Re: IIO Drivers

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

On 02/27/2013 06:15 PM, Chris Micali wrote:
> Lars, 
> 
> Thanks..  when I write 1 to scan_elements/in_voltage0_en via iio_cmdserv i get -2, from shell (echo 1>) i see write error: Invalid argument.  No output in dmesg that indicates what the error is/could be though.
> 
> -c

In your driver you commented out the INDIO_BUFFER_TRIGGERED mode flag, did
you add that back? Without it this won't work.

- Lars

> 
> 
> On Wednesday, February 27, 2013 at 11:34 AM, Lars-Peter Clausen wrote:
> 
>> On 02/27/2013 05:21 PM, Chris Micali wrote:
>>> Hi Lars,
>>> Thanks a lot for getting back to me. I've attached my code - it's pretty simple, I just copied an existing driver. As I mentioned individual reads are working fine (if i cat in_voltage0_raw) but buffered reads are failing. I've tracked the issue to industrialio-buffer.c in iio_compute_scan_bytes() which always returns zero because, i believe, the mask is 0. I haven't been able to find any docs on what 'scan masks' mean but I have seen a few drivers that supply available scan masks. Should I be specifying scan masks? 
>>> Thanks!
>>> -chris
>>>
>>
>>
>> Hi Chris,
>>
>> You need to enable the channels you want to sample in sysfs. If you are
>> using the command server you can for example do this by doing a 'write
>> ads... scan_elements/in_voltage0_en'
>>
>> - Lars
>>
>>
>>>
>>>
>>> On Wednesday, February 27, 2013 at 11:07 AM, Lars-Peter Clausen wrote:
>>>
>>>> On 02/26/2013 08:56 PM, Chris Micali wrote:
>>>>> Hello Lars,
>>>>>
>>>>> I'm doing a bit of hacking on a IIO driver based on some of your drivers on a 3.8 kernel (specifically writing a driver for a TI SPI adc.) I've been able to get a driver up and working such that I can read directly from the in_voltage0_raw on sysfs and get the correct values but I can't seem to get buffered access working (via iio_cmdsrv.) I've had a hard time finding any docs on this stuff and I was wondering if you could give me any pointers on where to look or who else perhaps to ask about this stuff? Any pointers would be very much appreciated!
>>>>>
>>>>> Thanks,
>>>>> Chris
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Hi,
>>>>
>>>> I'm afraid except for the the documentation in
>>>> drivers/staging/iio/Documentation/, the kernel doc comments and the skeleton
>>>> driver (drivers/staging/iio/iio_simple_dummy*) there is not much additional
>>>> documentation available.
>>>>
>>>> The general place to ask questions about IIO is the IIO mailinglist. I've
>>>> put it on CC, hope you don't mind.
>>>>
>>>> I think we can help you best if you post your code.
>>>>
>>>> - Lars 
> 
>