input: i8042: Make sure the keyboard is enabled

Add one more step into the init sequence. This fixes the keyboard on samus,
which otherwise does not work.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

drivers/input/i8042.c

@@ -134,6 +134,10 @@ static int kbd_reset(int quirk)
 	    kbd_read(I8042_DATA_REG) != KBD_POR)
 		goto err;
 
+	if (kbd_write(I8042_DATA_REG, CMD_DRAIN_OUTPUT) ||
+	    kbd_read(I8042_DATA_REG) != KBD_ACK)
+		goto err;
+
 	/* set AT translation and disable irq */
 	config = kbd_cmd_read(CMD_RD_CONFIG);
 	if (config == -1)

include/i8042.h

@@ -35,6 +35,7 @@
 #define CMD_KBD_DIS	0xad	/* keyboard disable */
 #define CMD_KBD_EN	0xae	/* keyboard enable */
 #define CMD_SET_KBD_LED	0xed	/* set keyboard led */
+#define CMD_DRAIN_OUTPUT 0xf4   /* drain output buffer */
 #define CMD_RESET_KBD	0xff	/* reset keyboard */
 
 /* i8042 command result */