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 85C4FC32772 for ; Mon, 22 Aug 2022 07:04:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232090AbiHVHEi convert rfc822-to-8bit (ORCPT ); Mon, 22 Aug 2022 03:04:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231440AbiHVHEh (ORCPT ); Mon, 22 Aug 2022 03:04:37 -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 361C61571A for ; Mon, 22 Aug 2022 00:04:34 -0700 (PDT) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1oQ1T7-0002ow-Hs; Mon, 22 Aug 2022 09:03:29 +0200 Received: from [2a0a:edc0:0:900:1d::4e] (helo=lupine) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1oQ1T1-001Flh-DM; Mon, 22 Aug 2022 09:03:23 +0200 Received: from pza by lupine with local (Exim 4.94.2) (envelope-from ) id 1oQ1T0-0002CG-NV; Mon, 22 Aug 2022 09:03:22 +0200 Message-ID: Subject: Re: [PATCH v6 17/17] mmc: sdhci-cadence: Support mmc hardware reset From: Philipp Zabel To: Brad Larson , linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, adrian.hunter@intel.com, alcooperx@gmail.com, andy.shevchenko@gmail.com, arnd@arndb.de, blarson@amd.com, brijeshkumar.singh@amd.com, catalin.marinas@arm.com, gsomlo@gmail.com, gerg@linux-m68k.org, krzk@kernel.org, krzysztof.kozlowski+dt@linaro.org, lee.jones@linaro.org, broonie@kernel.org, yamada.masahiro@socionext.com, piotrs@cadence.com, p.yadav@ti.com, rdunlap@infradead.org, robh+dt@kernel.org, samuel@sholland.org, fancer.lancer@gmail.com, suravee.suthikulpanit@amd.com, thomas.lendacky@amd.com, ulf.hansson@linaro.org, will@kernel.org, devicetree@vger.kernel.org Date: Mon, 22 Aug 2022 09:03:22 +0200 In-Reply-To: <20220820195750.70861-18-brad@pensando.io> References: <20220820195750.70861-1-brad@pensando.io> <20220820195750.70861-18-brad@pensando.io> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.38.3-1 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Brad, On Sa, 2022-08-20 at 12:57 -0700, Brad Larson wrote: [...] > +static void sdhci_mmc_hw_reset(struct mmc_host *mmc) > +{ > + struct sdhci_host *host = mmc_priv(mmc); > + struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host); > + > + dev_info(mmc_dev(host->mmc), "emmc hardware reset\n"); > + > + reset_control_assert(priv->rst_hw); > + /* For eMMC, minimum is 1us but give it 9us for good measure */ > + udelay(9); At a glance, this seems excessive. Is there a reason 9 us is better than, say, 2 or 3? [...] > @@ -520,6 +538,17 @@ static int sdhci_cdns_probe(struct platform_device *pdev) >   if (ret) >   goto free; >   > > > > + if (host->mmc->caps & MMC_CAP_HW_RESET) { > + priv->rst_hw = devm_reset_control_get_optional_exclusive(dev, "hw"); This should be described in cdns,sdhci.yaml first. regards Philipp