Interface Linux Android

Hi Swisstronics,

1. You need to implement linux driver to access LEDs on your eval board

2. You can implement android native service which can access this driver and control LEDs

http://developer.android.com/reference/android/app/Service.html

http://www.sschauhan.com/index.php?option=com_content&view=article&id=21:creating-service&catid=6:android-category&Itemid=3

http://developerlife.com/tutorials/?p=356

3. In application use service handle and call API/Functions to control LEDs

BR,

satish

Hello Satish

I do understand the mechanism with the Service. But my problem is the HAL level. How does it work with this similar to the Sensor Manager or the Sersor Service on the middle layer. Is there a tutorial or a doc about this? In general I do not understand how to make linux drivers available in the Android. What files are responsible for this configuration in the Android? And which classes can I use similar to the getSystemService(SENSOR_SERVICE). What do you mean with API/Functions?

Thanks Ivo

Hi,

1. It is not necessary that, you must write HAL layer for all stuff... If you can write your own service, which can directly interact with LED driver, then also its fine

2. HAL basically, put a line between android layer and linux so that, android layer should not directly dependent on linux configuration.

ex. for camera, android just call "camera->preview", now inside HAL, one can decided how to open a camera using linux driver.. One can open dummy camera and pass dummy frame also..

3. I am not aware of any tutorial on this, but you can just refer sensor code and "how to write service" -tutorial, you works should be achieved

Let me know if you want further info.

BR,

satish

Hello Satish

 I found in the net a way to implement it by the sysfs. I can access the LED like in

http://e2e.ti.com/support/dsp/sitara_arm174_microprocessors/f/416/p/106693/454794.aspx

It seems that it needs the NDK to access. Is there a way with a own driver to access the GPIO's without NDK? Do you have an example? How do you access the LED driver in your Service?

Thanks for your help

Hi,

1. At present we do not have such driver or service available at android layer.

2. Writing NDK is not a difficult..I think you should try on that..

BR,

satish

Hello Satish

Thank you for your advice. It works now but I do have to give me the permission by chmod on the export, direction and the value function manually by the console to get access. Then it works. with :

jstring Java_de_Versuch_LED_LEDAccessActivity_InitLED( JNIEnv* env, jobject thiz ){

     return (*env)->NewStringUTF(env, "199 export ging nicht");

if(system("echo 198 > /sys/class/gpio/export"))

    return (*env)->NewStringUTF(env, " 198 export ging nicht");

system(

"echo out > /sys/class/gpio/gpio199/direction");

system(

"echo out > /sys/class/gpio/gpio198/direction");

How can I get the permission thing solved?

Thanks Ivo