From patchwork Fri Jul 15 20:32:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Christian_Kohlsch=C3=BCtter?= X-Patchwork-Id: 591095 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 8941AC433EF for ; Fri, 15 Jul 2022 20:32:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230523AbiGOUcX (ORCPT ); Fri, 15 Jul 2022 16:32:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229532AbiGOUcW (ORCPT ); Fri, 15 Jul 2022 16:32:22 -0400 Received: from mail-ej1-x62b.google.com (mail-ej1-x62b.google.com [IPv6:2a00:1450:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F70B4B486 for ; Fri, 15 Jul 2022 13:32:19 -0700 (PDT) Received: by mail-ej1-x62b.google.com with SMTP id z23so10889352eju.8 for ; Fri, 15 Jul 2022 13:32:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kohlschutter-com.20210112.gappssmtp.com; s=20210112; h=from:content-transfer-encoding:mime-version:subject:message-id:date :cc:to; bh=QyhOR01DoxGCYnC4bLLESVLmV3qWJRFD3wmuOiKUM+s=; b=Z6VzxmO6hGDfHH8LKcLYuVI2nHVAeXPXEXU8HNTLXXfNsSamzoe7i1tvTSpIqGwnRX eb7uCb86aYA6r3Ymrl/fR2gyC+47oOTKX+SPPBtB3y+avXE52ROk7wcBBUrNBqtCLMlZ KGRP7NVaSEBG2ZRN3jrjcWJRx2mtwJT++GeRcCN381prDLZR977xf9Bi/9Qji60mBZAP Zi1UhzdRx3SYrHNE7l61cl/03Pe7GLS5B09Es0Ykf6YZDP8et4SjN7IOSByRn85s3ePC dzwy99tLcPsDy/MS9DPZu+YSExOjhogvC9DZ1TrU3sNesAfiB72SoZByHsVCfI9Rd/Rq JjVQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:content-transfer-encoding:mime-version :subject:message-id:date:cc:to; bh=QyhOR01DoxGCYnC4bLLESVLmV3qWJRFD3wmuOiKUM+s=; b=2IKlX8r4cWx0PRTCkFSGrOyGxUcGobRJ/asxCXjZ2iUaOyskUP2CdrsAgR1JI/s/XP 9GVOX5D6jbV7FzqSjUCrruWv5tZvBtjCpS4k8a/WM/40LxO9pk0Mulg7HrpZOuHeq02k yLh+iImeYF1Eqz5fHCUKifpe8pYH/iiadVOxvB9ot6SFeTSOw7FoiDG2yvfyb9D6j2rz i2QI4V5NfbOS+DnrXrLN6SfVhK0L0/KOlYg/Cbad0PNy1scKqSD75qJrrvNusu/vVgAR y5nAzYMsDLQDZrtsAH8nxb3QGrzZ2j0r6RiBTd2egskhDRLyWUJCFD9F9pfT5U1KGuJj eLYw== X-Gm-Message-State: AJIora+CzhbZV7Prui8iw6/PLNZBFMt/6eE5Mv8Jx50YyPEbKiageElx Yo1gDSLTsCgXcr+xCZEFvR5uAg== X-Google-Smtp-Source: AGRyM1snP/L4DiOZS/0MJdzbFUPKreO0jk3IPQtyANLnH4rMZRf2ATr75Ln58SBsVbEfxUEbkunwCg== X-Received: by 2002:a17:906:5343:b0:722:ea54:fe67 with SMTP id j3-20020a170906534300b00722ea54fe67mr15579245ejo.181.1657917138169; Fri, 15 Jul 2022 13:32:18 -0700 (PDT) Received: from smtpclient.apple (ip5b434222.dynamic.kabel-deutschland.de. [91.67.66.34]) by smtp.gmail.com with ESMTPSA id a15-20020a1709066d4f00b00715705dd23asm2375834ejt.89.2022.07.15.13.32.16 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Jul 2022 13:32:17 -0700 (PDT) From: =?utf-8?q?Christian_Kohlsch=C3=BCtter?= Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.100.31\)) Subject: [PATCH] regulator: core: Resolve supply name earlier to prevent double-init Message-Id: <3B4AE882-0C28-41E3-9466-F8E301567627@kohlschutter.com> Date: Fri, 15 Jul 2022 22:32:16 +0200 Cc: Robin Murphy , wens@kernel.org, =?utf-8?q?Heiko_St?= =?utf-8?q?=C3=BCbner?= , Markus Reichl , linux-arm-kernel , "open list:ARM/Rockchip SoC..." , Linux MMC List To: Liam Girdwood , Mark Brown , linux-kernel X-Mailer: Apple Mail (2.3696.100.31) Precedence: bulk List-ID: X-Mailing-List: linux-mmc@vger.kernel.org Previously, an unresolved regulator supply reference upon calling regulator_register on an always-on or boot-on regulator caused set_machine_constraints to be called twice. This in turn may initialize the regulator twice, leading to voltage glitches that are timing-dependent. A simple, unrelated configuration change may be enough to hide this problem, only to be surfaced by chance. One such example is the SD-Card voltage regulator in a NanoPI R4S that would not initialize reliably unless the registration flow was just complex enough to allow the regulator to properly reset between calls. Fix this by re-arranging regulator_register, trying resolve the regulator's supply early enough that set_machine_constraints does not need to be called twice. Signed-off-by: Christian Kohlschütter --- drivers/regulator/core.c | 42 ++++++++++++++++++++++++++-------------- 1 file changed, 28 insertions(+), 14 deletions(-) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index c4d844ffad7a..728840827e9c 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -5433,7 +5433,34 @@ regulator_register(const struct regulator_desc *regulator_desc, BLOCKING_INIT_NOTIFIER_HEAD(&rdev->notifier); INIT_DELAYED_WORK(&rdev->disable_work, regulator_disable_work); - /* preform any regulator specific init */ + /* set regulator constraints */ + if (init_data) + rdev->constraints = kmemdup(&init_data->constraints, + sizeof(*rdev->constraints), + GFP_KERNEL); + else + rdev->constraints = kzalloc(sizeof(*rdev->constraints), + GFP_KERNEL); + + if (init_data && init_data->supply_regulator) + rdev->supply_name = init_data->supply_regulator; + else if (regulator_desc->supply_name) + rdev->supply_name = regulator_desc->supply_name; + + if ((rdev->supply_name && !rdev->supply) && rdev->constraints + && (rdev->constraints->always_on || rdev->constraints->boot_on)) { + /* Try to resolve the name of the supplying regulator here first + * so we prevent double-initializing the regulator, which may + * cause timing-specific voltage brownouts/glitches that are + * hard to debug. + */ + ret = regulator_resolve_supply(rdev); + if (ret) + rdev_dbg(rdev, "unable to resolve supply early: %pe\n", + ERR_PTR(ret)); + } + + /* perform any regulator specific init */ if (init_data && init_data->regulator_init) { ret = init_data->regulator_init(rdev->reg_data); if (ret < 0) @@ -5459,24 +5486,11 @@ regulator_register(const struct regulator_desc *regulator_desc, (unsigned long) atomic_inc_return(®ulator_no)); dev_set_drvdata(&rdev->dev, rdev); - /* set regulator constraints */ - if (init_data) - rdev->constraints = kmemdup(&init_data->constraints, - sizeof(*rdev->constraints), - GFP_KERNEL); - else - rdev->constraints = kzalloc(sizeof(*rdev->constraints), - GFP_KERNEL); if (!rdev->constraints) { ret = -ENOMEM; goto wash; } - if (init_data && init_data->supply_regulator) - rdev->supply_name = init_data->supply_regulator; - else if (regulator_desc->supply_name) - rdev->supply_name = regulator_desc->supply_name; - ret = set_machine_constraints(rdev); if (ret == -EPROBE_DEFER) { /* Regulator might be in bypass mode and so needs its supply