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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 46966C3A59D for ; Tue, 20 Aug 2019 15:47:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1C92C22DA9 for ; Tue, 20 Aug 2019 15:47:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=megous.com header.i=@megous.com header.b="hP54zVon" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729961AbfHTPrR (ORCPT ); Tue, 20 Aug 2019 11:47:17 -0400 Received: from vps.xff.cz ([195.181.215.36]:34058 "EHLO vps.xff.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727006AbfHTPrR (ORCPT ); Tue, 20 Aug 2019 11:47:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megous.com; s=mail; t=1566316035; bh=+WetNuZhgsPVrJpioXtAn4eK1dq+iJ2qVlbpblbtjW4=; h=Date:From:To:Cc:Subject:References:X-My-GPG-KeyId:From; b=hP54zVonCSbd4zXVtywOUAO5skboSj0IERBMVv++b8InA7BK9VB27HeH7mYCTQuH2 4Le6mzzhSoXaVM6Dr/19kjLEesxX8WweIzbVQu0I2k75qcV+BB2m//1C81g4tlSYw1 aCtfMtwX+imflszImRWYPRPZENIcBTQ1VAySnfxU= Date: Tue, 20 Aug 2019 17:47:14 +0200 From: =?utf-8?Q?Ond=C5=99ej?= Jirman To: Andrew Lunn Cc: "David S. Miller" , Rob Herring , Mark Rutland , Maxime Ripard , Chen-Yu Tsai , Giuseppe Cavallaro , Alexandre Torgue , Jose Abreu , Maxime Coquelin , devicetree@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 3/6] net: stmmac: sun8i: Use devm_regulator_get for PHY regulator Message-ID: <20190820154714.2rt4ctovil5ol3u2@core.my.home> Mail-Followup-To: Andrew Lunn , "David S. Miller" , Rob Herring , Mark Rutland , Maxime Ripard , Chen-Yu Tsai , Giuseppe Cavallaro , Alexandre Torgue , Jose Abreu , Maxime Coquelin , devicetree@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org References: <20190820145343.29108-1-megous@megous.com> <20190820145343.29108-4-megous@megous.com> <20190820153939.GL29991@lunn.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190820153939.GL29991@lunn.ch> X-My-GPG-KeyId: EBFBDDE11FB918D44D1F56C1F9F0A873BE9777ED Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Andrew, On Tue, Aug 20, 2019 at 05:39:39PM +0200, Andrew Lunn wrote: > On Tue, Aug 20, 2019 at 04:53:40PM +0200, megous@megous.com wrote: > > From: Ondrej Jirman > > > > Use devm_regulator_get instead of devm_regulator_get_optional and rely > > on dummy supply. This avoids NULL checks before regulator_enable/disable > > calls. > > Hi Ondrej > > What do you mean by a dummy supply? I'm just trying to make sure you > are not breaking backwards compatibility. Sorry, I mean dummy regulator. See: https://elixir.bootlin.com/linux/latest/source/drivers/regulator/core.c#L1874 On systems that use DT (i.e. have_full_constraints() == true), when the regulator is not found (ENODEV, not specified in DT), regulator_get will return a fake dummy regulator that can be enabled/disabled, but doesn't do anything real. This can be used to avoid NULL checks and make the code simpler. regards, Ondrej > Thanks > Andrew