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serial: sh-sci: Correct pin initialization on (H)SCIF
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Correct pin initialization on (H)SCIF:
  - RTS must be deasserted (it's active low),
  - SCK must be an input, as it may be used as the optional external
    clock input.

Initial pin configuration must always be done:
  - Regardless of the presence of dedicated RTS and CTS pins: if the
    register exists, the RTS/CTS bits exist, too,
  - Regardless of hardware flow control being enabled or not: RTS must
    be deasserted.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Geert Uytterhoeven authored and Greg Kroah-Hartman committed Jun 25, 2016
1 parent 4780c09 commit d2b9775
Showing 1 changed file with 8 additions and 15 deletions.
23 changes: 8 additions & 15 deletions drivers/tty/serial/sh-sci.c
Original file line number Diff line number Diff line change
Expand Up @@ -712,21 +712,14 @@ static void sci_init_pins(struct uart_port *port, unsigned int cflag)
return;
}

/*
* For the generic path SCSPTR is necessary. Bail out if that's
* unavailable, too.
*/
if (!sci_getreg(port, SCSPTR)->size)
return;

if ((s->cfg->capabilities & SCIx_HAVE_RTSCTS) &&
((!(cflag & CRTSCTS)))) {
unsigned short status;

status = serial_port_in(port, SCSPTR);
status &= ~SCSPTR_CTSIO;
status |= SCSPTR_RTSIO;
serial_port_out(port, SCSPTR, status); /* Set RTS = 1 */
if (sci_getreg(port, SCSPTR)->size) {
u16 status = serial_port_in(port, SCSPTR);

/* RTS# is output, driven 1 */
status |= SCSPTR_RTSIO | SCSPTR_RTSDT;
/* CTS# and SCK are inputs */
status &= ~(SCSPTR_CTSIO | SCSPTR_SCKIO);
serial_port_out(port, SCSPTR, status);
}
}

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