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 D4782C4167B for ; Mon, 6 Nov 2023 21:36:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233180AbjKFVgq (ORCPT ); Mon, 6 Nov 2023 16:36:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38122 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233129AbjKFVgo (ORCPT ); Mon, 6 Nov 2023 16:36:44 -0500 Received: from mail.hugovil.com (mail.hugovil.com [162.243.120.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFCE0B0; Mon, 6 Nov 2023 13:36:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=hugovil.com ; s=x; h=Subject:Content-Transfer-Encoding:Mime-Version:Message-Id:Cc:To:From :Date:subject:date:message-id:reply-to; bh=7ov3LPWt5cacqUWxywHiXwMNsMacdsSxOeWnnH7Tztg=; b=xWMUkpS3+Dlfxt1MQtFgL3V7y6 uAr3XoRKR/dt3AeONNvpkwKyldbFYHiBe8NR4C2D0eB5xYElkhti1hHI4n63yxsa1nwySa8xFxQh+ N9vNIPz1Uxr15Pip85rSeK04n01cqSaafXx4QK59m3vrnHpTUph0ujjUERg2JV/MeByc=; Received: from modemcable168.174-80-70.mc.videotron.ca ([70.80.174.168]:34416 helo=pettiford) by mail.hugovil.com with esmtpa (Exim 4.92) (envelope-from ) id 1r07Gr-0002ME-K6; Mon, 06 Nov 2023 16:36:34 -0500 Date: Mon, 6 Nov 2023 16:36:33 -0500 From: Hugo Villeneuve To: Krzysztof Kozlowski Cc: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Hugo Villeneuve , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Message-Id: <20231106163633.764707a8140dfe750f875dc3@hugovil.com> In-Reply-To: References: <20231106185736.668966-1-hugo@hugovil.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 70.80.174.168 X-SA-Exim-Mail-From: hugo@hugovil.com Subject: Re: [PATCH] arm64: dts: imx8mn-var-som-symphony: add vcc supply for PCA9534 X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.hugovil.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 6 Nov 2023 21:39:42 +0100 Krzysztof Kozlowski wrote: > On 06/11/2023 19:57, Hugo Villeneuve wrote: > > From: Hugo Villeneuve > > > > The following warning is shown when probing device: > > > > pca953x 1-0020: supply vcc not found, using dummy regulator > > > > Add fixed 3.3v regulator as vcc supply to silence the warning. > > > > This is not really a warning. It's perfectly fine to use dummy > regulator. Adding such fixed supply has sense in following cases: > 1. Bindings require the supply, > 2. This is in fact exactly that supply (verified on schematics). > > Best regards, > Krzysztof Hi Krzysztof, this is case #2, but looking more closely at the carrier board (symphony) schematics, it is not exactly the "reg_3v3_fixed" supply I mentioned in the patch, as "reg_3v3_fixed" is located on the SOM and only powers SOM components. However, "reg_3v3_fixed", which is an always-on regulator (no software enable control), is used as the enable input to a mosfet switch (Q2) on the carrier board to generate the 3.3V (label BASE_PER_3V3 on the schematics) used by all peripherals on that carrier board. I guess I could then define a new "always-on" regulator labeled as, for example, base_per_3v3, and then assign the pca953x vcc-supply property to it? Hugo.