input: i8042: Provide feature to disable keyboard before booting kernel

The BIOS leaves the keyboard enabled during boot time so that any
keystroke would interfere kernel driver initialization.

Add a way to disable the keyboard to make sure no scancode will be
generated during the boot time. Note that the keyboard will be
re-enabled again after the kernel driver is up.

This code can be called from the board functions.
Signed-off-by: Louis Yung-Chieh Lo <yjlou@chromium.org>

Signed-off-by: Louis Yung-Chieh Lo <yjlou@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@ti.com>
diff --git a/include/i8042.h b/include/i8042.h
index aeb3f09..c48c057 100644
--- a/include/i8042.h
+++ b/include/i8042.h
@@ -75,6 +75,19 @@
 
 /* exports */
 
+/**
+ * Flush all buffer from keyboard controller to host.
+ */
+void i8042_flush(void);
+
+/**
+ * Disables the keyboard so that key strokes no longer generate scancodes to
+ * the host.
+ *
+ * @return 0 if ok, -1 if keyboard input was found while disabling
+ */
+int i8042_disable(void);
+
 int i8042_kbd_init(void);
 int i8042_tstc(void);
 int i8042_getc(void);