IRQ_HANDLED;
 }

 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
 {
 	/* Initialize channel registers */
 	iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));

 	/* Enable channel and configure rx ack */
 	iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));

 	/* Set the clock */
 	iowrite8(pd->iccl, ICCL(pd));
 	iowrite8(pd->icch, ICCH(pd));

 	pd->msg = usr_msg;
 	pd->pos = -1;
 	pd->sr = 0;

 	/* Enable all interrupts except wait */
 	iowrite8(ioread8(ICIC(pd)) | ICIC_ALE | ICIC_TACKE | ICIC_DTEE,
 		 ICIC(pd));
 	return 0;
 }

 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
 			      struct i2c_msg *msgs,
 			      int num)
 {
 	struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
 	struct i2c_msg	*msg;
 	int err = 0;
 	u_int8_t val;
 	int i, k, retry_count;

 	activate_ch(pd);

 	/* Process all messages */
 	for (i = 0; i < num; i++) {
 		msg = &msgs[i];

 		err = start_ch(pd, msg);
 		if (err)
 			break;

 		i2c_op(pd, OP_START, 0);

 		/* The interrupt handler takes care of the rest... */
 		k = wait_event_timeout(pd->wait,
 				       pd->sr & (ICSR_TACK | SW_DONE),
 				       5 * HZ);
 		if (!k)
 			dev_err(pd->dev, "Transfer request timed out\n");

 		retry_count = 10;
 again:
 		val = ioread8(ICSR(pd));

 		dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);

 		if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
 			err = -EIO;
 			break;
 		}

 		/* the interrupt handler may wake us up before the
 		 * transfer is finished, so poll the hardware
 		 * until we're done.
 		 */

 		if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) &&
 		      (val & ICSR_SDAM))) {
 			msleep(1);
 			if (retry_count--)
 				goto again;

 			err = -EIO;
 			dev_err(pd->dev, "Polling timed out\n");
 			break;
 		}
 	}

 	deactivate_ch(pd);

 	if (!err)
 		err = num;
 	return err;
 }

 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }

 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
 	.functionality	= sh_mobile_i2c_func,
 	.master_xfer	= sh_mobile_i2c_xfer,
 };

 static void sh_mobile_i2c_setup_channel(struct platform_device *dev)
 {
 	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
 	unsigned long peripheral_clk = clk_get_rate(pd->clk);
 	u_int32_t num;
 	u_int32_t denom;
 	u_int32_t tmp;

 	spin_lock_init(&pd->lock);
 	init_waitqueue_head(&pd->wait);

 	/* Calculate the value for iccl. From the data sheet:
 	 * iccl = (p clock / transfer rate) * (L / (L + H))
 	 * where L and H are the SCL low/high ratio (5/4 in this case).
 	 * We also round off the result.
 	 */
 	num = peripheral_clk * 5;
 	denom = NORMAL_SPEED * 9;
 	tmp = num * 10 / denom;
 	if (tmp % 10 >= 5)
 		pd->iccl = (u_int8_t)((num/denom) + 1);
 	else
 		pd->iccl = (u_int8_t)(num/denom);

 	/* Calculate the value for icch. From the data sheet:
 	   icch = (p clock / transfer rate) * (H / (L + H)) */
 	num = peripheral_clk * 4;
 	tmp = num * 10 / denom;
 	if (tmp % 10 >= 5)
 		pd->icch = (u_int8_t)((num/denom) + 1);
 	else
 		pd->icch = (u_int8_t)(num/denom);
 }

 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
 {
 	struct resource *res;
 	int ret = -ENXIO;
 	int q, m;
 	int k = 0;
 	int n = 0;

 	while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
 		for (n = res->start; hook && n <= res->end; n++) {
 			if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
 					dev->dev.bus_id, dev))
 				goto rollback;
 		}
 		k++;
 	}

 	if (hook)
 		return k > 0 ? 0 : -ENOENT;

 	k--;
 	ret = 0;

  rollback:
 	for (q = k; k >= 0; k--) {
 		for (m = n; m >= res->start; m--)
 			free_irq(m, dev);

