From patchwork Thu Sep 17 08:16:19 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ludovic Desroches X-Patchwork-Id: 7203241 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 77232BEEC1 for ; Thu, 17 Sep 2015 08:18:03 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B6821207DA for ; Thu, 17 Sep 2015 08:17:58 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D36D1207D7 for ; Thu, 17 Sep 2015 08:17:57 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZcUMm-00033s-Qh; Thu, 17 Sep 2015 08:16:28 +0000 Received: from eusmtp01.atmel.com ([212.144.249.243]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZcUMk-0002bK-4R for linux-arm-kernel@lists.infradead.org; Thu, 17 Sep 2015 08:16:26 +0000 Received: from ibiza.corp.atmel.com (10.161.101.13) by eusmtp01.atmel.com (10.161.101.31) with Microsoft SMTP Server id 14.3.235.1; Thu, 17 Sep 2015 10:15:59 +0200 From: Ludovic Desroches To: Subject: [PATCH 1/2] mmc: sdhci: add quirk SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST Date: Thu, 17 Sep 2015 10:16:19 +0200 Message-ID: <1442477780-30994-1-git-send-email-ludovic.desroches@atmel.com> X-Mailer: git-send-email 2.5.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150917_011626_379209_A5EFDA91 X-CRM114-Status: GOOD ( 10.29 ) X-Spam-Score: -4.2 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mmc@vger.kernel.org, nicolas.ferre@atmel.com, linux-kernel@vger.kernel.org, Ludovic Desroches , alexandre.belloni@free-electrons.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The Atmel sdhci device needs a new quirk. sdhci_set_clock set the Clock Control Register to 0 before computing the new value and writing it. It disables the internal clock which causes a reset mecanism. If we write the new value before this reset mecanism is done, it will prevent the stabilisation of the internal clock, so a delay is needed. This delay is about 2-3 cycles of the base clock. To be safe, a 1 ms delay is used. Signed-off-by: Ludovic Desroches --- Hi Ulf, Can you take these patches as fixes? I thought it was better to introduce a quirk instead of duplicating a part of the sdhci_set_clock function to implement my own set_clock function. Regards drivers/mmc/host/sdhci.c | 2 ++ drivers/mmc/host/sdhci.h | 5 +++++ 2 files changed, 7 insertions(+) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 64b7fdb..fbc7efd 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -1160,6 +1160,8 @@ void sdhci_set_clock(struct sdhci_host *host, unsigned int clock) host->mmc->actual_clock = 0; sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL); + if (host->quirks2 & SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST) + mdelay(1); if (clock == 0) return; diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index 7c02ff4..9d4aa31 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -412,6 +412,11 @@ struct sdhci_host { #define SDHCI_QUIRK2_ACMD23_BROKEN (1<<14) /* Broken Clock divider zero in controller */ #define SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN (1<<15) +/* + * When internal clock is disabled, a delay is needed before modifying the + * SD clock frequency or enabling back the internal clock. + */ +#define SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST (1<<16) int irq; /* Device IRQ */ void __iomem *ioaddr; /* Mapped address */