From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: "Getz, Robin" To: Lars-Peter Clausen Subject: Re: [PATCH v3] staging:iio: trigger: Add hrtimer trigger Date: Wed, 18 Apr 2012 07:58:34 -0400 CC: Jonathan Cameron , "linux-iio@vger.kernel.org" , Marten Svanfeldt References: <1334581381-18161-1-git-send-email-lars@metafoo.de> <4a3800e1-986a-4801-87a4-f0246425c87f@email.android.com> <4F8C4F17.5040101@metafoo.de> In-Reply-To: <4F8C4F17.5040101@metafoo.de> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Message-ID: <201204180758.34751.robin.getz@analog.com> List-ID: On Mon 16 Apr 2012 12:55, Lars-Peter Clausen pondered: > On 04/16/2012 06:17 PM, Jonathan Cameron wrote: > > Lars-Peter Clausen wrote: > >> From: Marten Svanfeldt > >> > >> 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? 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. -Robin