 		res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);
 		m = res->end;
 	}

 	return ret;
 }

 static int sh_mobile_i2c_probe(struct platform_device *dev)
 {
 	struct sh_mobile_i2c_data *pd;
 	struct i2c_adapter *adap;
 	struct resource *res;
 	int size;
 	int ret;

 	pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
 	if (pd == NULL) {
 		dev_err(&dev->dev, "cannot allocate private data\n");
 		return -ENOMEM;
 	}

 	pd->clk = clk_get(&dev->dev, "peripheral_clk");
 	if (IS_ERR(pd->clk)) {
 		dev_err(&dev->dev, "cannot get peripheral clock\n");
 		ret = PTR_ERR(pd->clk);
 		goto err;
 	}

 	ret = sh_mobile_i2c_hook_irqs(dev, 1);
 	if (ret) {
 		dev_err(&dev->dev, "cannot request IRQ\n");
 		goto err_clk;
 	}

 	pd->dev = &dev->dev;
 	platform_set_drvdata(dev, pd);

 	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
 	if (res == NULL) {
 		dev_err(&dev->dev, "cannot find IO resource\n");
 		ret = -ENOENT;
 		goto err_irq;
 	}

 	size = (res->end - res->start) + 1;

 	pd->reg = ioremap(res->start, size);
 	if (pd->reg == NULL) {
 		dev_err(&dev->dev, "cannot map IO\n");
 		ret = -ENXIO;
 		goto err_irq;
 	}

 	/* setup the private data */
 	adap = &pd->adap;
 	i2c_set_adapdata(adap, pd);

 	adap->owner = THIS_MODULE;
 	adap->algo = &sh_mobile_i2c_algorithm;
 	adap->dev.parent = &dev->dev;
 	adap->retries = 5;
 	adap->nr = dev->id;

 	strlcpy(adap->name, dev->name, sizeof(adap->name));

 	sh_mobile_i2c_setup_channel(dev);

 	ret = i2c_add_numbered_adapter(adap);
 	if (ret < 0) {
 		dev_err(&dev->dev, "cannot add numbered adapter\n");
 		goto err_all;
 	}

 	return 0;

  err_all:
 	iounmap(pd->reg);
  err_irq:
 	sh_mobile_i2c_hook_irqs(dev, 0);
  err_clk:
 	clk_put(pd->clk);
  err:
 	kfree(pd);
 	return ret;
 }

 static int sh_mobile_i2c_remove(struct platform_device *dev)
 {
 	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);

 	i2c_del_adapter(&pd->adap);
 	iounmap(pd->reg);
 	sh_mobile_i2c_hook_irqs(dev, 0);
 	clk_put(pd->clk);
 	kfree(pd);
 	return 0;
 }

 static struct platform_driver sh_mobile_i2c_driver = {
 	.driver		= {
 		.name		= "i2c-sh_mobile",
 		.owner		= THIS_MODULE,
 	},
 	.probe		= sh_mobile_i2c_probe,
 	.remove		= sh_mobile_i2c_remove,
 };

 static int __init sh_mobile_i2c_adap_init(void)
 {
 	return platform_driver_register(&sh_mobile_i2c_driver);
 }

 static void __exit sh_mobile_i2c_adap_exit(void)
 {
 	platform_driver_unregister(&sh_mobile_i2c_driver);
 }

 module_init(sh_mobile_i2c_adap_init);
 module_exit(sh_mobile_i2c_adap_exit);

 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
 MODULE_AUTHOR("Magnus Damm");
 MODULE_LICENSE("GPL v2");
	/*
	* SuperH Mobile I2C Controller
	*
	* Copyright (C) 2008 Magnus Damm
	*
	* Portions of the code based on out-of-tree driver i2c-sh7343.c
	* Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>
	*
	* 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
	*
	* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/

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

	enum sh_mobile_i2c_op {
	OP_START = 0,
	OP_TX_ONLY,
	OP_TX_STOP,
	OP_TX_TO_RX,
	OP_RX_ONLY,
	OP_RX_STOP,
	};

	struct sh_mobile_i2c_data {
	struct device *dev;
	void __iomem *reg;
	struct i2c_adapter adap;

	struct clk *clk;
	u_int8_t iccl;
	u_int8_t icch;

	spinlock_t lock;
	wait_queue_head_t wait;
	struct i2c_msg *msg;
	int pos;
	int sr;
	};

