/**
* \brief Read a byte from the SMBus.
*
* @param smbus_dev The base SMBus IO port
* @param addr The address location of the DIMM on the SMBus.
* @param offset The offset the data is located at.
*/
u8 smbus_read_byte(u32 smbus_dev, u8 addr, u8 offset)
{
u8 val;
/* Initialize SMBus sequence */
smbus_reset(smbus_dev);
/* Clear host data port. */
outb(0x00, SMBHSTDAT0(smbus_dev));
smbus_wait_until_ready(smbus_dev);
/* Actual addr to reg format. */
addr = (addr << 1);
addr |= 1; /* read command */
outb(addr, SMBXMITADD(smbus_dev));
outb(offset, SMBHSTCMD(smbus_dev));
/* Start transaction, byte data read. */
outb(0x48, SMBHSTCTL(smbus_dev));
smbus_wait_until_ready(smbus_dev);
val = inb(SMBHSTDAT0(smbus_dev));
return val;
}
/* Return negative errno 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 = 0, xact = 0;
struct i801_priv *priv = i2c_get_adapdata(adap);
mutex_lock(&priv->acpi_lock);
if (priv->acpi_reserved) {
mutex_unlock(&priv->acpi_lock);
return -EBUSY;
}
hwpec = (priv->features & FEATURE_SMBUS_PEC) && (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(priv));
xact = I801_QUICK;
break;
case I2C_SMBUS_BYTE:
outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
SMBHSTADD(priv));
if (read_write == I2C_SMBUS_WRITE)
outb_p(command, SMBHSTCMD(priv));
xact = I801_BYTE;
break;
case I2C_SMBUS_BYTE_DATA:
outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
SMBHSTADD(priv));
outb_p(command, SMBHSTCMD(priv));
if (read_write == I2C_SMBUS_WRITE)
outb_p(data->byte, SMBHSTDAT0(priv));
xact = I801_BYTE_DATA;
break;
case I2C_SMBUS_WORD_DATA:
outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
SMBHSTADD(priv));
outb_p(command, SMBHSTCMD(priv));
if (read_write == I2C_SMBUS_WRITE) {
outb_p(data->word & 0xff, SMBHSTDAT0(priv));
outb_p((data->word & 0xff00) >> 8, SMBHSTDAT1(priv));
}
xact = I801_WORD_DATA;
break;
case I2C_SMBUS_BLOCK_DATA:
outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
SMBHSTADD(priv));
outb_p(command, SMBHSTCMD(priv));
block = 1;
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
/* NB: page 240 of ICH5 datasheet shows that the R/#W
* bit should be cleared here, even when reading */
outb_p((addr & 0x7f) << 1, SMBHSTADD(priv));
if (read_write == I2C_SMBUS_READ) {
/* NB: page 240 of ICH5 datasheet also shows
* that DATA1 is the cmd field when reading */
outb_p(command, SMBHSTDAT1(priv));
} else
outb_p(command, SMBHSTCMD(priv));
block = 1;
break;
default:
dev_err(&priv->pci_dev->dev, "Unsupported transaction %d\n",
size);
ret = -EOPNOTSUPP;
goto out;
}