From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754868Ab2AQSlI (ORCPT ); Tue, 17 Jan 2012 13:41:08 -0500 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:45803 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754468Ab2AQSlG (ORCPT ); Tue, 17 Jan 2012 13:41:06 -0500 Date: Tue, 17 Jan 2012 18:40:48 +0000 From: Russell King To: Shreshtha Kumar SAHU Cc: gregkh@suse.de, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] amba-pl011: do not disable RTS during shutdown Message-ID: <20120117184047.GE22472@flint.arm.linux.org.uk> References: <1326796189-21722-1-git-send-email-shreshthakumar.sahu@stericsson.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1326796189-21722-1-git-send-email-shreshthakumar.sahu@stericsson.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 17, 2012 at 03:59:49PM +0530, Shreshtha Kumar SAHU wrote: > From: Shreshtha Kumar Sahu > > In present driver, shutdown clears RTS in CR register. But the > documentation "Documentation/serial/driver" suggests not to > disable RTS in shutdown(). Also RTS is preserved between shutdown > and startup calls, i.e. it is restored in startup if it was enabled > during shutdown. So that if autorts is set and RTS is set using > pl011_set_mctrl then it should continue even after shutdown->startup > sequence. And hence during set_termios it will enable RTS only if RTS > bit is set in UARTx_CR register. For throttling/unthrottling user > should call pl011_set_mctrl. > > Change-Id: I743f33fb10e7e655657cd5dae1ec585e914a65bc Please get rid of this line. > Signed-off-by: Shreshtha Kumar Sahu > Acked-by: Linus Walleij > --- > drivers/tty/serial/amba-pl011.c | 17 ++++++++++++++++- > 1 files changed, 16 insertions(+), 1 deletions(-) > > diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c > index 6958594..46a4690 100644 > --- a/drivers/tty/serial/amba-pl011.c > +++ b/drivers/tty/serial/amba-pl011.c > @@ -160,6 +160,7 @@ struct uart_amba_port { > unsigned int lcrh_tx; /* vendor-specific */ > unsigned int lcrh_rx; /* vendor-specific */ > bool autorts; > + bool rts_state; /* state during shutdown */ Do we really need a variable to track this? > char type[12]; > bool interrupt_may_hang; /* vendor-specific */ > #ifdef CONFIG_DMA_ENGINE > @@ -1412,6 +1413,8 @@ static int pl011_startup(struct uart_port *port) > barrier(); > > cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE; > + if (uap->rts_state) > + cr |= UART011_CR_RTS; > writew(cr, uap->port.membase + UART011_CR); Note that this should preserve DTR as well. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: