[U-Boot] [PATCH 03/20] serial: stm32: Fix warnings when compiling with W=1

[Patrick Delaunay]

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 at st.com>
Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>
---

 drivers/serial/serial_stm32.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/serial/serial_stm32.c b/drivers/serial/serial_stm32.c
index cca8b70..3ab536a 100644
--- 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);
-- 
2.7.4