diff --git a/arch/arm/src/stm32/stm32_i2c_alt.c b/arch/arm/src/stm32/stm32_i2c_alt.c
index a39248f56d..21f6696732 100644
--- a/arch/arm/src/stm32/stm32_i2c_alt.c
+++ b/arch/arm/src/stm32/stm32_i2c_alt.c
@@ -1890,7 +1890,7 @@ static int stm32_i2c_isr_process(struct stm32_i2c_priv_s *priv)
 #ifndef CONFIG_I2C_POLLED
 static int stm32_i2c_isr(int irq, void *context, FAR void *arg)
 {
-  struct stm32_i2c_priv_s *priv = (struct stm32_i2c_priv_s )arg;
+  struct stm32_i2c_priv_s *priv = (struct stm32_i2c_priv_s *)arg;
 
   DEBUGASSERT(priv != NULL);
   return stm32_i2c_isr_process(priv);