[U-Boot-Users] [PATCH] Round the serial port clock divisor value returned by calc_divisor()

[Hugo Villeneuve]

Round the serial port clock divisor value returned by
calc_divisor().

Signed-off-by: Hugo Villeneuve <hugo.villeneuve at lyrtech.com>

---

Rounding is important, especially when using high baud rates
values like 115200bps. When using the non-rounded value, some
boards will work and some won't.

 drivers/serial/serial.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
index 76425d8..7e315ad 100644
--- a/drivers/serial/serial.c
+++ b/drivers/serial/serial.c
@@ -124,6 +124,8 @@ static NS16550_t serial_ports[4] = {
 
 static int calc_divisor (NS16550_t port)
 {
+	u32 divisor_x10;
+
 #ifdef CONFIG_OMAP1510
 	/* If can't cleanly clock 115200 set div to 1 */
 	if ((CFG_NS16550_CLK == 12000000) && (gd->baudrate == 115200)) {
@@ -144,8 +146,11 @@ 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 with rounding by adding 0.5 */
+	divisor_x10 = (10 * CFG_NS16550_CLK) / MODE_X_DIV / gd->baudrate;
+
+	return (divisor_x10 + 5) / 10;
 }
 
 #if !defined(CONFIG_SERIAL_MULTI)