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@xxxxxxxxxx> 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@xxxxxxxxx> 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 >>>> >>>> >>>> >>>> >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
