regmap: Fix regcache debugfs initialization

Commit 6cfec04bcc ("regmap: Separate regmap dev initialization") moved the
regmap debugfs initialization after regcache initialization. This means
that the regmap debugfs directory is not created yet when the cache
initialization runs and so any debugfs files registered by the regcache are
created in the debugfs root directory rather than the debugfs directory of
the regmap instance. Fix this by adding a separate callback for the
regcache debugfs initialization which will be called after the parent
debugfs entry has been created.

Fixes: 6cfec04bcc (regmap: Separate regmap dev initialization)
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org

drivers/base/regmap/internal.h

@@ -146,6 +146,9 @@ struct regcache_ops {
 	enum regcache_type type;
 	int (*init)(struct regmap *map);
 	int (*exit)(struct regmap *map);
+#ifdef CONFIG_DEBUG_FS
+	void (*debugfs_init)(struct regmap *map);
+#endif
 	int (*read)(struct regmap *map, unsigned int reg, unsigned int *value);
 	int (*write)(struct regmap *map, unsigned int reg, unsigned int value);
 	int (*sync)(struct regmap *map, unsigned int min, unsigned int max);

drivers/base/regmap/regcache-rbtree.c

@@ -194,10 +194,6 @@ static void rbtree_debugfs_init(struct regmap *map)
 {
 	debugfs_create_file("rbtree", 0400, map->debugfs, map, &rbtree_fops);
 }
-#else
-static void rbtree_debugfs_init(struct regmap *map)
-{
-}
 #endif
 
 static int regcache_rbtree_init(struct regmap *map)
@@ -222,8 +218,6 @@ static int regcache_rbtree_init(struct regmap *map)
 			goto err;
 	}
 
-	rbtree_debugfs_init(map);
-
 	return 0;
 
 err:
@@ -532,6 +526,9 @@ struct regcache_ops regcache_rbtree_ops = {
 	.name = "rbtree",
 	.init = regcache_rbtree_init,
 	.exit = regcache_rbtree_exit,
+#ifdef CONFIG_DEBUG_FS
+	.debugfs_init = rbtree_debugfs_init,
+#endif
 	.read = regcache_rbtree_read,
 	.write = regcache_rbtree_write,
 	.sync = regcache_rbtree_sync,

drivers/base/regmap/regmap-debugfs.c

@@ -538,6 +538,9 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
 
 		next = rb_next(&range_node->node);
 	}
+
+	if (map->cache_ops && map->cache_ops->debugfs_init)
+		map->cache_ops->debugfs_init(map);
 }
 
 void regmap_debugfs_exit(struct regmap *map)