Re: iio_simple_dummy_buffer_dma

[Lars-Peter Clausen <lars@metafoo.de>]

hm, try to disable events, I think it breaks something

On 02/23/2016 05:19 PM, John Syne wrote:
> Oops, I didn’t copy the complete config:
> 
> CONFIG_IIO_DUMMY_EVGEN=m
> CONFIG_IIO_SIMPLE_DUMMY=m
> CONFIG_IIO_SIMPLE_DUMMY_EVENTS=y
> CONFIG_IIO_SIMPLE_DUMMY_BUFFER=y
> # CONFIG_IIO_SIMPLE_DUMMY_BUFFER_KFIFO is not set
> CONFIG_IIO_SIMPLE_DUMMY_BUFFER_DMA=y
> 
> Regards,
> John
> 
> 
> 
> 
>> On Feb 22, 2016, at 9:31 AM, Lars-Peter Clausen <lars@metafoo.de> wrote:
>>
>> On 02/22/2016 06:25 PM, John Syne wrote:
>>> Hi Lars,
>>>
>>> It seems like there are other config selections that are selecting KFIFO so it seems to be enabled always. I can enable DMA buffer, but I will see how to disable KFIFO. When I get this working, should I see a waveform in IIO Oscilloscope?
>>
>> Hi,
>>
>> There is one for the dummy buffer.
>>
>> IIO_SIMPLE_DUMMY_BUFFER_DMA needs to be set and
>> IIO_SIMPLE_DUMMY_BUFFER_KFIFO needs to be unset.
>>
>> - Lars
>>
>>
>>>
>>> Regards,
>>> John
>>>
>>>
>>>
>>>
>>>> On Feb 22, 2016, at 3:44 AM, Lars-Peter Clausen <lars@metafoo.de> wrote:
>>>>
>>>> On 02/22/2016 05:51 AM, John Syne wrote:
>>>>> BTW, I seem to remember that Lars removed iio_simple_dummy_buffer_dma.c in his V3 patch so this won’t be in the IIO repo, but I don’t know how to test the IIO DMA framework without this file.
>>>>>
>>>>
>>>> Hi,
>>>>
>>>> The patch was dropped for now to avoid conflicts with other ongoing work on
>>>> the dummy driver. The patch will come back in a slightly overhauled version
>>>> soonish.
>>>>
>>>> As for your problem, make sure that you have the part of the patch which
>>>> updates things so you can choose in Kconfig whether you want to use the DMA
>>>> buffer or the KFIFO buffer. And then select the DMA buffer in your .config.
>>>>
>>>> - Lars
>>>>
>>>>
>>>>> Regards,
>>>>> John
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> On Feb 21, 2016, at 8:41 PM, John Syne <john3909@gmail.com> wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I am interested in using the IIO DMA framework and tried to use your dummy driver. 
>>>>>>
>>>>>> I attempting to get the iio_dummy working with dma and seem to be having sum difficulty.
>>>>>>
>>>>>> Here is what I have done so far:
>>>>>>
>>>>>> I’m working on a BeagleBoneBlack running a 4.1 Linux Kernel. I have back ported the latest IIO code from git://git.kernel.org/pub/scm/linux/kernel/git/jic23
>>>>>>
>>>>>> As a test I tried ti_am335x_adc.ko and enabled in_voltage0_en and then enabled the buffer. Reading from /dev/iio:device0 provided the waveform of the signal generator I had connected to ADC0 on the board. I was even able to run iiod and then connected IIO Oscilloscope which showed the same waveform. I did get a message WARNING: High-speed mode not enabled, but I guess there is no mmap in the driver and that is probably the issue.
>>>>>>
>>>>>> In linux config, I have enabled the following:
>>>>>> CONFIG_IIO_SIMPLE_DUMMY_EVENTS
>>>>>> CONFIG_IIO_SIMPLE_DUMMY_BUFFER
>>>>>> CONFIG_IIO_SIMPLE_DUMMY_BUFFER_DMA
>>>>>> CONFIG_IIO_BUFFER_CB
>>>>>> CONFIG_IIO_BUFFER_DMA
>>>>>> CONFIG_IIO_BUFFER_DMAENGINE
>>>>>> CONFIG_IIO_KFIFO_BUF
>>>>>> CONFIG_IIO_TRIGGERED_BUFFER
>>>>>> CONFIG_IIO_TRIGGER
>>>>>> CONFIG_IIO_CONSUMERS_PER_TRIGGER 2
>>>>>>
>>>>>> When I "modprobe iio_dummy”, the following modules are loaded:
>>>>>>
>>>>>> industrialio
>>>>>> industrialio_buffer_dma
>>>>>> iio_dummy
>>>>>> kfifo_buf
>>>>>> iio_dummy_evgen
>>>>>>
>>>>>> I then modprobe iio_trig_sysfs which gives me /sys/bus/iio/device/iio_sysfs_trigger. To create a trigger I did:
>>>>>>
>>>>>>> echo 1 > /sys/bus/iio/device/iio_sysfs_trigger/add_trigger
>>>>>>> cat name /sys/bus/iio/device/trigger0/name
>>>>>>> sysfstrig1
>>>>>>> echo sysfstrig1 > /sys/bus/iio/device/iio:device0/trigger/current_trigger
>>>>>>
>>>>>> Now to enable a measurement:
>>>>>>
>>>>>>> echo 1 > /sys/bus/iio/device/iio:device0/scan_elements/in_voltage0_en
>>>>>>
>>>>>> Finally to enable the buffer:
>>>>>>
>>>>>>> echo 1 /sys/bus/iio/device/iio:device0/buffer/enable
>>>>>>
>>>>>> When I read "/dev/iio:device0" I get nothing. Connecting IIO Oscilloscope I get the following error message:
>>>>>>
>>>>>> WARNING: High-speed mode not enabled
>>>>>> ERROR: Reading from device failed: -110
>>>>>> Client Exited
>>>>>>
>>>>>> In iio_simple_dummy_buffer_dma.c, I see iio_dummy_dma_source which generates a rect, sine, tri and saw waveforms. Not sure what I need to do to get these waveforms to generate. Is this demo functional?
>>>>>>
>>>>>>
>>>>>> Regards,
>>>>>> John
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> --
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>>
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