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=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, 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 95E56C63699 for ; Tue, 10 Nov 2020 20:33:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 569132074B for ; Tue, 10 Nov 2020 20:33:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="0+9M3MIh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726706AbgKJUdN (ORCPT ); Tue, 10 Nov 2020 15:33:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:49786 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725862AbgKJUdM (ORCPT ); Tue, 10 Nov 2020 15:33:12 -0500 Received: from localhost (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4A8452065E; Tue, 10 Nov 2020 20:33:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605040391; bh=yJTYZmAXuxpcGEJyYxHhM5frnzHMmu2d66zn6Bja/hc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=0+9M3MIhvG1jKl+29RdqvQt51vR+oaGK/8GCDfVOFt7DeuVYh3d1crHlNZUC8WDds g9vkQkcCbbEoXNQpyaSLrzdPjoLqf+ydgGGXiFyaUf3ctGyVRw0DSvUJ1vfluiCeqN k/eioYuKDJ0bQsdAJATDhkiDO1uTXHoc1BDNDaN4= Date: Tue, 10 Nov 2020 20:32:57 +0000 From: Mark Brown To: Thierry Reding Cc: Dmitry Osipenko , Jonathan Hunter , Alan Stern , Peter Chen , Liam Girdwood , Adrian Hunter , Krzysztof Kozlowski , Greg Kroah-Hartman , Lee Jones , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Ulf Hansson , Mauro Carvalho Chehab , Rob Herring , Marek Szyprowski , Peter Geis , Nicolas Chauvet , linux-samsung-soc@vger.kernel.org, devel@driverdev.osuosl.org, linux-usb@vger.kernel.org, linux-pwm@vger.kernel.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linux-tegra@vger.kernel.org Subject: Re: [PATCH v1 11/30] drm/tegra: dc: Support OPP and SoC core voltage scaling Message-ID: <20201110203257.GC5957@sirena.org.uk> References: <20201104234427.26477-1-digetx@gmail.com> <20201104234427.26477-12-digetx@gmail.com> <20201110202945.GF2375022@ulmo> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="f+W+jCU1fRNres8c" Content-Disposition: inline In-Reply-To: <20201110202945.GF2375022@ulmo> X-Cookie: Disk crisis, please clean up! User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org --f+W+jCU1fRNres8c Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Nov 10, 2020 at 09:29:45PM +0100, Thierry Reding wrote: > On Thu, Nov 05, 2020 at 02:44:08AM +0300, Dmitry Osipenko wrote: > > + /* > > + * Voltage scaling is optional and trying to set voltage for a dummy > > + * regulator will error out. > > + */ > > + if (!device_property_present(dc->dev, "core-supply")) > > + return; > This is a potentially heavy operation, so I think we should avoid that > here. How about you use devm_regulator_get_optional() in ->probe()? That > returns -ENODEV if no regulator was specified, in which case you can set > dc->core_reg = NULL and use that as the condition here. Or enumerate the configurable voltages after getting the regulator and handle that appropriately which would be more robust in case there's missing or unusual constraints. --f+W+jCU1fRNres8c Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl+q+PkACgkQJNaLcl1U h9Di3Af+KvYDy9j9hzr4giaqciyG6ZuO/j4tEwL8vjsyaMREZ12mZ3xOOgu04UTQ KYUtOH+AIWAUWOBwJNWEgKiRd04eMyhD6IHeCT1lip3XWBxXOEr9/YGXba3fVI/J vvHATycSemWFAYfZ1yjhz2fAxz4zxgwujwivC1/YKWjHZi8vFTy16R9yY5Eex5l/ eplxyfun7IvJxFiVf5XDK4K2lGmn783N6VYofq6lAUknQ+TxScbl9QNyKNihB7Ys tOgGgxJpK6+xFKP8RWC34O3W++wjUL2sUZUhvVKP059roKdB0gej+D9DnV+RCYHf AloxftWStaHBnOpYPmbGoUoaK8isGQ== =oCrN -----END PGP SIGNATURE----- --f+W+jCU1fRNres8c--