SPI Only Supports 4 wire SPI interfaces

[SkydiverTricky]

Some peripheral devices only use 3 wires for SPI communication, CSEL, SCK and SDIO.

for example: https://www.st.com/resource/en/datasheet/cd00047926.pdf

The SpiPeripheral could be modified so that the input could be made an Inout, and one of the modes could be that 3 wire is enabled or disabled

[JimLewis]

I noted on the referenced data sheet that it says obsolete. Is there a non-obsolete part that does a 3 wire interface?