| Message ID | 1355329913-27666-1-git-send-email-s.trumtrar@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
? 2012?12?13? 00:31, Steffen Trumtrar ??: > 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. > flow control is explicitly enabled via settermios cflag CRTSCTS. > > Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de> > --- > 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. thanks Huang Shijie > ctrl2 &= ~(AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN); > } >
Hi, On Thu, Dec 13, 2012 at 10:20:27AM +0800, Huang Shijie wrote: > ? 2012?12?13? 00:31, Steffen Trumtrar ??: > > 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@pengutronix.de> > > --- > > 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
On Wed, Dec 12, 2012 at 05:31:53PM +0100, Steffen Trumtrar wrote: > 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 <s.trumtrar@pengutronix.de> [...] This is not the correct way to submit a patch to stable. See Documentation/stable_kernel_rules.txt Ben.
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; ctrl2 &= ~(AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN); }
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 <s.trumtrar@pengutronix.de> --- drivers/tty/serial/mxs-auart.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)