Best way to implement SPI drivers - specifically because they need CS pins

[andrethomas]

Have you look for this feature in other issues and in the wiki?
Yes

Is your feature request related to a problem? Please describe.
Support for SPI drivers is hinted at since there is already a #ifdef USE_SPI in the code but I'm not clear on how to proceed with CS implementation.

Describe the solution you'd like
Description from lead developers on best practice route to follow for implementing SPI drivers.

Describe alternatives you've considered
Adding additional outputs via I2C using something like MCP23008/MCP23017 to make provision for additional IO pins, or making it possible to use existing GPIO to use CS select but then one would have to find a clean way of implementing this also... and yes, I know adding expansion using the above mentioned chips have been discussed and frowned upon but we need to find a way to expand GPIO in an efficient and low-cost way.

Additional context
The only solution I currently have for sensors is to run the SPI code on a pro mini 3.3V and I wrote an I2C driver which pulls the values from the pro mini 328 as a JSON object and pushes it out over mqqt, or to the web interface I guess (although I have not needed to do the last part yet)

[Jason2866]

I am not a programmer.... Maybe this helps you
@arendst released the branch Display. With this branch a TFT SPI Display can be connected.
See #2557

[andrethomas]

Excellent find, thanks... will follow that one :)