3 files changed, 23 insertions, 1 deletions
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 348ff02eb93e..6483e0bda0cf 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -74,6 +74,7 @@ struct regmap {
 	struct reg_default *reg_defaults;
 	const void *reg_defaults_raw;
 	void *cache;
+	bool cache_dirty;
 };
 
 struct regcache_ops {
diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 666f6f5011dc..6ab9f0384d82 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -241,6 +241,8 @@ int regcache_sync(struct regmap *map)
 		map->cache_ops->name);
 	name = map->cache_ops->name;
 	trace_regcache_sync(map->dev, name, "start");
+	if (!map->cache_dirty)
+		goto out;
 	if (map->cache_ops->sync) {
 		ret = map->cache_ops->sync(map);
 	} else {
@@ -291,6 +293,23 @@ void regcache_cache_only(struct regmap *map, bool enable)
 EXPORT_SYMBOL_GPL(regcache_cache_only);
 
 /**
+ * regcache_mark_dirty: Mark the register cache as dirty
+ *
+ * @map: map to mark
+ *
+ * Mark the register cache as dirty, for example due to the device
+ * having been powered down for suspend.  If the cache is not marked
+ * as dirty then the cache sync will be suppressed.
+ */
+void regcache_mark_dirty(struct regmap *map)
+{
+	mutex_lock(&map->lock);
+	map->cache_dirty = true;
+	mutex_unlock(&map->lock);
+}
+EXPORT_SYMBOL_GPL(regcache_mark_dirty);
+
+/**
  * regcache_cache_bypass: Put a register map into cache bypass mode
  *
  * @map: map to configure
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index bf441db1ee90..3aca18dbf367 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -306,8 +306,10 @@ int _regmap_write(struct regmap *map, unsigned int reg,
 		ret = regcache_write(map, reg, val);
 		if (ret != 0)
 			return ret;
-		if (map->cache_only)
+		if (map->cache_only) {
+			map->cache_dirty = true;
 			return 0;
+		}
 	}
 
 	trace_regmap_reg_write(map->dev, reg, val);