drivers/i2c/busses/i2c-piix4.c - kernel/msm-4.19 - Gitiles

 /*
     piix4.c - Part of lm_sensors, Linux kernel modules for hardware
               monitoring
     Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl> and
     Philip Edelbrock <phil@netroedge.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, 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.
 */

 /*
    Supports:
 	Intel PIIX4, 440MX
 	Serverworks OSB4, CSB5, CSB6
 	SMSC Victory66

    Note: we assume there can only be one device, with one SMBus interface.
 */

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/pci.h>
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/stddef.h>
 #include <linux/sched.h>
 #include <linux/ioport.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/apm_bios.h>
 #include <linux/dmi.h>
 #include <asm/io.h>


 struct sd {
 	const unsigned short mfr;
 	const unsigned short dev;
 	const unsigned char fn;
 	const char *name;
 };

 /* PIIX4 SMBus address offsets */
 #define SMBHSTSTS	(0 + piix4_smba)
 #define SMBHSLVSTS	(1 + piix4_smba)
 #define SMBHSTCNT	(2 + piix4_smba)
 #define SMBHSTCMD	(3 + piix4_smba)
 #define SMBHSTADD	(4 + piix4_smba)
 #define SMBHSTDAT0	(5 + piix4_smba)
 #define SMBHSTDAT1	(6 + piix4_smba)
 #define SMBBLKDAT	(7 + piix4_smba)
 #define SMBSLVCNT	(8 + piix4_smba)
 #define SMBSHDWCMD	(9 + piix4_smba)
 #define SMBSLVEVT	(0xA + piix4_smba)
 #define SMBSLVDAT	(0xC + piix4_smba)

 /* count for request_region */
 #define SMBIOSIZE	8

 /* PCI Address Constants */
 #define SMBBA		0x090
 #define SMBHSTCFG	0x0D2
 #define SMBSLVC		0x0D3
 #define SMBSHDW1	0x0D4
 #define SMBSHDW2	0x0D5
 #define SMBREV		0x0D6

 /* Other settings */
 #define MAX_TIMEOUT	500
 #define  ENABLE_INT9	0

 /* PIIX4 constants */
 #define PIIX4_QUICK		0x00
 #define PIIX4_BYTE		0x04
 #define PIIX4_BYTE_DATA		0x08
 #define PIIX4_WORD_DATA		0x0C
 #define PIIX4_BLOCK_DATA	0x14

 /* insmod parameters */

 /* If force is set to anything different from 0, we forcibly enable the
    PIIX4. DANGEROUS! */
 static int force = 0;
 module_param (force, int, 0);
 MODULE_PARM_DESC(force, "Forcibly enable the PIIX4. DANGEROUS!");

 /* If force_addr is set to anything different from 0, we forcibly enable
    the PIIX4 at the given address. VERY DANGEROUS! */
 static int force_addr = 0;
 module_param (force_addr, int, 0);
 MODULE_PARM_DESC(force_addr,
 		 "Forcibly enable the PIIX4 at the given address. "
 		 "EXTREMELY DANGEROUS!");

 /* If fix_hstcfg is set to anything different from 0, we reset one of the
    registers to be a valid value. */
 static int fix_hstcfg = 0;
 module_param (fix_hstcfg, int, 0);
 MODULE_PARM_DESC(fix_hstcfg,
 		"Fix config register. Needed on some boards (Force CPCI735).");

 static int piix4_transaction(void);

 static unsigned short piix4_smba = 0;
 static struct i2c_adapter piix4_adapter;

 static struct dmi_system_id __devinitdata piix4_dmi_table[] = {
 	{
 		.ident = "IBM",
 		.matches = { DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
 	},
 	{ },
 };

 static int __devinit piix4_setup(struct pci_dev *PIIX4_dev,
 				const struct pci_device_id *id)
 {
 	unsigned char temp;

 	/* match up the function */
 	if (PCI_FUNC(PIIX4_dev->devfn) != id->driver_data)
 		return -ENODEV;

 	dev_info(&PIIX4_dev->dev, "Found %s device\n", pci_name(PIIX4_dev));

