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

 /*
  * Copyright (C) 2006-2007 PA Semi, Inc
  *
  * SMBus host driver for PA Semi PWRficient
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * 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/module.h>
 #include <linux/pci.h>
 #include <linux/kernel.h>
 #include <linux/stddef.h>
 #include <linux/sched.h>
 #include <linux/i2c.h>
 #include <linux/delay.h>
 #include <asm/io.h>

 static struct pci_driver pasemi_smb_driver;

 struct pasemi_smbus {
 	struct pci_dev		*dev;
 	struct i2c_adapter	 adapter;
 	unsigned long		 base;
 	int			 size;
 };

 /* Register offsets */
 #define REG_MTXFIFO	0x00
 #define REG_MRXFIFO	0x04
 #define REG_SMSTA	0x14
 #define REG_CTL		0x1c

 /* Register defs */
 #define MTXFIFO_READ	0x00000400
 #define MTXFIFO_STOP	0x00000200
 #define MTXFIFO_START	0x00000100
 #define MTXFIFO_DATA_M	0x000000ff

 #define MRXFIFO_EMPTY	0x00000100
 #define MRXFIFO_DATA_M	0x000000ff

 #define SMSTA_XEN	0x08000000

 #define CTL_MRR		0x00000400
 #define CTL_MTR		0x00000200
 #define CTL_CLK_M	0x000000ff

 #define CLK_100K_DIV	84
 #define CLK_400K_DIV	21

 static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val)
 {
 	dev_dbg(&smbus->dev->dev, "smbus write reg %lx val %08x\n",
 		smbus->base + reg, val);
 	outl(val, smbus->base + reg);
 }

 static inline int reg_read(struct pasemi_smbus *smbus, int reg)
 {
 	int ret;
 	ret = inl(smbus->base + reg);
 	dev_dbg(&smbus->dev->dev, "smbus read reg %lx val %08x\n",
 		smbus->base + reg, ret);
 	return ret;
 }

 #define TXFIFO_WR(smbus, reg)	reg_write((smbus), REG_MTXFIFO, (reg))
 #define RXFIFO_RD(smbus)	reg_read((smbus), REG_MRXFIFO)

 static void pasemi_smb_clear(struct pasemi_smbus *smbus)
 {
 	unsigned int status;

 	status = reg_read(smbus, REG_SMSTA);
 	reg_write(smbus, REG_SMSTA, status);
 }

 static unsigned int pasemi_smb_waitready(struct pasemi_smbus *smbus)
 {
 	int timeout = 10;
 	unsigned int status;

 	status = reg_read(smbus, REG_SMSTA);

 	while (!(status & SMSTA_XEN) && timeout--) {
 		msleep(1);
 		status = reg_read(smbus, REG_SMSTA);
 	}

 	if (timeout < 0) {
 		dev_warn(&smbus->dev->dev, "Timeout, status 0x%08x\n", status);
 		reg_write(smbus, REG_SMSTA, status);
 		return -ETIME;
 	}

 	/* Clear XEN */
 	reg_write(smbus, REG_SMSTA, SMSTA_XEN);

 	return 0;
 }

 static int pasemi_i2c_xfer_msg(struct i2c_adapter *adapter,
 			       struct i2c_msg *msg, int stop)
 {
 	struct pasemi_smbus *smbus = adapter->algo_data;
 	int read, i, err;
 	u32 rd;

 	read = msg->flags & I2C_M_RD ? 1 : 0;

 	TXFIFO_WR(smbus, MTXFIFO_START | (msg->addr << 1) | read);

 	if (read) {
 		TXFIFO_WR(smbus, msg->len | MTXFIFO_READ |
 				 (stop ? MTXFIFO_STOP : 0));

 		err = pasemi_smb_waitready(smbus);
 		if (err)
 			goto reset_out;

 		for (i = 0; i < msg->len; i++) {
 			rd = RXFIFO_RD(smbus);
 			if (rd & MRXFIFO_EMPTY) {
 				err = -ENODATA;
 				goto reset_out;
 			}
 			msg->buf[i] = rd & MRXFIFO_DATA_M;
 		}
 	} else {
 		for (i = 0; i < msg->len - 1; i++)
 			TXFIFO_WR(smbus, msg->buf[i]);

