It is necessary to confirm that the correct SPI mode is being used. SPI has four different modes, where CPOL and CPHA can be 0 or 1 independently. MAX7317 CPOL is 0 (i.e CLK inactive state is logic low), and CPHA is 0 (i.e data is valid on leading edge of clock). If SPI communication is correct, and the IO status still doesn't change, please ensure to pay attention to the sink current capability of the device (maximum output low voltage is 0.4V at sink current of 0.5mA). For a supply voltage of 3.3V, the pull up resistor at IO should be larger than (3.3 - 0.4)/(0.5mA) = 5.8kohm. A 10kohm pull-up resistor is recommended to satisfy the requirement. Pull-up resistors that are either too large or too small will result in errorneous IO output.