 	/* Don't access SMBus on IBM systems which get corrupted eeproms */
 	if (dmi_check_system(piix4_dmi_table) &&
 			PIIX4_dev->vendor == PCI_VENDOR_ID_INTEL) {
 		dev_err(&PIIX4_dev->dev, "IBM Laptop detected; this module "
 			"may corrupt your serial eeprom! Refusing to load "
 			"module!\n");
 		return -EPERM;
 	}

 	/* Determine the address of the SMBus areas */
 	if (force_addr) {
 		piix4_smba = force_addr & 0xfff0;
 		force = 0;
 	} else {
 		pci_read_config_word(PIIX4_dev, SMBBA, &piix4_smba);
 		piix4_smba &= 0xfff0;
 		if(piix4_smba == 0) {
 			dev_err(&PIIX4_dev->dev, "SMB base address "
 				"uninitialized - upgrade BIOS or use "
 				"force_addr=0xaddr\n");
 			return -ENODEV;
 		}
 	}

 	if (!request_region(piix4_smba, SMBIOSIZE, "piix4-smbus")) {
 		dev_err(&PIIX4_dev->dev, "SMB region 0x%x already in use!\n",
 			piix4_smba);
 		return -ENODEV;
 	}

 	pci_read_config_byte(PIIX4_dev, SMBHSTCFG, &temp);

 	/* Some BIOS will set up the chipset incorrectly and leave a register
 	   in an undefined state (causing I2C to act very strangely). */
 	if (temp & 0x02) {
 		if (fix_hstcfg) {
 			dev_info(&PIIX4_dev->dev, "Working around buggy BIOS "
 					"(I2C)\n");
 			temp &= 0xfd;
 			pci_write_config_byte(PIIX4_dev, SMBHSTCFG, temp);
 		} else {
 			dev_info(&PIIX4_dev->dev, "Unusual config register "
 					"value\n");
 			dev_info(&PIIX4_dev->dev, "Try using fix_hstcfg=1 if "
 					"you experience problems\n");
 		}
 	}

 	/* If force_addr is set, we program the new address here. Just to make
 	   sure, we disable the PIIX4 first. */
 	if (force_addr) {
 		pci_write_config_byte(PIIX4_dev, SMBHSTCFG, temp & 0xfe);
 		pci_write_config_word(PIIX4_dev, SMBBA, piix4_smba);
 		pci_write_config_byte(PIIX4_dev, SMBHSTCFG, temp | 0x01);
 		dev_info(&PIIX4_dev->dev, "WARNING: SMBus interface set to "
 			"new address %04x!\n", piix4_smba);
 	} else if ((temp & 1) == 0) {
 		if (force) {
 			/* This should never need to be done, but has been
 			 * noted that many Dell machines have the SMBus
 			 * interface on the PIIX4 disabled!? NOTE: This assumes
 			 * I/O space and other allocations WERE done by the
 			 * Bios!  Don't complain if your hardware does weird
 			 * things after enabling this. :') Check for Bios
 			 * updates before resorting to this.
 			 */
 			pci_write_config_byte(PIIX4_dev, SMBHSTCFG,
 					      temp | 1);
 			dev_printk(KERN_NOTICE, &PIIX4_dev->dev,
 				"WARNING: SMBus interface has been "
 				"FORCEFULLY ENABLED!\n");
 		} else {
 			dev_err(&PIIX4_dev->dev,
 				"Host SMBus controller not enabled!\n");
 			release_region(piix4_smba, SMBIOSIZE);
 			piix4_smba = 0;
 			return -ENODEV;
 		}
 	}

 	if ((temp & 0x0E) == 8)
 		dev_dbg(&PIIX4_dev->dev, "Using Interrupt 9 for SMBus.\n");
 	else if ((temp & 0x0E) == 0)
 		dev_dbg(&PIIX4_dev->dev, "Using Interrupt SMI# for SMBus.\n");
 	else
 		dev_err(&PIIX4_dev->dev, "Illegal Interrupt configuration "
 			"(or code out of date)!\n");

 	pci_read_config_byte(PIIX4_dev, SMBREV, &temp);
 	dev_dbg(&PIIX4_dev->dev, "SMBREV = 0x%X\n", temp);
 	dev_dbg(&PIIX4_dev->dev, "SMBA = 0x%X\n", piix4_smba);

 	return 0;
 }

 /* Another internally used function */
 static int piix4_transaction(void)
 {
 	int temp;
 	int result = 0;
 	int timeout = 0;

 	dev_dbg(&piix4_adapter.dev, "Transaction (pre): CNT=%02x, CMD=%02x, "
 		"ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb_p(SMBHSTCNT),
 		inb_p(SMBHSTCMD), inb_p(SMBHSTADD), inb_p(SMBHSTDAT0),
 		inb_p(SMBHSTDAT1));

