From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:41988 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751077AbdFCJIE (ORCPT ); Sat, 3 Jun 2017 05:08:04 -0400 Date: Sat, 3 Jun 2017 10:07:58 +0100 From: Jonathan Cameron To: Nikita Yushchenko Cc: Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Sanchayan Maity , Gregor Boirie , Matt Ranostay , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Chris Healy , Jeff White , Vladimir Barinov , Linus Walleij Subject: Re: [PATCH/RFC] iio: hi8435: do not enable all events by default Message-ID: <20170603100758.6164e219@kernel.org> In-Reply-To: References: <20170523080830.20571-1-nikita.yoush@cogentembedded.com> <20170524202735.3cf4e14e@kernel.org> <2e6019f5-94fc-bb13-f616-0c1cfe81a7db@cogentembedded.com> <20170528164846.3fa3d4d8@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On Mon, 29 May 2017 08:40:26 +0300 Nikita Yushchenko wrote: > >> Still, isn't there subsystem-level default that all events are disabled > >> by default? If such, then current hi8435 state breaks subsystem-level > >> rules, which is a [userspace-visible] bug. I'm not sure how far should > >> we go in bug compatibility. > > > > It is indeed the subsystem default (as much as we have one) > > > > This is a moderately obscure chip for linux systems, do we have a good handle > > on where it is being used - i.e. are most of the devices under control of > > people we can discuss this with? > > Company I work with, uses this chip in several boards; what they need is > a service that monitors all connected chip's outputs and detects > changes. They originally wanted gpio-style access to use with userspace > polling, and were not pleased with entire IIO thing. However it's > important for them to minimize required kernel patches against mainline, > thus if mainline supports this chip as IIO device that's ok for them. Was always an odd corner case - and I'll admit it wasn't one that made me very comfortable either. One option would be to put a GPIO bridge driver in place so that both interfaces are available. I know this is something Linus and I have thought about in the past for various use cases. > > Questions like default event enable state has little practical impact. > It's more about keeping architecture clean. I'm going to go with not changing this, even though it matters little to either of you. Simply because we clearly do have a non trivial number of users and this would be ABI breakage. Jonathan > > Nikita > -- > 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