regmap: add force_write option on _regmap_update_bits()

Sometimes we want to write data even though it doesn't change value.
Then, force_write option on _regmap_update_bits() helps this purpose.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regmap.c

@@ -34,7 +34,7 @@
 
 static int _regmap_update_bits(struct regmap *map, unsigned int reg,
 			       unsigned int mask, unsigned int val,
-			       bool *change);
+			       bool *change, bool force_write);
 
 static int _regmap_bus_reg_read(void *context, unsigned int reg,
 				unsigned int *val);
@@ -1178,7 +1178,7 @@ static int _regmap_select_page(struct regmap *map, unsigned int *reg,
 		ret = _regmap_update_bits(map, range->selector_reg,
 					  range->selector_mask,
 					  win_page << range->selector_shift,
-					  &page_chg);
+					  &page_chg, false);
 
 		map->work_buf = orig_work_buf;
 
@@ -2327,7 +2327,7 @@ EXPORT_SYMBOL_GPL(regmap_bulk_read);
 
 static int _regmap_update_bits(struct regmap *map, unsigned int reg,
 			       unsigned int mask, unsigned int val,
-			       bool *change)
+			       bool *change, bool force_write)
 {
 	int ret;
 	unsigned int tmp, orig;
@@ -2339,7 +2339,7 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg,
 	tmp = orig & ~mask;
 	tmp |= val & mask;
 
-	if (tmp != orig) {
+	if (force_write || (tmp != orig)) {
 		ret = _regmap_write(map, reg, tmp);
 		if (change)
 			*change = true;
@@ -2367,7 +2367,7 @@ int regmap_update_bits(struct regmap *map, unsigned int reg,
 	int ret;
 
 	map->lock(map->lock_arg);
-	ret = _regmap_update_bits(map, reg, mask, val, NULL);
+	ret = _regmap_update_bits(map, reg, mask, val, NULL, false);
 	map->unlock(map->lock_arg);
 
 	return ret;
@@ -2398,7 +2398,7 @@ int regmap_update_bits_async(struct regmap *map, unsigned int reg,
 
 	map->async = true;
 
-	ret = _regmap_update_bits(map, reg, mask, val, NULL);
+	ret = _regmap_update_bits(map, reg, mask, val, NULL, false);
 
 	map->async = false;
 
@@ -2427,7 +2427,7 @@ int regmap_update_bits_check(struct regmap *map, unsigned int reg,
 	int ret;
 
 	map->lock(map->lock_arg);
-	ret = _regmap_update_bits(map, reg, mask, val, change);
+	ret = _regmap_update_bits(map, reg, mask, val, change, false);
 	map->unlock(map->lock_arg);
 	return ret;
 }
@@ -2460,7 +2460,7 @@ int regmap_update_bits_check_async(struct regmap *map, unsigned int reg,
 
 	map->async = true;
 
-	ret = _regmap_update_bits(map, reg, mask, val, change);
+	ret = _regmap_update_bits(map, reg, mask, val, change, false);
 
 	map->async = false;