mfd: Add STMPE1600 support

STMPE1600 is a 16-bit port expander.
Datasheet is available here :
http://www2.st.com/content/st_com/en/products/interfaces-and-transceivers/
i-o-expanders-and-level-translators/i-o-expanders/stmpe1600.html

Signed-off-by: Amelie DELAUNAY <amelie.delaunay@st.com>
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/stmpe.h b/drivers/mfd/stmpe.h
index f127342..f7efdd8 100644
--- a/drivers/mfd/stmpe.h
+++ b/drivers/mfd/stmpe.h
@@ -164,6 +164,27 @@
 #define STMPE811_SYS_CTRL2_TS_OFF	(1 << 3)
 
 /*
+ * STMPE1600
+ */
+#define STMPE1600_ID			0x0016
+#define STMPE1600_NR_INTERNAL_IRQS	16
+
+#define STMPE1600_REG_CHIP_ID		0x00
+#define STMPE1600_REG_SYS_CTRL		0x03
+#define STMPE1600_REG_IEGPIOR_LSB	0x08
+#define STMPE1600_REG_IEGPIOR_MSB	0x09
+#define STMPE1600_REG_ISGPIOR_LSB	0x0A
+#define STMPE1600_REG_ISGPIOR_MSB	0x0B
+#define STMPE1600_REG_GPMR_LSB		0x10
+#define STMPE1600_REG_GPMR_MSB		0x11
+#define STMPE1600_REG_GPSR_LSB		0x12
+#define STMPE1600_REG_GPSR_MSB		0x13
+#define STMPE1600_REG_GPDR_LSB		0x14
+#define STMPE1600_REG_GPDR_MSB		0x15
+#define STMPE1600_REG_GPPIR_LSB		0x16
+#define STMPE1600_REG_GPPIR_MSB		0x17
+
+/*
  * STMPE1601
  */