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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS 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 B63F1C64EB8 for ; Thu, 4 Oct 2018 12:47:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 711BA20684 for ; Thu, 4 Oct 2018 12:47:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="L8W1DtK/"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="Ntx7AdYi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 711BA20684 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.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 S1727536AbeJDTko (ORCPT ); Thu, 4 Oct 2018 15:40:44 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:52466 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727314AbeJDTko (ORCPT ); Thu, 4 Oct 2018 15:40:44 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 6A03260C6A; Thu, 4 Oct 2018 12:47:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1538657255; bh=CqBTB/QUpVDFg8y1jMDx9F5OFMy9U7t9Eei6taBSi3U=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=L8W1DtK/1mLGPNfNUZT6gvuWcOo1WKoz3wNdB326NgzWCJWA8wwIHUjJqD4GobvuJ +Hu1iSDmQ11GojiOPUhz4/9H53e3c5HO8G1TALzFIPdv/EqujD23OrCOH33IWfuxzh wO8qmcTeZQ93n1A/q4mas3NRg8/0dkP7/UatOyo8= Received: from [10.252.220.101] (blr-c-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vbadigan@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 08C5B6043F; Thu, 4 Oct 2018 12:47:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1538657254; bh=CqBTB/QUpVDFg8y1jMDx9F5OFMy9U7t9Eei6taBSi3U=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=Ntx7AdYiDR8koK9ri66bkfPO2QrEAAvzXce19y4lP1kNsQxTtzIKE9ID+8MCtVHuK KVrAS1SvY+B/V01v5NHEM7acB/YBYGXykLzxAgvg9DVW2zC5xb7uHoHEnTf/ORLrHc ehLDDRyiTwlr6240hDJhkhz1uBCTC7alGlmPUcJc= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 08C5B6043F Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=vbadigan@codeaurora.org Subject: Re: [PATCH V2 1/3] mmc: sdhci: Allow platform controlled voltage switching To: Evan Green Cc: adrian.hunter@intel.com, Ulf Hansson , robh+dt@kernel.org, linux-mmc@vger.kernel.org, asutoshd@codeaurora.org, riteshh@codeaurora.org, stummala@codeaurora.org, sayali , Doug Anderson , vviswana@codeaurora.org, linux-kernel@vger.kernel.org References: <1537424558-17989-1-git-send-email-vbadigan@codeaurora.org> <1537424558-17989-2-git-send-email-vbadigan@codeaurora.org> From: Veerabhadrarao Badiganti Message-ID: <535b31b6-def4-63fd-c8a1-d1a10d8b4566@codeaurora.org> Date: Thu, 4 Oct 2018 18:16:49 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Evan, On 9/22/2018 1:38 AM, Evan Green wrote: > On Wed, Sep 19, 2018 at 11:24 PM Veerabhadrarao Badiganti > wrote: >> From: Vijay Viswanath >> >> Some controllers can have internal mechanism to inform the SW that it >> is ready for voltage switching. For such controllers, changing voltage >> before the HW is ready can result in various issues. >> >> During setup/cleanup of host, check whether regulator enable/disable >> was already done by platform driver. >> >> Signed-off-by: Vijay Viswanath >> Signed-off-by: Veerabhadrarao Badiganti >> --- >> drivers/mmc/host/sdhci.c | 22 +++++++++++++++------- >> drivers/mmc/host/sdhci.h | 1 + >> 2 files changed, 16 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >> index 99bdae5..04b3fd2 100644 >> --- a/drivers/mmc/host/sdhci.c >> +++ b/drivers/mmc/host/sdhci.c >> @@ -3616,6 +3616,7 @@ int sdhci_setup_host(struct sdhci_host *host) >> unsigned int override_timeout_clk; >> u32 max_clk; >> int ret; >> + bool enable_vqmmc = false; >> >> WARN_ON(host == NULL); >> if (host == NULL) >> @@ -3629,9 +3630,12 @@ int sdhci_setup_host(struct sdhci_host *host) >> * the host can take the appropriate action if regulators are not >> * available. >> */ >> - ret = mmc_regulator_get_supply(mmc); >> - if (ret) >> - return ret; >> + if (!mmc->supply.vmmc) { >> + ret = mmc_regulator_get_supply(mmc); >> + if (ret) >> + return ret; >> + enable_vqmmc = true; > The coupling of logic strikes me as a little bit odd, it's saying if > vmmc is already present, then don't turn on vqmmc. I guess what it's > trying to say is "hands off all the regulators, I've got this". It > might be cleaner to set enable_vqmmc based on whether or not > mmc->supply.vqmmc exists before the get_supply call, rather than > coupling it into whether or not vmmc exists. > > Actually, what might be even nicer is to change > mmc_regulator_get_supply to only get supplies that it doesn't already > have. You'd still have your enable_vqmmc local, but the > mmc_regulator_get_supply call would be outside the conditional, and > the logic of "don't enable vqmmc if it existed before" would make more > sense. Yes, its saying if platform driver has already controlling the regulators, don't enable/disable them anymore. Agree with you on the conditional check.  Will update it to Vcmmc instead of vmmc. >> + } >> >> DBG("Version: 0x%08x | Present: 0x%08x\n", >> sdhci_readw(host, SDHCI_HOST_VERSION), >> @@ -3880,7 +3884,11 @@ int sdhci_setup_host(struct sdhci_host *host) >> mmc->caps |= MMC_CAP_NEEDS_POLL; >> >> if (!IS_ERR(mmc->supply.vqmmc)) { >> - ret = regulator_enable(mmc->supply.vqmmc); >> + if (enable_vqmmc) { >> + ret = regulator_enable(mmc->supply.vqmmc); >> + host->vqmmc_enabled = !ret; >> + } else >> + ret = 0; > I think it's preferred that if your "if" had curly braces, then the > else part needs it too. Actually, can you move the if (ret) pr_warn > stuff up and inside of your if statement above? That keeps the logic > together, and then you don't need an else case at all! sure. Will update. >> /* If vqmmc provides no 1.8V signalling, then there's no UHS */ >> if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000, >> @@ -4136,7 +4144,7 @@ int sdhci_setup_host(struct sdhci_host *host) >> return 0; >> >> unreg: >> - if (!IS_ERR(mmc->supply.vqmmc)) >> + if (host->vqmmc_enabled) >> regulator_disable(mmc->supply.vqmmc); >> undma: >> if (host->align_buffer) >> @@ -4154,7 +4162,7 @@ void sdhci_cleanup_host(struct sdhci_host *host) >> { >> struct mmc_host *mmc = host->mmc; >> >> - if (!IS_ERR(mmc->supply.vqmmc)) >> + if (host->vqmmc_enabled) >> regulator_disable(mmc->supply.vqmmc); >> >> if (host->align_buffer) >> @@ -4287,7 +4295,7 @@ void sdhci_remove_host(struct sdhci_host *host, int dead) >> >> tasklet_kill(&host->finish_tasklet); >> >> - if (!IS_ERR(mmc->supply.vqmmc)) >> + if (host->vqmmc_enabled) >> regulator_disable(mmc->supply.vqmmc); >> >> if (host->align_buffer) >> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h >> index b001cf4..3c28152 100644 >> --- a/drivers/mmc/host/sdhci.h >> +++ b/drivers/mmc/host/sdhci.h >> @@ -524,6 +524,7 @@ struct sdhci_host { >> bool pending_reset; /* Cmd/data reset is pending */ >> bool irq_wake_enabled; /* IRQ wakeup is enabled */ >> bool v4_mode; /* Host Version 4 Enable */ >> + bool vqmmc_enabled; /* Vqmmc is enabled */ > This is kind of unpleasant. It's confused by the fact that other host > controllers have a vqmmc_enabled member, but they use it to mean what > it sounds like, "is vqmmc currently enabled". Here you're really using > it to mean "don't ever disable vqmmc in sdhci, because the platform > code sort of owns vqmmc". It only "sort of" owns it in that sdhci is > still free to call regulator_is_supported_voltage and > mmc_regulator_set_vqmmc, but somehow not regulator_disable. Is there > any way to clean up the semantics here? Except the regualtor_enable()/disable() calls other regulator-operations are direct operations. Only enable() & disable() uses a reference couters to track whether number regualtor_enable() calls matches with number of regualtor_disable() calls or not. In V1 patch-set this was done without need to this flag but it was suggested have this flag for ensuring enable/disable counters are in sync. >> struct mmc_request *mrqs_done[SDHCI_MAX_MRQS]; /* Requests done */ >> struct mmc_command *cmd; /* Current command */ >> -- >> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc., is a member of Code Aurora Forum, a Linux Foundation Collaborative Project >>