 	/* Make sure the SMBus host is ready to start transmitting */
 	if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
 		dev_dbg(&piix4_adapter.dev, "SMBus busy (%02x). "
 			"Resetting...\n", temp);
 		outb_p(temp, SMBHSTSTS);
 		if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
 			dev_err(&piix4_adapter.dev, "Failed! (%02x)\n", temp);
 			return -1;
 		} else {
 			dev_dbg(&piix4_adapter.dev, "Successfull!\n");
 		}
 	}

 	/* start the transaction by setting bit 6 */
 	outb_p(inb(SMBHSTCNT) | 0x040, SMBHSTCNT);

 	/* We will always wait for a fraction of a second! (See PIIX4 docs errata) */
 	do {
 		msleep(1);
 		temp = inb_p(SMBHSTSTS);
 	} while ((temp & 0x01) && (timeout++ < MAX_TIMEOUT));

 	/* If the SMBus is still busy, we give up */
 	if (timeout >= MAX_TIMEOUT) {
 		dev_err(&piix4_adapter.dev, "SMBus Timeout!\n");
 		result = -1;
 	}

 	if (temp & 0x10) {
 		result = -1;
 		dev_err(&piix4_adapter.dev, "Error: Failed bus transaction\n");
 	}

 	if (temp & 0x08) {
 		result = -1;
 		dev_dbg(&piix4_adapter.dev, "Bus collision! SMBus may be "
 			"locked until next hard reset. (sorry!)\n");
 		/* Clock stops and slave is stuck in mid-transmission */
 	}

 	if (temp & 0x04) {
 		result = -1;
 		dev_dbg(&piix4_adapter.dev, "Error: no response!\n");
 	}

 	if (inb_p(SMBHSTSTS) != 0x00)
 		outb_p(inb(SMBHSTSTS), SMBHSTSTS);

 	if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
 		dev_err(&piix4_adapter.dev, "Failed reset at end of "
 			"transaction (%02x)\n", temp);
 	}
 	dev_dbg(&piix4_adapter.dev, "Transaction (post): CNT=%02x, CMD=%02x, "
 		"ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb_p(SMBHSTCNT),
 		inb_p(SMBHSTCMD), inb_p(SMBHSTADD), inb_p(SMBHSTDAT0),
 		inb_p(SMBHSTDAT1));
 	return result;
 }

 /* Return -1 on error. */
 static s32 piix4_access(struct i2c_adapter * adap, u16 addr,
 		 unsigned short flags, char read_write,
 		 u8 command, int size, union i2c_smbus_data * data)
 {
 	int i, len;

 	switch (size) {
 	case I2C_SMBUS_PROC_CALL:
 		dev_err(&adap->dev, "I2C_SMBUS_PROC_CALL not supported!\n");
 		return -1;
 	case I2C_SMBUS_QUICK:
 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMBHSTADD);
 		size = PIIX4_QUICK;
 		break;
 	case I2C_SMBUS_BYTE:
 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMBHSTADD);
 		if (read_write == I2C_SMBUS_WRITE)
 			outb_p(command, SMBHSTCMD);
 		size = PIIX4_BYTE;
 		break;
 	case I2C_SMBUS_BYTE_DATA:
 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMBHSTADD);
 		outb_p(command, SMBHSTCMD);
 		if (read_write == I2C_SMBUS_WRITE)
 			outb_p(data->byte, SMBHSTDAT0);
 		size = PIIX4_BYTE_DATA;
 		break;
 	case I2C_SMBUS_WORD_DATA:
 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMBHSTADD);
 		outb_p(command, SMBHSTCMD);
 		if (read_write == I2C_SMBUS_WRITE) {
 			outb_p(data->word & 0xff, SMBHSTDAT0);
 			outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
 		}
 		size = PIIX4_WORD_DATA;
 		break;
 	case I2C_SMBUS_BLOCK_DATA:
 		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMBHSTADD);
 		outb_p(command, SMBHSTCMD);
 		if (read_write == I2C_SMBUS_WRITE) {
 			len = data->block[0];
 			if (len < 0)
 				len = 0;
 			if (len > 32)
 				len = 32;
 			outb_p(len, SMBHSTDAT0);
 			i = inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
 			for (i = 1; i <= len; i++)
 				outb_p(data->block[i], SMBBLKDAT);
 		}
 		size = PIIX4_BLOCK_DATA;
 		break;
 	}

