diff --git a/drivers/video/fbdev/da8xx-fb.c b/drivers/video/fbdev/da8xx-fb.c
index 788f6b37fce7..10c876c95772 100644
--- a/drivers/video/fbdev/da8xx-fb.c
+++ b/drivers/video/fbdev/da8xx-fb.c
@@ -419,7 +419,7 @@ static void lcd_cfg_horizontal_sync(int back_porch, int pulse_width,
 {
 	u32 reg;
 
-	reg = lcdc_read(LCD_RASTER_TIMING_0_REG) & 0xf;
+	reg = lcdc_read(LCD_RASTER_TIMING_0_REG) & 0x3ff;
 	reg |= (((back_porch-1) & 0xff) << 24)
 	    | (((front_porch-1) & 0xff) << 16)
 	    | (((pulse_width-1) & 0x3f) << 10);