regmap: detach regmap from dev on regmap_exit

BugLink: https://bugs.launchpad.net/bugs/2095283

commit 3061e17 upstream.

At the end of __regmap_init(), if dev is not NULL, regmap_attach_dev()
is called, which adds a devres reference to the regmap, to be able to
retrieve a dev's regmap by name using dev_get_regmap().

When calling regmap_exit, the opposite does not happen, and the
reference is kept until the dev is detached.

Add a regmap_detach_dev() function and call it in regmap_exit() to make
sure that the devres reference is not kept.

Cc: stable@vger.kernel.org
Fixes: 72b39f6 ("regmap: Implement dev_get_regmap()")
Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com>
Rule: add
Link: https://lore.kernel.org/stable/20241128130554.362486-1-demonsingur%40gmail.com
Link: https://patch.msgid.link/20241128131625.363835-1-demonsingur@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>

Author: Demon000

drivers/base/regmap/regmap.c

@@ -663,6 +663,17 @@ int regmap_attach_dev(struct device *dev, struct regmap *map,
 }
 EXPORT_SYMBOL_GPL(regmap_attach_dev);
 
+static int dev_get_regmap_match(struct device *dev, void *res, void *data);
+
+static int regmap_detach_dev(struct device *dev, struct regmap *map)
+{
+	if (!dev)
+		return 0;
+
+	return devres_release(dev, dev_get_regmap_release,
+			      dev_get_regmap_match, (void *)map->name);
+}
+
 static enum regmap_endian regmap_get_reg_endian(const struct regmap_bus *bus,
 					const struct regmap_config *config)
 {
@@ -1497,6 +1508,7 @@ int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config)
 {
 	int ret;
 
+	regmap_detach_dev(map->dev, map);
 	regcache_exit(map);
 	regmap_debugfs_exit(map);