This chapter examines GPIO driver access using the Raspbian Linux sysfs pseudo file system. Using the Raspbian driver allows even a shell script to configure, read, or write to GPIO pins.
The C/C++ programmer might be quick to dismiss this approach as too slow. But the driver does provide reasonable edge detection that is not possible with the direct register access approach. The driver has the advantage of receiving interrupts about GPIO state changes. This information can be passed onto the program using system calls such as poll(2).
/sys/class/gpio
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