They use diodes on CLK and CS pins while also pulling them up on VCC.
I would like to ask why the use those diodes?
Maybe as an ESD protection?
And on another note:
Let's say, on the PCB I am currently designing, I have multiple SPI devices on my bus. Should I add those same pull-up resistors on all of the devices or just place them once for the whole bus?
Maybe I should use multiple buses?
Yes, I know about the sink current of my μC and I should adjust the values accordingly if I have to place multiple pull-up resistors. But should I?