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authorHugo Villeneuve <hugo.villeneuve@lyrtech.com>2008-07-08 14:54:58 -0400
committerWolfgang Denk <wd@denx.de>2008-07-10 00:48:31 +0200
commit89134ea1f67208fd3160bdbb0b9eaab4eab98484 (patch)
treec4366e03007cb41a64f62e709a4d7511adaae082 /drivers/serial
parent2b1fa9d383cbbb7d347c1583bd6ca4e181ba8e9e (diff)
Round the serial port clock divisor value returned by calc_divisor()
Round the serial port clock divisor value returned by calc_divisor(). Signed-off-by: Hugo Villeneuve <hugo.villeneuve@lyrtech.com> Signed-off-by: John Roberts <john.roberts@pwav.com>
Diffstat (limited to 'drivers/serial')
-rw-r--r--drivers/serial/serial.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
index 76425d8790..182ca2d149 100644
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -144,8 +144,13 @@ static int calc_divisor (NS16550_t port)
#else
#define MODE_X_DIV 16
#endif
- return (CFG_NS16550_CLK / MODE_X_DIV / gd->baudrate);
+ /* Compute divisor value. Normally, we should simply return:
+ * CFG_NS16550_CLK) / MODE_X_DIV / gd->baudrate
+ * but we need to round that value by adding 0.5 or 8/16.
+ * Rounding is especially important at high baud rates.
+ */
+ return (((16 * CFG_NS16550_CLK) / MODE_X_DIV / gd->baudrate) + 8) / 16;
}
#if !defined(CONFIG_SERIAL_MULTI)