serial: mxs-auart: fix baud rate range

commit df57cf6a879502cd6e5559c1f2d6db12128e074f upstream.

Currently mxs-auart doesn't care correctly about the baud rate divisor.
According to reference manual the baud rate divisor must be between
0x000000EC and 0x003FFFC0. So calculate the possible baud rate range
and use it for uart_get_baud_rate().

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index ab7d11e..4f224e8 100644 (file)
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -76,6 +76,8 @@
 #define AUART_CTRL2_TXE                                (1 << 8)
 #define AUART_CTRL2_UARTEN                     (1 << 0)
 
+#define AUART_LINECTRL_BAUD_DIV_MAX            0x003fffc0
+#define AUART_LINECTRL_BAUD_DIV_MIN            0x000000ec
 #define AUART_LINECTRL_BAUD_DIVINT_SHIFT       16
 #define AUART_LINECTRL_BAUD_DIVINT_MASK                0xffff0000
 #define AUART_LINECTRL_BAUD_DIVINT(v)          (((v) & 0xffff) << 16)
@@ -285,7 +287,7 @@ static void mxs_auart_settermios(struct uart_port *u,
                                 struct ktermios *old)
 {
        u32 bm, ctrl, ctrl2, div;
-       unsigned int cflag, baud;
+       unsigned int cflag, baud, baud_min, baud_max;
 
        cflag = termios->c_cflag;
 
@@ -361,7 +363,9 @@ static void mxs_auart_settermios(struct uart_port *u,
                ctrl2 &= ~AUART_CTRL2_CTSEN;
 
        /* set baud rate */
-       baud = uart_get_baud_rate(u, termios, old, 0, u->uartclk);
+       baud_min = DIV_ROUND_UP(u->uartclk * 32, AUART_LINECTRL_BAUD_DIV_MAX);
+       baud_max = u->uartclk * 32 / AUART_LINECTRL_BAUD_DIV_MIN;
+       baud = uart_get_baud_rate(u, termios, old, baud_min, baud_max);
        div = u->uartclk * 32 / baud;
        ctrl |= AUART_LINECTRL_BAUD_DIVFRAC(div & 0x3F);
        ctrl |= AUART_LINECTRL_BAUD_DIVINT(div >> 6);