GPIO toggling MAX speed on STM32mp2 in LINUX

[asadullah4571]

Hi All, 
can any one tell me what is the Maximum Speed of toggling GPIO on userspace and the kernel space.
I was trying with kernel module programming with IOREMAP API i got 35 Nano seconds. but my requirement is maximum 8 Nano second, 
can any one please let me know is there any possibility. toggling GPIO at 8 nano second.  

[Zakaria1]

Hello @asadullah4571,

I believe the 8-nanosecond timing is achievable, but you need to ensure that the IO speed is properly configured, IO compensation is enabled, and verify that the caches are enabled. Referring to Table 63 of DS14284, I see that the (Output high to low level fall time and output low to high level rise time) is 1.5ns when VDD is at 3.3V and 1.3ns when VDD is at 1.8V.

Best Regards,
Zakaria