hi all,
I occurred the familiar issue with that.
I want to open the /dev/snd/hwC0D0 to do the I/O control.
But the different thing is that I failed at opening the device node.
Dear Mars,
Did you find the same situation while opening the device node?
Since I wrote this code into Android ALSA part. (See also /hardware/
alsa-sound/)
Did you confirm that you've already been success on "open"?
Thanks for your information.
BR,
Tec
On 3月10日, 下午4時48分, Mars Alucard <k...@cis.nctu.edu.tw> wrote:
> Hi,
>
> In my Android application, I need to use IOCTL() to do I2C R/W
> operations.
>
> My native C application could do it successfully, no matter by
> standalone or dynamically linking .so, but...
> ioctl() returns -1 when Android application loads shared library (.so)
> and calls the function including ioctl() via JNI.
>
> Could Android application directly use ioctl() in shared library (.so)
> thruogh JNI with any tips?
>
> Or, if Android application needs to use ioctl() in native C code,
> could some methods help to do this?
> (Like Service Manager, Binder, Android source code, or something
> else?)
>
> I've tried to find articles for several days to solve this issue, but
> still get no ideas now.
>
> (Followings are the environment and testing steps for my trials.)
>
> 1. Testing Steps for Native C Application on Android (Successful)
> (1) Chiefly I want to execute the two statements below on Android:
>
> unsigned int hI2C = open("/dev/i2c-2", O_RDWR);
> int retI2C = ioctl(hI2C, I2C_SLAVE, 0x0C);
>
> (2) A native C application is compiled on Ubuntu, and then put to
> Beagle/G1.
> (3) The native C application could work well to open I2C and bind/read/
> write I2C slave address 0x0C.
> (4)
> Even more, the native C application could dynamically link the shared
> library (.so) in 2. (1) below,
> and then call JNI function to execute the statements in 1. (1) above
> successfully.
>
> 2. Testing Steps for Android Application with JNI + Shared Library .so
> (Unsuccessful)
> (1) I make a shared library (.so) with JNI, including the statements
> in 1. (1) above, by the commands below:
>
> ~/arm-2007q3/bin/arm-none-linux-gnueabi-gcc -I/usr/lib/jvm/java-6-sun/
> include -I/usr/lib/jvm/java-6-sun/include/linux -fpic -c XXX.c
> ~/arm-2007q3/bin/arm-none-linux-gnueabi-ld -T ~/arm-2007q3/arm-none-
> linux-gnueabi/lib/ldscripts/armelf_linux_eabi.xsc -shared -o libXXX.so
> XXX.o
>
> (2) An Android application is compiled by Eclipse on WIN32, with a few
> system-level permission. (enabled by "uses-permission")
> (3) Then put the Android application (.apk) and shared library (.so)
> to Beagle/G1, with chmod 777.
> (4) Run the Android application, to load the shared library and call
> JNI function to execute the statements in 1. (1) above.
> (5) The Android application could load the shared library, call JNI
> functions, and execute almost all statements well, BUT...
> (6) When the Android application call JNI function to execute ioctl(),
> ioctl() return -1, which means FAILED.
>
> 3. Environment
> (1) Platform: Android @ T1 OMAP Beagle Board & Google Phone
> (2) WIN32: JDK v1.60_12 & Eclipse v3.42 (with a few system-level
> permissions enabled by "uses-permission")
> (3) Linux: Ubuntu & JDK v1.60_10 & arm-2007q3 ( with arm-non-linux-
> gnueabi-gcc/ld)
>
> Many thanks,
>
> Mars Alucard
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