From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8001A2F73DC; Mon, 5 May 2025 23:19:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746487164; cv=none; b=FtR5RWJyaz8JYoSpZhdPsvHyRTvZzM8vefQCQWPiYtxp2mon/dkpNX27yqUcLesvXwDavl2NWAKws3dCsxwI480ilmxx2m9wbCdBcTZ16ZDpiKc1IsNcVmPZRO5oUBhxXnRz+2txPVWXkNuYdJOtpni0VkvRX2bGR9TNCr9URF4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746487164; c=relaxed/simple; bh=ZFIcwb0g0kDDhWsTZCB0yBqkcdUTb8VNvTcKcSfzyP8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=Wb8XlDhXnyk8ssdhyg9EbT/hwALYcy3spD2Wi8HplbQhayd6xtjPPddcrsbwFUvgP0zTYgg2Sd1R12qzPEFGUEyB/sdkG3rStYNoXfsuRR5M75MTWpG6YgTkSPr8NGqeS2RrBsQLQl64vcUOe2DQbqj2RTqyDaymrKsl9zokbyc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aUcrfbb1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aUcrfbb1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5E98CC4CEED; Mon, 5 May 2025 23:19:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746487163; bh=ZFIcwb0g0kDDhWsTZCB0yBqkcdUTb8VNvTcKcSfzyP8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aUcrfbb1QiZ4Um9P46/TOyb0OHmOsBlEjGkgmQvZJzuPHOc1uwGIB9KaCVeIeQrxU qYCLG7/CadXErjYfR7pgQN5XziMTIL9YK/J4XWlDJT6VwAIwmze+b5JiszpWWJnJ5F rYR2iHad5zePz3oNNEBn+glaXn0jeVOthdfEXD97/bMndrNy4q2BBkJ5QU0MORJ3XO hCRkuOuFiVamw11Sch7o04pwu3JmbtVF4QfwANpTcrwy+MjVdjjm4ZWNJ7P6pkminB v42BqR9fZRUmjjbH08GD5wQTAckTzIsVQCgIBgGu6KujJOXog3V+Ybs13uMwAqxnO3 FLmZ151OhZIQw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Erick Shepherd , Kyle Roeschley , Brad Mouring , Adrian Hunter , Ulf Hansson , Sasha Levin , linux-mmc@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 035/114] mmc: sdhci: Disable SD card clock before changing parameters Date: Mon, 5 May 2025 19:16:58 -0400 Message-Id: <20250505231817.2697367-35-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505231817.2697367-1-sashal@kernel.org> References: <20250505231817.2697367-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.10.237 Content-Transfer-Encoding: 8bit From: Erick Shepherd [ Upstream commit fb3bbc46c94f261b6156ee863c1b06c84cf157dc ] Per the SD Host Controller Simplified Specification v4.20 ยง3.2.3, change the SD card clock parameters only after first disabling the external card clock. Doing this fixes a spurious clock pulse on Baytrail and Apollo Lake SD controllers which otherwise breaks voltage switching with a specific Swissbit SD card. Signed-off-by: Kyle Roeschley Signed-off-by: Brad Mouring Signed-off-by: Erick Shepherd Acked-by: Adrian Hunter Link: https://lore.kernel.org/r/20250211214645.469279-1-erick.shepherd@ni.com Signed-off-by: Ulf Hansson Signed-off-by: Sasha Levin --- drivers/mmc/host/sdhci.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 9091930f58591..3d601a3f31c1e 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -2010,10 +2010,15 @@ void sdhci_set_clock(struct sdhci_host *host, unsigned int clock) host->mmc->actual_clock = 0; - sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL); + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL); + if (clk & SDHCI_CLOCK_CARD_EN) + sdhci_writew(host, clk & ~SDHCI_CLOCK_CARD_EN, + SDHCI_CLOCK_CONTROL); - if (clock == 0) + if (clock == 0) { + sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL); return; + } clk = sdhci_calc_clk(host, clock, &host->mmc->actual_clock); sdhci_enable_clk(host, clk); -- 2.39.5