From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932877AbbELQ4W (ORCPT ); Tue, 12 May 2015 12:56:22 -0400 Received: from smtp-out-122.synserver.de ([212.40.185.122]:1053 "EHLO smtp-out-122.synserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753036AbbELQ4U (ORCPT ); Tue, 12 May 2015 12:56:20 -0400 X-SynServer-TrustedSrc: 1 X-SynServer-AuthUser: lars@metafoo.de X-SynServer-PPID: 7123 Message-ID: <555230B0.3050700@metafoo.de> Date: Tue, 12 May 2015 18:56:16 +0200 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.6.0 MIME-Version: 1.0 To: Jonathan Cameron , Robert Dolca , linux-iio@vger.kernel.org CC: linux-kernel@vger.kernel.org, Hartmut Knaack , Peter Meerwald , Denis CIOCCA Subject: Re: [PATCH RFC 1/3] iio: Add symlink to triggers in the device's trigger folder References: <1429174868-11953-1-git-send-email-robert.dolca@intel.com> <1429174868-11953-2-git-send-email-robert.dolca@intel.com> <554CD236.4000404@kernel.org> In-Reply-To: <554CD236.4000404@kernel.org> 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 On 05/08/2015 05:11 PM, Jonathan Cameron wrote: > On 16/04/15 05:01, Robert Dolca wrote: >> This patch adds a new function called iio_trigger_register_with_dev >> which is a wrapper for iio_trigger_register. Besides the iio_trigger >> struct this function requires iio_dev struct. It adds the trigger in >> the device's trigger list and saves a reference to the device in the >> trigger's struct. >> >> When the device is registered, in the trigger folder of the device >> (where current_trigger file resides) a symlink is being created for >> each trigger that was registered width iio_trigger_register_with_dev. >> >> # ls -l /sys/bus/iio/devices/iio:device0/trigger/ >> total 0 >> -rw-r--r-- 1 root root 4096 Apr 16 08:33 current_trigger >> lrwxrwxrwx 1 root root 0 Apr 16 08:33 trigger0 -> ../../trigg >> er0 >> >> This should be used for device specific triggers. Doing this the user space >> applications can figure out what if the trigger registered by a specific device >> and what should they write in the current_trigger file. Currently some >> applications rely on the trigger name and this does not always work. >> >> This implementation assumes that the trigger is registered before the device is >> registered. If the order is not this the symlink will not be created but >> everything else will work as before. >> >> Signed-off-by: Robert Dolca > I was rather hoping we'd get a few more comments on this. > In principle I like the idea, but it's new ABI and does make life > a tiny bit more complex, so what do people think? > > Few trivial code comments inline. I don't think it adds more information. Both the trigger and the device get registered for the same parent device, so you can already easily find the trigger for a device by going to the parent device and taking a look at the triggers registered by the parent device.