Re: [PATCH v1 2/2] iio:iio-interrupt-trigger: sysfs poll support

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

On 02/22/2016 02:07 PM, Gregor Boirie wrote:
> On 02/22/2016 12:37 PM, Lars-Peter Clausen wrote:
>> Add a sysfs file entry for each interrupt trigger instance allowing
>> userspace to :
>> * poll for interrupt events ;
>>>> Why?
>>> On our platform, several sensors are driven by a dedicated "real-time"
>>> CPU (bare-metal context). This CPU interrupts Linux in a periodic manner
>>> which in turn wakes a user process up to perform sensor fusion.
>>> This sysfs poll support allows the user process to explictly wait for
>>> this dedicated CPU interrupt to fetch data located in RAM then process
>>> them.
>> So you are only using the IIO trigger in this setup, but no buffers or
>> devices? If you just want to forward the interrupt to userspace UIO might be
>> the better solution in this case:
>> https://www.kernel.org/doc/htmldocs/uio-howto/about.html
>>
>> - Lars
> I forgot to mention I also need the trigger to initiate in-kernel sampling
> for other IIO devices. These samples are also retrieved by the process
> performing
> fusion.

You should still be able to export the interrupt using UIO by sharing the IRQ.

- Lars