Many people will ask "why not do this in user space?" The article answers this:
Unlike Linux user space, the Linux kernel space has support for interrupts. The first example in this article demonstrates how you can write an LKM that uses GPIOs and interrupts to achieve a faster response time than is possible in user space.
Unlike Linux user space, the Linux kernel space has support for interrupts. The first example in this article demonstrates how you can write an LKM that uses GPIOs and interrupts to achieve a faster response time than is possible in user space.