drivers/i2c/busses/i2c-amd756.c - arm/linux - Git at Google

 /*
     Copyright (c) 1999-2002 Merlin Hughes <merlin@merlin.org>

     Shamelessly ripped from i2c-piix4.c:

     Copyright (c) 1998, 1999  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.
 */

 /*
     2002-04-08: Added nForce support. (Csaba Halasz)
     2002-10-03: Fixed nForce PnP I/O port. (Michael Steil)
     2002-12-28: Rewritten into something that resembles a Linux driver (hch)
     2003-11-29: Added back AMD8111 removed by the previous rewrite.
                 (Philip Pokorny)
 */

 /*
    Supports AMD756, AMD766, AMD768, AMD8111 and nVidia nForce
    Note: we assume there can only be one device, with one SMBus interface.
 */

 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/stddef.h>
 #include <linux/ioport.h>
 #include <linux/i2c.h>
 #include <linux/acpi.h>
 #include <linux/io.h>

 /* AMD756 SMBus address offsets */
 #define SMB_ADDR_OFFSET		0xE0
 #define SMB_IOSIZE		16
 #define SMB_GLOBAL_STATUS	(0x0 + amd756_ioport)
 #define SMB_GLOBAL_ENABLE	(0x2 + amd756_ioport)
 #define SMB_HOST_ADDRESS	(0x4 + amd756_ioport)
 #define SMB_HOST_DATA		(0x6 + amd756_ioport)
 #define SMB_HOST_COMMAND	(0x8 + amd756_ioport)
 #define SMB_HOST_BLOCK_DATA	(0x9 + amd756_ioport)
 #define SMB_HAS_DATA		(0xA + amd756_ioport)
 #define SMB_HAS_DEVICE_ADDRESS	(0xC + amd756_ioport)
 #define SMB_HAS_HOST_ADDRESS	(0xE + amd756_ioport)
 #define SMB_SNOOP_ADDRESS	(0xF + amd756_ioport)

 /* PCI Address Constants */

 /* address of I/O space */
 #define SMBBA		0x058		/* mh */
 #define SMBBANFORCE	0x014

 /* general configuration */
 #define SMBGCFG		0x041		/* mh */

 /* silicon revision code */
 #define SMBREV		0x008

 /* Other settings */
 #define MAX_TIMEOUT	500

 /* AMD756 constants */
 #define AMD756_QUICK		0x00
 #define AMD756_BYTE		0x01
 #define AMD756_BYTE_DATA	0x02
 #define AMD756_WORD_DATA	0x03
 #define AMD756_PROCESS_CALL	0x04
 #define AMD756_BLOCK_DATA	0x05

 static struct pci_driver amd756_driver;
 static unsigned short amd756_ioport;

 /*
   SMBUS event = I/O 28-29 bit 11
      see E0 for the status bits and enabled in E2

 */
 #define GS_ABRT_STS	(1 << 0)
 #define GS_COL_STS	(1 << 1)
 #define GS_PRERR_STS	(1 << 2)
 #define GS_HST_STS	(1 << 3)
 #define GS_HCYC_STS	(1 << 4)
 #define GS_TO_STS	(1 << 5)
 #define GS_SMB_STS	(1 << 11)

 #define GS_CLEAR_STS	(GS_ABRT_STS | GS_COL_STS | GS_PRERR_STS | \
 			 GS_HCYC_STS | GS_TO_STS )

 #define GE_CYC_TYPE_MASK	(7)
 #define GE_HOST_STC		(1 << 3)
 #define GE_ABORT		(1 << 5)


 static int amd756_transaction(struct i2c_adapter *adap)
 {
 	int temp;
 	int result = 0;
 	int timeout = 0;

 	dev_dbg(&adap->dev, "Transaction (pre): GS=%04x, GE=%04x, ADD=%04x, "
 		"DAT=%04x\n", inw_p(SMB_GLOBAL_STATUS),
 		inw_p(SMB_GLOBAL_ENABLE), inw_p(SMB_HOST_ADDRESS),
 		inb_p(SMB_HOST_DATA));

