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| author |   Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2017-03-20 10:05:38 +0100 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-03-31 17:26:19 +0200 |
| commit | a6040bc610554c66088fda3608ae5d6307c548e4 (patch) | |
| tree | dc48ee9e2a785b6cec21708314feaccd7d060fc9 /drivers/tty | |
| parent | Linux 4.11-rc4 (diff) | |
| download | linux-dev-a6040bc610554c66088fda3608ae5d6307c548e4.tar.xz linux-dev-a6040bc610554c66088fda3608ae5d6307c548e4.zip | |
serial: mxs-auart: Fix baudrate calculation
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>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -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 6989b227d134..be94246b6fcc 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -1088,7 +1088,7 @@ 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); |