dm: serial: Move baud rate calculation to ns16550.c

Move the function that calculates the baud rate divisor into ns16550.c so
it can be used by that file.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/ns16550.h b/include/ns16550.h
index d1f3a906c09..d93e28e3eca 100644
--- a/include/ns16550.h
+++ b/include/ns16550.h
@@ -170,3 +170,16 @@ void NS16550_putc(NS16550_t com_port, char c);
 char NS16550_getc(NS16550_t com_port);
 int NS16550_tstc(NS16550_t com_port);
 void NS16550_reinit(NS16550_t com_port, int baud_divisor);
+
+/**
+ * ns16550_calc_divisor() - calculate the divisor given clock and baud rate
+ *
+ * Given the UART input clock and required baudrate, calculate the divisor
+ * that should be used.
+ *
+ * @port:	UART port
+ * @clock:	UART input clock speed in Hz
+ * @baudrate:	Required baud rate
+ * @return baud rate divisor that should be used
+ */
+int ns16550_calc_divisor(NS16550_t port, int clock, int baudrate);