XP_SET_BITS
XP_SET_BITS(s0, XP_DRIVER_SCRATCH_0, COMMAND, cmd);
XP_SET_BITS(s0, XP_DRIVER_SCRATCH_0, SUB_COMMAND, sub_cmd);
XP_SET_BITS(mutex_id, XP_I2C_MUTEX, ID, phy_data->port_id);
XP_SET_BITS(mutex_id, XP_I2C_MUTEX, ACTIVE, 1);