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 70E4323496F; Mon, 19 May 2025 21:22:51 +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=1747689771; cv=none; b=kDr8ygPwl7wUW1gmWdJcrUonE/zi6YpRlQjcpa3xreRc/tamp8XtMA9IMiyzz/86rb5BgMDstbdpptIE/JkeF3VYB1CxDmV8SrHB0buVII0t4uajTxYWaoDesQ58siR3FSbNBpB/1k6x3T8MnBEv6+3arufeTvFvIMUa+fpwipM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747689771; c=relaxed/simple; bh=D7IBcVOI+yPkwGYr35IJjIYa1iRv9LBRLXIHo2RAt/c=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=hHgzTwvvVWj+kLKKYpuR+2DCmiTHUQw/mFmDZtdB2K4rzUflLjj7uCNIkrnCnzXFWVnpfRslVxD7L+k6ADU6GPJ84BKDhGKQoF1CPzQNGBzt9RXPK64yEtkfgFW8/Knlyy67ZqWZdW/5U82MEDk6sL37kUjNfO5mfPU/TtXZBvY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=guL1eDFN; 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="guL1eDFN" 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> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.91 Content-Transfer-Encoding: 8bit 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