Hi,
On Thu, Dec 13, 2012 at 10:20:27AM +0800, Huang Shijie wrote:
> 于 2012年12月13日 00:31, Steffen Trumtrar 写道:
> > With the patch "serial: mxs-auart: fix the wrong RTS hardware flow control" the
> > mainline mxs-uart driver now sets RTSEN only when hardware flow control is
> > enabled via software. It is not possible any longer to set RTS manually via
> > software. However, the manual modification is a valid operation.
> > Regain the possibility to set RTS via software and only set RTSEN when hardware
> Is there any user case to set the RTS via software?
> I am confused at this.
there are cases where the RTS is used in a non-standard way. And the always-on
hardware flowcontrol breaks these (e.g. Echelon FT5000).
And as stated in the commit message, it is a valid operation to use software
flow control.
> > flow control is explicitly enabled via settermios cflag CRTSCTS.
> >
> > Signed-off-by: Steffen Trumtrar <s.trumtrar@xxxxxxxxxxxxxx>
> > ---
> > drivers/tty/serial/mxs-auart.c | 8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
> > index 6db23b0..9b62c4b 100644
> > --- a/drivers/tty/serial/mxs-auart.c
> > +++ b/drivers/tty/serial/mxs-auart.c
> > @@ -412,10 +412,12 @@ static void mxs_auart_set_mctrl(struct uart_port *u, unsigned mctrl)
> >
> > u32 ctrl = readl(u->membase + AUART_CTRL2);
> >
> > - ctrl &= ~AUART_CTRL2_RTSEN;
> > + ctrl &= ~(AUART_CTRL2_RTSEN | AUART_CTRL2_RTS);
> > if (mctrl & TIOCM_RTS) {
> > if (tty_port_cts_enabled(&u->state->port))
> > ctrl |= AUART_CTRL2_RTSEN;
> > + else
> > + ctrl |= AUART_CTRL2_RTS;
> > }
> >
> > s->ctrl = mctrl;
> > @@ -678,6 +680,10 @@ static void mxs_auart_settermios(struct uart_port *u,
> > }
> > ctrl2 |= AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN;
> > } else {
> > + u->flags |= ASYNC_CTS_FLOW;
> > + ctrl2 |= AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN;
> > + } else {
> > + u->flags &= ~ASYNC_CTS_FLOW;
> bug.
>
> Your code adds TWO "else" here.
>
Oops, wrong merge resolution. Will fix that.
Regards,
Steffen
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