[ARM] 4357/1: AT91: Support slower serial baud-rates

[powerpc.git] / drivers / serial / atmel_serial.c

diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 935f48f..3320bcd 100644 (file)
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -484,11 +484,16 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios * termios,
        unsigned long flags;
        unsigned int mode, imr, quot, baud;
 
+       /* Get current mode register */
+       mode = UART_GET_MR(port) & ~(ATMEL_US_USCLKS | ATMEL_US_CHRL | ATMEL_US_NBSTOP | ATMEL_US_PAR);
+
        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
        quot = uart_get_divisor(port, baud);
 
-       /* Get current mode register */
-       mode = UART_GET_MR(port) & ~(ATMEL_US_CHRL | ATMEL_US_NBSTOP | ATMEL_US_PAR);
+       if (quot > 65535) {             /* BRGR is 16-bit, so switch to slower clock */
+               quot /= 8;
+               mode |= ATMEL_US_USCLKS_MCK_DIV8;
+       }
 
        /* byte size */
        switch (termios->c_cflag & CSIZE) {