 	/* Make sure the SMBus host is ready to start transmitting */
 	if ((temp = inw_p(SMB_GLOBAL_STATUS)) & (GS_HST_STS | GS_SMB_STS)) {
 		dev_dbg(&adap->dev, "SMBus busy (%04x). Waiting...\n", temp);
 		do {
 			msleep(1);
 			temp = inw_p(SMB_GLOBAL_STATUS);
 		} while ((temp & (GS_HST_STS | GS_SMB_STS)) &&
 		         (timeout++ < MAX_TIMEOUT));
 		/* If the SMBus is still busy, we give up */
 		if (timeout > MAX_TIMEOUT) {
 			dev_dbg(&adap->dev, "Busy wait timeout (%04x)\n", temp);
 			goto abort;
 		}
 		timeout = 0;
 	}

 	/* start the transaction by setting the start bit */
 	outw_p(inw(SMB_GLOBAL_ENABLE) | GE_HOST_STC, SMB_GLOBAL_ENABLE);

 	/* We will always wait for a fraction of a second! */
 	do {
 		msleep(1);
 		temp = inw_p(SMB_GLOBAL_STATUS);
 	} while ((temp & GS_HST_STS) && (timeout++ < MAX_TIMEOUT));

 	/* If the SMBus is still busy, we give up */
 	if (timeout > MAX_TIMEOUT) {
 		dev_dbg(&adap->dev, "Completion timeout!\n");
 		goto abort;
 	}

 	if (temp & GS_PRERR_STS) {
 		result = -ENXIO;
 		dev_dbg(&adap->dev, "SMBus Protocol error (no response)!\n");
 	}

 	if (temp & GS_COL_STS) {
 		result = -EIO;
 		dev_warn(&adap->dev, "SMBus collision!\n");
 	}

 	if (temp & GS_TO_STS) {
 		result = -ETIMEDOUT;
 		dev_dbg(&adap->dev, "SMBus protocol timeout!\n");
 	}

 	if (temp & GS_HCYC_STS)
 		dev_dbg(&adap->dev, "SMBus protocol success!\n");

 	outw_p(GS_CLEAR_STS, SMB_GLOBAL_STATUS);

 #ifdef DEBUG
 	if (((temp = inw_p(SMB_GLOBAL_STATUS)) & GS_CLEAR_STS) != 0x00) {
 		dev_dbg(&adap->dev,
 			"Failed reset at end of transaction (%04x)\n", temp);
 	}
 #endif

 	dev_dbg(&adap->dev,
 		"Transaction (post): GS=%04x, GE=%04x, ADD=%04x, DAT=%04x\n",
 		inw_p(SMB_GLOBAL_STATUS), inw_p(SMB_GLOBAL_ENABLE),
 		inw_p(SMB_HOST_ADDRESS), inb_p(SMB_HOST_DATA));

 	return result;

  abort:
 	dev_warn(&adap->dev, "Sending abort\n");
 	outw_p(inw(SMB_GLOBAL_ENABLE) | GE_ABORT, SMB_GLOBAL_ENABLE);
 	msleep(100);
 	outw_p(GS_CLEAR_STS, SMB_GLOBAL_STATUS);
 	return -EIO;
 }

 /* Return negative errno on error. */
 static s32 amd756_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;
 	int status;

 	switch (size) {
 	case I2C_SMBUS_QUICK:
 		outw_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMB_HOST_ADDRESS);
 		size = AMD756_QUICK;
 		break;
 	case I2C_SMBUS_BYTE:
 		outw_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMB_HOST_ADDRESS);
 		if (read_write == I2C_SMBUS_WRITE)
 			outb_p(command, SMB_HOST_DATA);
 		size = AMD756_BYTE;
 		break;
 	case I2C_SMBUS_BYTE_DATA:
 		outw_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMB_HOST_ADDRESS);
 		outb_p(command, SMB_HOST_COMMAND);
 		if (read_write == I2C_SMBUS_WRITE)
 			outw_p(data->byte, SMB_HOST_DATA);
 		size = AMD756_BYTE_DATA;
 		break;
 	case I2C_SMBUS_WORD_DATA:
 		outw_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMB_HOST_ADDRESS);
 		outb_p(command, SMB_HOST_COMMAND);
 		if (read_write == I2C_SMBUS_WRITE)
 			outw_p(data->word, SMB_HOST_DATA);	/* TODO: endian???? */
 		size = AMD756_WORD_DATA;
 		break;
 	case I2C_SMBUS_BLOCK_DATA:
 		outw_p(((addr & 0x7f) << 1) | (read_write & 0x01),
 		       SMB_HOST_ADDRESS);
 		outb_p(command, SMB_HOST_COMMAND);
 		if (read_write == I2C_SMBUS_WRITE) {
 			len = data->block[0];
 			if (len < 0)
 				len = 0;
 			if (len > 32)
 				len = 32;
 			outw_p(len, SMB_HOST_DATA);
 			/* i = inw_p(SMBHSTCNT); Reset SMBBLKDAT */
 			for (i = 1; i <= len; i++)
 				outb_p(data->block[i],
 				       SMB_HOST_BLOCK_DATA);
 		}
 		size = AMD756_BLOCK_DATA;
 		break;
 	default:
 		dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 		return -EOPNOTSUPP;
 	}

