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Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs

From Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Newsgroups linux.kernel
Subject Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs
Date 2016-09-30 11:20 +0200
Message-ID <sn294-8iN-7@gated-at.bofh.it> (permalink)
References <sn1PN-7WT-13@gated-at.bofh.it> <sn1PN-7WT-19@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Hello Richard,

On Fri, Sep 30, 2016 at 10:58:00AM +0200, Richard Genoud wrote:
> Commit 1cf6e8fc8341 ("tty/serial: at91: fix RTS line management when
> hardware handshake is enabled") broke the hardware handshake when GPIOs
> were used.
> 
> Hardware handshake with GPIOs used to work before this commit because
> the CRTSCTS flag (termios->c_cflag) was set, but not the
> ATMEL_US_USMODE_HWHS flag (controller register) ; so hardware handshake
> enabled, but not handled by the controller.

What does the HWHS flag control? What if only RTS is a gpio and CTS is
not? Or the other way round?

What is the problematic setup? I guess it's RTS and CTS are gpios and
with that setting ATMEL_US_USMODE_HWHS is wrong? What happens if that
happens?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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Thread

[PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs Richard Genoud <richard.genoud@gmail.com> - 2016-09-30 11:00 +0200
  Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs Uwe Kleine-König          <u.kleine-koenig@pengutronix.de> - 2016-09-30 11:20 +0200
    Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs Richard Genoud <richard.genoud@gmail.com> - 2016-09-30 13:10 +0200
      Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2016-09-30 13:20 +0200
        Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs Richard Genoud <richard.genoud@gmail.com> - 2016-09-30 13:50 +0200
          Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2016-09-30 14:00 +0200
            Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs Richard Genoud <richard.genoud@gmail.com> - 2016-09-30 14:30 +0200
      Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with GPIOs Uwe Kleine-König          <u.kleine-koenig@pengutronix.de> - 2016-10-04 09:30 +0200
        Re: [PATCHv4 2/3] tty/serial: at91: fix hardware handshake with  GPIOs Richard Genoud <richard.genoud@gmail.com> - 2016-10-07 17:30 +0200

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