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serial: sh-sci: Don't overwrite clock selection in serial_console_write()

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Blindly writing the default configuration value into the SCSCR register
may change the clock selection bits, breaking the serial console if the
current driver settings differ from the default settings.

Keep the current clock selection bits to prevent this from happening
on e.g. r8a7791/koelsch when support for the BRG will be added.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Geert Uytterhoeven 2015-11-18 16:20:44 +01:00
parent bdcb382697
commit a67969b5fd
1 changed files with 5 additions and 3 deletions
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8
drivers/tty/serial/sh-sci.c
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@ -2420,7 +2420,7 @@ static void serial_console_write(struct console *co, const char *s,
{
struct sci_port *sci_port = &sci_ports[co->index];
struct uart_port *port = &sci_port->port;
unsigned short bits, ctrl;
unsigned short bits, ctrl, ctrl_temp;
unsigned long flags;
int locked = 1;
@ -2432,9 +2432,11 @@ static void serial_console_write(struct console *co, const char *s,
else
spin_lock(&port->lock);
/* first save the SCSCR then disable the interrupts */
/* first save SCSCR then disable interrupts, keep clock source */
ctrl = serial_port_in(port, SCSCR);
serial_port_out(port, SCSCR, sci_port->cfg->scscr);
ctrl_temp = (sci_port->cfg->scscr & ~(SCSCR_CKE1 | SCSCR_CKE0)) |
(ctrl & (SCSCR_CKE1 | SCSCR_CKE0));
serial_port_out(port, SCSCR, ctrl_temp);
uart_console_write(port, s, count, serial_console_putchar);