From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladimir Barinov Subject: Re: [PATCH v7 4/5] iio: trigger: Introduce IIO hrtimer based trigger Date: Wed, 02 Sep 2015 15:16:42 +0300 Message-ID: <55E6E8AA.6070108@cogentembedded.com> References: <1439246562-17515-1-git-send-email-daniel.baluta@intel.com> <1439246562-17515-5-git-send-email-daniel.baluta@intel.com> <55D1D786.2010407@cogentembedded.com> <55E46B45.8040909@metafoo.de> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: knaack.h-Mmb7MZpHnFY@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, octavian.purdila-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, pebolle-IWqWACnzNjzz+pZb47iToQ@public.gmane.org, patrick.porlan-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, adriana.reus-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, constantin.musca-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, marten-4zOpVvZifTgX8gGd4fc/mEEOCMrvLtNR@public.gmane.org, cristina.opriceana-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, pmeerw-jW+XmwGofnusTnJN9+BGXg@public.gmane.org, hch-jcswGhMUV9g@public.gmane.org, viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org To: Lars-Peter Clausen , Daniel Baluta , jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, jlbec-aKy9MeLSZ9dg9hUCZPvPmw@public.gmane.org, linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Return-path: In-Reply-To: <55E46B45.8040909-Qo5EllUWu/uELgA04lAiVw@public.gmane.org> Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org Hi Lars, On 31.08.2015 17:57, Lars-Peter Clausen wrote: > On 08/17/2015 02:45 PM, Vladimir Barinov wrote: >> Hello Daniel, >> >> I've verified that your hrtimer trigger works. >> >> I have minor suggestions. >> >> Will not it be useful to have ability to stop/start hrtimer polling >> not only during attach/detach trigger. >> >> f.e. writing 0 to sampling_frequency will hrtimer_cancel >> and writing any valid frequency will hrtimer_start. > What's the use case for this? Setting sampling frequency to 0 Hz. I do agree that 0Hz is meaningless and the same effect is achieved by removing trigger from iio device, but having 0 Hz frequency could probably be more consecutive for this trigger instead of returning EINVAL. Regards, Vladimir From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754419AbbIBMQs (ORCPT ); Wed, 2 Sep 2015 08:16:48 -0400 Received: from mail-wi0-f181.google.com ([209.85.212.181]:36235 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753226AbbIBMQq (ORCPT ); Wed, 2 Sep 2015 08:16:46 -0400 Message-ID: <55E6E8AA.6070108@cogentembedded.com> Date: Wed, 02 Sep 2015 15:16:42 +0300 From: Vladimir Barinov User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: Lars-Peter Clausen , Daniel Baluta , jic23@kernel.org, jlbec@evilplan.org, linux-iio@vger.kernel.org, linux-fsdevel@vger.kernel.org CC: knaack.h@gmx.de, linux-kernel@vger.kernel.org, octavian.purdila@intel.com, pebolle@tiscali.nl, patrick.porlan@intel.com, adriana.reus@intel.com, constantin.musca@intel.com, marten@intuitiveaerial.com, cristina.opriceana@gmail.com, pmeerw@pmeerw.net, hch@lst.de, viro@zeniv.linux.org.uk, akpm@linux-foundation.org Subject: Re: [PATCH v7 4/5] iio: trigger: Introduce IIO hrtimer based trigger References: <1439246562-17515-1-git-send-email-daniel.baluta@intel.com> <1439246562-17515-5-git-send-email-daniel.baluta@intel.com> <55D1D786.2010407@cogentembedded.com> <55E46B45.8040909@metafoo.de> In-Reply-To: <55E46B45.8040909@metafoo.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Lars, On 31.08.2015 17:57, Lars-Peter Clausen wrote: > On 08/17/2015 02:45 PM, Vladimir Barinov wrote: >> Hello Daniel, >> >> I've verified that your hrtimer trigger works. >> >> I have minor suggestions. >> >> Will not it be useful to have ability to stop/start hrtimer polling >> not only during attach/detach trigger. >> >> f.e. writing 0 to sampling_frequency will hrtimer_cancel >> and writing any valid frequency will hrtimer_start. > What's the use case for this? Setting sampling frequency to 0 Hz. I do agree that 0Hz is meaningless and the same effect is achieved by removing trigger from iio device, but having 0 Hz frequency could probably be more consecutive for this trigger instead of returning EINVAL. Regards, Vladimir