From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steffen Trumtrar Subject: Re: [PATCH v2] mxs: uart: allow setting RTS from software Date: Thu, 13 Dec 2012 14:19:12 +0100 Message-ID: <20121213131912.GB27832@pengutronix.de> References: <1355388135-3676-1-git-send-email-s.trumtrar@pengutronix.de> <50C9ABB4.8010900@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from metis.ext.pengutronix.de ([92.198.50.35]:52220 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751597Ab2LMNTO (ORCPT ); Thu, 13 Dec 2012 08:19:14 -0500 Content-Disposition: inline In-Reply-To: <50C9ABB4.8010900@freescale.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Huang Shijie Cc: linux-serial@vger.kernel.org, stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Alan Cox On Thu, Dec 13, 2012 at 06:19:32PM +0800, Huang Shijie wrote: > =E4=BA=8E 2012=E5=B9=B412=E6=9C=8813=E6=97=A5 16:42, Steffen Trumtrar= =E5=86=99=E9=81=93: > > With the patch "serial: mxs-auart: fix the wrong RTS hardware flow = control" the > > mainline mxs-uart driver now sets RTSEN only when hardware flow con= trol is > > enabled via software. It is not possible any longer to set RTS manu= ally via > > software. However, the manual modification is a valid operation. > > Regain the possibility to set RTS via software and only set RTSEN w= hen hardware > > flow control is explicitly enabled via settermios cflag CRTSCTS. > > > > Signed-off-by: Steffen Trumtrar > > --- > > drivers/tty/serial/mxs-auart.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mx= s-auart.c > > index 6db23b0..21d9b12 100644 > > --- a/drivers/tty/serial/mxs-auart.c > > +++ b/drivers/tty/serial/mxs-auart.c > > @@ -412,10 +412,12 @@ static void mxs_auart_set_mctrl(struct uart_p= ort *u, unsigned mctrl) > > =20 > > u32 ctrl =3D readl(u->membase + AUART_CTRL2); > > =20 > > - ctrl &=3D ~AUART_CTRL2_RTSEN; > > + ctrl &=3D ~(AUART_CTRL2_RTSEN | AUART_CTRL2_RTS); > > if (mctrl & TIOCM_RTS) { > > if (tty_port_cts_enabled(&u->state->port)) > > ctrl |=3D AUART_CTRL2_RTSEN; > > + else > > + ctrl |=3D AUART_CTRL2_RTS; > > } > > =20 > > s->ctrl =3D mctrl; > > @@ -676,8 +678,10 @@ static void mxs_auart_settermios(struct uart_p= ort *u, > > ctrl2 |=3D AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE > > | AUART_CTRL2_DMAONERR; > > } > > + u->flags |=3D ASYNC_CTS_FLOW; > > ctrl2 |=3D AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN; > > } else { > > + u->flags &=3D ~ASYNC_CTS_FLOW; > I think these two lines is not needed. > uart_change_speed() has set/unset ASYNC_CTS_FLOW for us. I don't know that much of the inner workings of the serial framework, b= ut it seems like it is guaranteed, that uart_change_speed is called before th= e mxs_auart_settermios. And therefore you are right and the two lines can= be dropped. Regards, Steffen --=20 Pengutronix e.K. | = | Industrial Linux Solutions | http://www.pengutronix.de/= | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 = | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-555= 5 | -- To unsubscribe from this list: send the line "unsubscribe linux-serial"= in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html