serial: Add define for max baud rate divisor

Add a define for the maximum baud rate divisor, to improve code
readability.

Signed-off-by: Ed Blake <ed.blake@sondrel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index fb45770..fef9823 100644 (file)
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -61,7 +61,7 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
         * registers to their default values.
         */
        baud = uart_get_baud_rate(port, termios, old,
-                                 port->uartclk / 16 / 0xffff,
+                                 port->uartclk / 16 / UART_DIV_MAX,
                                  port->uartclk);
 
        if (baud <= 115200) {

diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index 833771b..4938d33 100644 (file)
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -199,7 +199,7 @@ static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud,
         * Old custom speed handling.
         */
        if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) {
-               priv->quot = port->custom_divisor & 0xffff;
+               priv->quot = port->custom_divisor & UART_DIV_MAX;
                /*
                 * I assume that nobody is using this. But hey, if somebody
                 * would like to specify the divisor _and_ the mode then the
@@ -358,7 +358,7 @@ static void omap_8250_set_termios(struct uart_port *port,
         * Ask the core to calculate the divisor for us.
         */
        baud = uart_get_baud_rate(port, termios, old,
-                                 port->uartclk / 16 / 0xffff,
+                                 port->uartclk / 16 / UART_DIV_MAX,
                                  port->uartclk / 13);
        omap_8250_get_divisor(port, baud, priv);
 

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index f0cc04f..01ab218 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2601,7 +2601,7 @@ static unsigned int serial8250_get_baud_rate(struct uart_port *port,
         * causing transmission errors.
         */
        return uart_get_baud_rate(port, termios, old,
-                                 port->uartclk / 16 / 0xffff,
+                                 port->uartclk / 16 / UART_DIV_MAX,
                                  port->uartclk);
 }
 

diff --git a/include/uapi/linux/serial_reg.h b/include/uapi/linux/serial_reg.h
index 5db7688..dea0572 100644 (file)
--- a/include/uapi/linux/serial_reg.h
+++ b/include/uapi/linux/serial_reg.h
@@ -157,6 +157,7 @@
  */
 #define UART_DLL       0       /* Out: Divisor Latch Low */
 #define UART_DLM       1       /* Out: Divisor Latch High */
+#define UART_DIV_MAX   0xFFFF  /* Max divisor value */
 
 /*
  * LCR=0xBF (or DLAB=1 for 16C660)