 	outb_p((size & 0x1C) + (ENABLE_INT9 & 1), SMBHSTCNT);

 	if (piix4_transaction())	/* Error in transaction */
 		return -1;

 	if ((read_write == I2C_SMBUS_WRITE) || (size == PIIX4_QUICK))
 		return 0;


 	switch (size) {
 	case PIIX4_BYTE:	/* Where is the result put? I assume here it is in
 				   SMBHSTDAT0 but it might just as well be in the
 				   SMBHSTCMD. No clue in the docs */

 		data->byte = inb_p(SMBHSTDAT0);
 		break;
 	case PIIX4_BYTE_DATA:
 		data->byte = inb_p(SMBHSTDAT0);
 		break;
 	case PIIX4_WORD_DATA:
 		data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
 		break;
 	case PIIX4_BLOCK_DATA:
 		data->block[0] = inb_p(SMBHSTDAT0);
 		i = inb_p(SMBHSTCNT);	/* Reset SMBBLKDAT */
 		for (i = 1; i <= data->block[0]; i++)
 			data->block[i] = inb_p(SMBBLKDAT);
 		break;
 	}
 	return 0;
 }

 static u32 piix4_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;
 }

 static struct i2c_algorithm smbus_algorithm = {
 	.smbus_xfer	= piix4_access,
 	.functionality	= piix4_func,
 };

 static struct i2c_adapter piix4_adapter = {
 	.owner		= THIS_MODULE,
 	.class		= I2C_CLASS_HWMON,
 	.algo		= &smbus_algorithm,
 	.name		= "unset",
 };

 static struct pci_device_id piix4_ids[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3),
 	  .driver_data = 3 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_OSB4),
 	  .driver_data = 0 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_CSB5),
 	  .driver_data = 0 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_CSB6),
 	  .driver_data = 0 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82443MX_3),
 	  .driver_data = 3 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_EFAR, PCI_DEVICE_ID_EFAR_SLC90E66_3),
 	  .driver_data = 0 },
 	{ 0, }
 };

 MODULE_DEVICE_TABLE (pci, piix4_ids);

 static int __devinit piix4_probe(struct pci_dev *dev,
 				const struct pci_device_id *id)
 {
 	int retval;

 	retval = piix4_setup(dev, id);
 	if (retval)
 		return retval;

 	/* set up the driverfs linkage to our parent device */
 	piix4_adapter.dev.parent = &dev->dev;

 	snprintf(piix4_adapter.name, I2C_NAME_SIZE,
 		"SMBus PIIX4 adapter at %04x", piix4_smba);

 	if ((retval = i2c_add_adapter(&piix4_adapter))) {
 		dev_err(&dev->dev, "Couldn't register adapter!\n");
 		release_region(piix4_smba, SMBIOSIZE);
 		piix4_smba = 0;
 	}

 	return retval;
 }

 static void __devexit piix4_remove(struct pci_dev *dev)
 {
 	if (piix4_smba) {
 		i2c_del_adapter(&piix4_adapter);
 		release_region(piix4_smba, SMBIOSIZE);
 		piix4_smba = 0;
 	}
 }

 static struct pci_driver piix4_driver = {
 	.name		= "piix4_smbus",
 	.id_table	= piix4_ids,
 	.probe		= piix4_probe,
 	.remove		= __devexit_p(piix4_remove),
 };

 static int __init i2c_piix4_init(void)
 {
 	return pci_register_driver(&piix4_driver);
 }

 static void __exit i2c_piix4_exit(void)
 {
 	pci_unregister_driver(&piix4_driver);
 }