 		TXFIFO_WR(smbus, msg->buf[msg->len] |
 			  (stop ? MTXFIFO_STOP : 0));
 	}

 	return 0;

  reset_out:
 	reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
 		  (CLK_100K_DIV & CTL_CLK_M)));
 	return err;
 }

 static int pasemi_i2c_xfer(struct i2c_adapter *adapter,
 			   struct i2c_msg *msgs, int num)
 {
 	struct pasemi_smbus *smbus = adapter->algo_data;
 	int ret, i;

 	pasemi_smb_clear(smbus);

 	ret = 0;

 	for (i = 0; i < num && !ret; i++)
 		ret = pasemi_i2c_xfer_msg(adapter, &msgs[i], (i == (num - 1)));

 	return ret ? ret : num;
 }

 static int pasemi_smb_xfer(struct i2c_adapter *adapter,
 		u16 addr, unsigned short flags, char read_write, u8 command,
 		int size, union i2c_smbus_data *data)
 {
 	struct pasemi_smbus *smbus = adapter->algo_data;
 	unsigned int rd;
 	int read_flag, err;
 	int len = 0, i;

 	/* All our ops take 8-bit shifted addresses */
 	addr <<= 1;
 	read_flag = read_write == I2C_SMBUS_READ;

 	pasemi_smb_clear(smbus);

 	switch (size) {
 	case I2C_SMBUS_QUICK:
 		TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START |
 			  MTXFIFO_STOP);
 		break;
 	case I2C_SMBUS_BYTE:
 		TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START);
 		if (read_write)
 			TXFIFO_WR(smbus, 1 | MTXFIFO_STOP | MTXFIFO_READ);
 		else
 			TXFIFO_WR(smbus, MTXFIFO_STOP | command);
 		break;
 	case I2C_SMBUS_BYTE_DATA:
 		TXFIFO_WR(smbus, addr | MTXFIFO_START);
 		TXFIFO_WR(smbus, command);
 		if (read_write) {
 			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
 			TXFIFO_WR(smbus, 1 | MTXFIFO_READ | MTXFIFO_STOP);
 		} else {
 			TXFIFO_WR(smbus, MTXFIFO_STOP | data->byte);
 		}
 		break;
 	case I2C_SMBUS_WORD_DATA:
 		TXFIFO_WR(smbus, addr | MTXFIFO_START);
 		TXFIFO_WR(smbus, command);
 		if (read_write) {
 			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
 			TXFIFO_WR(smbus, 2 | MTXFIFO_READ | MTXFIFO_STOP);
 		} else {
 			TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
 			TXFIFO_WR(smbus, MTXFIFO_STOP | (data->word >> 8));
 		}
 		break;
 	case I2C_SMBUS_BLOCK_DATA:
 		TXFIFO_WR(smbus, addr | MTXFIFO_START);
 		TXFIFO_WR(smbus, command);
 		if (read_write) {
 			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
 			TXFIFO_WR(smbus, 1 | MTXFIFO_READ);
 			rd = RXFIFO_RD(smbus);
 			len = min_t(u8, (rd & MRXFIFO_DATA_M),
 				    I2C_SMBUS_BLOCK_MAX);
 			TXFIFO_WR(smbus, (len + 1) | MTXFIFO_READ |
 					 MTXFIFO_STOP);
 		} else {
 			len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX);
 			TXFIFO_WR(smbus, len);
 			for (i = 1; i < len; i++)
 				TXFIFO_WR(smbus, data->block[i]);
 			TXFIFO_WR(smbus, data->block[len] | MTXFIFO_STOP);
 		}
 		break;
 	case I2C_SMBUS_PROC_CALL:
 		read_write = I2C_SMBUS_READ;
 		TXFIFO_WR(smbus, addr | MTXFIFO_START);
 		TXFIFO_WR(smbus, command);
 		TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
 		TXFIFO_WR(smbus, (data->word >> 8) & MTXFIFO_DATA_M);
 		TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
 		TXFIFO_WR(smbus, 2 | MTXFIFO_STOP | MTXFIFO_READ);
 		break;
 	case I2C_SMBUS_BLOCK_PROC_CALL:
 		len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX - 1);
 		read_write = I2C_SMBUS_READ;
 		TXFIFO_WR(smbus, addr | MTXFIFO_START);
 		TXFIFO_WR(smbus, command);
 		TXFIFO_WR(smbus, len);
 		for (i = 1; i <= len; i++)
 			TXFIFO_WR(smbus, data->block[i]);
 		TXFIFO_WR(smbus, addr | I2C_SMBUS_READ);
 		TXFIFO_WR(smbus, MTXFIFO_READ | 1);
 		rd = RXFIFO_RD(smbus);
 		len = min_t(u8, (rd & MRXFIFO_DATA_M),
 			    I2C_SMBUS_BLOCK_MAX - len);
 		TXFIFO_WR(smbus, (len + 1) | MTXFIFO_READ | MTXFIFO_STOP);
 		break;

