From: Lanqing Liu Date: Tue, 19 Feb 2019 07:31:11 +0000 (+0800) Subject: serial: sprd: Modify the baud rate calculation formula X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5b9cea15a3de5d65000d49f626b71b00d42a0577;p=linux.git serial: sprd: Modify the baud rate calculation formula 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 Signed-off-by: Baolin Wang Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c index 4287ca305b6be..1891a45ac05d0 100644 --- a/drivers/tty/serial/sprd_serial.c +++ b/drivers/tty/serial/sprd_serial.c @@ -371,7 +371,7 @@ 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) {