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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B4CA6C3ABDD for ; Mon, 19 May 2025 21:32:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4savt1oZzFHTdK2FXDzF5yFP5dIEMWAQtiWse0iDXzw=; b=rgcqzXhEedNUbEme6xMUajRLE9 q4QsVT0uDB4BiOCeLHllRtExy9KQUAPbQCdWKhogR/gyMZvgRz6x1sPQsun1GYn5MbphRf1xSPlPr 87kQsZkZMaoYOOabVDCdtZqeYDZXmwYyukVFA9GC396Sak56Hqvm9aCHSl+KIF2zUe09rxDz9NS7A pD2Keu/EhpkR/GbA7Kre4HoskAWOO57Aoi3ZelnY8cxtkWzyd8wVu/v4GBXStiRTbY4kYG28PQjy6 aVVsMfsAtkDnX2iTVUhqqwmJ2cF6cgT7SHeWACIAVi0eKYSDUQZ7lKyXBQrm2bUh6uYDo8U1JWxp6 G8mDxctA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uH86M-0000000AZ9G-3bCq; Mon, 19 May 2025 21:32:50 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uH7wh-0000000AWH2-3KnJ for linux-arm-kernel@lists.infradead.org; Mon, 19 May 2025 21:22:51 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 3C145629E3; Mon, 19 May 2025 21:22:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4374C4CEE4; Mon, 19 May 2025 21:22:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747689770; bh=D7IBcVOI+yPkwGYr35IJjIYa1iRv9LBRLXIHo2RAt/c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=guL1eDFNIKRtaBNuiuxhOr6ObFUgfWKK+PzlaoM8mA4ukHV7llx4ZN3KCqOr0iaVa PXiNKGRW0Co6C2yL8cI96uBdTtC2LfHbfJQZZxbkpF/SVRs45C5Wvarx//J1EzMVer Ri8MdXJA3xQbk1TDQnh2gM7I+zFA0sA/ujKVD5eK7bNqGZE+vjgDloMetLk4U/s1iL 1nLo3c8THNh/MT3XhBrBodkq2AGd2Xi3+ZvMfhFpeJMFDSV48wXzNyvap4Zc4CGJz7 hx/ZnAK1lNghfOm80w3q+UX9rIy19nzAXSn7dnQya6pO1Y+6iQQDJQp85oFp8Ij0KA jhrq+8IPNPYgQ== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Alessandro Grassi , Mark Brown , Sasha Levin , mripard@kernel.org, wens@csie.org, linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 6.6 08/11] spi: spi-sun4i: fix early activation Date: Mon, 19 May 2025 17:22:34 -0400 Message-Id: <20250519212237.1986368-8-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250519212237.1986368-1-sashal@kernel.org> References: <20250519212237.1986368-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.91 Content-Transfer-Encoding: 8bit X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Alessandro Grassi [ Upstream commit fb98bd0a13de2c9d96cb5c00c81b5ca118ac9d71 ] The SPI interface is activated before the CPOL setting is applied. In that moment, the clock idles high and CS goes low. After a short delay, CPOL and other settings are applied, which may cause the clock to change state and idle low. This transition is not part of a clock cycle, and it can confuse the receiving device. To prevent this unexpected transition, activate the interface while CPOL and the other settings are being applied. Signed-off-by: Alessandro Grassi Link: https://patch.msgid.link/20250502095520.13825-1-alessandro.grassi@mailbox.org Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-sun4i.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c index b8947265d329e..5b2cb225a4198 100644 --- a/drivers/spi/spi-sun4i.c +++ b/drivers/spi/spi-sun4i.c @@ -263,6 +263,9 @@ static int sun4i_spi_transfer_one(struct spi_master *master, else reg |= SUN4I_CTL_DHB; + /* Now that the settings are correct, enable the interface */ + reg |= SUN4I_CTL_ENABLE; + sun4i_spi_write(sspi, SUN4I_CTL_REG, reg); /* Ensure that we have a parent clock fast enough */ @@ -403,7 +406,7 @@ static int sun4i_spi_runtime_resume(struct device *dev) } sun4i_spi_write(sspi, SUN4I_CTL_REG, - SUN4I_CTL_ENABLE | SUN4I_CTL_MASTER | SUN4I_CTL_TP); + SUN4I_CTL_MASTER | SUN4I_CTL_TP); return 0; -- 2.39.5