From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D66BC433EF for ; Tue, 12 Apr 2022 16:19:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235283AbiDLQV5 convert rfc822-to-8bit (ORCPT ); Tue, 12 Apr 2022 12:21:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236190AbiDLQV4 (ORCPT ); Tue, 12 Apr 2022 12:21:56 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B12B37AA8 for ; Tue, 12 Apr 2022 09:19:38 -0700 (PDT) Received: from fraeml704-chm.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Kd9qH0784z68737; Wed, 13 Apr 2022 00:17:31 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml704-chm.china.huawei.com (10.206.15.53) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2375.24; Tue, 12 Apr 2022 18:19:35 +0200 Received: from localhost (10.202.226.41) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 12 Apr 2022 17:19:34 +0100 Date: Tue, 12 Apr 2022 17:19:33 +0100 From: Jonathan Cameron To: Nuno =?ISO-8859-1?Q?S=E1?= CC: =?ISO-8859-1?Q?Ma=EDra?= Canal , Andy Shevchenko , Jonathan Cameron , linux-iio , "Bogdan, Dragos" , "Hegbeli, Ciprian" , Cosmin Tanislav , Puranjay Mohan Subject: Re: GSoC Proposal 2022 Message-ID: <20220412171933.00002d1d@Huawei.com> In-Reply-To: References: <20220410182819.23967855@jic23-huawei> <20220411095219.000058a8@Huawei.com> <59c37b67bbc4a24336e5220a7ad4f242d854fb76.camel@gmail.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.29; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8BIT X-Originating-IP: [10.202.226.41] X-ClientProxiedBy: lhreml719-chm.china.huawei.com (10.201.108.70) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Tue, 12 Apr 2022 16:23:55 +0200 Nuno Sá wrote: > On Tue, 2022-04-12 at 09:24 -0300, Maíra Canal wrote: > > On 04/12, Nuno Sá wrote: > > > On Tue, 2022-04-12 at 11:48 +0300, Andy Shevchenko wrote: > > > > On Tue, Apr 12, 2022 at 10:43 AM Maíra Canal > > > > wrote: > > > > > On 04/11, Jonathan Cameron wrote: > > > > > > The MAX31875 looks to be a fairly simple one (maybe a good > > > candidate > > > for a first driver) but, IMO, having it in IIO boils down to have > > > support for continuos mode which would mean triggered buffer > > > support. > > > > I took another look at the Maxim Integrated catalog and end up > > finding > > the MAX31889 Temperature Sensor. > > > > I guess this sensor has an interesting challenge level with the need > > to > > implement FIFO and interrupts support. > > > > Have you guys some thoughts on this one? Hmm. The fifo is interesting, but I'm somewhat doubtful that it's actually much use when connected to a linux system. The sampling rate is 1Hz. At that rate even in busy systems or low power situations, there is little reason not to just poll the device. You 'could' wire up a PWM or similar to the gpio and have it operate like a 'self clocked' device but with sampling rates so low it's a fairly contrived situation. Temperature sensors in general are often a bad fit for IIO precisely because they are mostly designed for monitoring type purposes which HWMON covers. The exceptions are high speed or high accuracy devices or weird ones like infrared thermometers. For the corner cases we have the option of the iio-hwmon bridge driver but they need to be more obviously not suited to hwmon than this one to justify their presence in IIO. In general hwmon drivers are simpler, so if you can get away with it they are a better choice. (also some hwmon specific features like multiple levels of even of the same type for warning / critical detection). Jonathan > > > > At first glance, it looks like a better choice when compared with > MAX31875... > > - Nuno Sá > > > > > >