[GSOC] GPIO status and I2C start

[Andre Marques]

Hello,

The Raspberry Pi GPIO interrupts are already working, and a test case is 
available to test that [1]. A function is also provided to debounce a 
switch if needed. The test case requires two switches and two LEDS using 
the same setup described at [2] by only changing the pin numbers.

The test works by setting interrupts on both edges of the switches, 
which handlers will turn on or off the corresponding LED. One of the 
LEDs also has a level interrupt which prints a message on the screen 
when the LED is on (high level).

While I wait for some feedback on that, I will be looking at the next 
step: the I2C interface. To test both the I2C and the SPI interfaces I 
have here a simple display [3]. The idea is to create a low level driver 
for I2C to provide the needed directives for the libi2c API, so the 
driver for the display will actually use the libi2c API. Any thoughts 
here are welcome too!

Thanks,
André Marques.

[1] - 
https://github.com/asuol/rtems/blob/GPIO_API/testsuites/samples/LIBGPIO_TEST_IQR/init.c
[2] - http://asuolgsoc2014.wordpress.com/2014/06/22/testing-the-gpio-api/
[3] - http://www.newhavendisplay.com/nhd0216k3zflgbwv3-p-5738.html