input: Add i.MX matrix keypad driver

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 59 insertions, 0 deletions

diff --git a/include/matrix_keypad.h b/include/matrix_keypad.h
new file mode 100644
index 0000000000..60de428ae0
--- /dev/null
+++ b/include/matrix_keypad.h
@@ -0,0 +1,59 @@
+#ifndef _MATRIX_KEYPAD_H
+#define _MATRIX_KEYPAD_H
+
+#define MATRIX_MAX_ROWS		32
+#define MATRIX_MAX_COLS		32
+
+#define KEY(row, col, val)	((((row) & (MATRIX_MAX_ROWS - 1)) << 24) |\
+				 (((col) & (MATRIX_MAX_COLS - 1)) << 16) |\
+				 ((val) & 0xffff))
+
+#define KEY_ROW(k)		(((k) >> 24) & 0xff)
+#define KEY_COL(k)		(((k) >> 16) & 0xff)
+#define KEY_VAL(k)		((k) & 0xffff)
+
+#define MATRIX_SCAN_CODE(row, col, row_shift)	(((row) << (row_shift)) + (col))
+
+/**
+ * struct matrix_keymap_data - keymap for matrix keyboards
+ * @keymap: pointer to array of uint32 values encoded with KEY() macro
+ *	representing keymap
+ * @keymap_size: number of entries (initialized) in this keymap
+ *
+ * This structure is supposed to be used by platform code to supply
+ * keymaps to drivers that implement matrix-like keypads/keyboards.
+ */
+struct matrix_keymap_data {
+	const uint32_t *keymap;
+	unsigned int	keymap_size;
+};
+
+/**
+ * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
+ * @keymap_data: keymap supplied by the platform code
+ * @row_shift: number of bits to shift row value by to advance to the next
+ * line in the keymap
+ * @keymap: expanded version of keymap that is suitable for use by
+ * matrix keyboad driver
+ * This function converts platform keymap (encoded with KEY() macro) into
+ * an array of keycodes that is suitable for using in a standard matrix
+ * keyboard driver that uses row and col as indices.
+ */
+static inline void
+matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
+			   unsigned int row_shift,
+			   unsigned short *keymap)
+{
+	int i;
+
+	for (i = 0; i < keymap_data->keymap_size; i++) {
+		unsigned int key = keymap_data->keymap[i];
+		unsigned int row = KEY_ROW(key);
+		unsigned int col = KEY_COL(key);
+		unsigned short code = KEY_VAL(key);
+
+		keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
+	}
+}
+
+#endif /* _MATRIX_KEYPAD_H */