From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.aswsp.com ([193.34.35.150]:50024 "EHLO mail.aswsp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751176AbcBVNHe (ORCPT ); Mon, 22 Feb 2016 08:07:34 -0500 Message-ID: <56CB0814.9040604@parrot.com> Date: Mon, 22 Feb 2016 14:07:32 +0100 From: Gregor Boirie MIME-Version: 1.0 To: Lars-Peter Clausen , Jonathan Cameron , CC: Hartmut Knaack , Peter Meerwald Subject: Re: [PATCH v1 2/2] iio:iio-interrupt-trigger: sysfs poll support References: <87bbff0671c93b998547114d7f595a0bee57e817.1455908065.git.gregor.boirie@parrot.com> <56CA195B.9010200@kernel.org> <56CAF1DD.8070807@parrot.com> <56CAF312.1040200@metafoo.de> In-Reply-To: <56CAF312.1040200@metafoo.de> Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org 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. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html