serial: zynq: Use DIV_ROUND_CLOSEST() to calcurate divider value

Since the calulation of "bgen" is rounded down, using a higher
baudrate will result in a larger difference from the actual
baudrate. Should use DIV_ROUND_CLOSEST() like the Linux driver.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Link: https://lore.kernel.org/r/1657676339-6055-1-git-send-email-hayashi.kunihiko@socionext.com
Signed-off-by: Michal Simek <michal.simek@amd.com>

diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c
index 83adfb5..295337a 100644 (file)
--- a/drivers/serial/serial_zynq.c
+++ b/drivers/serial/serial_zynq.c
@@ -75,7 +75,7 @@ static void _uart_zynq_serial_setbrg(struct uart_zynq *regs,
         * Find acceptable values for baud generation.
         */
        for (bdiv = 4; bdiv < 255; bdiv++) {
-               bgen = clock / (baud * (bdiv + 1));
+               bgen = DIV_ROUND_CLOSEST(clock, baud * (bdiv + 1));
                if (bgen < 2 || bgen > 65535)
                        continue;