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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 69085C43331 for ; Fri, 6 Sep 2019 14:45:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 450D8206A5 for ; Fri, 6 Sep 2019 14:45:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392912AbfIFOpP (ORCPT ); Fri, 6 Sep 2019 10:45:15 -0400 Received: from foss.arm.com ([217.140.110.172]:57400 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726168AbfIFOpP (ORCPT ); Fri, 6 Sep 2019 10:45:15 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2B7AB28; Fri, 6 Sep 2019 07:45:14 -0700 (PDT) Received: from [10.1.196.133] (e112269-lin.cambridge.arm.com [10.1.196.133]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 752063F718; Fri, 6 Sep 2019 07:45:13 -0700 (PDT) Subject: Re: [PATCH] drm/panfrost: Fix regulator_get_optional() misuse To: Mark Brown Cc: David Airlie , Tomeu Vizoso , dri-devel , "linux-kernel@vger.kernel.org" References: <20190904123032.23263-1-broonie@kernel.org> <20190905124014.GA4053@sirena.co.uk> <93b8910d-fc01-4c16-fd7e-86abfc3cc617@arm.com> <20190905163420.GD4053@sirena.co.uk> <58594735-c079-74e5-26c8-4911f073d4df@arm.com> <20190906105523.GR23391@sirena.co.uk> From: Steven Price Message-ID: <1bfa2b93-301f-22ff-7208-b337b8f3820d@arm.com> Date: Fri, 6 Sep 2019 15:45:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190906105523.GR23391@sirena.co.uk> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/09/2019 11:55, Mark Brown wrote: [...] >>> However you're probably better off hiding all this stuff with the >>> generic OPP code rather than open coding it - this already has much >>> better handling for this, it supports voltage ranges rather than single >>> voltages and optional regulators already. I'm not 100% clear why this >>> is open coded TBH but I might be missing something, if there's some >>> restriction preventing the generic code being used it seems like those >>> sohuld be fixed. > >> To be honest I've no idea how to use the generic OPP code to do this. I >> suspect the original open coding was cargo-culted from another driver: >> the comments in the function look like they were lifted from >> drivers/devfreq/rk3399_dmc.c. Any help tidying this up would be appreciated. > > Yes, there's a lot of cargo culting of bad regulator API usage in > the DRM subsystem for some reason, I keep having to do these > periodic sweeps and there's always stuff in there. I think a lot > of it comes from BSP code that just gets dropped in without > review and then cut'n'pasted but I've not figured out why DRM is > so badly affected. I've been working on tidying up the devfreq usage in Panfrost. From what I can see your patch is correct and I just needed to work out how to fix my DT. Steve