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Re: imx: RS-485 problems during TX, maybe DMA related

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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

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Thread

imx: RS-485 problems during TX, maybe DMA related Clemens Gruber <clemens.gruber@pqgruber.com> - 2017-01-04 17:20 +0100
  Re: imx: RS-485 problems during TX, maybe DMA related Fabio Estevam <festevam@gmail.com> - 2017-01-06 22:30 +0100
    Re: imx: RS-485 problems during TX, maybe DMA related Clemens Gruber <clemens.gruber@pqgruber.com> - 2017-01-07 00:00 +0100
      Re: imx: RS-485 problems during TX, maybe DMA related Fabio Estevam <festevam@gmail.com> - 2017-01-07 01:40 +0100
        Re: imx: RS-485 problems during TX, maybe DMA related Clemens Gruber <clemens.gruber@pqgruber.com> - 2017-01-07 14:50 +0100
          Re: imx: RS-485 problems during TX, maybe DMA related Fabio Estevam <festevam@gmail.com> - 2017-01-07 16:00 +0100
            Re: imx: RS-485 problems during TX, maybe DMA related Clemens Gruber <clemens.gruber@pqgruber.com> - 2017-01-07 16:40 +0100
              Re: imx: RS-485 problems during TX, maybe DMA related Fabio Estevam <festevam@gmail.com> - 2017-01-07 17:50 +0100
                Re: imx: RS-485 problems during TX, maybe DMA related Clemens Gruber <clemens.gruber@pqgruber.com> - 2017-01-07 22:00 +0100
                Re: imx: RS-485 problems during TX, maybe DMA related Fabio Estevam <festevam@gmail.com> - 2017-01-07 22:50 +0100
                Re: imx: RS-485 problems during TX, maybe DMA related Clemens Gruber <clemens.gruber@pqgruber.com> - 2017-01-08 00:10 +0100
                Re: imx: RS-485 problems during TX, maybe DMA related Fabio Estevam <festevam@gmail.com> - 2017-01-08 03:40 +0100
                Re: imx: RS-485 problems during TX, maybe DMA related Clemens Gruber <clemens.gruber@pqgruber.com> - 2017-01-08 19:10 +0100
                Re: imx: RS-485 problems during TX, maybe DMA related Fabio Estevam <festevam@gmail.com> - 2017-01-08 22:50 +0100
                Re: imx: RS-485 problems during TX, maybe DMA related Clemens Gruber <clemens.gruber@pqgruber.com> - 2017-01-11 01:40 +0100
                Re: imx: RS-485 problems during TX, maybe DMA related Fabio Estevam <festevam@gmail.com> - 2017-01-11 13:00 +0100
                Re: imx: RS-485 problems during TX, maybe DMA related Fabio Estevam <festevam@gmail.com> - 2017-01-08 16:20 +0100

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