Re: IIO Drivers

[Jonathan Cameron <jic23@kernel.org>]

On 02/27/2013 07:32 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)
> 
If you do track down why this is happening, please do report back
so we can get it fixed.  I wasn't previously aware of any particular
issues in the example code so any feedback is helpful!

Looking foward to seeing the driver code when you are happy with it.

Jonathan
> 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
> 
> 
>