On 4/18/2012 12:58 PM, Getz, Robin wrote:
On Mon 16 Apr 2012 12:55, Lars-Peter Clausen pondered:
On 04/16/2012 06:17 PM, Jonathan Cameron wrote:
Lars-Peter Clausen<lars@xxxxxxxxxx> wrote:
From: Marten Svanfeldt<marten@xxxxxxxxxxxxxxxxxxx>
This patch adds a IIO trigger driver which uses a highres timer to
provide a
frequency based trigger.
Fine as it stands but same issue arises as we had with userspace trigger
still. What are we doing registering a pure software element not
associated to any specific hardware via a platform device. Why not do it
on userspace asking for one as we do with the sysfs file based trigger?
I suppose this is a general question how we want to mange our triggers in
general. None of the other existing trigger drivers does direct IO access
and just use existing infrastructure. They could all be easily be
instantiated by writing a string or number to a sysfs file. So where do we
draw the line?
Fair point. Personally I'd go for whether it is about explicit hardware
or not. So gpio / general
interrupt makes sense in platform code. I suspect we'll kill off the
RTC one anyway on the way
out of staging.
Isn't there an issue of accuracy? the timing accuracy of sysfs/userspace is
non-existant with respect to what you need to do in most of these cases.
I'm not suggesting there is any problem with having a hrtimer based
trigger (in fact
I am throughly in favour!) its just a question of whether it should be
registered in the
board file / device tree or done via a magic string write as Lars-Peter
mentions above
(which is what we do the sysfs file based trigger precisely because
there was a pretty
strong feeling against implying non existent hardware...)
--
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
