From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from saturn.retrosnub.co.uk ([178.18.118.26]:34488 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932323AbcE2To3 (ORCPT ); Sun, 29 May 2016 15:44:29 -0400 Subject: Re: [RFC 0/7] Deal with iio trigger names To: Crestez Dan Leonard , linux-iio@vger.kernel.org References: Cc: linux-kernel@vger.kernel.org, Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Daniel Baluta From: Jonathan Cameron Message-ID: <58325d90-7718-391c-fc7c-b75460cad371@kernel.org> Date: Sun, 29 May 2016 20:44:27 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 23/05/16 19:39, Crestez Dan Leonard wrote: > IIO documents that trigger names are unique but does not actually guarantee > this. You can easily create a software trigger with a duplicate name if you > enable CONFIG_IIO_HRTIMER_TRIGGER: > > mkdir /sys/kernel/config/iio/triggers/hrtimer/\ > `cat /sys/bus/iio/devices/trigger0/name` > > You can also get in this situation if you connect two identical st_sensors. > > My attempt to fix this is by adding a new 'current_trigger_id' ABI which is a > numeric ID (X from triggerX) rather than a non-unique string. I tested that > this works as expected when connecting two LIS3DH to the same system. This is > in patches 4,5. > > In theory the current_trigger ABI could be overloaded to looks for something > matching "trigger[0-9]+" but this would be nastier. There would be a need to > prevent registering triggers that match that expression in order to prevent > stuff like: > > mkdir /sys/kernel/config/iio/triggers/hrtimer/trigger1 > > Such an overload wouldn't work on read and make it impossible to unambigiously > determine the currently selected trigger. > > > Patch 6 disallows registering duplicate trigger names. This makes drivers > which currently do that break at probe time. > > Patch 7 attempts to ensure that all drivers include indio_dev->id when calling > iio_trigger_alloc. This obviously changes trigger names. > > > Either 4,5 or 6,7 fix this issue, but 4,5 causes fewer compat issues. > > > Patches 1,2,3 are just minor features in tools/generic_buffer. They supersede > the v2 I posted earlier: Please don't do this in future. When reviewing lots of series, one tends to relying on sorting by name to make sure you find the latest version of a series. Do this and people don't know there is a new version embedded in a different series (in this case I picked up V2 when you had found an issue in it). Jonathan > > https://www.spinics.net/lists/linux-iio/msg24867.html > > Crestez Dan Leonard (7): > iio: generic_buffer: Cleanup when receiving signals > iio: generic_buffer: Add --device-num option > iio: generic_buffer: Add --trigger-num option > iio: Add current_trigger_id alternative > iio: generic_buffer: Use current_trigger_id > iio: Refuse to register triggers with duplicate names > iio: Make trigger names unique > > Documentation/ABI/testing/sysfs-bus-iio | 9 + > Documentation/DocBook/iio.tmpl | 4 +- > drivers/iio/adc/max1027.c | 4 +- > drivers/iio/common/st_sensors/st_sensors_trigger.c | 2 +- > drivers/iio/industrialio-trigger.c | 136 ++++++++--- > drivers/iio/light/gp2ap020a00f.c | 4 +- > tools/iio/generic_buffer.c | 269 ++++++++++++++------- > 7 files changed, 309 insertions(+), 119 deletions(-) >