This of course opens up security holes. On Thu, Dec 30, 2010 at 9:19 AM, A Curtis <[email protected]> wrote:
> I got this working! > > Basically I did not realize that SYSFS was more sophisticated than / > proc and actually supported file permissions. > > This is basically what I did to access a GPIO from Java land. > > echo "128" >/sys/class/gpio/export > echo "out" > /sys/devices/virtual/gpio/gpio128/direction > chmod 0666 /sys/devices/virtual/gpio/gpio128/value > > Now you have GPIO #128 exported in sysfs, configured as an output and > accessible to your Java application. > > Anything else that is accessible via sysfs can be handled in a similar > way. > > Enjoy! > > > > On Dec 29, 4:36 pm, A Curtis <[email protected]> wrote: > > Chris, > > > > Have you tried to access sysfs directly frdom Java? I have not been > > able to get this to work. > > > > Could you provide a code fragment? > > > > TIA > > > > On Nov 23, 10:12 am, Chris Stratton <[email protected]> wrote: > > > > > > > > > > > > > > > > > On Nov 23, 5:33 am, Mikkel Christensen <[email protected]> > > > wrote: > > > > > > If the LED is already exposed in sysfs you are lucky and it should be > > > > quite easy. Otherwise create a Kernel device driver that does the > > > > exposure of the LED to sysfs. > > > > > If it's already exposed in sysfs, you don't need to use native code. > > > You should be able to access the special file directly from java if > > > you have the permissions set right. If they are wrong, you can't > > > access it from the ndk either. > > > > > > Then in the /jni/native.cpp function do the proper write to the sysfs > > > > entry like this (note: this depends on how the led is exposed trough > > > > sysfs): > > > > > > ret = system("echo 1 > /sys/class/leds/red/brightness"); > > > > > Chaining the echo command seems wasteful. Why not just write to the > > > special file yourself? > > -- > unsubscribe: > [email protected]<android-porting%[email protected]> > website: http://groups.google.com/group/android-porting > -- Dianne Hackborn Android framework engineer [email protected] Note: please don't send private questions to me, as I don't have time to provide private support, and so won't reply to such e-mails. All such questions should be posted on public forums, where I and others can see and answer them. -- unsubscribe: [email protected] website: http://groups.google.com/group/android-porting
