Re: IIO Drivers

[Chris Micali <chrismicali@gmail.com>]

I'll give it a shot - thanks!  


On Wednesday, February 27, 2013 at 3:15 PM, Lars-Peter Clausen wrote:

> On 02/27/2013 09:06 PM, Chris Micali wrote:
> > Thanks lars - i'm actually on 3.8, you don't happen to have a DT example do you?  
>  
>  
>  
> uhm, should be just as simple:
>  
> hrtimer-trigger@0 {
> compatible = "iio-trigger-hrtimer";
> };
>  
> You need to add the proper of match table to the driver though.
>  
> - Lars
>  
> >  
> >  
> > On Wednesday, February 27, 2013 at 3:02 PM, Lars-Peter Clausen wrote:
> >  
> > > On 02/27/2013 08:50 PM, Chris Micali wrote:
> > > > Last question :) I'd like to sample from this device as quickly as possible - so I'm assuming I need to trigger quickly? Should I use iio-trig-periodic-rtc? Any hints/instructions on how to use that? Should the driver supply it's own trigger that uses an hrtimer instead?
> > > >  
> > > > Thanks!
> > > > Chris
> > >  
> > >  
> > >  
> > >  
> > >  
> > > Hi,
> > >  
> > > There is a generic hrtimer based trigger:
> > > https://github.com/lclausen-adi/linux-2.6/commit/a3b5c3f7aafbcac562d6f00a6589b110bd9fb71c
> > >  
> > > Unfortunately it's not upstream ready yet.
> > >  
> > > I can be registered via a platform_device
> > >  
> > > static struct platform_device iio_trigger_hrtimer = {
> > > .name = "iio-trigger-hrtimer",
> > > .id = 0,
> > > };
> > >  
> > > - Lars
> > >  
> > > >  
> > > >  
> > > > On Wednesday, February 27, 2013 at 2:32 PM, Chris Micali wrote:  
> > > > > Guys,  
> > > > >  
> > > > > Thanks a lot for the help! I finally tracked down issues, it was a combination of a few things:
> > > > >  
> > > > > 1. The .channel had to be 0, not 1 in the driver (scan_index didn't matter)
> > > > > 2. 1 or more scan_elements have to be enabled as you mentioned
> > > > > 2. When echoing into the sysfs files it has to have a space after the number (cat 1 > in_voltage0_en and not cat 1>in_vo…) (duh!)
> > > > > 3. The generic_buffer.c program had a few bugs in it causing crashes. I updated the iio_utils.h to a newer version I found here: https://github.com/analogdevicesinc/iio-oscilloscope and then made a few modifications (the newer iio_utils did not parse a few things right in the channel details like bigendian/littleendian)
> > > > >  
> > > > > So generic_buffer is now correctly sampling (although it crashes after a couple, it's probably another iio_utils issue)
> > > > >  
> > > > > Thanks!!
> > > > >  
> > > > > -chris
> > > > >  
> > > > >  
> > > > > On Wednesday, February 27, 2013 at 1:51 PM, Lars-Peter Clausen wrote:
> > > > >  
> > > > > > On 02/27/2013 07:28 PM, Jonathan Cameron wrote:
> > > > > > > On 02/27/2013 05:36 PM, Chris Micali wrote:
> > > > > > > > lars,  
> > > > > > > >  
> > > > > > > > I was under the impression that flag gets added automatically by iio_triggered_buffer_setup (industrialiio-triggers.c:77) - I actually am now able to enable the scan_element after changing my channel .channel and .scan_index to 0 (trying to match exactly the other drivers.)
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > > Yea, you are right I missed the iio_triggered_buffer_setup part.
> > > > > >  
> > > > > > > Strange, scan_index should have defaulted to zero and the .channel value shouldn't have mattered
> > > > > > > for buffered reads (just effects naming). Might have caused issues with userspace expecting a channel 0
> > > > > > > though...
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > > I guess the scan_index had nothing to do with this, but I suggested to set
> > > > > > scan_elements/in_voltage0_en to 1, so this clearly wouldn't have worked with
> > > > > > .channel being 1.
> > > > > >  
> > > > > > >  
> > > > > > > > When i run general_buffer (from the docs dir) with that scan element enabled it can no longer read the trigger (Could not open /trigger/current_trigger Failed to write current_trigger file) - this succeeds if that scan_element is not enabled.  
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > >  
> > > > > > You can't change the trigger if the buffer is currently enabled. Make sure that
> > > > > > he buffer is disabled (check the buffer/enable attribute).
> > > > > >  
> > > > > > - Lars
> > > > > > u
> > > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > >  
> > > > --
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