Even if the ESPRESSObin is the reference platform of this book, in this paragraph, we'll explain how a kernel developer can modify the pins settings for different platforms due to the fact this task may vary across different implementations. In fact, even if all of these implementations are device tree-based, they have some differences among each other that must be outlined.
Current CPUs are very complex systems — so complex that most of them are given the acronym SoC, which means System-On-Chip; in fact, in a single chip, we may find not only the Central Processing Unit (CPU) but also a lot of peripherals, which the CPU can use to communicate with the external environment. So, we can have the display controller, the keyboard controller, a USB host or device controller, disks, and network controllers all together inside...