LCD and ADC simultaneously

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1

Hello.

I am running Ubuntu 12.10 (GNU/Linux 3.2.32-psp25 armv7l) in a Beaglebone. I have a LCD7 touchscreen installed.

I want to read some analog signals with my board, connecting them to AIN5, AIN6 and AIN7, but when I read any of these inputs, I lose the touchscreen functionality.

Does anyone have detected the same behaviour? Is there any way to use the touchscreen and the AD inputs at the same time?

Thanks in advance.

Juan

2

I have found this page: http://processors.wiki.ti.com/index.php/AM335x_ADC_Driver’s_Guide

where I have seen this:

Platform data

ADC platform data is not added by default. To add the same make changes in board file(arch/arm/mach-omap2/board-am335xevm.c) as shown below.

<i>#include <linux/platform_data/ti_adc.h>
</i>

<i>static struct adc_data am335x_adc_data = {
        .adc_channels = 4,
};
</i>

<i>static struct mfd_tscadc_board tscadc = {
        .tsc_init = &am335x_touchscreen_data,
        .adc_init = &am335x_adc_data,
};
</i>

The parameter “adc_channels” needs to hold data related to how many channels you want to use for ADC.

  • If ADC and touchscreen are used together, add platform data as shown above.

Does anyone know what it means? Is it supposed that I have to download Kernel Source Code, change those parameters and recompile the kernel to get TS and ADC working together?

3

Hello again.

I have tried to rebuild with the changes suggested but it doesn’t work. I can’t rebuild because there is not "linux/platform_data/ti_adc.h" in my source code.

Searching the web I have found this:

http://arago-project.org/git/projects/?p=linux-am33x.git;a=shortlog;h=refs/heads/adc-fixes

It seems that the fix is quite recent, so maybe is not implemented in Ubuntu yet. I wonder how long it takes to be included in a Ubuntu image release. Does anyone know it? Thanks.

4

There is a patched version for a multi-function device TSC/ADC MFD in other linux distributions.

https://lwn.net/Articles/517628/

It seems that TSC/ADC MFD is not available in Ubuntu yet.

Does anybody know how to make a patch request in Ubuntu for a beaglebone?

Thanks in advance