GPIOPin.getValue() runs into Exceptions for an input pin

[Peter Saitz]

Hi

I would suggest the following code change in gpio.c (line 814 to 822) 
for better compatibility to various Linux GPIO implementations:

     if(48 == inBuffer[0]) { // char "0" is FALSE
         *value = JAVACALL_FALSE;
     } else if((49 <= inBuffer[0]) && (57 >= inBuffer[0])) { // accept 
char "1" to "9" as TRUE
         *value = JAVACALL_TRUE;
     } else { // treat all other none numeric chars as failure
         JAVACALL_REPORT_WARN3(JC_DIO, "Error values from value GPIO pin 
%d file was read: %d %d", handle->number, inBuffer[0], inBuffer[1]);
         return JAVACALL_DIO_FAIL;
     }
     return JAVACALL_DIO_OK;

Greetings to everyone
Peter Saitz

_________________________

Peter Saitz
Software Developer

Savien Technologies GmbH.
Bierhäuselberggasse 31
A-1140 Wien

mailto: peter.saitz at savien.at
phone: +43 699 19650224

Am 29.10.2015 um 12:27 schrieb Peter Saitz:
>
> Hi
>
> This could be the reason for my problem I have reported on October 23, 
> 2015:
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpio/gpio-generic.c?id=25b35da7f4cce82271859f1b6eabd9f3bd41a2bb 
>
>
> Some Linux implementations of /sys/class/gpio/gpioNN/value return 0 
> for low generic GPIO, and something != 0 for high GPIO.
>
> In gpio.c line 814 to 821 only "0" (decimal 48) and "1" (decmal 49) 
> will be accepted. All other values result in JAVACALL_DIO_FAIL (line 
> 820). On my Ubuntu Linux, I receive a "2" (decimal 50).
>
> The BufferUnderflowException in 
> com.oracle.dio.impl.EventQueueManager.handleEvent() (line 98) seems to 
> be an additional failure, which occurres when read_value_from_pin() 
> returns JAVACALL_DIO_FAIL. Perhaps I'm the first who came into this 
> situation.
>
> With kind regards from Vienna/Austria
> Peter Saitz
>
> _________________________
>
> Peter Saitz
> Software Developer
>
> Savien Technologies GmbH.
> Bierhäuselberggasse 31
> A-1140 Wien
>
> mailto: peter.saitz at savien.at
> phone: +43 699 19650224
>
>
> On October 23, 2015 at 09:53 PM Peter Saitz wrote:
>>
>> Hi
>>
>> As I have mentioned in my last mail (October 21, 2015), I have ported 
>> OpenJDK Digital I/O to an embedded board with a Freescale i.MX6 Quad 
>> processor, running Ubunto Linux, built dio.jar and libdio.s on the 
>> board.
>>
>> When I configure a GPIO pin for output, *GPIOPin.getValue()* crashes 
>> with the following appearance:
>>
>>    From: src/share/linux/native/com/oracle/dio/gpio/gpio.c, line 819
>>    Error values from value GPIO pin 124 file was readed: 50 54
>>    From: src/share/linux/native/com/oracle/dio/gpio/gpio.c, line 819
>>    Error values from value GPIO pin 124 file was readed: 50 54
>>
>>    java.io.IOException
>>             at com.oracle.dio.gpio.impl.GPIOPinImpl.readPin0(Native 
>> Method)
>>             at 
>> com.oracle.dio.gpio.impl.GPIOPinImpl.getValue(GPIOPinImpl.java:118)
>>             .....
>>    ===== Uncaught exception catched =====
>>    java.nio.BufferUnderflowException
>>             at java.nio.Buffer.nextGetIndex(Buffer.java:500)
>>             at 
>> java.nio.ByteBufferAsIntBufferB.get(ByteBufferAsIntBufferB.java:111)
>>             at 
>> com.oracle.dio.impl.EventQueueManager.handleEvent(EventQueueManager.java:98) 
>>
>>             at 
>> com.oracle.dio.impl.EventQueue.dispatch(EventQueue.java:161)
>>             at 
>> com.oracle.dio.impl.EventQueue.access$500(EventQueue.java:38)
>>             at 
>> com.oracle.dio.impl.EventQueue$EventDispatchThread.run(EventQueue.java:116) 
>>
>>             at java.lang.Thread.run(Thread.java:745)
>>
>>
>> Note: It's not a copy/paste problem, the first 2 lines from gpio.c 
>> came realy 2 times.
>>
>> Here the relevant code from my sources:
>>
>>    GPIOPinConfig pinConfig = new GPIOPinConfig.Builder()
>>             .setControllerNumber(0)
>>             .setPinNumber(124)
>>             .setDirection(GPIOPinConfig.DIR_INPUT_ONLY)
>>             .setTrigger(GPIOPinConfig.TRIGGER_BOTH_EDGES)
>>             .setDriveMode(GPIOPinConfig.MODE_INPUT_PULL_DOWN)
>>             .setInitValue(true)
>>             .build();
>>    GPIOPin pin = (GPIOPin)DeviceManager.open(GPIOPin.class, pinConfig);
>>
>>    ...... in another method ......
>>    boolean value = pin.getValue();
>>
>>
>> Who can help or fix this bug?
>>
>> Note:
>> I'm using the latest release from http://hg.openjdk.java.net/dio/dev
>>
>> With kind regards
>> Peter Saitz
>>
>