 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
 		"Philip Edelbrock <phil@netroedge.com>");
 MODULE_DESCRIPTION("PIIX4 SMBus driver");
 MODULE_LICENSE("GPL");

 module_init(i2c_piix4_init);
 module_exit(i2c_piix4_exit);
	/*
	piix4.c - Part of lm_sensors, Linux kernel modules for hardware
	monitoring
	Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl> and
	Philip Edelbrock <phil@netroedge.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, 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.
	*/

	/*
	Supports:
	Intel PIIX4, 440MX
	Serverworks OSB4, CSB5, CSB6
	SMSC Victory66

	Note: we assume there can only be one device, with one SMBus interface.
	*/

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/pci.h>
	#include <linux/kernel.h>
	#include <linux/delay.h>
	#include <linux/stddef.h>
	#include <linux/sched.h>
	#include <linux/ioport.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/apm_bios.h>
	#include <linux/dmi.h>
	#include <asm/io.h>


	struct sd {
	const unsigned short mfr;
	const unsigned short dev;
	const unsigned char fn;
	const char *name;
	};

	/* PIIX4 SMBus address offsets */
	#define SMBHSTSTS (0 + piix4_smba)
	#define SMBHSLVSTS (1 + piix4_smba)
	#define SMBHSTCNT (2 + piix4_smba)
	#define SMBHSTCMD (3 + piix4_smba)
	#define SMBHSTADD (4 + piix4_smba)
	#define SMBHSTDAT0 (5 + piix4_smba)
	#define SMBHSTDAT1 (6 + piix4_smba)
	#define SMBBLKDAT (7 + piix4_smba)
	#define SMBSLVCNT (8 + piix4_smba)
	#define SMBSHDWCMD (9 + piix4_smba)
	#define SMBSLVEVT (0xA + piix4_smba)
	#define SMBSLVDAT (0xC + piix4_smba)

	/* count for request_region */
	#define SMBIOSIZE 8

	/* PCI Address Constants */
	#define SMBBA 0x090
	#define SMBHSTCFG 0x0D2
	#define SMBSLVC 0x0D3
	#define SMBSHDW1 0x0D4
	#define SMBSHDW2 0x0D5
	#define SMBREV 0x0D6

	/* Other settings */
	#define MAX_TIMEOUT 500
	#define ENABLE_INT9 0

	/* PIIX4 constants */
	#define PIIX4_QUICK 0x00
	#define PIIX4_BYTE 0x04
	#define PIIX4_BYTE_DATA 0x08
	#define PIIX4_WORD_DATA 0x0C
	#define PIIX4_BLOCK_DATA 0x14

	/* insmod parameters */

	/* If force is set to anything different from 0, we forcibly enable the
	PIIX4. DANGEROUS! */
	static int force = 0;
	module_param (force, int, 0);
	MODULE_PARM_DESC(force, "Forcibly enable the PIIX4. DANGEROUS!");

	/* If force_addr is set to anything different from 0, we forcibly enable
	the PIIX4 at the given address. VERY DANGEROUS! */
	static int force_addr = 0;
	module_param (force_addr, int, 0);
	MODULE_PARM_DESC(force_addr,
	"Forcibly enable the PIIX4 at the given address. "
	"EXTREMELY DANGEROUS!");

	/* If fix_hstcfg is set to anything different from 0, we reset one of the
	registers to be a valid value. */
	static int fix_hstcfg = 0;
	module_param (fix_hstcfg, int, 0);
	MODULE_PARM_DESC(fix_hstcfg,
	"Fix config register. Needed on some boards (Force CPCI735).");

	static int piix4_transaction(void);

	static unsigned short piix4_smba = 0;
	static struct i2c_adapter piix4_adapter;

	static struct dmi_system_id __devinitdata piix4_dmi_table[] = {
	{
	.ident = "IBM",
	.matches = { DMI_MATCH(DMI_SYS_VENDOR, "IBM"), },
	},
	{ },
	};

	static int __devinit piix4_setup(struct pci_dev *PIIX4_dev,
	const struct pci_device_id *id)
	{
	unsigned char temp;

	/* match up the function */
	if (PCI_FUNC(PIIX4_dev->devfn) != id->driver_data)
	return -ENODEV;

	dev_info(&PIIX4_dev->dev, "Found %s device\n", pci_name(PIIX4_dev));