 	default:
 		dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
 		return -EINVAL;
 	}

 	err = pasemi_smb_waitready(smbus);
 	if (err)
 		goto reset_out;

 	if (read_write == I2C_SMBUS_WRITE)
 		return 0;

 	switch (size) {
 	case I2C_SMBUS_BYTE:
 	case I2C_SMBUS_BYTE_DATA:
 		rd = RXFIFO_RD(smbus);
 		if (rd & MRXFIFO_EMPTY) {
 			err = -ENODATA;
 			goto reset_out;
 		}
 		data->byte = rd & MRXFIFO_DATA_M;
 		break;
 	case I2C_SMBUS_WORD_DATA:
 	case I2C_SMBUS_PROC_CALL:
 		rd = RXFIFO_RD(smbus);
 		if (rd & MRXFIFO_EMPTY) {
 			err = -ENODATA;
 			goto reset_out;
 		}
 		data->word = rd & MRXFIFO_DATA_M;
 		rd = RXFIFO_RD(smbus);
 		if (rd & MRXFIFO_EMPTY) {
 			err = -ENODATA;
 			goto reset_out;
 		}
 		data->word |= (rd & MRXFIFO_DATA_M) << 8;
 		break;
 	case I2C_SMBUS_BLOCK_DATA:
 	case I2C_SMBUS_BLOCK_PROC_CALL:
 		data->block[0] = len;
 		for (i = 1; i <= len; i ++) {
 			rd = RXFIFO_RD(smbus);
 			if (rd & MRXFIFO_EMPTY) {
 				err = -ENODATA;
 				goto reset_out;
 			}
 			data->block[i] = rd & MRXFIFO_DATA_M;
 		}
 		break;
 	}

 	return 0;

  reset_out:
 	reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
 		  (CLK_100K_DIV & CTL_CLK_M)));
 	return err;
 }

 static u32 pasemi_smb_func(struct i2c_adapter *adapter)
 {
 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 	       I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_PROC_CALL |
 	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL | I2C_FUNC_I2C;
 }

 static const struct i2c_algorithm smbus_algorithm = {
 	.master_xfer	= pasemi_i2c_xfer,
 	.smbus_xfer	= pasemi_smb_xfer,
 	.functionality	= pasemi_smb_func,
 };

 static int __devinit pasemi_smb_probe(struct pci_dev *dev,
 				      const struct pci_device_id *id)
 {
 	struct pasemi_smbus *smbus;
 	int error;

 	if (!(pci_resource_flags(dev, 0) & IORESOURCE_IO))
 		return -ENODEV;

 	smbus = kzalloc(sizeof(struct pasemi_smbus), GFP_KERNEL);
 	if (!smbus)
 		return -ENOMEM;

 	smbus->dev = dev;
 	smbus->base = pci_resource_start(dev, 0);
 	smbus->size = pci_resource_len(dev, 0);

 	if (!request_region(smbus->base, smbus->size,
 			    pasemi_smb_driver.name)) {
 		error = -EBUSY;
 		goto out_kfree;
 	}

 	smbus->adapter.owner = THIS_MODULE;
 	snprintf(smbus->adapter.name, I2C_NAME_SIZE,
 		 "PA Semi SMBus adapter at 0x%lx", smbus->base);
 	smbus->adapter.class = I2C_CLASS_HWMON;
 	smbus->adapter.algo = &smbus_algorithm;
 	smbus->adapter.algo_data = smbus;

