How to add a device to Linux kernel
I am working on a platform where loadable module is not an option(for security reason). When the kernel boots, if I look into /dev, I assume it shows all the device that are compiled as part of the kernel. My question is, how to I add a device to the kernel? For example, gpio driver source code is available in the /linux/driver/gpio directly. What do I need to do so it will be compiled as part of the kernel and, when the kernel boots, I will see a gpio device in /dev?