P0_OUT
i2c_smbus_write_byte_data(ioexp_client, P0_OUT, 0xff);
rc = i2c_smbus_read_byte_data(ioexp_client, P0_OUT);
rc = i2c_smbus_write_byte_data(ioexp_client, P0_OUT, out);
rc = i2c_smbus_write_byte_data(ioexp_client, P0_OUT, out);
rc = i2c_smbus_write_byte_data(ioexp_client, P0_OUT, out);