	#define NORMAL_SPEED 100000 /* FAST_SPEED 400000 */

	/* Register offsets */
	#define ICDR(pd) (pd->reg + 0x00)
	#define ICCR(pd) (pd->reg + 0x04)
	#define ICSR(pd) (pd->reg + 0x08)
	#define ICIC(pd) (pd->reg + 0x0c)
	#define ICCL(pd) (pd->reg + 0x10)
	#define ICCH(pd) (pd->reg + 0x14)

	/* Register bits */
	#define ICCR_ICE 0x80
	#define ICCR_RACK 0x40
	#define ICCR_TRS 0x10
	#define ICCR_BBSY 0x04
	#define ICCR_SCP 0x01

	#define ICSR_SCLM 0x80
	#define ICSR_SDAM 0x40
	#define SW_DONE 0x20
	#define ICSR_BUSY 0x10
	#define ICSR_AL 0x08
	#define ICSR_TACK 0x04
	#define ICSR_WAIT 0x02
	#define ICSR_DTE 0x01

	#define ICIC_ALE 0x08
	#define ICIC_TACKE 0x04
	#define ICIC_WAITE 0x02
	#define ICIC_DTEE 0x01

	static void activate_ch(struct sh_mobile_i2c_data *pd)
	{
	/* Make sure the clock is enabled */
	clk_enable(pd->clk);

	/* Enable channel and configure rx ack */
	iowrite8(ioread8(ICCR(pd)) \| ICCR_ICE, ICCR(pd));

	/* Mask all interrupts */
	iowrite8(0, ICIC(pd));

	/* Set the clock */
	iowrite8(pd->iccl, ICCL(pd));
	iowrite8(pd->icch, ICCH(pd));
	}

	static void deactivate_ch(struct sh_mobile_i2c_data *pd)
	{
	/* Clear/disable interrupts */
	iowrite8(0, ICSR(pd));
	iowrite8(0, ICIC(pd));

	/* Disable channel */
	iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));

	/* Disable clock */
	clk_disable(pd->clk);
	}

	static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
	enum sh_mobile_i2c_op op, unsigned char data)
	{
	unsigned char ret = 0;
	unsigned long flags;

	dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);

	spin_lock_irqsave(&pd->lock, flags);

	switch (op) {
	case OP_START:
	iowrite8(0x94, ICCR(pd));
	break;
	case OP_TX_ONLY:
	iowrite8(data, ICDR(pd));
	break;
	case OP_TX_STOP:
	iowrite8(data, ICDR(pd));
	iowrite8(0x90, ICCR(pd));
	iowrite8(ICIC_ALE \| ICIC_TACKE, ICIC(pd));
	break;
	case OP_TX_TO_RX:
	iowrite8(data, ICDR(pd));
	iowrite8(0x81, ICCR(pd));
	break;
	case OP_RX_ONLY:
	ret = ioread8(ICDR(pd));
	break;
	case OP_RX_STOP:
	ret = ioread8(ICDR(pd));
	iowrite8(0xc0, ICCR(pd));
	break;
	}

	spin_unlock_irqrestore(&pd->lock, flags);

	dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
	return ret;
	}

	static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
	{
	struct platform_device *dev = dev_id;
	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
	struct i2c_msg *msg = pd->msg;
	unsigned char data, sr;
	int wakeup = 0;

	sr = ioread8(ICSR(pd));
	pd->sr \|= sr;

	dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
	(msg->flags & I2C_M_RD) ? "read" : "write",
	pd->pos, msg->len);

	if (sr & (ICSR_AL \| ICSR_TACK)) {
	iowrite8(0, ICIC(pd)); /* disable interrupts */
	wakeup = 1;
	goto do_wakeup;
	}

	if (pd->pos == msg->len) {
	i2c_op(pd, OP_RX_ONLY, 0);
	wakeup = 1;
	goto do_wakeup;
	}

	if (pd->pos == -1) {
	data = (msg->addr & 0x7f) << 1;
	data \|= (msg->flags & I2C_M_RD) ? 1 : 0;
	} else
	data = msg->buf[pd->pos];