 	/* How about enabling interrupts... */
 	outw_p(size & GE_CYC_TYPE_MASK, SMB_GLOBAL_ENABLE);

 	status = amd756_transaction(adap);
 	if (status)
 		return status;

 	if ((read_write == I2C_SMBUS_WRITE) || (size == AMD756_QUICK))
 		return 0;


 	switch (size) {
 	case AMD756_BYTE:
 		data->byte = inw_p(SMB_HOST_DATA);
 		break;
 	case AMD756_BYTE_DATA:
 		data->byte = inw_p(SMB_HOST_DATA);
 		break;
 	case AMD756_WORD_DATA:
 		data->word = inw_p(SMB_HOST_DATA);	/* TODO: endian???? */
 		break;
 	case AMD756_BLOCK_DATA:
 		data->block[0] = inw_p(SMB_HOST_DATA) & 0x3f;
 		if(data->block[0] > 32)
 			data->block[0] = 32;
 		/* i = inw_p(SMBHSTCNT); Reset SMBBLKDAT */
 		for (i = 1; i <= data->block[0]; i++)
 			data->block[i] = inb_p(SMB_HOST_BLOCK_DATA);
 		break;
 	}

 	return 0;
 }

 static u32 amd756_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 const struct i2c_algorithm smbus_algorithm = {
 	.smbus_xfer	= amd756_access,
 	.functionality	= amd756_func,
 };

 struct i2c_adapter amd756_smbus = {
 	.owner		= THIS_MODULE,
 	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
 	.algo		= &smbus_algorithm,
 };

 enum chiptype { AMD756, AMD766, AMD768, NFORCE, AMD8111 };
 static const char* chipname[] = {
 	"AMD756", "AMD766", "AMD768",
 	"nVidia nForce", "AMD8111",
 };

 static const struct pci_device_id amd756_ids[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_VIPER_740B),
 	  .driver_data = AMD756 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_VIPER_7413),
 	  .driver_data = AMD766 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_OPUS_7443),
 	  .driver_data = AMD768 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8111_SMBUS),
 	  .driver_data = AMD8111 },
 	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_SMBUS),
 	  .driver_data = NFORCE },
 	{ 0, }
 };

 MODULE_DEVICE_TABLE (pci, amd756_ids);

 static int amd756_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	int nforce = (id->driver_data == NFORCE);
 	int error;
 	u8 temp;

 	if (amd756_ioport) {
 		dev_err(&pdev->dev, "Only one device supported "
 		       "(you have a strange motherboard, btw)\n");
 		return -ENODEV;
 	}

 	if (nforce) {
 		if (PCI_FUNC(pdev->devfn) != 1)
 			return -ENODEV;

 		pci_read_config_word(pdev, SMBBANFORCE, &amd756_ioport);
 		amd756_ioport &= 0xfffc;
 	} else { /* amd */
 		if (PCI_FUNC(pdev->devfn) != 3)
 			return -ENODEV;

 		pci_read_config_byte(pdev, SMBGCFG, &temp);
 		if ((temp & 128) == 0) {
 			dev_err(&pdev->dev,
 				"Error: SMBus controller I/O not enabled!\n");
 			return -ENODEV;
 		}

