Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753147AbbFHJPE (ORCPT ); Mon, 8 Jun 2015 05:15:04 -0400 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:45073 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751896AbbFHJOy (ORCPT ); Mon, 8 Jun 2015 05:14:54 -0400 Date: Mon, 8 Jun 2015 10:14:48 +0100 From: Russell King - ARM Linux To: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Cc: Bhuvanchandra DV , devicetree@vger.kernel.org, kernel@pengutronix.de, moorray3@wp.pl, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, stefan@agner.ch, bhuvanchandra.dv@gmail.com, linux-serial@vger.kernel.org, shawn.guo@linaro.org, jslaby@suse.cz, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH V2 2/3] tty: serial: fsl_lpuart: remove RTS/CTS control from set/get_mctrl Message-ID: <20150608091448.GT7557@n2100.arm.linux.org.uk> References: <1433136067-20644-1-git-send-email-bhuvanchandra.dv@toradex.com> <1433136067-20644-3-git-send-email-bhuvanchandra.dv@toradex.com> <20150608064113.GX18985@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20150608064113.GX18985@pengutronix.de> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2316 Lines: 54 On Mon, Jun 08, 2015 at 08:41:13AM +0200, Uwe Kleine-K?nig wrote: > Hello, > > On Mon, Jun 01, 2015 at 10:51:06AM +0530, Bhuvanchandra DV wrote: > > The LPUART does not provide manual control of RTS/CTS signals, > > those can only be controlled by the hardware directly. Therefore > > manual control of those signals through mctrl can not be provided. > > The current implementation enables/disables the automatic control, > > which is not what mctrl should do, hence remove the incorrect > > implementation. > > > > Signed-off-by: Bhuvanchandra DV > > --- > > drivers/tty/serial/fsl_lpuart.c | 63 +++++------------------------------------ > > 1 file changed, 7 insertions(+), 56 deletions(-) > > > > diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c > > index 08ce76f..532cfb7 100644 > > --- a/drivers/tty/serial/fsl_lpuart.c > > +++ b/drivers/tty/serial/fsl_lpuart.c > > @@ -822,64 +822,15 @@ static unsigned int lpuart32_tx_empty(struct uart_port *port) > > > > static unsigned int lpuart_get_mctrl(struct uart_port *port) > > { > > - unsigned int temp = 0; > > - unsigned char reg; > > - > > - reg = readb(port->membase + UARTMODEM); > > - if (reg & UARTMODEM_TXCTSE) > > - temp |= TIOCM_CTS; > > - > > - if (reg & UARTMODEM_RXRTSE) > > - temp |= TIOCM_RTS; > > - > > - return temp; > >From reading the commit log I would expect that you only touch the > set_mctrl function, but not get_mctrl. Assuming your code change is > right, can you mention this in the commit log please? The bits > UARTMODEM_TXCTSE and UARTMODEM_RXRTSE only control the automatic mode? Dumb serial writers common fault #1 is to make get_mctrl return TIOCM_RTS and/or TIOCM_DTR. It should never return these. This is a sure sign that the serial writer doesn't know what they're doing, and doesn't understand the interface they're implementing. That's a good enough reason IMHO to reject a driver prior to merging. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/