	if ((pd->pos == -1) \|\| !(msg->flags & I2C_M_RD)) {
	if (msg->flags & I2C_M_RD)
	i2c_op(pd, OP_TX_TO_RX, data);
	else if (pd->pos == (msg->len - 1)) {
	i2c_op(pd, OP_TX_STOP, data);
	wakeup = 1;
	} else
	i2c_op(pd, OP_TX_ONLY, data);
	} else {
	if (pd->pos == (msg->len - 1))
	data = i2c_op(pd, OP_RX_STOP, 0);
	else
	data = i2c_op(pd, OP_RX_ONLY, 0);

	msg->buf[pd->pos] = data;
	}
	pd->pos++;

	do_wakeup:
	if (wakeup) {
	pd->sr \|= SW_DONE;
	wake_up(&pd->wait);
	}

	return IRQ_HANDLED;
	}

	static int start_ch(struct sh_mobile_i2c_data pd, struct i2c_msg usr_msg)
	{
	/* Initialize channel registers */
	iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));

	/* Enable channel and configure rx ack */
	iowrite8(ioread8(ICCR(pd)) \| ICCR_ICE, ICCR(pd));

	/* Set the clock */
	iowrite8(pd->iccl, ICCL(pd));
	iowrite8(pd->icch, ICCH(pd));

	pd->msg = usr_msg;
	pd->pos = -1;
	pd->sr = 0;

	/* Enable all interrupts except wait */
	iowrite8(ioread8(ICIC(pd)) \| ICIC_ALE \| ICIC_TACKE \| ICIC_DTEE,
	ICIC(pd));
	return 0;
	}

	static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
	struct i2c_msg *msgs,
	int num)
	{
	struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
	struct i2c_msg *msg;
	int err = 0;
	u_int8_t val;
	int i, k, retry_count;

	activate_ch(pd);

	/* Process all messages */
	for (i = 0; i < num; i++) {
	msg = &msgs[i];

	err = start_ch(pd, msg);
	if (err)
	break;

	i2c_op(pd, OP_START, 0);

	/* The interrupt handler takes care of the rest... */
	k = wait_event_timeout(pd->wait,
	pd->sr & (ICSR_TACK \| SW_DONE),
	5 * HZ);
	if (!k)
	dev_err(pd->dev, "Transfer request timed out\n");

	retry_count = 10;
	again:
	val = ioread8(ICSR(pd));

	dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);

	if ((val \| pd->sr) & (ICSR_TACK \| ICSR_AL)) {
	err = -EIO;
	break;
	}

	/* the interrupt handler may wake us up before the
	* transfer is finished, so poll the hardware
	* until we're done.
	*/

	if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) &&
	(val & ICSR_SDAM))) {
	msleep(1);
	if (retry_count--)
	goto again;

	err = -EIO;
	dev_err(pd->dev, "Polling timed out\n");
	break;
	}
	}

	deactivate_ch(pd);

	if (!err)
	err = num;
	return err;
	}

	static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
	{
	return I2C_FUNC_I2C \| I2C_FUNC_SMBUS_EMUL;
	}

	static struct i2c_algorithm sh_mobile_i2c_algorithm = {
	.functionality = sh_mobile_i2c_func,
	.master_xfer = sh_mobile_i2c_xfer,
	};

	static void sh_mobile_i2c_setup_channel(struct platform_device *dev)
	{
	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
	unsigned long peripheral_clk = clk_get_rate(pd->clk);
	u_int32_t num;
	u_int32_t denom;
	u_int32_t tmp;

	spin_lock_init(&pd->lock);
	init_waitqueue_head(&pd->wait);

	/* Calculate the value for iccl. From the data sheet:
	* iccl = (p clock / transfer rate) * (L / (L + H))
	* where L and H are the SCL low/high ratio (5/4 in this case).
	* We also round off the result.
	*/
	num = peripheral_clk * 5;
	denom = NORMAL_SPEED * 9;
	tmp = num * 10 / denom;
	if (tmp % 10 >= 5)
	pd->iccl = (u_int8_t)((num/denom) + 1);
	else
	pd->iccl = (u_int8_t)(num/denom);

