4th lesson 3rd Section _android Lighting System _ Writing HAL_LIGHTS.C

JNI file: Com_android_server_ledservice.cpp

Registering the local method will load the HAL file:

3. Writing the HAL program for the Android lighting system

Java:frameworks/base/services/core/java/com/android/server/lights/lightsservice.java
Jni:frameworks/base/services/core/jni/com_android_server_lights_lightsservice.cpp
Hal:lights.c

Default color: Frameworks/base/core/res/res/values/config.xml
Battery Light: Frameworks/base/services/core/java/com/android/server/batteryservice.java
Notification Light: Frameworks/base/services/core/java/com/android/server/notification/notificationmanagerservice.java

How to write Lights HAL
A. Implementing a hw_module_t structure called the HMI
B. Implement an open function that returns a light_device_t struct based on name
C. Implement multiple light_device_t structures, each corresponding to a device
The 1th member in the light_device_t structure is the hw_device_t structure, followed by a set_light function

Hal:lights.c

upload the new file to the server directory: Hardware/libhardware/modules/lights/led_hal.chardware/libhardware/modules/ lights/android.mk

The android.mk content is as follows: Local_path:= $ (call my-dir) include $ (clear_vars) Local_module:=  Lights.tiny4412local_module_relative_path:= hwlocal_c_includes:= hardware/libhardwarelocal_src _files:= lights.clocal_shared_libraries:= libloglocal_module_tags:= enginclude $ (build_ shared_library) Modify VI vendor/friendly-arm/tiny4412/device-Tiny4412.mkifeq ($ (board_uses_pwmlights), false  + = #       $ (vendor_path)/proprietary/lights.tiny4412.so:system/lib/hw/  Lights.tiny4412.soendif

Compile:
Execute the following commands before executing the MMM command:

$ mmm hardware/libhardware/modules/lights$ make snod$. /gen-img.sh

Use this command to make sure that the lights.c we provide has been programmed into System.img:diff vendor out/target/product/tiny4412/system/lib/hw/lights.tiny4412.so

No Code modification to force compilation-B

The kernel also needs to be modified: Modify Permissions1. drivers/leds/led-classC0644Switch0666Static structDevice_attribute led_class_attrs[] ={__attr (brightness,0666, Led_brightness_show, Led_brightness_store), __attr (Max_brightness,0444, Led_max_brightness_show, NULL), #ifdef config_leds_triggers __attr (Trigger,0666, Led_trigger_show, Led_trigger_store),#endif__attr_null,};2. DRIVERS/LEDS/LEDTRIG-TIMER.C:0644Switch0666#ifDefined (CONFIG_MACH_IPCAM)StaticDevice_attr (delay_on,0666, Led_delay_on_show, led_delay_on_store);StaticDevice_attr (Delay_off,0666, Led_delay_off_show, led_delay_off_store);#elseStaticDevice_attr (delay_on,0666, Led_delay_on_show, led_delay_on_store);StaticDevice_attr (Delay_off,0666, Led_delay_off_show, led_delay_off_store);#endifmake zimage Use this command to ensure that the lights.c we provide has been programmed into System.img:diff vendor/friendly-arm/tiny4412/proprietary/lights.tiny4412.so out/target/product/tiny4412/system/lib/hw/Lights.tiny4412.sologcat lights:v*:s

4th lesson 3rd Section _android Lighting System _ Writing HAL_LIGHTS.C