On Mon, Feb 22, 2016 at 6:41 AM, 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 Nit: 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? -- 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