	/* Calculate the value for icch. From the data sheet:
	icch = (p clock / transfer rate) * (H / (L + H)) */
	num = peripheral_clk * 4;
	tmp = num * 10 / denom;
	if (tmp % 10 >= 5)
	pd->icch = (u_int8_t)((num/denom) + 1);
	else
	pd->icch = (u_int8_t)(num/denom);
	}

	static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
	{
	struct resource *res;
	int ret = -ENXIO;
	int q, m;
	int k = 0;
	int n = 0;

	while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
	for (n = res->start; hook && n <= res->end; n++) {
	if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
	dev->dev.bus_id, dev))
	goto rollback;
	}
	k++;
	}

	if (hook)
	return k > 0 ? 0 : -ENOENT;

	k--;
	ret = 0;

	rollback:
	for (q = k; k >= 0; k--) {
	for (m = n; m >= res->start; m--)
	free_irq(m, dev);

	res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);
	m = res->end;
	}

	return ret;
	}

	static int sh_mobile_i2c_probe(struct platform_device *dev)
	{
	struct sh_mobile_i2c_data *pd;
	struct i2c_adapter *adap;
	struct resource *res;
	int size;
	int ret;

	pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
	if (pd == NULL) {
	dev_err(&dev->dev, "cannot allocate private data\n");
	return -ENOMEM;
	}

	pd->clk = clk_get(&dev->dev, "peripheral_clk");
	if (IS_ERR(pd->clk)) {
	dev_err(&dev->dev, "cannot get peripheral clock\n");
	ret = PTR_ERR(pd->clk);
	goto err;
	}

	ret = sh_mobile_i2c_hook_irqs(dev, 1);
	if (ret) {
	dev_err(&dev->dev, "cannot request IRQ\n");
	goto err_clk;
	}

	pd->dev = &dev->dev;
	platform_set_drvdata(dev, pd);

	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
	if (res == NULL) {
	dev_err(&dev->dev, "cannot find IO resource\n");
	ret = -ENOENT;
	goto err_irq;
	}

	size = (res->end - res->start) + 1;

	pd->reg = ioremap(res->start, size);
	if (pd->reg == NULL) {
	dev_err(&dev->dev, "cannot map IO\n");
	ret = -ENXIO;
	goto err_irq;
	}

	/* setup the private data */
	adap = &pd->adap;
	i2c_set_adapdata(adap, pd);

	adap->owner = THIS_MODULE;
	adap->algo = &sh_mobile_i2c_algorithm;
	adap->dev.parent = &dev->dev;
	adap->retries = 5;
	adap->nr = dev->id;

	strlcpy(adap->name, dev->name, sizeof(adap->name));

	sh_mobile_i2c_setup_channel(dev);

	ret = i2c_add_numbered_adapter(adap);
	if (ret < 0) {
	dev_err(&dev->dev, "cannot add numbered adapter\n");
	goto err_all;
	}

	return 0;

	err_all:
	iounmap(pd->reg);
	err_irq:
	sh_mobile_i2c_hook_irqs(dev, 0);
	err_clk:
	clk_put(pd->clk);
	err:
	kfree(pd);
	return ret;
	}

	static int sh_mobile_i2c_remove(struct platform_device *dev)
	{
	struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);

	i2c_del_adapter(&pd->adap);
	iounmap(pd->reg);
	sh_mobile_i2c_hook_irqs(dev, 0);
	clk_put(pd->clk);
	kfree(pd);
	return 0;
	}

	static struct platform_driver sh_mobile_i2c_driver = {
	.driver = {
	.name = "i2c-sh_mobile",
	.owner = THIS_MODULE,
	},
	.probe = sh_mobile_i2c_probe,
	.remove = sh_mobile_i2c_remove,
	};

	static int __init sh_mobile_i2c_adap_init(void)
	{
	return platform_driver_register(&sh_mobile_i2c_driver);
	}

	static void __exit sh_mobile_i2c_adap_exit(void)
	{
	platform_driver_unregister(&sh_mobile_i2c_driver);
	}

	module_init(sh_mobile_i2c_adap_init);
	module_exit(sh_mobile_i2c_adap_exit);

	MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
	MODULE_AUTHOR("Magnus Damm");
	MODULE_LICENSE("GPL v2");