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 86980C433EF for ; Thu, 9 Jun 2022 07:47:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237725AbiFIHre (ORCPT ); Thu, 9 Jun 2022 03:47:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232338AbiFIHre (ORCPT ); Thu, 9 Jun 2022 03:47:34 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EBCB42EC6 for ; Thu, 9 Jun 2022 00:47:30 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=[IPv6:::1]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nzCsy-0001aH-Ju; Thu, 09 Jun 2022 09:47:20 +0200 Message-ID: Subject: Re: [PATCH v9 5/8] PCI: imx6: Refine the regulator usage From: Lucas Stach To: Hongxing Zhu , "bhelgaas@google.com" , "robh+dt@kernel.org" , "broonie@kernel.org" , "lorenzo.pieralisi@arm.com" , "jingoohan1@gmail.com" , "festevam@gmail.com" , "francesco.dolcini@toradex.com" Cc: "linux-pci@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "kernel@pengutronix.de" , dl-linux-imx Date: Thu, 09 Jun 2022 09:47:18 +0200 In-Reply-To: References: <1651801629-30223-1-git-send-email-hongxing.zhu@nxp.com> <1651801629-30223-6-git-send-email-hongxing.zhu@nxp.com> <2427cef355dc1b9d1667a2c80448d2e23b97c447.camel@pengutronix.de> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.40.4 (3.40.4-1.fc34) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: l.stach@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-pci@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Am Donnerstag, dem 09.06.2022 um 06:17 +0000 schrieb Hongxing Zhu: > > -----Original Message----- > > From: Lucas Stach > > Sent: 2022年6月8日 15:27 > > To: Hongxing Zhu ; bhelgaas@google.com; > > robh+dt@kernel.org; broonie@kernel.org; lorenzo.pieralisi@arm.com; > > jingoohan1@gmail.com; festevam@gmail.com; > > francesco.dolcini@toradex.com > > Cc: linux-pci@vger.kernel.org; > > linux-arm-kernel@lists.infradead.org; > > linux-kernel@vger.kernel.org; kernel@pengutronix.de; dl-linux-imx > > > > Subject: Re: [PATCH v9 5/8] PCI: imx6: Refine the regulator usage > > > > Am Freitag, dem 06.05.2022 um 09:47 +0800 schrieb Richard Zhu: > > > The driver should undo any enables it did itself. The regulator > > > disable shouldn't be basing decisions on regulator_is_enabled(). > > > > > > To keep the balance of the regulator usage counter, disable the > > > regulator just behind of imx6_pcie_assert_core_reset() in resume > > > and > > shutdown. > > > > > > Signed-off-by: Richard Zhu > > > --- > > >  drivers/pci/controller/dwc/pci-imx6.c | 19 +++++++------------ > > >  1 file changed, 7 insertions(+), 12 deletions(-) > > > > > > diff --git a/drivers/pci/controller/dwc/pci-imx6.c > > > b/drivers/pci/controller/dwc/pci-imx6.c > > > index 7005a7910003..3ce3993d5797 100644 > > > --- a/drivers/pci/controller/dwc/pci-imx6.c > > > +++ b/drivers/pci/controller/dwc/pci-imx6.c > > > @@ -369,8 +369,6 @@ static int imx6_pcie_attach_pd(struct device > > > *dev) > > > > > >  static void imx6_pcie_assert_core_reset(struct imx6_pcie > > > *imx6_pcie) > > > { > > > - struct device *dev = imx6_pcie->pci->dev; > > > - > > >   switch (imx6_pcie->drvdata->variant) { > > >   case IMX7D: > > >   case IMX8MQ: > > > @@ -400,14 +398,6 @@ static void > > > imx6_pcie_assert_core_reset(struct > > imx6_pcie *imx6_pcie) > > >   IMX6Q_GPR1_PCIE_REF_CLK_EN, 0 > > > << 16); > > >   break; > > >   } > > > - > > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie- > > > >vpcie) > 0) { > > > - int ret = regulator_disable(imx6_pcie->vpcie); > > > - > > > - if (ret) > > > - dev_err(dev, "failed to disable vpcie > > > regulator: %d\n", > > > - ret); > > > - } > > >  } > > > > > >  static unsigned int imx6_pcie_grp_offset(const struct imx6_pcie > > > *imx6_pcie) @@ -580,7 +570,7 @@ static int > > imx6_pcie_deassert_core_reset(struct imx6_pcie *imx6_pcie) > > >   struct device *dev = pci->dev; > > >   int ret, err; > > > > > > - if (imx6_pcie->vpcie && !regulator_is_enabled(imx6_pcie- > > > >vpcie)) { > > > + if (imx6_pcie->vpcie) { > > >   ret = regulator_enable(imx6_pcie->vpcie); > > >   if (ret) { > > >   dev_err(dev, "failed to enable vpcie > > > regulator: %d\n", @@ > > -653,7 > > > +643,7 @@ static int imx6_pcie_deassert_core_reset(struct > > > imx6_pcie > > *imx6_pcie) > > >   return 0; > > > > > >  err_clks: > > > - if (imx6_pcie->vpcie && regulator_is_enabled(imx6_pcie- > > > >vpcie) > 0) { > > > + if (imx6_pcie->vpcie) { > > >   ret = regulator_disable(imx6_pcie->vpcie); > > >   if (ret) > > >   dev_err(dev, "failed to disable vpcie > > > regulator: %d\n", @@ > > -1026,6 > > > +1016,9 @@ static int imx6_pcie_resume_noirq(struct device *dev) > > >   return 0; > > > > > >   imx6_pcie_assert_core_reset(imx6_pcie); > > > + if (imx6_pcie->vpcie) > > > + regulator_disable(imx6_pcie->vpcie); > > > + > > This one looks misplaced. Surely you want the regulator to be on > > when > > resuming the PCIe subsystem. Isn't this just papering over a wrong > > usage count > > here, because there is no regulator_disable in > > imx6_pcie_suspend_noirq, > > where I would expect this to happen? > > > Hi Lucas: > Thanks for your comments. > There was one regulator_disable() operation at the end of the >  imx6_pcie_assert_core_reset() function before. > When create the 5/8 patch, I follow the same behavior to disable the > regulator just behind the imx6_pcie_assert_core_reset() function. > > Yes, it is. Imx6_pcie_suspend_noirq doesn't have the > regulator_disable. > The regulaor_enable is contained in imx6_pcie_deassert_core_reset(). > Both of the regulator_disable and regulator_enabe are invoked once in >  imx6_pcie_resume_noirq. > So, the regulator is on and has a balanced usage count after resume. > Yea, my argument is that when we are moving around the regulator handling anyways, we should move the regulator_disable into the suspend function. It's the right thing to do: we don't want the bus to be powered when the system is in suspend and while the use-count is correct, it's confusing to read the resume function otherwise. Regards, Lucas