Input: add twl4030_keypad driver

Add a driver for the keypad controller on TWL4030 family chips.
These support up to an 8x8 key matrix.  The TWL4030 multifunction
chips are mostly used on OMAP3 (or OMAP 2430) based boards.

[dtor@mail.ru: switch to matrix-keypad framework, fix changing
keymap from userspace]
Reviewed-by: Trilok Soni <soni.trilok@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

include/linux/i2c/twl4030.h

@@ -25,6 +25,9 @@
 #ifndef __TWL4030_H_
 #define __TWL4030_H_
 
+#include <linux/types.h>
+#include <linux/input/matrix_keypad.h>
+
 /*
  * Using the twl4030 core we address registers using a pair
  *	{ module id, relative register offset }
@@ -302,13 +305,17 @@ struct twl4030_madc_platform_data {
 	int		irq_line;
 };
 
+/* Boards have uniqe mappings of {col, row} --> keycode.
+ * Column and row are 4 bits, but range only from 0..7.
+ * a PERSISTENT_KEY is "always on" and never reported.
+ */
+#define PERSISTENT_KEY(c, r)	KEY((c), (r), KEY_RESERVED)
+
 struct twl4030_keypad_data {
-	int rows;
-	int cols;
-	int *keymap;
-	int irq;
-	unsigned int keymapsize;
-	unsigned int rep:1;
+	const struct matrix_keymap_data *keymap_data;
+	unsigned rows;
+	unsigned cols;
+	bool rep;
 };
 
 enum twl4030_usb_mode {