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From: George Hilliard <ghilliard@kopismobile.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	kernel@pengutronix.de, devicetree@vger.kernel.org,
	NXP Linux Team <linux-imx@nxp.com>,
	linux-serial@vger.kernel.org
Subject: Re: [PATCH v2 2/2] tty: imx serial: Implement support for reversing TX and RX polarity
Date: Tue, 11 Feb 2020 10:18:12 -0600	[thread overview]
Message-ID: <CALM8J=dy2yRxJHYEhAyXwCwmubuRCGwd3W5gvGH=kYgxCgKASQ@mail.gmail.com> (raw)
In-Reply-To: <20200211073834.ndtusa7vvmvsydz4@pengutronix.de>

On Tue, Feb 11, 2020 at 1:38 AM Uwe Kleine-König
<u.kleine-koenig@pengutronix.de> wrote:
>
> Hello George,
>
> On Mon, Feb 10, 2020 at 05:03:14PM -0600, George Hilliard wrote:
> > On Mon, Feb 10, 2020 at 2:50 PM Uwe Kleine-König
> > <u.kleine-koenig@pengutronix.de> wrote:
> > > On Mon, Feb 10, 2020 at 01:29:49PM -0600, George Hilliard wrote:
> > > > @@ -1390,6 +1392,8 @@ static int imx_uart_startup(struct uart_port *port)
> > > >       ucr4 = imx_uart_readl(sport, UCR4) & ~UCR4_OREN;
> > > >       if (!sport->dma_is_enabled)
> > > >               ucr4 |= UCR4_OREN;
> > > > +     if (sport->inverted_rx)
> > > > +             ucr4 |= UCR4_INVR;
> > >
> > > You fail to clear this bit if .inverted_rx is false.
> >
> > I believe this is taken care of by the SRST asserted slightly above
> > this - UCR* is reset by this.
>
> The i.MX6 manual states: Reset the transmit and receive state machines,
> all FIFOs and register USR1, USR2, UBIR, UBMR, UBRC, URXD, UTXD and
> UTS[6-3]. UCR* isn't mentioned here. So please at least confirm your
> belief experimentally.

Oh, I see now - I misread "S" vs "C".  You are correct; I will send v3
with both changes.
Even with experimental evidence, there's no guarantee made by NXP, so
I'll handle it.

Thanks,
George

      reply	other threads:[~2020-02-11 16:18 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-10 19:29 [PATCH v2 0/2] Implement support for inverted serial TX/RX on i.MX George Hilliard
2020-02-10 19:29 ` [PATCH v2 1/2] dt-bindings: serial: document fsl,inverted-tx and -rx options George Hilliard
2020-02-10 19:29 ` [PATCH v2 2/2] tty: imx serial: Implement support for reversing TX and RX polarity George Hilliard
2020-02-10 20:50   ` Uwe Kleine-König
2020-02-10 23:03     ` George Hilliard
2020-02-11  7:38       ` Uwe Kleine-König
2020-02-11 16:18         ` George Hilliard [this message]

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