From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752144AbcLFMvg (ORCPT ); Tue, 6 Dec 2016 07:51:36 -0500 Received: from mail-wj0-f174.google.com ([209.85.210.174]:36632 "EHLO mail-wj0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751592AbcLFMve (ORCPT ); Tue, 6 Dec 2016 07:51:34 -0500 Date: Tue, 6 Dec 2016 12:45:43 +0000 From: Lee Jones To: Peter Griffin Cc: Patrice Chotard , gregkh@linuxfoundation.org, jslaby@suse.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel@stlinux.com Subject: Re: [STLinux Kernel] [PATCH 2/3] serial: st-asc: Provide RTS functionality Message-ID: <20161206124543.GC25385@dell.home> References: <20161202141146.31281-1-lee.jones@linaro.org> <20161202141146.31281-2-lee.jones@linaro.org> <5e652529-8dcb-568e-a748-0ec745099211@st.com> <20161206123131.GA15382@griffinp-ThinkPad-X1-Carbon-2nd> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20161206123131.GA15382@griffinp-ThinkPad-X1-Carbon-2nd> User-Agent: Mutt/1.6.2 (2016-07-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 06 Dec 2016, Peter Griffin wrote: > On Mon, 05 Dec 2016, Patrice Chotard wrote: > > On 12/02/2016 03:11 PM, Lee Jones wrote: > > > Until this point, it has not been possible for serial applications > > > to toggle the UART RTS line. This can be useful with certain > > > configurations. For example, when using a Mezzanine on a Linaro > > > 96board, RTS line is used to take the the on-board microcontroller > > > > typo "the the on" > > > > > in and out of reset. > > > > > > Signed-off-by: Lee Jones > > > --- > > > drivers/tty/serial/st-asc.c | 14 ++++++++++++++ > > > 1 file changed, 14 insertions(+) > > > > > > diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c > > > index 379e5bd..ce46898 100644 > > > --- a/drivers/tty/serial/st-asc.c > > > +++ b/drivers/tty/serial/st-asc.c > > > @@ -30,6 +30,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > > > > #define DRIVER_NAME "st-asc" > > > #define ASC_SERIAL_NAME "ttyAS" > > > @@ -38,6 +39,7 @@ > > > > > > struct asc_port { > > > struct uart_port port; > > > + struct gpio_desc *rts; > > > struct clk *clk; > > > unsigned int hw_flow_control:1; > > > unsigned int force_m1:1; > > > @@ -381,12 +383,16 @@ static unsigned int asc_tx_empty(struct uart_port *port) > > > > > > static void asc_set_mctrl(struct uart_port *port, unsigned int mctrl) > > > { > > > + struct asc_port *ascport = to_asc_port(port); > > > + > > > /* > > > * This routine is used for seting signals of: DTR, DCD, CTS/RTS > > > * We use ASC's hardware for CTS/RTS, so don't need any for that. > > > * Some boards have DTR and DCD implemented using PIO pins, > > > * code to do this should be hooked in here. > > > */ > > > + > > > + gpiod_set_value(ascport->rts, mctrl & TIOCM_RTS); > > This now puts the code and the comment above out of sync with each > other. > > However just checking the stih410 datasheet and I don't think this patch > to control RTS via a GPIO is required anyway. > > The correct way of handling this is to add UART10_RTS and UART10_CTS pins > to the pinctrl_serial0 group so they are properly configured for their cts/rts > alternate function. Once the pins are correctly configured, the IP block should > control the signals correctly like the comment says. That was the first thing I tried. It didn't work. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog