CV_SMB_CTRL_FORCE_SMBUS
smb_ctrl |= CV_SMB_CTRL_FORCE_SMBUS;
phy_reg &= ~CV_SMB_CTRL_FORCE_SMBUS;
phy_reg &= ~CV_SMB_CTRL_FORCE_SMBUS;
phy_data |= CV_SMB_CTRL_FORCE_SMBUS;
phy_data &= ~CV_SMB_CTRL_FORCE_SMBUS;