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 62BA7242D88; Mon, 19 May 2025 21:23:29 +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=1747689809; cv=none; b=GwlSZBafi0E5tlN1Vu3+9PwvYn/WJ22538d9JwqdNp92ZgJpPVt72JV0AazhtXoEs9EO/SacGyp+bWFeFK9kiZTR9+NAV8/VcjePVJijRvxb2qI/XXYO3dLAis/l6EB6q5Zo46YRcrR2Zep/OzL4IYxcpuxHGj1PsSHArpKqmx4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747689809; c=relaxed/simple; bh=pOFSHYTAt9k+byuw5GnkOTfdc/p6LzC2lKTZF/eBYfU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=hapZ6SRCb9zqezYCpO/lA49D+5VpGrx/qT0ztxHIhN1f+5JyBj+Xr5f9CN3VYWC4duGQA7ERprrahLZ2tanZkfjqqnZk+TCHczPqJ2K3fn8FfyH+u8igSaLEGVIADqPF5W+/UePcBr2vOeNVV+yz16XbPU9NMDzCQxbK1LH48dI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tSZhlLVW; 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="tSZhlLVW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2BF96C4CEF2; Mon, 19 May 2025 21:23:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747689809; bh=pOFSHYTAt9k+byuw5GnkOTfdc/p6LzC2lKTZF/eBYfU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tSZhlLVWdKf4eVh8R0Wvinky0zVzGMcdXQzc0RM2kJioHCzRmCjxaPUN5NsbRGZbr EEcSBcYdItZyfzT50+1DFB7cVzu2qnfCeofzlgL542OfKuyXYqJd0s5xXaK8e+NgLw l18/TRsHk3AeJaPBZQPWrfmkwrsTeDLBxJdnhGdjttDvzM3fbkL8kTyQQ37XqYhDw6 6yblqG6hnpN0WbvRUGuRt23ifzUG5uqwf9na/WmUSGAFYiD/oUC0hVYrR5zB29wLWY loV6MeWi8phe1srk/j0FW48zGfaf09TExQ0KJgkgE2+YQLsFoWeDtwDzLtwfmj1yQr tfwzpaS6nzlCw== 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 5.10 5/6] spi: spi-sun4i: fix early activation Date: Mon, 19 May 2025 17:23:19 -0400 Message-Id: <20250519212320.1986749-5-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250519212320.1986749-1-sashal@kernel.org> References: <20250519212320.1986749-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.10.237 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 1fdfc6e6691d2..a8fba310d7004 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