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 F0677270ECB; Tue, 8 Apr 2025 12:39:27 +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=1744115968; cv=none; b=mHemvua3IOMljfQHGVHHWRQvOY8iQmatbnEQbTdg+tOTF63vwwAzGcfiHLRpc2JlouEtNjHEq3mgdnnvEnhNZ+NRoXg0AOWpP4KBtF0HR1Cr3+ptIDFg+0sHZOiyI4gjNtTb/Gk+uzPqliqZIYmURpdjYxNDtaE9kzPDxXlBjeM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744115968; c=relaxed/simple; bh=uSgovpjzsgwy/d4UzCE9SkrEcqhKcXdwUFrjl81/WXU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QViY6m7avWQ1NuIFrI4w9Or08v+825HAjxFHFQNISGsqJsETrz7mh4yEzUv82k32M2Z5ews9LiWEQPBMF2QNNXhPFagkniL3w1PtUrECEGGBT3xvBrTByf13L7AhEUpFlBrMjtQoLGI5v7PXyPKSg/VttorJOSy9fvdX2KkAERI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kU83Yjtp; 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="kU83Yjtp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81788C4CEE5; Tue, 8 Apr 2025 12:39:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744115967; bh=uSgovpjzsgwy/d4UzCE9SkrEcqhKcXdwUFrjl81/WXU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kU83Yjtp3Tkpv0NPm34PPJ6Fe3N8awUwrpG60DOmIsao11/xSmH4hNC/2Kl8bif+R /vMW+fGsz8o98HOAT56rZOy2p33uz7oiJP01YyToSvQIoH7z3z07DlSkX4ab8Q/HAP Wqoks3ciA8foLQsObEG4A5q675LwfnU7wkgXTrvY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Sherry Sun , Frank Li , Sasha Levin Subject: [PATCH 6.1 172/204] tty: serial: fsl_lpuart: disable transmitter before changing RS485 related registers Date: Tue, 8 Apr 2025 12:51:42 +0200 Message-ID: <20250408104825.364006188@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104820.266892317@linuxfoundation.org> References: <20250408104820.266892317@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sherry Sun [ Upstream commit f5cb528d6441eb860250a2f085773aac4f44085e ] According to the LPUART reference manual, TXRTSE and TXRTSPOL of MODIR register only can be changed when the transmitter is disabled. So disable the transmitter before changing RS485 related registers and re-enable it after the change is done. Fixes: 67b01837861c ("tty: serial: lpuart: Add RS485 support for 32-bit uart flavour") Cc: stable Signed-off-by: Sherry Sun Reviewed-by: Frank Li Link: https://lore.kernel.org/r/20250312022503.1342990-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/fsl_lpuart.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index e96354edff6e9..011f175936132 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -1395,6 +1395,19 @@ static int lpuart32_config_rs485(struct uart_port *port, struct ktermios *termio unsigned long modem = lpuart32_read(&sport->port, UARTMODIR) & ~(UARTMODIR_TXRTSPOL | UARTMODIR_TXRTSE); + u32 ctrl; + + /* TXRTSE and TXRTSPOL only can be changed when transmitter is disabled. */ + ctrl = lpuart32_read(&sport->port, UARTCTRL); + if (ctrl & UARTCTRL_TE) { + /* wait for the transmit engine to complete */ + lpuart32_wait_bit_set(&sport->port, UARTSTAT, UARTSTAT_TC); + lpuart32_write(&sport->port, ctrl & ~UARTCTRL_TE, UARTCTRL); + + while (lpuart32_read(&sport->port, UARTCTRL) & UARTCTRL_TE) + cpu_relax(); + } + lpuart32_write(&sport->port, modem, UARTMODIR); if (rs485->flags & SER_RS485_ENABLED) { @@ -1414,6 +1427,10 @@ static int lpuart32_config_rs485(struct uart_port *port, struct ktermios *termio } lpuart32_write(&sport->port, modem, UARTMODIR); + + if (ctrl & UARTCTRL_TE) + lpuart32_write(&sport->port, ctrl, UARTCTRL); + return 0; } -- 2.39.5