mfd: retu: Add Tahvo support

Tahvo is a multi-function device on Nokia 770, implementing USB
transceiver and charge/battery control.

It's so close to Retu that a single driver can support both.

Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/include/linux/mfd/retu.h b/include/linux/mfd/retu.h
index 1e2715d..65471c4 100644
--- a/include/linux/mfd/retu.h
+++ b/include/linux/mfd/retu.h
@@ -1,5 +1,5 @@
 /*
- * Retu MFD driver interface
+ * Retu/Tahvo MFD driver interface
  *
  * This file is subject to the terms and conditions of the GNU General
  * Public License. See the file "COPYING" in the main directory of this
@@ -19,4 +19,10 @@
 #define RETU_REG_CC1		0x0d		/* Common control register 1 */
 #define RETU_REG_STATUS		0x16		/* Status register */
 
+/* Interrupt sources */
+#define TAHVO_INT_VBUS		0		/* VBUS state */
+
+/* Interrupt status */
+#define TAHVO_STAT_VBUS		(1 << TAHVO_INT_VBUS)
+
 #endif /* __LINUX_MFD_RETU_H */