diff options
| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2017-03-20 10:05:38 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-08 09:30:34 +0200 |
| commit | 5289f1ce39a798e46f31db8efc2e3f99eebf73df (patch) | |
| tree | 35f6a19f7f9fc33482949c0128aa6029aa37b832 | |
| parent | 67e41b1368b146ff6508a4efe5552400412d2f32 (diff) | |
serial: mxs-auart: Fix baudrate calculation
commit a6040bc610554c66088fda3608ae5d6307c548e4 upstream.
The reference manual for the i.MX28 recommends to calculate the divisor
as
divisor = (UARTCLK * 32) / baud rate, rounded to the nearest integer
, so let's do this. For a typical setup of UARTCLK = 24 MHz and baud
rate = 115200 this changes the divisor from 6666 to 6667 and so the
actual baud rate improves from 115211.521 Bd (error ≅ 0.01 %) to
115194.240 Bd (error ≅ 0.005 %).
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/mxs-auart.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index 770454e0dfa3..07390f8c3681 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -1085,7 +1085,7 @@ static void mxs_auart_settermios(struct uart_port *u, AUART_LINECTRL_BAUD_DIV_MAX); baud_max = u->uartclk * 32 / AUART_LINECTRL_BAUD_DIV_MIN; baud = uart_get_baud_rate(u, termios, old, baud_min, baud_max); - div = u->uartclk * 32 / baud; + div = DIV_ROUND_CLOSEST(u->uartclk * 32, baud); } ctrl |= AUART_LINECTRL_BAUD_DIVFRAC(div & 0x3F); |