From 9d482cc353bd0391730730b26e4c2938dc90e477 Mon Sep 17 00:00:00 2001 From: Takashi Yoshii Date: Fri, 16 Nov 2012 10:52:49 +0900 Subject: [PATCH] serial: sh-sci: support lower baud rate Support prescaler 1/16 and 1/64, in addition to current 1 and 1/4. Supporting below 2400bps was dropped long time ago in mainline. Since then, setting lower rate has been resulting in erroneous register value, without indicating any errors through API. This patch adds more prescaler to support lower rates again. This still doesn't check range, but we won't hit the case because even 50bps at 48MHz clock is now supported. Signed-off-by: Takashi Yoshii Signed-off-by: Shinya Kuribayashi Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sh-sci.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 6c1fddb..a54c47d 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1815,7 +1815,7 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, { struct sci_port *s = to_sci_port(port); struct plat_sci_reg *reg; - unsigned int baud, smr_val, max_baud; + unsigned int baud, smr_val, max_baud, cks; int t = -1; /* @@ -1849,21 +1849,18 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, uart_update_timeout(port, termios->c_cflag, baud); - serial_port_out(port, SCSMR, smr_val); + for (cks = 0; t >= 256 && cks <= 3; cks++) + t >>= 2; - dev_dbg(port->dev, "%s: SMR %x, t %x, SCSCR %x\n", __func__, smr_val, t, - s->cfg->scscr); + dev_dbg(port->dev, "%s: SMR %x, cks %x, t %x, SCSCR %x\n", + __func__, smr_val, cks, t, s->cfg->scscr); if (t >= 0) { - if (t >= 256) { - serial_port_out(port, SCSMR, (serial_port_in(port, SCSMR) & ~3) | 1); - t >>= 2; - } else - serial_port_out(port, SCSMR, serial_port_in(port, SCSMR) & ~3); - + serial_port_out(port, SCSMR, (smr_val & ~3) | cks); serial_port_out(port, SCBRR, t); udelay((1000000+(baud-1)) / baud); /* Wait one bit interval */ - } + } else + serial_port_out(port, SCSMR, smr_val); sci_init_pins(port, termios->c_cflag); -- 2.7.4