	/* Don't access SMBus on IBM systems which get corrupted eeproms */
	if (dmi_check_system(piix4_dmi_table) &&
	PIIX4_dev->vendor == PCI_VENDOR_ID_INTEL) {
	dev_err(&PIIX4_dev->dev, "IBM Laptop detected; this module "
	"may corrupt your serial eeprom! Refusing to load "
	"module!\n");
	return -EPERM;
	}

	/* Determine the address of the SMBus areas */
	if (force_addr) {
	piix4_smba = force_addr & 0xfff0;
	force = 0;
	} else {
	pci_read_config_word(PIIX4_dev, SMBBA, &piix4_smba);
	piix4_smba &= 0xfff0;
	if(piix4_smba == 0) {
	dev_err(&PIIX4_dev->dev, "SMB base address "
	"uninitialized - upgrade BIOS or use "
	"force_addr=0xaddr\n");
	return -ENODEV;
	}
	}

	if (!request_region(piix4_smba, SMBIOSIZE, "piix4-smbus")) {
	dev_err(&PIIX4_dev->dev, "SMB region 0x%x already in use!\n",
	piix4_smba);
	return -ENODEV;
	}

	pci_read_config_byte(PIIX4_dev, SMBHSTCFG, &temp);

	/* Some BIOS will set up the chipset incorrectly and leave a register
	in an undefined state (causing I2C to act very strangely). */
	if (temp & 0x02) {
	if (fix_hstcfg) {
	dev_info(&PIIX4_dev->dev, "Working around buggy BIOS "
	"(I2C)\n");
	temp &= 0xfd;
	pci_write_config_byte(PIIX4_dev, SMBHSTCFG, temp);
	} else {
	dev_info(&PIIX4_dev->dev, "Unusual config register "
	"value\n");
	dev_info(&PIIX4_dev->dev, "Try using fix_hstcfg=1 if "
	"you experience problems\n");
	}
	}

	/* If force_addr is set, we program the new address here. Just to make
	sure, we disable the PIIX4 first. */
	if (force_addr) {
	pci_write_config_byte(PIIX4_dev, SMBHSTCFG, temp & 0xfe);
	pci_write_config_word(PIIX4_dev, SMBBA, piix4_smba);
	pci_write_config_byte(PIIX4_dev, SMBHSTCFG, temp \| 0x01);
	dev_info(&PIIX4_dev->dev, "WARNING: SMBus interface set to "
	"new address %04x!\n", piix4_smba);
	} else if ((temp & 1) == 0) {
	if (force) {
	/* This should never need to be done, but has been
	* noted that many Dell machines have the SMBus
	* interface on the PIIX4 disabled!? NOTE: This assumes
	* I/O space and other allocations WERE done by the
	* Bios! Don't complain if your hardware does weird
	* things after enabling this. :') Check for Bios
	* updates before resorting to this.
	*/
	pci_write_config_byte(PIIX4_dev, SMBHSTCFG,
	temp \| 1);
	dev_printk(KERN_NOTICE, &PIIX4_dev->dev,
	"WARNING: SMBus interface has been "
	"FORCEFULLY ENABLED!\n");
	} else {
	dev_err(&PIIX4_dev->dev,
	"Host SMBus controller not enabled!\n");
	release_region(piix4_smba, SMBIOSIZE);
	piix4_smba = 0;
	return -ENODEV;
	}
	}

	if ((temp & 0x0E) == 8)
	dev_dbg(&PIIX4_dev->dev, "Using Interrupt 9 for SMBus.\n");
	else if ((temp & 0x0E) == 0)
	dev_dbg(&PIIX4_dev->dev, "Using Interrupt SMI# for SMBus.\n");
	else
	dev_err(&PIIX4_dev->dev, "Illegal Interrupt configuration "
	"(or code out of date)!\n");

	pci_read_config_byte(PIIX4_dev, SMBREV, &temp);
	dev_dbg(&PIIX4_dev->dev, "SMBREV = 0x%X\n", temp);
	dev_dbg(&PIIX4_dev->dev, "SMBA = 0x%X\n", piix4_smba);

	return 0;
	}

	/* Another internally used function */
	static int piix4_transaction(void)
	{
	int temp;
	int result = 0;
	int timeout = 0;

	dev_dbg(&piix4_adapter.dev, "Transaction (pre): CNT=%02x, CMD=%02x, "
	"ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb_p(SMBHSTCNT),
	inb_p(SMBHSTCMD), inb_p(SMBHSTADD), inb_p(SMBHSTDAT0),
	inb_p(SMBHSTDAT1));