 	/* set up the driverfs linkage to our parent device */
 	smbus->adapter.dev.parent = &dev->dev;

 	reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
 		  (CLK_100K_DIV & CTL_CLK_M)));

 	error = i2c_add_adapter(&smbus->adapter);
 	if (error)
 		goto out_release_region;

 	pci_set_drvdata(dev, smbus);

 	return 0;

  out_release_region:
 	release_region(smbus->base, smbus->size);
  out_kfree:
 	kfree(smbus);
 	return error;
 }

 static void __devexit pasemi_smb_remove(struct pci_dev *dev)
 {
 	struct pasemi_smbus *smbus = pci_get_drvdata(dev);

 	i2c_del_adapter(&smbus->adapter);
 	release_region(smbus->base, smbus->size);
 	kfree(smbus);
 }

 static struct pci_device_id pasemi_smb_ids[] = {
 	{ PCI_DEVICE(0x1959, 0xa003) },
 	{ 0, }
 };

 MODULE_DEVICE_TABLE(pci, pasemi_smb_ids);

 static struct pci_driver pasemi_smb_driver = {
 	.name		= "i2c-pasemi",
 	.id_table	= pasemi_smb_ids,
 	.probe		= pasemi_smb_probe,
 	.remove		= __devexit_p(pasemi_smb_remove),
 };

 static int __init pasemi_smb_init(void)
 {
 	return pci_register_driver(&pasemi_smb_driver);
 }

 static void __exit pasemi_smb_exit(void)
 {
 	pci_unregister_driver(&pasemi_smb_driver);
 }

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR ("Olof Johansson <olof@lixom.net>");
 MODULE_DESCRIPTION("PA Semi PWRficient SMBus driver");

 module_init(pasemi_smb_init);
 module_exit(pasemi_smb_exit);
	/*
	* Copyright (C) 2006-2007 PA Semi, Inc
	*
	* SMBus host driver for PA Semi PWRficient
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* 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/module.h>
	#include <linux/pci.h>
	#include <linux/kernel.h>
	#include <linux/stddef.h>
	#include <linux/sched.h>
	#include <linux/i2c.h>
	#include <linux/delay.h>
	#include <asm/io.h>

	static struct pci_driver pasemi_smb_driver;

	struct pasemi_smbus {
	struct pci_dev *dev;
	struct i2c_adapter adapter;
	unsigned long base;
	int size;
	};

	/* Register offsets */
	#define REG_MTXFIFO 0x00
	#define REG_MRXFIFO 0x04
	#define REG_SMSTA 0x14
	#define REG_CTL 0x1c

	/* Register defs */
	#define MTXFIFO_READ 0x00000400
	#define MTXFIFO_STOP 0x00000200
	#define MTXFIFO_START 0x00000100
	#define MTXFIFO_DATA_M 0x000000ff

	#define MRXFIFO_EMPTY 0x00000100
	#define MRXFIFO_DATA_M 0x000000ff

	#define SMSTA_XEN 0x08000000

	#define CTL_MRR 0x00000400
	#define CTL_MTR 0x00000200
	#define CTL_CLK_M 0x000000ff

	#define CLK_100K_DIV 84
	#define CLK_400K_DIV 21

	static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val)
	{
	dev_dbg(&smbus->dev->dev, "smbus write reg %lx val %08x\n",
	smbus->base + reg, val);
	outl(val, smbus->base + reg);
	}

	static inline int reg_read(struct pasemi_smbus *smbus, int reg)
	{
	int ret;
	ret = inl(smbus->base + reg);
	dev_dbg(&smbus->dev->dev, "smbus read reg %lx val %08x\n",
	smbus->base + reg, ret);
	return ret;
	}

