Help getting LED flash to work?

Got it..  I guess anyone who's done kernel stuff would know this but I haven't done a bunch - you need to open the ioctl, do your ops, then close it.

This code, in a simple Java app that opens the camera, has a button which calls setFlash() alternately with 1/0, and then closes the camera on exit seems to work perfectly - flash go on, flash go off, flash go on, flash go off  ;D

If anyone's interested I could post the Java code (it's straightforward) or a sample APK.

#include <string.h>
#include <jni.h>
#include <fcntl.h>
#include <linux/ioctl.h>
#include <linux/videodev2.h>

/* This is a trivial JNI example where we use a native method
 * to return a new VM String. See the corresponding Java source
 * file located at:
 *
 *   apps/samples/hello-jni/project/src/com/example/HelloJni/HelloJni.java
 */
#define VIDIOC_S_FLASH_CAMERA      _IOW  ('V', 98, void *)
#define VIDIOC_S_FLASH_MOVIE      _IOW  ('V', 99, void *)
#define VIDIOC_S_CAMERA_START    _IO  ('V', BASE_VIDIOC_PRIVATE + 0)
#define VIDIOC_S_CAMERA_STOP    _IO  ('V', BASE_VIDIOC_PRIVATE + 1)

extern "C" {

static int fd;
JNIEXPORT void JNICALL
Java_jvr_test_FlashTest_openCamera( JNIEnv* env,
                                            jobject thiz)
{
   fd = open("/dev/video13", O_RDWR);
   int r = ioctl(fd, VIDIOC_S_CAMERA_START, (unsigned long)1);
}

JNIEXPORT void JNICALL
Java_jvr_test_FlashTest_closeCamera( JNIEnv* env,
                                            jobject thiz)
{
   int r = ioctl(fd, VIDIOC_S_CAMERA_STOP, (unsigned long)1);
   close(fd);
}

JNIEXPORT jstring JNICALL
Java_jvr_test_FlashTest_setFlash( JNIEnv* env,
                                            jobject thiz, int i)
{
   struct v4l2_control cont;
   cont.id = 0;
   cont.value = i;
   //int r = ioctl(fd, VIDIOC_S_CAMERA_START, &cont);
   int r = ioctl(fd, VIDIOC_S_FLASH_MOVIE, &cont);
   if (i)
          return env->NewStringUTF("Flash On");
   else   
          return env->NewStringUTF("Flash Off");
}

}

I have no clue abotu the programming what-so-ever but please post up so that people can test and i can leech :)

I am really going to have to start learning to code and all this sillyness. just a matter of time i suppose.  Time which i don't have in the first place....well, back to the lab to tweak the delorean!

How do I install this on the phone again? Sorry I came here on the mobile browser and downloaded it. It is asking me though is I want to use one of the emulators on my phone to open?

Nevermind. did some searching and am downloading app manager to install from sd card. I will let you know.

Ok have it installed and added as a widget to the home screen. It is causes a force close though? Could I have installed it wrong?

Worked for me!  Awesome job.

Edit...  didn't have to do the camera trick either.

Edit2:  yeah, may have used the camera after reboot...

Ya I just tried it without reading all the posts and my phone froze. Worked after a reboot and using the camera flash before using the app. Also the widget takes up two spaces which I don't think you meant to do.

Yeah, I don't know much android yet so just hacked together bits and pieces of stuff out there.  Layout's just a quick "make it work" job. 

I'll do something a little nicer (maybe just a little button with a red light in the middle indicating on, no red light indicating off) and fix the camera bug soon.  Maybe also allow selection of "torch mode" and "camera mode" in a configuration or by double tapping the button or something.