Saturday, 15 June 2013

Update. ADC + Touchscreen interaction


IRC meeting on #beagle-gsoc went well. Just some introductions. And I asked a question to which I should've known the answer.

Anyways. I was confused about the interaction of the drivers of the 8-channel ADC and the touchscreen input driver. I had missed a file which was the actual ADC driver. I was only looking at the ADC IIO file and the touchscreen input driver files. Both the ADC IIO and the touchscreen use the same ADC source file which is found in a different folder. I missed that and [Russ] pointed it out to me I think.

I should have noticed the common header..

Links below are for the mainline kernel..

For the IIO driver, you find it in drivers/iio/adc/ti_am335x_adc.c
For the touchscreen driver you find it in drivers/input/touchscreen/ti_am335x_tsc.c
For the base file both use, I found it in drivers/mfd/ti_am335x_tscadc.c

Depending on the kernel tree you browse. You might find some of these files in the staging folder. (staging folder is the place where linux kernel developers put drivers and stuff that isn't fully refined enough to be incorporated in the main master branch)

At the moment I am going through stuff in the Useful links post.
I'm playing around git. Its a really powerful tool with an equally steep learning curve.

My beaglebone black should be on its way. has a really great overview of the ADC and touchscreen driver and how to get them to work.

Greg KH (my mentor for the project and a great guy) has a repository with some great tutorials on kernel development.

I have gone through the tutorial. Now, I will play around and get my head ok with the beagleboard kernel patches repository maintained by Koen (co-mentor for the project and another great guy).

I have a feeling that a significant part of my work will be forward porting the developments of the ADC driver in the 3.2 kernel tree by TI to the 3.8 kernel tree for the beaglebone. This done correctly should cover quite a few mile-stones of the GSoC project I proposed.

I will have a 3.8 mainline kernel tree patched using the beagleboard repository.
And I will have a clone of the kernel tree maintained by TI.

Maneuvering through the repositories using git is going to have a steep learning curve. But I'm starting to get a handle on things.

GSoC 2013 officially starts on MONDAY!


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