Overview of the device model from sysfs

sysfs is a non-persistent virtual filesystem that provides a global view of the system and exposes the kernel objects hierarchy (topology) using their kobjects. Each kobject shows up as a directory. The files in these directories represent the kernel variables that are exported by the related kobject. These files are called attributes and can be read or written.

If any registered kobject creates a directory in sysfs, where the directory is created depends on the parent of this kobject (which is also a kobject, thus highlighting internal object hierarchies). In sysfs, top-level directories represent the common ancestors of object hierarchies or the subsystems that the objects belong to.

These top-level sysfs directories can be found in the /sys/ directory, as follows:

/sys$ tree -L 1
├── block
├── bus
├── class
├── dev
├── devices...