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 2577019EEBD; Mon, 2 Jun 2025 14:36:43 +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=1748875005; cv=none; b=W4d28W66tS5enAQH5aNj81OD1rFH+09qKF6qreQ3gxc/4PMa6dUDUVRI2zVf9YBrZbubfcdFe20lcmZIBoa9VUb+B/Mcqb5SBalZ5kHh19opnDKns3LotLGPpp7XN6tdZmZei5wpsqp+Z/mwqMZTOeNp3lSky9l17DWZ6aQP8sE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748875005; c=relaxed/simple; bh=kEimrVSgp59fLpjwoxM50erot04KMdjS0LrrhdirU3g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eG0r6ZlVeFSqK2CJmYSmvw7UxSWhtCt65v7WkPAWR8ebJl54hQKcWNsSc2XlIdz5mFUxkicOFAnAEHdPaKD7NvgtxmhDQzu2yGV/VjbGwUskABIBUsSXuM5HfEzlyFwHhPnbUoa/pdnioqvsDdRMlZhHzTM7ddqzCTMczXCXCMY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=camztdWM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="camztdWM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37BA6C4CEEB; Mon, 2 Jun 2025 14:36:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748875003; bh=kEimrVSgp59fLpjwoxM50erot04KMdjS0LrrhdirU3g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=camztdWMHlTWv8q/QJFizJoO+fUHg9oR82QcoEo1w+9nhl73ixH7G7K50F8Kd2RPP 9FFrNliNtzDCbBMgi0o38aa4HseOBMs2afHdiN1CW87M5v78tlpIcJor+PeK7FpTFg DowpTNyMkBQnRfsQlBZQjgQN3yS7urmWG6VACsJc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alessandro Grassi , Mark Brown , Sasha Levin Subject: [PATCH 5.4 201/204] spi: spi-sun4i: fix early activation Date: Mon, 2 Jun 2025 15:48:54 +0200 Message-ID: <20250602134303.570815318@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250602134255.449974357@linuxfoundation.org> References: <20250602134255.449974357@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ 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 cbfac6596fad5..2bdac65789b62 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