Re: mraa_spi_bit_per_word Problem

If your code it looks like you're sending 4 bytes (32 bits).  I assume the CS line should remain low for all 4 bytes.

Are you saying that you need to send 16 bits for each byte?  I.e. does your device expect 16 bits for each of address, reg, port_a, and port_b?  If so, you should probably make your array 8 bytes and pad with zeros between each element:

data[0] = 0;

data[1] = address;

data[2] = 0;

data[3] = red;

...

Note, the padding might need to be reversed if the device expects little-endian byte order.