regmap: add regmap_write_bits()

regmap_write_bits() is similar to regmap_update_bits(),
but regmap_write_bits() write data to register even though
it is same value.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 69ec411..d93bb9a 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -2375,6 +2375,29 @@
 EXPORT_SYMBOL_GPL(regmap_update_bits);
 
 /**
+ * regmap_write_bits: Perform a read/modify/write cycle on the register map
+ *
+ * @map: Register map to update
+ * @reg: Register to update
+ * @mask: Bitmask to change
+ * @val: New value for bitmask
+ *
+ * Returns zero for success, a negative number on error.
+ */
+int regmap_write_bits(struct regmap *map, unsigned int reg,
+		      unsigned int mask, unsigned int val)
+{
+	int ret;
+
+	map->lock(map->lock_arg);
+	ret = _regmap_update_bits(map, reg, mask, val, NULL, true);
+	map->unlock(map->lock_arg);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_write_bits);
+
+/**
  * regmap_update_bits_async: Perform a read/modify/write cycle on the register
  *                           map asynchronously
  *
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 59c55ea..e4b9ad4 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -424,6 +424,8 @@
 		     size_t val_count);
 int regmap_update_bits(struct regmap *map, unsigned int reg,
 		       unsigned int mask, unsigned int val);
+int regmap_write_bits(struct regmap *map, unsigned int reg,
+		       unsigned int mask, unsigned int val);
 int regmap_update_bits_async(struct regmap *map, unsigned int reg,
 			     unsigned int mask, unsigned int val);
 int regmap_update_bits_check(struct regmap *map, unsigned int reg,
@@ -645,6 +647,13 @@
 	return -EINVAL;
 }
 
+static inline int regmap_write_bits(struct regmap *map, unsigned int reg,
+				     unsigned int mask, unsigned int val)
+{
+	WARN_ONCE(1, "regmap API is disabled");
+	return -EINVAL;
+}
+
 static inline int regmap_update_bits_async(struct regmap *map,
 					   unsigned int reg,
 					   unsigned int mask, unsigned int val)