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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham 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 CDFAEC6778C for ; Tue, 3 Jul 2018 05:39:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7FEC924222 for ; Tue, 3 Jul 2018 05:39:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="VNBaD4Eo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7FEC924222 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932974AbeGCFjE (ORCPT ); Tue, 3 Jul 2018 01:39:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:59684 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932868AbeGCFjA (ORCPT ); Tue, 3 Jul 2018 01:39:00 -0400 Received: from dragon (unknown [104.237.91.44]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B794C24220; Tue, 3 Jul 2018 05:38:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1530596340; bh=pEsB0CvdbpHl9pMyj5jpGCUKAB2m1xOCAwWjv+KNv2U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=VNBaD4EoLdJ4i8fQZcPRFaW3nEqTs74WwG3tlvol4FKYYP3nCRpXeCebX1qHghr6u gFwqR+OqGlKEljHwC/3fYTEJTn4v/PwbEADqt8bmWEQqB5RVdcOOiRboXV2/4hvoNb 2Iz3NFT8x4tUK30MYesSRc7on25yy2jr2FIuS7uw= Date: Tue, 3 Jul 2018 13:38:45 +0800 From: Shawn Guo To: Robin Gong Cc: "festevam@gmail.com" , Anson Huang , "mark.rutland@arm.com" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "robh+dt@kernel.org" , dl-linux-imx , "kernel@pengutronix.de" , Fabio Estevam , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v1] ARM: dts: imx6sl-evk: keep sw4 always on Message-ID: <20180703053843.GC4348@dragon> References: <1530526335.15665.13.camel@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1530526335.15665.13.camel@nxp.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 02, 2018 at 02:12:52AM +0000, Robin Gong wrote: > But in fact, the original dts is not correct without 'regulator-always- > on'since SW4 is the critical DDR power rail, although, it's kept on in > the previous kernel by no switches enable/disable interfaces provided > in pfuze driver. Adding new property which can be done totally by the > common 'regulator-always-on' is not a good choice. Keep the dts patch > adding 'regulator-always-on' ahead of pfuze driver pach adding > enable/disable interface is enough for such case I think.  We can not just break the installed DTBs like this. If patching regulator driver with a new property is really difficult, we could migrate the existing users in a 'soft' way: - Add required regulator-always-on for regulator nodes in DTS. - Patch i.MX platform code to check the presence of regulator-always-on property for critical regulators, and give a big warning if it's missing. - Wait for a couple of release cycles for users to migrate. - Add regulator driver patch back and break users who keep ignoring the warning. Shawn