	#define TXFIFO_WR(smbus, reg) reg_write((smbus), REG_MTXFIFO, (reg))
	#define RXFIFO_RD(smbus) reg_read((smbus), REG_MRXFIFO)

	static void pasemi_smb_clear(struct pasemi_smbus *smbus)
	{
	unsigned int status;

	status = reg_read(smbus, REG_SMSTA);
	reg_write(smbus, REG_SMSTA, status);
	}

	static unsigned int pasemi_smb_waitready(struct pasemi_smbus *smbus)
	{
	int timeout = 10;
	unsigned int status;

	status = reg_read(smbus, REG_SMSTA);

	while (!(status & SMSTA_XEN) && timeout--) {
	msleep(1);
	status = reg_read(smbus, REG_SMSTA);
	}

	if (timeout < 0) {
	dev_warn(&smbus->dev->dev, "Timeout, status 0x%08x\n", status);
	reg_write(smbus, REG_SMSTA, status);
	return -ETIME;
	}

	/* Clear XEN */
	reg_write(smbus, REG_SMSTA, SMSTA_XEN);

	return 0;
	}

	static int pasemi_i2c_xfer_msg(struct i2c_adapter *adapter,
	struct i2c_msg *msg, int stop)
	{
	struct pasemi_smbus *smbus = adapter->algo_data;
	int read, i, err;
	u32 rd;

	read = msg->flags & I2C_M_RD ? 1 : 0;

	TXFIFO_WR(smbus, MTXFIFO_START \| (msg->addr << 1) \| read);

	if (read) {
	TXFIFO_WR(smbus, msg->len \| MTXFIFO_READ \|
	(stop ? MTXFIFO_STOP : 0));

	err = pasemi_smb_waitready(smbus);
	if (err)
	goto reset_out;

	for (i = 0; i < msg->len; i++) {
	rd = RXFIFO_RD(smbus);
	if (rd & MRXFIFO_EMPTY) {
	err = -ENODATA;
	goto reset_out;
	}
	msg->buf[i] = rd & MRXFIFO_DATA_M;
	}
	} else {
	for (i = 0; i < msg->len - 1; i++)
	TXFIFO_WR(smbus, msg->buf[i]);

	TXFIFO_WR(smbus, msg->buf[msg->len] \|
	(stop ? MTXFIFO_STOP : 0));
	}

	return 0;

	reset_out:
	reg_write(smbus, REG_CTL, (CTL_MTR \| CTL_MRR \|
	(CLK_100K_DIV & CTL_CLK_M)));
	return err;
	}

	static int pasemi_i2c_xfer(struct i2c_adapter *adapter,
	struct i2c_msg *msgs, int num)
	{
	struct pasemi_smbus *smbus = adapter->algo_data;
	int ret, i;

	pasemi_smb_clear(smbus);

	ret = 0;

	for (i = 0; i < num && !ret; i++)
	ret = pasemi_i2c_xfer_msg(adapter, &msgs[i], (i == (num - 1)));

	return ret ? ret : num;
	}

	static int pasemi_smb_xfer(struct i2c_adapter *adapter,
	u16 addr, unsigned short flags, char read_write, u8 command,
	int size, union i2c_smbus_data *data)
	{
	struct pasemi_smbus *smbus = adapter->algo_data;
	unsigned int rd;
	int read_flag, err;
	int len = 0, i;

	/* All our ops take 8-bit shifted addresses */
	addr <<= 1;
	read_flag = read_write == I2C_SMBUS_READ;

	pasemi_smb_clear(smbus);

