From: Clemens Gruber <clemens.gruber@pqgruber.com>
To: Fabio Estevam <festevam@gmail.com>
Cc: 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-kernel@vger.kernel.org
Subject: Re: imx: RS-485 problems during TX, maybe DMA related
Date: Sat, 7 Jan 2017 14:45:57 +0100 [thread overview]
Message-ID: <20170107134557.GA12299@archie.localdomain> (raw)
In-Reply-To: <CAOMZO5CywajwZEL8K2ATfS80WzqY69YVX+3S7hq9_HmNdNAwaw@mail.gmail.com>
Hi Fabio,
On Fri, Jan 06, 2017 at 10:31:16PM -0200, Fabio Estevam wrote:
> Yes, I have tried like this:
>
> &uart4 {
> pinctrl-names = "default";
> pinctrl-0 = <&pinctrl_uart4>;
> uart-has-rtscts;
> status = "okay";
> };
>
> pinctrl_uart4: uart4grp {
> fsl,pins = <
> MX6QDL_PAD_CSI0_DAT12__UART4_TX_DATA 0x1b0b1
> MX6QDL_PAD_KEY_ROW0__UART4_RX_DATA 0x1b0b1
> MX6QDL_PAD_CSI0_DAT16__UART4_CTS_B 0x1b0b1
> >;
> };
I also mux RTS_B even though it is unused, not sure if it this makes a
difference to also add MX6QDL_PAD_CSI0_DAT17_UART4_RTS_B in your case?
It should work like this, I don't think using an extra GPIO is
necessary.
>
> So I was never able to observe the DE pin toggling correctly.
But did you set SER_RS485_RX_DURING_TX in your flags? This is counter
intuitive, but I observed that it would not work otherwise.
> Maybe you could share your userspace application with me offline?
I am using a patched version of the busybox stty utility, I posted the
patch here, feel free to use it:
https://gist.github.com/clemensg/29bd68b3cfd719bd01002a2acde9662c
I use stty -F /dev/ttymxc4 clocal cread -hupcl -ixon -opost rs485
-rs485rtsonsend rs485rtsaftersend rs485rxduringtx
But for you it is probably rs485rtsonsend and -rs485rtsaftersend?
Regards,
Clemens
next prev parent reply other threads:[~2017-01-07 13:46 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
2017-01-06 22:50 ` Clemens Gruber
2017-01-07 0:31 ` Fabio Estevam
2017-01-07 13:45 ` Clemens Gruber [this message]
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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