From: Lanqing Liu lanqing.liu@unisoc.com
[Upstream commit 5b9cea15a3de5d65000d49f626b71b00d42a0577]
When the source clock is not divisible by the expected baud rate and the remainder is not less than half of the expected baud rate, the old formular will round up the frequency division coefficient. This will make the actual baud rate less than the expected value and can not meet the external transmission requirements.
Thus this patch modifies the baud rate calculation formula to support the serial controller output the maximum baud rate.
Signed-off-by: Lanqing Liu lanqing.liu@unisoc.com Signed-off-by: Baolin Wang baolin.wang@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Baolin Wang baolin.wang@linaro.org --- drivers/tty/serial/sprd_serial.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c index e902494..72e96ab8 100644 --- a/drivers/tty/serial/sprd_serial.c +++ b/drivers/tty/serial/sprd_serial.c @@ -380,7 +380,7 @@ static void sprd_set_termios(struct uart_port *port, /* ask the core to calculate the divisor for us */ baud = uart_get_baud_rate(port, termios, old, 0, SPRD_BAUD_IO_LIMIT);
- quot = (unsigned int)((port->uartclk + baud / 2) / baud); + quot = port->uartclk / baud;
/* set data length */ switch (termios->c_cflag & CSIZE) {