	switch (size) {
	case I2C_SMBUS_QUICK:
	TXFIFO_WR(smbus, addr \| read_flag \| MTXFIFO_START \|
	MTXFIFO_STOP);
	break;
	case I2C_SMBUS_BYTE:
	TXFIFO_WR(smbus, addr \| read_flag \| MTXFIFO_START);
	if (read_write)
	TXFIFO_WR(smbus, 1 \| MTXFIFO_STOP \| MTXFIFO_READ);
	else
	TXFIFO_WR(smbus, MTXFIFO_STOP \| command);
	break;
	case I2C_SMBUS_BYTE_DATA:
	TXFIFO_WR(smbus, addr \| MTXFIFO_START);
	TXFIFO_WR(smbus, command);
	if (read_write) {
	TXFIFO_WR(smbus, addr \| I2C_SMBUS_READ \| MTXFIFO_START);
	TXFIFO_WR(smbus, 1 \| MTXFIFO_READ \| MTXFIFO_STOP);
	} else {
	TXFIFO_WR(smbus, MTXFIFO_STOP \| data->byte);
	}
	break;
	case I2C_SMBUS_WORD_DATA:
	TXFIFO_WR(smbus, addr \| MTXFIFO_START);
	TXFIFO_WR(smbus, command);
	if (read_write) {
	TXFIFO_WR(smbus, addr \| I2C_SMBUS_READ \| MTXFIFO_START);
	TXFIFO_WR(smbus, 2 \| MTXFIFO_READ \| MTXFIFO_STOP);
	} else {
	TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
	TXFIFO_WR(smbus, MTXFIFO_STOP \| (data->word >> 8));
	}
	break;
	case I2C_SMBUS_BLOCK_DATA:
	TXFIFO_WR(smbus, addr \| MTXFIFO_START);
	TXFIFO_WR(smbus, command);
	if (read_write) {
	TXFIFO_WR(smbus, addr \| I2C_SMBUS_READ \| MTXFIFO_START);
	TXFIFO_WR(smbus, 1 \| MTXFIFO_READ);
	rd = RXFIFO_RD(smbus);
	len = min_t(u8, (rd & MRXFIFO_DATA_M),
	I2C_SMBUS_BLOCK_MAX);
	TXFIFO_WR(smbus, (len + 1) \| MTXFIFO_READ \|
	MTXFIFO_STOP);
	} else {
	len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX);
	TXFIFO_WR(smbus, len);
	for (i = 1; i < len; i++)
	TXFIFO_WR(smbus, data->block[i]);
	TXFIFO_WR(smbus, data->block[len] \| MTXFIFO_STOP);
	}
	break;
	case I2C_SMBUS_PROC_CALL:
	read_write = I2C_SMBUS_READ;
	TXFIFO_WR(smbus, addr \| MTXFIFO_START);
	TXFIFO_WR(smbus, command);
	TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
	TXFIFO_WR(smbus, (data->word >> 8) & MTXFIFO_DATA_M);
	TXFIFO_WR(smbus, addr \| I2C_SMBUS_READ \| MTXFIFO_START);
	TXFIFO_WR(smbus, 2 \| MTXFIFO_STOP \| MTXFIFO_READ);
	break;
	case I2C_SMBUS_BLOCK_PROC_CALL:
	len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX - 1);
	read_write = I2C_SMBUS_READ;
	TXFIFO_WR(smbus, addr \| MTXFIFO_START);
	TXFIFO_WR(smbus, command);
	TXFIFO_WR(smbus, len);
	for (i = 1; i <= len; i++)
	TXFIFO_WR(smbus, data->block[i]);
	TXFIFO_WR(smbus, addr \| I2C_SMBUS_READ);
	TXFIFO_WR(smbus, MTXFIFO_READ \| 1);
	rd = RXFIFO_RD(smbus);
	len = min_t(u8, (rd & MRXFIFO_DATA_M),
	I2C_SMBUS_BLOCK_MAX - len);
	TXFIFO_WR(smbus, (len + 1) \| MTXFIFO_READ \| MTXFIFO_STOP);
	break;

	default:
	dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
	return -EINVAL;
	}

	err = pasemi_smb_waitready(smbus);
	if (err)
	goto reset_out;

	if (read_write == I2C_SMBUS_WRITE)
	return 0;

	switch (size) {
	case I2C_SMBUS_BYTE:
	case I2C_SMBUS_BYTE_DATA:
	rd = RXFIFO_RD(smbus);
	if (rd & MRXFIFO_EMPTY) {
	err = -ENODATA;
	goto reset_out;
	}
	data->byte = rd & MRXFIFO_DATA_M;
	break;
	case I2C_SMBUS_WORD_DATA:
	case I2C_SMBUS_PROC_CALL:
	rd = RXFIFO_RD(smbus);
	if (rd & MRXFIFO_EMPTY) {
	err = -ENODATA;
	goto reset_out;
	}
	data->word = rd & MRXFIFO_DATA_M;
	rd = RXFIFO_RD(smbus);
	if (rd & MRXFIFO_EMPTY) {
	err = -ENODATA;
	goto reset_out;
	}
	data->word \|= (rd & MRXFIFO_DATA_M) << 8;
	break;
	case I2C_SMBUS_BLOCK_DATA:
	case I2C_SMBUS_BLOCK_PROC_CALL:
	data->block[0] = len;
	for (i = 1; i <= len; i ++) {
	rd = RXFIFO_RD(smbus);
	if (rd & MRXFIFO_EMPTY) {
	err = -ENODATA;
	goto reset_out;
	}
	data->block[i] = rd & MRXFIFO_DATA_M;
	}
	break;
	}

