[PATCH v3 08/11] serial: sh-sci: Correct pin initialization on (H)SCIF

From: Geert Uytterhoeven
Date: Fri Jun 03 2016 - 06:00:28 EST


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@xxxxxxxxx>
---
v3:
- No changes,

v2:
- New.
---
drivers/tty/serial/sh-sci.c | 23 ++++++++---------------
1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index ce7bd165929ea078..c46999f20917964e 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -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);
}
}

--
1.9.1