From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH 4/4] serial: core: Mask mctrl with TIOCM_RTS too if rs485 on and RTS_AFTER_SEND set. Date: Wed, 06 Jun 2018 15:03:40 +0300 Message-ID: References: <20180606094942.71190-1-giulio.benetti@micronovasrl.com> <20180606094942.71190-3-giulio.benetti@micronovasrl.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180606094942.71190-3-giulio.benetti@micronovasrl.com> Sender: linux-kernel-owner@vger.kernel.org To: Giulio Benetti Cc: matwey.kornilov@gmail.com, Greg Kroah-Hartman , Jiri Slaby , Matthias Brugger , Kees Cook , Sean Young , "open list:SERIAL DRIVERS" , open list List-Id: linux-serial@vger.kernel.org On Wed, 2018-06-06 at 11:49 +0200, Giulio Benetti wrote: > If rs485 is enabled and RTS_AFTER_SEND is set on startup need to keep > TIOCM_RTS asserted to keep rs485 transceiver in RX when idle. > > Check if rs485 is on and RTS_AFTER_SEND is set and mask port->mctrl > with > TIOCM_RTS too and not only TIOCM_DTR. > This one feels wrong to be in serial_core.c. Perhaps in 8250/8250*.c. > Signed-off-by: Giulio Benetti > --- > drivers/tty/serial/serial_core.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/serial_core.c > b/drivers/tty/serial/serial_core.c > index 0466f9f08a91..06d9441f6d20 100644 > --- a/drivers/tty/serial/serial_core.c > +++ b/drivers/tty/serial/serial_core.c > @@ -2288,6 +2288,16 @@ uart_configure_port(struct uart_driver *drv, > struct uart_state *state, > > if (port->type != PORT_UNKNOWN) { > unsigned long flags; > + int rs485_on = port->rs485_config && > + (port->rs485.flags & SER_RS485_ENABLED); > + int RTS_after_send = !!(port->rs485.flags & > + SER_RS485_RTS_AFTER_SEND); > + int mctrl; > + > + if (rs485_on && RTS_after_send) > + mctrl = port->mctrl & (TIOCM_DTR | > TIOCM_RTS); > + else > + mctrl = port->mctrl & TIOCM_DTR; > > uart_report_port(drv, port); > > @@ -2300,7 +2310,7 @@ uart_configure_port(struct uart_driver *drv, > struct uart_state *state, > * We probably don't need a spinlock around this, but > */ > spin_lock_irqsave(&port->lock, flags); > - port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR); > + port->ops->set_mctrl(port, mctrl); > spin_unlock_irqrestore(&port->lock, flags); > > /* -- Andy Shevchenko Intel Finland Oy