regmap: debugfs: document why we don't create the debugfs entries

This is a follow-up to commit a5ba91c380b8 ("regmap: debugfs: emit a
debug message when locking is disabled"). I figured that a user may
see this message, grep the code, come to this place and he still won't
know why we actually disabled debugfs.

Add a comment explaining the reason.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index ae962b756863907537723ede518b7d276451a706..f3266334063eb4828a287f96b73a2c26738dc8ec 100644 (file)
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -529,6 +529,13 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
        struct regmap_range_node *range_node;
        const char *devname = "dummy";
 
+       /*
+        * Userspace can initiate reads from the hardware over debugfs.
+        * Normally internal regmap structures and buffers are protected with
+        * a mutex or a spinlock, but if the regmap owner decided to disable
+        * all locking mechanisms, this is no longer the case. For safety:
+        * don't create the debugfs entries if locking is disabled.
+        */
        if (map->debugfs_disable) {
                dev_dbg(map->dev, "regmap locking disabled - not creating debugfs entries\n");
                return;