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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2017-03-20 10:05:38 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-31 17:26:19 +0200
commita6040bc610554c66088fda3608ae5d6307c548e4 (patch)
treedc48ee9e2a785b6cec21708314feaccd7d060fc9
parentc02ed2e75ef4c74e41e421acb4ef1494671585e8 (diff)
downloadlinux-a6040bc610554c66088fda3608ae5d6307c548e4.tar.bz2
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>
-rw-r--r--drivers/tty/serial/mxs-auart.c2
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);