 		/* Determine the address of the SMBus areas */
 		/* Technically it is a dword but... */
 		pci_read_config_word(pdev, SMBBA, &amd756_ioport);
 		amd756_ioport &= 0xff00;
 		amd756_ioport += SMB_ADDR_OFFSET;
 	}

 	error = acpi_check_region(amd756_ioport, SMB_IOSIZE,
 				  amd756_driver.name);
 	if (error)
 		return -ENODEV;

 	if (!request_region(amd756_ioport, SMB_IOSIZE, amd756_driver.name)) {
 		dev_err(&pdev->dev, "SMB region 0x%x already in use!\n",
 			amd756_ioport);
 		return -ENODEV;
 	}

 	pci_read_config_byte(pdev, SMBREV, &temp);
 	dev_dbg(&pdev->dev, "SMBREV = 0x%X\n", temp);
 	dev_dbg(&pdev->dev, "AMD756_smba = 0x%X\n", amd756_ioport);

 	/* set up the sysfs linkage to our parent device */
 	amd756_smbus.dev.parent = &pdev->dev;

 	snprintf(amd756_smbus.name, sizeof(amd756_smbus.name),
 		 "SMBus %s adapter at %04x", chipname[id->driver_data],
 		 amd756_ioport);

 	error = i2c_add_adapter(&amd756_smbus);
 	if (error) {
 		dev_err(&pdev->dev,
 			"Adapter registration failed, module not inserted\n");
 		goto out_err;
 	}

 	return 0;

  out_err:
 	release_region(amd756_ioport, SMB_IOSIZE);
 	return error;
 }

 static void amd756_remove(struct pci_dev *dev)
 {
 	i2c_del_adapter(&amd756_smbus);
 	release_region(amd756_ioport, SMB_IOSIZE);
 }

 static struct pci_driver amd756_driver = {
 	.name		= "amd756_smbus",
 	.id_table	= amd756_ids,
 	.probe		= amd756_probe,
 	.remove		= amd756_remove,
 };

 module_pci_driver(amd756_driver);

 MODULE_AUTHOR("Merlin Hughes <merlin@merlin.org>");
 MODULE_DESCRIPTION("AMD756/766/768/8111 and nVidia nForce SMBus driver");
 MODULE_LICENSE("GPL");

 EXPORT_SYMBOL(amd756_smbus);
	/*
	Copyright (c) 1999-2002 Merlin Hughes <merlin@merlin.org>

	Shamelessly ripped from i2c-piix4.c:

	Copyright (c) 1998, 1999 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.
	*/

	/*
	2002-04-08: Added nForce support. (Csaba Halasz)
	2002-10-03: Fixed nForce PnP I/O port. (Michael Steil)
	2002-12-28: Rewritten into something that resembles a Linux driver (hch)
	2003-11-29: Added back AMD8111 removed by the previous rewrite.
	(Philip Pokorny)
	*/

	/*
	Supports AMD756, AMD766, AMD768, AMD8111 and nVidia nForce
	Note: we assume there can only be one device, with one SMBus interface.
	*/

	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/kernel.h>
	#include <linux/delay.h>
	#include <linux/stddef.h>
	#include <linux/ioport.h>
	#include <linux/i2c.h>
	#include <linux/acpi.h>
	#include <linux/io.h>

	/* AMD756 SMBus address offsets */
	#define SMB_ADDR_OFFSET 0xE0
	#define SMB_IOSIZE 16
	#define SMB_GLOBAL_STATUS (0x0 + amd756_ioport)
	#define SMB_GLOBAL_ENABLE (0x2 + amd756_ioport)
	#define SMB_HOST_ADDRESS (0x4 + amd756_ioport)
	#define SMB_HOST_DATA (0x6 + amd756_ioport)
	#define SMB_HOST_COMMAND (0x8 + amd756_ioport)
	#define SMB_HOST_BLOCK_DATA (0x9 + amd756_ioport)
	#define SMB_HAS_DATA (0xA + amd756_ioport)
	#define SMB_HAS_DEVICE_ADDRESS (0xC + amd756_ioport)
	#define SMB_HAS_HOST_ADDRESS (0xE + amd756_ioport)
	#define SMB_SNOOP_ADDRESS (0xF + amd756_ioport)

