mutexes

[Ian Lepore]

On Thu, 2020-07-30 at 00:56 +0530, Kamal R. Prasad wrote:
> hello,
> 
> i have 2 instances of an spi controller (pl022) on my setup. can someone
> tell me :-
> 1. is there any danger if we interleave spi io transfers between these 2
> controllers i.e  spi transfer starts on controller 0 and before it can
> finish, controller 1 starts spi transfer. the 2 controllers have different
> spi slave devices.
> 2. assuming there is an issue with that, how to setup a mutex in the code
> path so that it is common to both instances of pl022 driver?
> 

I have never encountered a system with multiple instances of a SPI
controller where they interfered with each other in any way.  Unless
there is documentation to the contrary for your hardware, I think it is
safe to assume that you can have two unrelated SPI transfers happening
on the two different instances without any problems.

-- Ian