	return 0;

	reset_out:
	reg_write(smbus, REG_CTL, (CTL_MTR \| CTL_MRR \|
	(CLK_100K_DIV & CTL_CLK_M)));
	return err;
	}

	static u32 pasemi_smb_func(struct i2c_adapter *adapter)
	{
	return I2C_FUNC_SMBUS_QUICK \| I2C_FUNC_SMBUS_BYTE \|
	I2C_FUNC_SMBUS_BYTE_DATA \| I2C_FUNC_SMBUS_WORD_DATA \|
	I2C_FUNC_SMBUS_BLOCK_DATA \| I2C_FUNC_SMBUS_PROC_CALL \|
	I2C_FUNC_SMBUS_BLOCK_PROC_CALL \| I2C_FUNC_I2C;
	}

	static const struct i2c_algorithm smbus_algorithm = {
	.master_xfer = pasemi_i2c_xfer,
	.smbus_xfer = pasemi_smb_xfer,
	.functionality = pasemi_smb_func,
	};

	static int __devinit pasemi_smb_probe(struct pci_dev *dev,
	const struct pci_device_id *id)
	{
	struct pasemi_smbus *smbus;
	int error;

	if (!(pci_resource_flags(dev, 0) & IORESOURCE_IO))
	return -ENODEV;

	smbus = kzalloc(sizeof(struct pasemi_smbus), GFP_KERNEL);
	if (!smbus)
	return -ENOMEM;

	smbus->dev = dev;
	smbus->base = pci_resource_start(dev, 0);
	smbus->size = pci_resource_len(dev, 0);

	if (!request_region(smbus->base, smbus->size,
	pasemi_smb_driver.name)) {
	error = -EBUSY;
	goto out_kfree;
	}

	smbus->adapter.owner = THIS_MODULE;
	snprintf(smbus->adapter.name, I2C_NAME_SIZE,
	"PA Semi SMBus adapter at 0x%lx", smbus->base);
	smbus->adapter.class = I2C_CLASS_HWMON;
	smbus->adapter.algo = &smbus_algorithm;
	smbus->adapter.algo_data = smbus;

	/* set up the driverfs linkage to our parent device */
	smbus->adapter.dev.parent = &dev->dev;

	reg_write(smbus, REG_CTL, (CTL_MTR \| CTL_MRR \|
	(CLK_100K_DIV & CTL_CLK_M)));

	error = i2c_add_adapter(&smbus->adapter);
	if (error)
	goto out_release_region;

	pci_set_drvdata(dev, smbus);

	return 0;

	out_release_region:
	release_region(smbus->base, smbus->size);
	out_kfree:
	kfree(smbus);
	return error;
	}

	static void __devexit pasemi_smb_remove(struct pci_dev *dev)
	{
	struct pasemi_smbus *smbus = pci_get_drvdata(dev);

	i2c_del_adapter(&smbus->adapter);
	release_region(smbus->base, smbus->size);
	kfree(smbus);
	}

	static struct pci_device_id pasemi_smb_ids[] = {
	{ PCI_DEVICE(0x1959, 0xa003) },
	{ 0, }
	};

	MODULE_DEVICE_TABLE(pci, pasemi_smb_ids);

	static struct pci_driver pasemi_smb_driver = {
	.name = "i2c-pasemi",
	.id_table = pasemi_smb_ids,
	.probe = pasemi_smb_probe,
	.remove = __devexit_p(pasemi_smb_remove),
	};

	static int __init pasemi_smb_init(void)
	{
	return pci_register_driver(&pasemi_smb_driver);
	}

	static void __exit pasemi_smb_exit(void)
	{
	pci_unregister_driver(&pasemi_smb_driver);
	}

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR ("Olof Johansson <olof@lixom.net>");
	MODULE_DESCRIPTION("PA Semi PWRficient SMBus driver");

	module_init(pasemi_smb_init);
	module_exit(pasemi_smb_exit);