	/* PCI Address Constants */

	/* address of I/O space */
	#define SMBBA 0x058 /* mh */
	#define SMBBANFORCE 0x014

	/* general configuration */
	#define SMBGCFG 0x041 /* mh */

	/* silicon revision code */
	#define SMBREV 0x008

	/* Other settings */
	#define MAX_TIMEOUT 500

	/* AMD756 constants */
	#define AMD756_QUICK 0x00
	#define AMD756_BYTE 0x01
	#define AMD756_BYTE_DATA 0x02
	#define AMD756_WORD_DATA 0x03
	#define AMD756_PROCESS_CALL 0x04
	#define AMD756_BLOCK_DATA 0x05

	static struct pci_driver amd756_driver;
	static unsigned short amd756_ioport;

	/*
	SMBUS event = I/O 28-29 bit 11
	see E0 for the status bits and enabled in E2

	*/
	#define GS_ABRT_STS (1 << 0)
	#define GS_COL_STS (1 << 1)
	#define GS_PRERR_STS (1 << 2)
	#define GS_HST_STS (1 << 3)
	#define GS_HCYC_STS (1 << 4)
	#define GS_TO_STS (1 << 5)
	#define GS_SMB_STS (1 << 11)

	#define GS_CLEAR_STS (GS_ABRT_STS \| GS_COL_STS \| GS_PRERR_STS \| \
	GS_HCYC_STS \| GS_TO_STS )

	#define GE_CYC_TYPE_MASK (7)
	#define GE_HOST_STC (1 << 3)
	#define GE_ABORT (1 << 5)


	static int amd756_transaction(struct i2c_adapter *adap)
	{
	int temp;
	int result = 0;
	int timeout = 0;

	dev_dbg(&adap->dev, "Transaction (pre): GS=%04x, GE=%04x, ADD=%04x, "
	"DAT=%04x\n", inw_p(SMB_GLOBAL_STATUS),
	inw_p(SMB_GLOBAL_ENABLE), inw_p(SMB_HOST_ADDRESS),
	inb_p(SMB_HOST_DATA));

	/* Make sure the SMBus host is ready to start transmitting */
	if ((temp = inw_p(SMB_GLOBAL_STATUS)) & (GS_HST_STS \| GS_SMB_STS)) {
	dev_dbg(&adap->dev, "SMBus busy (%04x). Waiting...\n", temp);
	do {
	msleep(1);
	temp = inw_p(SMB_GLOBAL_STATUS);
	} while ((temp & (GS_HST_STS \| GS_SMB_STS)) &&
	(timeout++ < MAX_TIMEOUT));
	/* If the SMBus is still busy, we give up */
	if (timeout > MAX_TIMEOUT) {
	dev_dbg(&adap->dev, "Busy wait timeout (%04x)\n", temp);
	goto abort;
	}
	timeout = 0;
	}

	/* start the transaction by setting the start bit */
	outw_p(inw(SMB_GLOBAL_ENABLE) \| GE_HOST_STC, SMB_GLOBAL_ENABLE);

	/* We will always wait for a fraction of a second! */
	do {
	msleep(1);
	temp = inw_p(SMB_GLOBAL_STATUS);
	} while ((temp & GS_HST_STS) && (timeout++ < MAX_TIMEOUT));

	/* If the SMBus is still busy, we give up */
	if (timeout > MAX_TIMEOUT) {
	dev_dbg(&adap->dev, "Completion timeout!\n");
	goto abort;
	}

	if (temp & GS_PRERR_STS) {
	result = -ENXIO;
	dev_dbg(&adap->dev, "SMBus Protocol error (no response)!\n");
	}

	if (temp & GS_COL_STS) {
	result = -EIO;
	dev_warn(&adap->dev, "SMBus collision!\n");
	}

	if (temp & GS_TO_STS) {
	result = -ETIMEDOUT;
	dev_dbg(&adap->dev, "SMBus protocol timeout!\n");
	}

	if (temp & GS_HCYC_STS)
	dev_dbg(&adap->dev, "SMBus protocol success!\n");

	outw_p(GS_CLEAR_STS, SMB_GLOBAL_STATUS);

	#ifdef DEBUG
	if (((temp = inw_p(SMB_GLOBAL_STATUS)) & GS_CLEAR_STS) != 0x00) {
	dev_dbg(&adap->dev,
	"Failed reset at end of transaction (%04x)\n", temp);
	}
	#endif

	dev_dbg(&adap->dev,
	"Transaction (post): GS=%04x, GE=%04x, ADD=%04x, DAT=%04x\n",
	inw_p(SMB_GLOBAL_STATUS), inw_p(SMB_GLOBAL_ENABLE),
	inw_p(SMB_HOST_ADDRESS), inb_p(SMB_HOST_DATA));

	return result;

	abort:
	dev_warn(&adap->dev, "Sending abort\n");
	outw_p(inw(SMB_GLOBAL_ENABLE) \| GE_ABORT, SMB_GLOBAL_ENABLE);
	msleep(100);
	outw_p(GS_CLEAR_STS, SMB_GLOBAL_STATUS);
	return -EIO;
	}

	/* Return negative errno on error. */
	static s32 amd756_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;
	int status;

	switch (size) {
	case I2C_SMBUS_QUICK:
	outw_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMB_HOST_ADDRESS);
	size = AMD756_QUICK;
	break;
	case I2C_SMBUS_BYTE:
	outw_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMB_HOST_ADDRESS);
	if (read_write == I2C_SMBUS_WRITE)
	outb_p(command, SMB_HOST_DATA);
	size = AMD756_BYTE;
	break;
	case I2C_SMBUS_BYTE_DATA:
	outw_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMB_HOST_ADDRESS);
	outb_p(command, SMB_HOST_COMMAND);
	if (read_write == I2C_SMBUS_WRITE)
	outw_p(data->byte, SMB_HOST_DATA);
	size = AMD756_BYTE_DATA;
	break;
	case I2C_SMBUS_WORD_DATA:
	outw_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMB_HOST_ADDRESS);
	outb_p(command, SMB_HOST_COMMAND);
	if (read_write == I2C_SMBUS_WRITE)
	outw_p(data->word, SMB_HOST_DATA); /* TODO: endian???? */
	size = AMD756_WORD_DATA;
	break;
	case I2C_SMBUS_BLOCK_DATA:
	outw_p(((addr & 0x7f) << 1) \| (read_write & 0x01),
	SMB_HOST_ADDRESS);
	outb_p(command, SMB_HOST_COMMAND);
	if (read_write == I2C_SMBUS_WRITE) {
	len = data->block[0];
	if (len < 0)
	len = 0;
	if (len > 32)
	len = 32;
	outw_p(len, SMB_HOST_DATA);
	/* i = inw_p(SMBHSTCNT); Reset SMBBLKDAT */
	for (i = 1; i <= len; i++)
	outb_p(data->block[i],
	SMB_HOST_BLOCK_DATA);
	}
	size = AMD756_BLOCK_DATA;
	break;
	default:
	dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
	return -EOPNOTSUPP;
	}

	/* How about enabling interrupts... */
	outw_p(size & GE_CYC_TYPE_MASK, SMB_GLOBAL_ENABLE);

	status = amd756_transaction(adap);
	if (status)
	return status;

	if ((read_write == I2C_SMBUS_WRITE) \|\| (size == AMD756_QUICK))
	return 0;


	switch (size) {
	case AMD756_BYTE:
	data->byte = inw_p(SMB_HOST_DATA);
	break;
	case AMD756_BYTE_DATA:
	data->byte = inw_p(SMB_HOST_DATA);
	break;
	case AMD756_WORD_DATA:
	data->word = inw_p(SMB_HOST_DATA); /* TODO: endian???? */
	break;
	case AMD756_BLOCK_DATA:
	data->block[0] = inw_p(SMB_HOST_DATA) & 0x3f;
	if(data->block[0] > 32)
	data->block[0] = 32;
	/* i = inw_p(SMBHSTCNT); Reset SMBBLKDAT */
	for (i = 1; i <= data->block[0]; i++)
	data->block[i] = inb_p(SMB_HOST_BLOCK_DATA);
	break;
	}

	return 0;
	}

	static u32 amd756_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 const struct i2c_algorithm smbus_algorithm = {
	.smbus_xfer = amd756_access,
	.functionality = amd756_func,
	};