	/* Make sure the SMBus host is ready to start transmitting */
	if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
	dev_dbg(&piix4_adapter.dev, "SMBus busy (%02x). "
	"Resetting...\n", temp);
	outb_p(temp, SMBHSTSTS);
	if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
	dev_err(&piix4_adapter.dev, "Failed! (%02x)\n", temp);
	return -1;
	} else {
	dev_dbg(&piix4_adapter.dev, "Successfull!\n");
	}
	}

	/* start the transaction by setting bit 6 */
	outb_p(inb(SMBHSTCNT) \| 0x040, SMBHSTCNT);

	/* We will always wait for a fraction of a second! (See PIIX4 docs errata) */
	do {
	msleep(1);
	temp = inb_p(SMBHSTSTS);
	} while ((temp & 0x01) && (timeout++ < MAX_TIMEOUT));

	/* If the SMBus is still busy, we give up */
	if (timeout >= MAX_TIMEOUT) {
	dev_err(&piix4_adapter.dev, "SMBus Timeout!\n");
	result = -1;
	}

	if (temp & 0x10) {
	result = -1;
	dev_err(&piix4_adapter.dev, "Error: Failed bus transaction\n");
	}

	if (temp & 0x08) {
	result = -1;
	dev_dbg(&piix4_adapter.dev, "Bus collision! SMBus may be "
	"locked until next hard reset. (sorry!)\n");
	/* Clock stops and slave is stuck in mid-transmission */
	}

	if (temp & 0x04) {
	result = -1;
	dev_dbg(&piix4_adapter.dev, "Error: no response!\n");
	}

	if (inb_p(SMBHSTSTS) != 0x00)
	outb_p(inb(SMBHSTSTS), SMBHSTSTS);

	if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
	dev_err(&piix4_adapter.dev, "Failed reset at end of "
	"transaction (%02x)\n", temp);
	}
	dev_dbg(&piix4_adapter.dev, "Transaction (post): CNT=%02x, CMD=%02x, "
	"ADD=%02x, DAT0=%02x, DAT1=%02x\n", inb_p(SMBHSTCNT),
	inb_p(SMBHSTCMD), inb_p(SMBHSTADD), inb_p(SMBHSTDAT0),
	inb_p(SMBHSTDAT1));
	return result;
	}

	/* Return -1 on error. */
	static s32 piix4_access(struct i2c_adapter * adap, u16 addr,
	unsigned short flags, char read_write,
	u8 command, int size, union i2c_smbus_data * data)
	{
	int i, len;

	switch (size) {
	case I2C_SMBUS_PROC_CALL:
	dev_err(&adap->dev, "I2C_SMBUS_PROC_CALL not supported!\n");
	return -1;
	case I2C_SMBUS_QUICK:
	outb_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMBHSTADD);
	size = PIIX4_QUICK;
	break;
	case I2C_SMBUS_BYTE:
	outb_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMBHSTADD);
	if (read_write == I2C_SMBUS_WRITE)
	outb_p(command, SMBHSTCMD);
	size = PIIX4_BYTE;
	break;
	case I2C_SMBUS_BYTE_DATA:
	outb_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMBHSTADD);
	outb_p(command, SMBHSTCMD);
	if (read_write == I2C_SMBUS_WRITE)
	outb_p(data->byte, SMBHSTDAT0);
	size = PIIX4_BYTE_DATA;
	break;
	case I2C_SMBUS_WORD_DATA:
	outb_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMBHSTADD);
	outb_p(command, SMBHSTCMD);
	if (read_write == I2C_SMBUS_WRITE) {
	outb_p(data->word & 0xff, SMBHSTDAT0);
	outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1);
	}
	size = PIIX4_WORD_DATA;
	break;
	case I2C_SMBUS_BLOCK_DATA:
	outb_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMBHSTADD);
	outb_p(command, SMBHSTCMD);
	if (read_write == I2C_SMBUS_WRITE) {
	len = data->block[0];
	if (len < 0)
	len = 0;
	if (len > 32)
	len = 32;
	outb_p(len, SMBHSTDAT0);
	i = inb_p(SMBHSTCNT); /* Reset SMBBLKDAT */
	for (i = 1; i <= len; i++)
	outb_p(data->block[i], SMBBLKDAT);
	}
	size = PIIX4_BLOCK_DATA;
	break;
	}

