From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.mailbox.org ([80.241.60.215]:47597 "EHLO mx2.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751669AbdEVFho (ORCPT ); Mon, 22 May 2017 01:37:44 -0400 Subject: Re: spear_adc driver help needed ? To: Jonathan Cameron , Thomas Petazzoni References: <20170518094146.6504821a@free-electrons.com> <73991880-8585-95a3-3d67-6544717c1264@kernel.org> Cc: linux-iio@vger.kernel.org, Hartmut Knaack From: Stefan Roese Message-ID: <47f2b9d4-ed21-2e4a-b637-9ad46b8e89c4@denx.de> Date: Mon, 22 May 2017 07:37:40 +0200 MIME-Version: 1.0 In-Reply-To: <73991880-8585-95a3-3d67-6544717c1264@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On 21.05.2017 16:33, Jonathan Cameron wrote: > On 18/05/17 08:41, Thomas Petazzoni wrote: >> Hello Jonathan, >> >> I've been working on a SPEAr600 platform recently, which uses the >> spear_adc driver, and was about to start working on moving the driver >> out of staging... only to discover in 4.12-rc1 that you already moved >> it out of staging. > Yeah, this one hit the question of: > Is it is good enough to move it or should we bin it as no improvements are > really happening and no one seems to have one? > > I went with the it's good enough option being an optimist. >> >> In the commit log that moves it out of staging, you're saying: >> >> There are some unanswered questions due to disagreements between >> the code >> and various datasheets (including between different datasheets >> for the same >> part). >> I don't think that is necessarily a reason to keep it in >> staging however. >> I'm partly posting this patch inorder to reignite debate and with >> a bit >> of luck find someone who has one of these to test! >> >> What are the unanswered questions you are talking about? > These all came up in the previous attempt to move the driver out of staging > back in 2014 > > http://www.spinics.net/lists/linux-iio/msg12443.html > In particular the results of Harmut tracking down a datahsheet and going > through some elements of it in detail. >> >> Also, I am currently using the driver on a SPEAr600 device, so I can do >> some testing. > Cool. >> >> The driver has support for the SPEAr3xx, but it isn't used anywhere: >> there is no compatible string for it, and nowhere is old-style probing >> used for "spear-adc". > Stefan (cc'd) might know who is likely to be using it... > > However after a bit of digging in the history, his original patch said > that it was untested and proper support might eventually be added. This is also my understanding (that's so looong ago, sorry). Somebody suggested / requested to add support support for SPEAr3xx to this driver as well. I definitely never tested it on this platform and don't remember anybody who did. >> >> So I'm thinking of: >> >> - Dropping SPEAr3xx support, because it's unused. This will also >> remove the ugly checks done on the compatible string all over the >> place. > I agree. >> >> - Moving to a "base + offset" style of register accesses, rather than >> the struct-based accesses. > Yeah, with the 3xx stuff gone that would tidy things up further. > > Only exception would be if someone rapidly jumps up and down and says > they use the 3xx support as is or have working patches they were aiming to > submit to make it work. > > Thanks for working on this. I'd forgotten that stuff was even in there! >> >> What do you think ? > Would be great to tidy this up, particularly as it sounds like there > are actually users. Sometimes I wonder on some of the stuff I've > lifted out of staging over the years ;) From the history above, its quite likely that this driver has never been tested / used on SPEAr3xx. So I vote for dropping this support. Thanks, Stefan