diff --git a/drivers/lcd/ssd1289_lld.c b/drivers/lcd/ssd1289_lld.c
index d1d34310..e0d7fb28 100644
--- a/drivers/lcd/ssd1289_lld.c
+++ b/drivers/lcd/ssd1289_lld.c
@@ -8,7 +8,7 @@ extern uint16_t lcd_width, lcd_height;
 
 #ifdef LCD_USE_GPIO
 
-static __inline lld_lcdWriteGPIO(uint16_t d) {
+static __inline void lld_lcdWriteGPIO(uint16_t d) {
 	LCD_DATA_PORT_1->BSRR = ((((~d >> 12 & 0xF) << 16) | (d >> 12 & 0xF)) << LCD_DATA_PORT_1_BASE);
 	LCD_DATA_PORT_2->BSRR = ((((~d >> 8 & 0xF) << 16) | (d >> 8 & 0xF)) << LCD_DATA_PORT_2_BASE);
 	LCD_DATA_PORT_3->BSRR = ((((~d >> 4 & 0xF) << 16) | (d >> 4 & 0xF)) << LCD_DATA_PORT_3_BASE);