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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 <lanqing.liu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lanqing Liu 2019-02-19 15:31:11 +08:00 committed by Greg Kroah-Hartman
parent 0e585aabc5
commit 5b9cea15a3
1 changed files with 1 additions and 1 deletions
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2
drivers/tty/serial/sprd_serial.c
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@ -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) {