Android system porting and Driver development (II.)

The ultimate goal of Android transplant development is to develop mobile phone products. From the developer's point of view, this type of development is based on the hardware system, and builds the Android software system. This type of development works at the bottom of the Android system. In terms of software systems, the main work is focused on the following two areas. (1) The related device driver driver in Linux is the interface between hardware and upper layer software. In Android phone system, need basic screen, touch screen, keyboard and other drivers, as well as audio, camera, phone Modem, Wi-Fi, Bluetooth and other device drivers. (2) The hardware abstraction layer in the Android native framework works in the hardware abstraction layer of Android in user space, between the driver and Android system. Android systems typically have standard interface definitions for the hardware abstraction layer, and implementing these interfaces in the development process provides the hardware abstraction layer for the Android system. The above two parts combine together to complete the software porting of Android system. The success of the transplant depends on the quality of the driver and the level of understanding of the Android Hardware Abstraction layer interface. The work of Android porting development is done by the core library, Dalvik virtual machine, hardware abstraction layer, Linux kernel layer and hardware system.

Our task is to develop a driver for one of the hardware that will be used on the Android system. Because Android is Linux-based, developing an Android driver is actually a Linux driver. For most subsystems, the hardware abstraction layer and the driver need to be implemented according to the actual system, such as the sensor part, audio section, video part, camera part, and phone part. In addition, there are some subsystems of the hardware abstraction layer is standard, only need to implement the Linux kernel driver, such as input part, vibrator part, Wireless LAN part and Bluetooth part and so on. For systems that have a standard hardware abstraction layer, sometimes it is often necessary to do some configuration work. With the update and development of Android system, it is not only a platform for mobile devices, but also for consumer electronics and smart appliances, such as the 3.0 version is mainly for tablets, in addition to electronic books, digital TV, set-top boxes, fixed phones and other gradually using Android system. On these platforms, it is often necessary to implement fewer parts than mobile devices.

Android system porting and Driver development (II.)