From: Fabio Estevam <festevam@gmail.com>
To: Clemens Gruber <clemens.gruber@pqgruber.com>
Cc: "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Nandor Han" <nandor.han@ge.com>,
"Lucas Stach" <l.stach@pengutronix.de>,
"Fabio Estevam" <fabio.estevam@freescale.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: imx: RS-485 problems during TX, maybe DMA related
Date: Fri, 6 Jan 2017 19:22:32 -0200 [thread overview]
Message-ID: <CAOMZO5C3enuThR1DpcwNnqFdxd8tGoBwd76O62Gnviz8x1_a9w@mail.gmail.com> (raw)
In-Reply-To: <20170104160024.GA13442@archie.localdomain>
Hi Clemens,
On Wed, Jan 4, 2017 at 2:00 PM, Clemens Gruber
<clemens.gruber@pqgruber.com> wrote:
> Hi,
>
> I observed odd behavior of the current tty/serial/imx.c driver in RS-485
> mode.
>
> RX works fine, but TX does not: When sending data, it arrives multiple
I am also trying to get rs485 in half-duplex mode to work on mx6dl
with kernel 4.9.
RX also works for me, but TX does not.
On my board it is the MX6QDL_PAD_CSI0_DAT16__UART4_RTS_B pin that
controls the rs485 transceiver flow, but I do not
see RTS to toggle to 1 during transmit. It stays always at 0.
I see you use CTS pin instead, but I thought RTS pin should be used.
On my userspace application I have:
/* enable RS485 mode: */
rs485conf.flags |= SER_RS485_ENABLED;
/* set logical level for RTS pin equal to 1 when sending: */
rs485conf.flags |= SER_RS485_RTS_ON_SEND;
/* set logical level for RTS pin equal to 0 after sending: */
rs485conf.flags &= ~(SER_RS485_RTS_AFTER_SEND);
Any ideas as to how to make RTS go to one so that the data can go
through the rs485 transceiver?
Thanks
next prev parent reply other threads:[~2017-01-06 21:22 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-04 16:00 imx: RS-485 problems during TX, maybe DMA related Clemens Gruber
2017-01-06 21:22 ` Fabio Estevam [this message]
2017-01-06 22:50 ` Clemens Gruber
2017-01-07 0:31 ` Fabio Estevam
2017-01-07 13:45 ` Clemens Gruber
2017-01-07 14:57 ` Fabio Estevam
2017-01-07 15:34 ` Clemens Gruber
2017-01-07 16:48 ` Fabio Estevam
2017-01-07 20:59 ` Clemens Gruber
2017-01-07 21:43 ` Fabio Estevam
2017-01-07 23:06 ` Clemens Gruber
2017-01-08 2:30 ` Fabio Estevam
2017-01-08 18:06 ` Clemens Gruber
2017-01-08 21:46 ` Fabio Estevam
2017-01-11 0:33 ` Clemens Gruber
2017-01-11 11:51 ` Fabio Estevam
2017-01-08 15:12 ` Fabio Estevam
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