i2c-i801.c

i2c 在linux下的驱动设计

			dev_dbg(&I801_dev->dev,
				"Bad status (%02x) at end of transaction\n",
				temp);
		}
		dev_dbg(&I801_dev->dev, "Block (post %d): CNT=%02x, CMD=%02x, "
			"ADD=%02x, DAT0=%02x, BLKDAT=%02x\n", i,
			inb_p(SMBHSTCNT), inb_p(SMBHSTCMD), inb_p(SMBHSTADD),
			inb_p(SMBHSTDAT0), inb_p(SMBBLKDAT));

		if (result < 0)
			goto END;
	}

	if (hwpec) {
		/* wait for INTR bit as advised by Intel */
		timeout = 0;
		do {
			msleep(1);
			temp = inb_p(SMBHSTSTS);
		} while ((!(temp & 0x02))
			   && (timeout++ < MAX_TIMEOUT));

		if (timeout >= MAX_TIMEOUT) {
			dev_dbg(&I801_dev->dev, "PEC Timeout!\n");
		}
		outb_p(temp, SMBHSTSTS); 
	}
	result = 0;
END:
	if (command == I2C_SMBUS_I2C_BLOCK_DATA) {
		/* restore saved configuration register value */
		pci_write_config_byte(I801_dev, SMBHSTCFG, hostc);
	}
	return result;
}

/* Return -1 on error. */
static s32 i801_access(struct i2c_adapter * adap, u16 addr,
		       unsigned short flags, char read_write, u8 command,
		       int size, union i2c_smbus_data * data)
{
	int hwpec;
	int block = 0;
	int ret, xact = 0;

	hwpec = isich4 && (flags & I2C_CLIENT_PEC)
		&& size != I2C_SMBUS_QUICK
		&& size != I2C_SMBUS_I2C_BLOCK_DATA;

	switch (size) {
	case I2C_SMBUS_QUICK:
		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
		       SMBHSTADD);
		xact = I801_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);
		xact = I801_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);
		xact = I801_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);
		}
		xact = I801_WORD_DATA;
		break;
	case I2C_SMBUS_BLOCK_DATA:
	case I2C_SMBUS_I2C_BLOCK_DATA:
		outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
		       SMBHSTADD);
		outb_p(command, SMBHSTCMD);
		block = 1;
		break;
	case I2C_SMBUS_PROC_CALL:
	default:
		dev_err(&I801_dev->dev, "Unsupported transaction %d\n", size);
		return -1;
	}

	outb_p(hwpec, SMBAUXCTL);	/* enable/disable hardware PEC */

	if(block)
		ret = i801_block_transaction(data, read_write, size, hwpec);
	else {
		outb_p(xact | ENABLE_INT9, SMBHSTCNT);
		ret = i801_transaction();
	}

	/* Some BIOSes don't like it when PEC is enabled at reboot or resume
	   time, so we forcibly disable it after every transaction. */
	if (hwpec)
		outb_p(0, SMBAUXCTL);

	if(block)
		return ret;
	if(ret)
		return -1;
	if ((read_write == I2C_SMBUS_WRITE) || (xact == I801_QUICK))
		return 0;

	switch (xact & 0x7f) {
	case I801_BYTE:	/* Result put in SMBHSTDAT0 */
	case I801_BYTE_DATA:
		data->byte = inb_p(SMBHSTDAT0);
		break;
	case I801_WORD_DATA:
		data->word = inb_p(SMBHSTDAT0) + (inb_p(SMBHSTDAT1) << 8);
		break;
	}
	return 0;
}


static u32 i801_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_WRITE_I2C_BLOCK
	     | (isich4 ? I2C_FUNC_SMBUS_HWPEC_CALC : 0);
}

static const struct i2c_algorithm smbus_algorithm = {
	.smbus_xfer	= i801_access,
	.functionality	= i801_func,
};

static struct i2c_adapter i801_adapter = {
	.owner		= THIS_MODULE,
	.id		= I2C_HW_SMBUS_I801,
	.class		= I2C_CLASS_HWMON,
	.algo		= &smbus_algorithm,
};

static struct pci_device_id i801_ids[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801AA_3) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801AB_3) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801BA_2) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801CA_3) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801DB_3) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801EB_3) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_4) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH6_16) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH7_17) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB2_17) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH8_5) },
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ICH9_6) },
	{ 0, }
};

MODULE_DEVICE_TABLE (pci, i801_ids);

static int __devinit i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
	unsigned char temp;
	int err;

	I801_dev = dev;
	switch (dev->device) {
	case PCI_DEVICE_ID_INTEL_82801DB_3:
	case PCI_DEVICE_ID_INTEL_82801EB_3:
	case PCI_DEVICE_ID_INTEL_ESB_4:
	case PCI_DEVICE_ID_INTEL_ICH6_16:
	case PCI_DEVICE_ID_INTEL_ICH7_17:
	case PCI_DEVICE_ID_INTEL_ESB2_17:
	case PCI_DEVICE_ID_INTEL_ICH8_5:
	case PCI_DEVICE_ID_INTEL_ICH9_6:
		isich4 = 1;
		break;
	default:
		isich4 = 0;
	}

	err = pci_enable_device(dev);
	if (err) {
		dev_err(&dev->dev, "Failed to enable SMBus PCI device (%d)\n",
			err);
		goto exit;
	}

	/* Determine the address of the SMBus area */
	i801_smba = pci_resource_start(dev, SMBBAR);
	if (!i801_smba) {
		dev_err(&dev->dev, "SMBus base address uninitialized, "
			"upgrade BIOS\n");
		err = -ENODEV;
		goto exit;
	}

	err = pci_request_region(dev, SMBBAR, i801_driver.name);
	if (err) {
		dev_err(&dev->dev, "Failed to request SMBus region "
			"0x%lx-0x%Lx\n", i801_smba,
			(unsigned long long)pci_resource_end(dev, SMBBAR));
		goto exit;
	}

	pci_read_config_byte(I801_dev, SMBHSTCFG, &temp);
	i801_original_hstcfg = temp;
	temp &= ~SMBHSTCFG_I2C_EN;	/* SMBus timing */
	if (!(temp & SMBHSTCFG_HST_EN)) {
		dev_info(&dev->dev, "Enabling SMBus device\n");
		temp |= SMBHSTCFG_HST_EN;
	}
	pci_write_config_byte(I801_dev, SMBHSTCFG, temp);

	if (temp & SMBHSTCFG_SMB_SMI_EN)
		dev_dbg(&dev->dev, "SMBus using interrupt SMI#\n");
	else
		dev_dbg(&dev->dev, "SMBus using PCI Interrupt\n");

	/* set up the sysfs linkage to our parent device */
	i801_adapter.dev.parent = &dev->dev;

	snprintf(i801_adapter.name, I2C_NAME_SIZE,
		"SMBus I801 adapter at %04lx", i801_smba);
	err = i2c_add_adapter(&i801_adapter);
	if (err) {
		dev_err(&dev->dev, "Failed to add SMBus adapter\n");
		goto exit_release;
	}
	return 0;

exit_release:
	pci_release_region(dev, SMBBAR);
exit:
	return err;
}

static void __devexit i801_remove(struct pci_dev *dev)
{
	i2c_del_adapter(&i801_adapter);
	pci_write_config_byte(I801_dev, SMBHSTCFG, i801_original_hstcfg);
	pci_release_region(dev, SMBBAR);
	/*
	 * do not call pci_disable_device(dev) since it can cause hard hangs on
	 * some systems during power-off (eg. Fujitsu-Siemens Lifebook E8010)
	 */
}

#ifdef CONFIG_PM
static int i801_suspend(struct pci_dev *dev, pm_message_t mesg)
{
	pci_save_state(dev);
	pci_write_config_byte(dev, SMBHSTCFG, i801_original_hstcfg);
	pci_set_power_state(dev, pci_choose_state(dev, mesg));
	return 0;
}

static int i801_resume(struct pci_dev *dev)
{
	pci_set_power_state(dev, PCI_D0);
	pci_restore_state(dev);
	return pci_enable_device(dev);
}
#else
#define i801_suspend NULL
#define i801_resume NULL
#endif

static struct pci_driver i801_driver = {
	.name		= "i801_smbus",
	.id_table	= i801_ids,
	.probe		= i801_probe,
	.remove		= __devexit_p(i801_remove),
	.suspend	= i801_suspend,
	.resume		= i801_resume,
};

static int __init i2c_i801_init(void)
{
	return pci_register_driver(&i801_driver);
}

static void __exit i2c_i801_exit(void)
{
	pci_unregister_driver(&i801_driver);
}

MODULE_AUTHOR ("Frodo Looijaard <[e-mail]>, "
		"Philip Edelbrock <[e-mail]>, "
		"and Mark D. Studebaker <[e-mail]>");
MODULE_DESCRIPTION("I801 SMBus driver");
MODULE_LICENSE("GPL");

module_init(i2c_i801_init);
module_exit(i2c_i801_exit);