	outb_p((size & 0x1C) + (ENABLE_INT9 & 1), SMBHSTCNT);

	if (piix4_transaction()) /* Error in transaction */
	return -1;

	if ((read_write == I2C_SMBUS_WRITE) \|\| (size == PIIX4_QUICK))
	return 0;


	switch (size) {
	case PIIX4_BYTE: /* Where is the result put? I assume here it is in
	SMBHSTDAT0 but it might just as well be in the
	SMBHSTCMD. No clue in the docs */

	data->byte = inb_p(SMBHSTDAT0);
	break;
	case PIIX4_BYTE_DATA:
	data->byte = inb_p(SMBHSTDAT0);
	break;
	case PIIX4_WORD_DATA:
	data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
	break;
	case PIIX4_BLOCK_DATA:
	data->block[0] = inb_p(SMBHSTDAT0);
	i = inb_p(SMBHSTCNT); /* Reset SMBBLKDAT */
	for (i = 1; i <= data->block[0]; i++)
	data->block[i] = inb_p(SMBBLKDAT);
	break;
	}
	return 0;
	}

	static u32 piix4_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;
	}

	static struct i2c_algorithm smbus_algorithm = {
	.smbus_xfer = piix4_access,
	.functionality = piix4_func,
	};

	static struct i2c_adapter piix4_adapter = {
	.owner = THIS_MODULE,
	.class = I2C_CLASS_HWMON,
	.algo = &smbus_algorithm,
	.name = "unset",
	};

	static struct pci_device_id piix4_ids[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_3),
	.driver_data = 3 },
	{ PCI_DEVICE(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_OSB4),
	.driver_data = 0 },
	{ PCI_DEVICE(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_CSB5),
	.driver_data = 0 },
	{ PCI_DEVICE(PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_CSB6),
	.driver_data = 0 },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82443MX_3),
	.driver_data = 3 },
	{ PCI_DEVICE(PCI_VENDOR_ID_EFAR, PCI_DEVICE_ID_EFAR_SLC90E66_3),
	.driver_data = 0 },
	{ 0, }
	};

	MODULE_DEVICE_TABLE (pci, piix4_ids);

	static int __devinit piix4_probe(struct pci_dev *dev,
	const struct pci_device_id *id)
	{
	int retval;

	retval = piix4_setup(dev, id);
	if (retval)
	return retval;

	/* set up the driverfs linkage to our parent device */
	piix4_adapter.dev.parent = &dev->dev;

	snprintf(piix4_adapter.name, I2C_NAME_SIZE,
	"SMBus PIIX4 adapter at %04x", piix4_smba);

	if ((retval = i2c_add_adapter(&piix4_adapter))) {
	dev_err(&dev->dev, "Couldn't register adapter!\n");
	release_region(piix4_smba, SMBIOSIZE);
	piix4_smba = 0;
	}

	return retval;
	}

	static void __devexit piix4_remove(struct pci_dev *dev)
	{
	if (piix4_smba) {
	i2c_del_adapter(&piix4_adapter);
	release_region(piix4_smba, SMBIOSIZE);
	piix4_smba = 0;
	}
	}

	static struct pci_driver piix4_driver = {
	.name = "piix4_smbus",
	.id_table = piix4_ids,
	.probe = piix4_probe,
	.remove = __devexit_p(piix4_remove),
	};

	static int __init i2c_piix4_init(void)
	{
	return pci_register_driver(&piix4_driver);
	}

	static void __exit i2c_piix4_exit(void)
	{
	pci_unregister_driver(&piix4_driver);
	}

	MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
	"Philip Edelbrock <phil@netroedge.com>");
	MODULE_DESCRIPTION("PIIX4 SMBus driver");
	MODULE_LICENSE("GPL");

	module_init(i2c_piix4_init);
	module_exit(i2c_piix4_exit);