Debug GPIO calls

configname: CONFIG_DEBUG_GPIO

Linux Kernel Configuration
└─>Device Drivers
└─>GPIO Support
└─>Debug GPIO calls
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
Say Y here to add some extra checks and diagnostics to GPIO calls.
These checks help ensure that GPIOs have been properly initialized
before they are used, and that sleeping calls are not made from
non-sleeping contexts. They can make bitbanged serial protocols
slower. The diagnostics help catch the type of setup errors
that are most common when setting up new platforms or boards.