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Commit cfa6eb23 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Greg Kroah-Hartman
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serial: sh-sci: Fix (AUTO)RTS in sci_init_pins() 



If a UART has dedicated RTS/CTS pins, and hardware control flow is
disabled (or AUTORTS is not yet effective), changing any serial port
configuration deasserts RTS, as .set_termios() calls sci_init_pins().

To fix this, consider the current (AUTO)RTS state when (re)initializing
the pins.  Note that for SCIFA/SCIFB, AUTORTS needs explicit
configuration of the RTS# pin function, while (H)SCIF handles this
automatically.

Fixes: d2b9775d ("serial: sh-sci: Correct pin initialization on (H)SCIF")
Fixes: e9d7a45a ("serial: sh-sci: Add pin initialization for SCIFA/SCIFB")
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5f76895e

drivers/tty/serial/sh-sci.c

+19 −6
Original line number Diff line number Diff line
@@ -683,24 +683,37 @@ static void sci_init_pins(struct uart_port *port, unsigned int cflag) 
	}



	if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {

		u16 data = serial_port_in(port, SCPDR);

		u16 ctrl = serial_port_in(port, SCPCR);



		/* Enable RXD and TXD pin functions */

		ctrl &= ~(SCPCR_RXDC | SCPCR_TXDC);

		if (to_sci_port(port)->has_rtscts) {

			/* RTS# is output, driven 1 */

			/* RTS# is output, active low, unless autorts */

			if (!(port->mctrl & TIOCM_RTS)) {

				ctrl |= SCPCR_RTSC;

				data |= SCPDR_RTSD;

			} else if (!s->autorts) {

				ctrl |= SCPCR_RTSC;

			serial_port_out(port, SCPDR,

				serial_port_in(port, SCPDR) | SCPDR_RTSD);

				data &= ~SCPDR_RTSD;

			} else {

				/* Enable RTS# pin function */

				ctrl &= ~SCPCR_RTSC;

			}

			/* Enable CTS# pin function */

			ctrl &= ~SCPCR_CTSC;

		}

		serial_port_out(port, SCPDR, data);

		serial_port_out(port, SCPCR, ctrl);

	} else if (sci_getreg(port, SCSPTR)->size) {

		u16 status = serial_port_in(port, SCSPTR);



		/* RTS# is output, driven 1 */

		status |= SCSPTR_RTSIO | SCSPTR_RTSDT;

		/* RTS# is always output; and active low, unless autorts */

		status |= SCSPTR_RTSIO;

		if (!(port->mctrl & TIOCM_RTS))

			status |= SCSPTR_RTSDT;

		else if (!s->autorts)

			status &= ~SCSPTR_RTSDT;

		/* CTS# and SCK are inputs */

		status &= ~(SCSPTR_CTSIO | SCSPTR_SCKIO);

		serial_port_out(port, SCSPTR, status);