mfd: Add a prcmu_abb_write_masked routine to db8500-prcmu

This patch adds driver support for the I2C read-modify-write
service in the U8500 PRCMU firmware.

Signed-off-by: Mattias Nilsson <mattias.i.nilsson@stericsson.com>
Reviewed-by: Jonas ABERG <jonas.aberg@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/dbx500-prcmu.h b/include/linux/mfd/dbx500-prcmu.h
index eaa99a0..d7674eb 100644
--- a/include/linux/mfd/dbx500-prcmu.h
+++ b/include/linux/mfd/dbx500-prcmu.h
@@ -368,6 +368,7 @@
 
 int prcmu_abb_read(u8 slave, u8 reg, u8 *value, u8 size);
 int prcmu_abb_write(u8 slave, u8 reg, u8 *value, u8 size);
+int prcmu_abb_write_masked(u8 slave, u8 reg, u8 *value, u8 *mask, u8 size);
 
 int prcmu_config_clkout(u8 clkout, u8 source, u8 div);
 
@@ -620,6 +621,12 @@
 	return -ENOSYS;
 }
 
+static inline int prcmu_abb_write_masked(u8 slave, u8 reg, u8 *value, u8 *mask,
+	u8 size)
+{
+	return -ENOSYS;
+}
+
 static inline int prcmu_config_clkout(u8 clkout, u8 source, u8 div)
 {
 	return 0;