[yocto] Accessing BeagleBone Analog inputs

[Tim Orling]

You will probably have more luck getting an answer on the meta-ti mailing list:
https://lists.yoctoproject.org/listinfo/meta-ti


> On Feb 9, 2018, at 10:17 AM, Chris Kottaridis <chriskot at quietwind.net> wrote:
> 
> I followed the steps to create a beaglebone found here:
> 
> http://www.jumpnowtek.com/beaglebone/BeagleBone-Systems-with-Yocto.html
> 
> They worked like a charm, thanksyou junponowtek.
> 
> And then followed this doc to try and get the ADC available:
> 
> http://processors.wiki.ti.com/index.php/Linux_Core_ADC_Users_Guide
> 
> I loaded the module and it shows up in lsmod along with other modules it brings in:
> 
> # lsmod
> Module                  Size  Used by
> ti_am335x_adc          16384  0
> kfifo_buf              16384  1 ti_am335x_adc
> industrialio           57344  2 ti_am335x_adc,kfifo_buf
> ti_am335x_tscadc       16384  1 ti_am335x_adc
> 
> My arch/arm/boot/dts/am335x-evm.dts file shows
> 
> &tscadc {
>         status = "okay";
>         tsc {
>                 ti,wires = <4>;
>                 ti,x-plate-resistance = <200>;
>                 ti,coordinate-readouts = <5>;
>                 ti,wire-config = <0x00 0x11 0x22 0x33>;
>                 ti,charge-delay = <0x400>;
>         };
> 
>         adc {
>                 ti,adc-channels = <4 5 6 7>;
>         };
> };
> 
> According to the doc above loading the module should create the following:
> 
> >On loading the module you would see the IIO device created
> 
> root at arago-armv7:~# ls -al /sys/bus/iio/devices/iio\:device0/
> drwxr-xr-x    5 root     root             0 Nov  1 22:06 .
> drwxr-xr-x    4 root     root             0 Nov  1 22:06 ..
> drwxr-xr-x    2 root     root             0 Nov  1 22:06 buffer
> -r--r--r--    1 root     root          4096 Nov  1 22:06 dev
> -rw-r--r--    1 root     root          4096 Nov  1 22:06 in_voltage4_raw
> -rw-r--r--    1 root     root          4096 Nov  1 22:06 in_voltage5_raw
> -rw-r--r--    1 root     root          4096 Nov  1 22:06 in_voltage6_raw
> -rw-r--r--    1 root     root          4096 Nov  1 22:06 in_voltage7_raw
> -r--r--r--    1 root     root          4096 Nov  1 22:06 name
> lrwxrwxrwx    1 root     root             0 Nov  1 22:06 of_node -> ../../../../../../firmware/devicetree/base/ocp/tscadc at 44e0d000/adc
> drwxr-xr-x    2 root     root             0 Nov  1 22:06 power
> drwxr-xr-x    2 root     root             0 Nov  1 22:06 scan_elements
> lrwxrwxrwx    1 root     root             0 Nov  1 22:06 subsystem -> ../../../../../../bus/iio
> -rw-r--r--    1 root     root          4096 Nov  1 22:06 uevent
> 
> While the /sys/bus/iio directory got created when I loaded the module the device directory is empty
> 
> # ls /sys/bus/iio/devices
> #
> 
> What am I missing that is preventing the ADC interface from being created ?
> 
> Any pointers would be appreciated.
> 
> Thanks
> Chris K
> -- 
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