How to build and install the Android sensor HAL

AN4156

10/12

Doc ID 023584 Rev 1

3

How to build and install the Android sensor HAL

The build system in Android is very easy thanks to the Android build environment and to the

Android makefiles. After having successfully downloaded and compiled the Android

sources, the user can compile and add/substitute the sensor HAL library.

To do this, copy the sensor HAL library folder in the android sources path, usually located in:

[Root Android Sources]/vendor/[vendor name]/[boardname]/

Before the build operation of the library, the user must initialize the Android environment:

[Root Android Sources]$ source build/envsetup.sh

[Root Android Sources]$ lunch [target board]

It is now possible to build the library; just launch the “mm” command in the HAL folder. The

result of this process is a dynamic library located in:

[Root Android Sources]/out/target/product/[board

name]/system/lib/hw/sensors.[board name].so

The user can add this library or substitute the existing library using adb push, but they

must remount the Android system partition to push it:

[Root Android Sources]$ adb shell]

[Android shell]$ mount

...

ro,relatime,barrier=1,data=ordered 0 0

...

[Android shell]$ mount -o remount,rw

/dev/block/platform/omap/omap_hsmmc.0/by-name/system

[Root Android Sources]/out/target/product/[board

name]/system/lib/hw/adb push sensors.[board name].so

/system/lib/hw/