mfd: Make use of the ab8500 firmware read-modify-write service

This patch updates the AB8500 driver to make use of the I2C
read-modify-write service in the PRCMU firmware.

Signed-off-by: Mattias Nilsson <mattias.i.nilsson@stericsson.com>
Reviewed-by: Mattias Wallin <mattias.wallin@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/include/linux/mfd/abx500/ab8500.h b/include/linux/mfd/abx500/ab8500.h
index 78ed95b..3b551a1 100644
--- a/include/linux/mfd/abx500/ab8500.h
+++ b/include/linux/mfd/abx500/ab8500.h
@@ -217,6 +217,7 @@
  * @version: chip version id (e.g. ab8500 or ab9540)
  * @chip_id: chip revision id
  * @write: register write
+ * @write_masked: masked register write
  * @read: register read
  * @rx_buf: rx buf for SPI
  * @tx_buf: tx buf for SPI
@@ -236,8 +237,9 @@
 	enum ab8500_version version;
 	u8		chip_id;
 
-	int (*write) (struct ab8500 *a8500, u16 addr, u8 data);
-	int (*read) (struct ab8500 *a8500, u16 addr);
+	int (*write)(struct ab8500 *ab8500, u16 addr, u8 data);
+	int (*write_masked)(struct ab8500 *ab8500, u16 addr, u8 mask, u8 data);
+	int (*read)(struct ab8500 *ab8500, u16 addr);
 
 	unsigned long	tx_buf[4];
 	unsigned long	rx_buf[4];