%Device Driver Model
%Thadeu Cascardo

# Linux 2.6 Device Driver Model

* Design and Implementation by GregKH
* kobjects
* sysfs

# Buses

* A way to communicate with device
* Interface between Linux and hardware
* May allow hotplug of devices
* Examples:
	- USB
	- PCI
	- I2C
	- SPI
	- ACPI
	- Platform
* /sys/bus/

# Classes

* A view of the device
* Interface between Linux and user space software
* The interface may use character devices and/or sysfs or other interfaces
* Specific interface classes:
	- block devices
	- network devices
* Other classes:
	- tty
	- video4linux
	- input
	- backlight
	- rtc
* /sys/class/

# Drivers

* Implement the communication with the hardware, usually through a bus
* Present a view of the device, communicating with user space
* Basically, links the bus and the class for a given device model (or a family)

# Device

* An object representing a device in the bus or a class device
* Establishes an hierarchy through the parent link
* A class device usually has a device in the bus as its parent