mfd: Add stmpe auto sleep feature

Some STMPE devices support entering sleep mode automatically on a
specified timeout of inactivity on the I2C bus with the host system.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Sundar R Iyer <sundar.iyer@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/stmpe.h b/drivers/mfd/stmpe.h
index 991f0ec..0dbdc4e 100644
--- a/drivers/mfd/stmpe.h
+++ b/drivers/mfd/stmpe.h
@@ -49,6 +49,7 @@
  *		Called with the I/O lock held.
  * @get_altfunc: callback to get the alternate function number for the
  *		 specific block
+ * @enable_autosleep: callback to configure autosleep with specified timeout
  */
 struct stmpe_variant_info {
 	const char *name;
@@ -62,6 +63,7 @@
 	int num_irqs;
 	int (*enable)(struct stmpe *stmpe, unsigned int blocks, bool enable);
 	int (*get_altfunc)(struct stmpe *stmpe, enum stmpe_block block);
+	int (*enable_autosleep)(struct stmpe *stmpe, int autosleep_timeout);
 };
 
 #define STMPE_ICR_LSB_HIGH	(1 << 2)
@@ -118,6 +120,7 @@
 #define STMPE1601_NR_INTERNAL_IRQS	9
 
 #define STMPE1601_REG_SYS_CTRL			0x02
+#define STMPE1601_REG_SYS_CTRL2			0x03
 #define STMPE1601_REG_ICR_LSB			0x11
 #define STMPE1601_REG_IER_LSB			0x13
 #define STMPE1601_REG_ISR_MSB			0x14
@@ -137,6 +140,10 @@
 #define STMPE1601_SYS_CTRL_ENABLE_KPC		(1 << 1)
 #define STMPE1601_SYSCON_ENABLE_SPWM		(1 << 0)
 
+/* The 1601/2403 share the same masks */
+#define STMPE1601_AUTOSLEEP_TIMEOUT_MASK	(0x7)
+#define STPME1601_AUTOSLEEP_ENABLE		(1 << 3)
+
 /*
  * STMPE24xx
  */