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 X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14DC8C07E99 for ; Mon, 12 Jul 2021 22:36:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4B3161206 for ; Mon, 12 Jul 2021 22:36:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230030AbhGLWjW (ORCPT ); Mon, 12 Jul 2021 18:39:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:59066 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229931AbhGLWjW (ORCPT ); Mon, 12 Jul 2021 18:39:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 303CF61183; Mon, 12 Jul 2021 22:36:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626129393; bh=ZLUAxjTwJuR1eoy9AUGR/u9jh4N+I5I/fJ261D+fEQk=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=HOmcKa4Z9wxBEQ9WYqiglwEhp3GIsvbMPGxKk8yReBkc9xoCypcbo8DSB3XreUBAs x/q8pHobaTJlwT2XnfKGKWOSDuDFyfSmy+RKeymJeBo8ZHFgH0CDiriZqFdMOkavis TipwjcettlCG9w5QkkFlwwdsQESA5PIIGM82CDaMqfVOoNn17hkXW5+9OaVUhZ4WfL txUY8Ocbzw5NSfvRvSb0Pu9L2onlsZxpnSn12qAYxFV17HahRbaWSTqFsMHJTPCow1 aeJZd718H+PvQAUC07Hb6JoxXv2OCMes/TMU18gflDEcFMcHkYuqX64Hh/qqVBUlbU A86c7L4B6Qhcg== Date: Mon, 12 Jul 2021 17:36:31 -0500 From: Bjorn Helgaas To: Andy Shevchenko Cc: Vaibhav Gupta , linux-kernel-mentees@lists.linuxfoundation.org, Shuah Khan , bjorn@helgaas.com, andy@kernel.org, Linus Walleij , Bartosz Golaszewski , "Rafael J. Wysocki" , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [Linux-kernel-mentees] [PATCH v1] gpio: ml: ioh: Convert to dev_pm_ops Message-ID: <20210712223631.GA1682719@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Jul 12, 2021 at 02:48:12PM +0300, Andy Shevchenko wrote: > On Thu, Jul 08, 2021 at 04:47:06PM -0500, Bjorn Helgaas wrote: > > On Thu, Apr 02, 2020 at 11:23:27PM +0300, Andy Shevchenko wrote: > > > On Thu, Apr 2, 2020 at 11:16 PM Bjorn Helgaas wrote: > > > > On Thu, Apr 02, 2020 at 09:33:46PM +0300, Andy Shevchenko wrote: > > > > > On Thu, Apr 2, 2020 at 6:52 PM Vaibhav Gupta wrote: > > > > > > > > > > > > Convert the legacy callback .suspend() and .resume() > > > > > > to the generic ones. > > > > > > > > > > Thank you for the patch. > > > > > > > > > > Rather then doing this I think the best approach is to unify gpio-pch > > > > > and gpio-ml-ioh together. > > > > > Under umbrella of the task, the clean ups like above are highly > > > > > appreciated. > > > > > > > > I'd be all in favor of that, but what Vaibhav is working toward is > > > > eliminating use of legacy PM in PCI drivers. I think unifying drivers > > > > is really out of scope for that project. > > > > > > > > If you'd rather leave gpio-ml-ioh.c alone for now, I suggest that > > > > Vaibhav move on to other PCI drivers that use legacy PM. If we > > > > convert all the others away from legacy PM and gpio-ml-ioh.c is the > > > > only one remaining, then I guess we can revisit this :) > > > > > > Then skip this driver for good. > > > > > > > Or, maybe converting gpio-ml-ioh.c now, along the lines of > > > > 226e6b866d74 ("gpio: pch: Convert to dev_pm_ops"), would be one small > > > > step towards the eventual unification, by making gpio-pch and > > > > gpio-ml-ioh a little more similar. > > > > > > I think it will delay the real work here (very old code motivates > > > better to get rid of it then semi-fixed one). > > > > With respect, I think it is unreasonable to use the fact that > > gpio-ml-ioh and gpio-pch should be unified to hold up the conversion > > of gpio-ml-ioh to generic power management. > > > > I do not want to skip gpio-ml-ioh for good, because it is one of the > > few remaining drivers that use the legacy PCI PM interfaces. We are > > very close to being able to remove a significant amount of ugly code > > from the PCI core. > > Makes sense (1). > > > gpio-ml-ioh and gpio-pch do look quite similar, and no doubt it would > > be great to unify them. But without datasheets or hardware to test, > > Datasheets are publicly available (at least one may google and find some > information about those PCH chips). I have in possession the hardware for > gpio-pch. I can easily test that part at least. If you have a URL for those datasheets, can you share it? I spent some time looking but all I found was 1-2 page marketing brochures. > > that's not a trivial task, and I don't think that burden should fall > > on anyone who wants to make any improvements to these drivers. > > > Another alternative would be to remove legacy PCI PM usage > > (ioh_gpio_suspend() and ioh_gpio_resume()) from gpio-ml-ioh. That > > would mean gpio-ml-ioh wouldn't support power management at all, which > > isn't a good thing, but maybe it would be even more motivation to > > unify it with gpio-pch (which has already been converted by > > 226e6b866d74 ("gpio: pch: Convert to dev_pm_ops"))? > > With regard to (1) probably we may exceptionally accept the fix to > gpio-ml-ioh, but I really prefer to do the much more _useful_ job on > it by unifying the two. Should Vaibhav re-post this patch, or do you want to pull it from the archives? I just checked and it still applies cleanly to v5.14-rc1. Here it is for reference: https://lore.kernel.org/lkml/20200402155057.30667-1-vaibhavgupta40@gmail.com/ I'll post a couple small patches toward unifying them. They don't do the whole job but they're baby steps. Bjorn