From: Bit Pusher <ken.w.mar...@gmail.com>
Reply-To: <beagleboard@googlegroups.com>
Date: Tuesday, December 3, 2013 at 6:39 PM
To: <beagleboard@googlegroups.com>
Subject: [beagleboard] Re: Deleting Device Tree Overlays
> If I load my device tree overlay to use the high-speed GPIO pins first, and
> then try to read the ADC using Adafruit_BBIO, it kicks me out of python:
>
> ~/pru\> sudo python
> Python 2.7.5+ (default, Sep 19 2013, 14:17:30)
> [GCC 4.8.1] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> >>> import Adafruit_BBIO.ADC as ADC
>>>> >>> ADC.setup()
>>>> >>> ADC.read("P9_40")
> ~/pru\>
>
> notice no value returned and no python prompt. I suspect this indicates a
> problem.
> I then rebooted (reset switch), waited until the network started working again
> (it takes 5 minutes each time for the network to work, something needs to
> timeout)
> and then did the same, but this time did not load the device overlay to change
> one pru gpio to a high-speed output and got as expected
>
> ~/pru\> sudo python
> Python 2.7.5+ (default, Sep 19 2013, 14:17:30)
> [GCC 4.8.1] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> >>> import Adafruit_BBIO.ADC as ADC
>>>> >>> ADC.setup()
>>>> >>> ADC.read("P9_40")
> 0.8072222471237183
>>>> >>>
>
> I should mention that when I load both overlays, with my overlay first, >cat
> $SLOTS shows them both there, just the ADC overlay load does not
> work correctly. If I run the ADC.setup() first, and then run
> ~/pru\>>sudo sh -c "echo BB-BONE-PRU > $SLOTS" to load my overlay, then
>
> /lib/firmware\> cat $SLOTS
> 0: 54:PF---
> 1: 55:PF---
> 2: 56:PF---
> 3: 57:PF---
> 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
> 5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
> 7: ff:P-O-L Override Board Name,00A0,Override Manuf,cape-bone-iio
> 9: ff:P-O-L Override Board Name,00A0,Override Manuf,BB-BONE-PRU
> /lib/firmware\>
>
> and both overlays are shown but the high
> speed pin does not work.
> Loading just my overlay only, works as expected as far as I can tell (i.e. the
> led turns on and off).
> I'm guessing things are not quite as expected.
> Also, could someone point me to the file in kernel source that loads overlays?
GIT is your friend and you can use it to find what you want in the kernel.
Simply use ³git grep capemgr² and it will show you all the files that
reference the cape manager, which is what loads and removes overlays. You
will notice that there are several patches that attempt to fix crashes
related to capemgr.
Regards,
John
> Thanks.
> Bit Pusher
>
>
> On Tuesday, December 3, 2013 12:16:34 PM UTC-5, Zachary Thorson wrote:
>> Correct me if I am wrong, but it appears that you simply want to use ADC and
>> PRU pins whose pins DO NOT physically overlap on the board? The
>> cape-bone-iio device tree only grabs the ADC0-ADC7 pins plus analog power and
>> ground, so it should not interfere with the PRU pins.
>>
>> What issue are you getting when you try to load the PRU overlay after loading
>> the ADC overlay?
>>
>> Note: The adafruit library has a cleanup function in code, but it is
>> commented out due to the lockup on load that you are describing.
>>
>> Zach
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