	struct i2c_adapter amd756_smbus = {
	.owner = THIS_MODULE,
	.class = I2C_CLASS_HWMON \| I2C_CLASS_SPD,
	.algo = &smbus_algorithm,
	};

	enum chiptype { AMD756, AMD766, AMD768, NFORCE, AMD8111 };
	static const char* chipname[] = {
	"AMD756", "AMD766", "AMD768",
	"nVidia nForce", "AMD8111",
	};

	static const struct pci_device_id amd756_ids[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_VIPER_740B),
	.driver_data = AMD756 },
	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_VIPER_7413),
	.driver_data = AMD766 },
	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_OPUS_7443),
	.driver_data = AMD768 },
	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_8111_SMBUS),
	.driver_data = AMD8111 },
	{ PCI_DEVICE(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_SMBUS),
	.driver_data = NFORCE },
	{ 0, }
	};

	MODULE_DEVICE_TABLE (pci, amd756_ids);

	static int amd756_probe(struct pci_dev pdev, const struct pci_device_id id)
	{
	int nforce = (id->driver_data == NFORCE);
	int error;
	u8 temp;

	if (amd756_ioport) {
	dev_err(&pdev->dev, "Only one device supported "
	"(you have a strange motherboard, btw)\n");
	return -ENODEV;
	}

	if (nforce) {
	if (PCI_FUNC(pdev->devfn) != 1)
	return -ENODEV;

	pci_read_config_word(pdev, SMBBANFORCE, &amd756_ioport);
	amd756_ioport &= 0xfffc;
	} else { /* amd */
	if (PCI_FUNC(pdev->devfn) != 3)
	return -ENODEV;

	pci_read_config_byte(pdev, SMBGCFG, &temp);
	if ((temp & 128) == 0) {
	dev_err(&pdev->dev,
	"Error: SMBus controller I/O not enabled!\n");
	return -ENODEV;
	}

	/* Determine the address of the SMBus areas */
	/* Technically it is a dword but... */
	pci_read_config_word(pdev, SMBBA, &amd756_ioport);
	amd756_ioport &= 0xff00;
	amd756_ioport += SMB_ADDR_OFFSET;
	}

	error = acpi_check_region(amd756_ioport, SMB_IOSIZE,
	amd756_driver.name);
	if (error)
	return -ENODEV;

	if (!request_region(amd756_ioport, SMB_IOSIZE, amd756_driver.name)) {
	dev_err(&pdev->dev, "SMB region 0x%x already in use!\n",
	amd756_ioport);
	return -ENODEV;
	}

	pci_read_config_byte(pdev, SMBREV, &temp);
	dev_dbg(&pdev->dev, "SMBREV = 0x%X\n", temp);
	dev_dbg(&pdev->dev, "AMD756_smba = 0x%X\n", amd756_ioport);

	/* set up the sysfs linkage to our parent device */
	amd756_smbus.dev.parent = &pdev->dev;

	snprintf(amd756_smbus.name, sizeof(amd756_smbus.name),
	"SMBus %s adapter at %04x", chipname[id->driver_data],
	amd756_ioport);

	error = i2c_add_adapter(&amd756_smbus);
	if (error) {
	dev_err(&pdev->dev,
	"Adapter registration failed, module not inserted\n");
	goto out_err;
	}

	return 0;

	out_err:
	release_region(amd756_ioport, SMB_IOSIZE);
	return error;
	}

	static void amd756_remove(struct pci_dev *dev)
	{
	i2c_del_adapter(&amd756_smbus);
	release_region(amd756_ioport, SMB_IOSIZE);
	}

	static struct pci_driver amd756_driver = {
	.name = "amd756_smbus",
	.id_table = amd756_ids,
	.probe = amd756_probe,
	.remove = amd756_remove,
	};

	module_pci_driver(amd756_driver);

	MODULE_AUTHOR("Merlin Hughes <merlin@merlin.org>");
	MODULE_DESCRIPTION("AMD756/766/768/8111 and nVidia nForce SMBus driver");
	MODULE_LICENSE("GPL");

	EXPORT_SYMBOL(amd756_smbus);