Android Driver Development 9

Hardware Abstraction Layer: HAL

Hal is a set of libraries built on Linux drivers. This library is not part of the Linux kernel, but is an application that belongs to the Linux kernel layer.

Google joins Hal for Android to: Unify the hardware's calling interface. Solve the GPL copyright issue. For some special requirements.

This chapter also describes in detail the addition of HAL for LED drivers:

1. Write a procedure that supports the HAL Linux driver.

2. Streamline the LED driver.

3. Test read-write register operation.

4. Write the HAL module that calls the LED driver

5. Write the service that invokes the HAL module.

The storage path and naming rules for the 6.HAL module.

7. Write the Java library that invokes the service.

8. Test the LED driver.

Android Driver Development 9