Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754142AbcDBRSH (ORCPT ); Sat, 2 Apr 2016 13:18:07 -0400 Received: from pygmy.kinoho.net ([134.0.27.24]:38064 "EHLO pygmy.kinoho.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752928AbcDBRRf (ORCPT ); Sat, 2 Apr 2016 13:17:35 -0400 From: Grigori Goronzy To: Johan Hovold Cc: Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Grigori Goronzy Subject: [PATCH v2 12/14] USB: ch341: improve B0 handling Date: Sat, 2 Apr 2016 19:07:21 +0200 Message-Id: <1459616843-23829-13-git-send-email-greg@chown.ath.cx> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1459616843-23829-1-git-send-email-greg@chown.ath.cx> References: <1459616843-23829-1-git-send-email-greg@chown.ath.cx> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1578 Lines: 42 Check for B0 in a more idiomatic way and make sure to not enable RTS/CTS hardware flow control in B0 as it may override the control lines. Also make sure to only enable RTS/DTR if there's a transition from B0. Signed-off-by: Grigori Goronzy --- drivers/usb/serial/ch341.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index ba654e1..3b9a43d 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -396,10 +396,12 @@ static void ch341_set_termios(struct tty_struct *tty, if (cflag & CSTOPB) ctrl |= CH341_LCR_STOP_BITS_2; - if (baud_rate) { - spin_lock_irqsave(&priv->lock, flags); - priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); - spin_unlock_irqrestore(&priv->lock, flags); + if ((cflag & CBAUD) != B0) { + if (old_termios && (old_termios->c_cflag & CBAUD) == B0) { + spin_lock_irqsave(&priv->lock, flags); + priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); + spin_unlock_irqrestore(&priv->lock, flags); + } r = ch341_init_set_baudrate(port->serial->dev, priv, ctrl); if (r < 0) priv->baud_rate = tty_termios_baud_rate(old_termios); @@ -411,7 +413,7 @@ static void ch341_set_termios(struct tty_struct *tty, ch341_set_handshake(port->serial->dev, priv->line_control); - if (cflag & CRTSCTS) { + if ((cflag & CRTSCTS) && ((cflag & CBAUD) != B0)) { r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG, CH341_REG_RTSCTS | ((uint16_t)CH341_REG_RTSCTS << 8), 0x0101); -- 1.9.1