On Thu, Dec 13, 2012 at 06:19:32PM +0800, Huang Shijie wrote: > 于 2012年12月13日 16:42, 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 > > flow control is explicitly enabled via settermios cflag CRTSCTS. > > > > Signed-off-by: Steffen Trumtrar <[email protected]> > > --- > > drivers/tty/serial/mxs-auart.c | 6 +++++- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c > > index 6db23b0..21d9b12 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; > > @@ -676,8 +678,10 @@ static void mxs_auart_settermios(struct uart_port *u, > > ctrl2 |= AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE > > | AUART_CTRL2_DMAONERR; > > } > > + u->flags |= ASYNC_CTS_FLOW; > > ctrl2 |= AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN; > > } else { > > + u->flags &= ~ASYNC_CTS_FLOW; > I think these two lines is not needed. > uart_change_speed() has set/unset ASYNC_CTS_FLOW for us.
I don't know that much of the inner workings of the serial framework, but it seems like it is guaranteed, that uart_change_speed is called before the mxs_auart_settermios. And therefore you are right and the two lines can be dropped. Regards, Steffen -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
