serial: stm32: Fix warnings when compiling with W=1

This patch solves the following warnings:

drivers/serial/serial_stm32.c: In function 'stm32_serial_probe':
warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
  if (plat->clock_rate < 0) {
                       ^

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>

diff --git a/drivers/serial/serial_stm32.c b/drivers/serial/serial_stm32.c
index cca8b707acc42c8d3d10486a4a359940cdbba290..3ab536a52ac032c270b3d341c1ca2554d1ecbe8d 100644 (file)
--- a/drivers/serial/serial_stm32.c
+++ b/drivers/serial/serial_stm32.c
@@ -195,9 +195,9 @@ static int stm32_serial_probe(struct udevice *dev)
        }
 
        plat->clock_rate = clk_get_rate(&clk);
-       if (plat->clock_rate < 0) {
+       if (!plat->clock_rate) {
                clk_disable(&clk);
-               return plat->clock_rate;
+               return -EINVAL;
        };
 
        _stm32_serial_init(plat->base, plat->uart_info);