linux-kernel - [PATCH 2/4] regmap: Allow disabling debugfs via regmap

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Message-ID: <20251129142042.344359-3-richard@nod.at>
Date: Sat, 29 Nov 2025 15:20:40 +0100
From: Richard Weinberger <richard@....at>
To: linux-kernel@...r.kernel.org
Cc: linux-omap@...r.kernel.org,
	devicetree@...r.kernel.org,
	arnd@...db.de,
	lee@...nel.org,
	dakr@...nel.org,
	rafael@...nel.org,
	gregkh@...uxfoundation.org,
	broonie@...nel.org,
	tony@...mide.com,
	rogerq@...nel.org,
	khilman@...libre.com,
	andreas@...nade.info,
	aaro.koskinen@....fi,
	conor+dt@...nel.org,
	krzk+dt@...nel.org,
	robh@...nel.org,
	Richard Weinberger <richard@....at>
Subject: [PATCH 2/4] regmap: Allow disabling debugfs via regmap_config

Regmap already disables register access via debugfs as soon as a register
map is used without taking locks.
Go a step further and allow disabling debugfs via regmap_config such that
device drivers can decide on their own whether uncontrolled register access
via debugfs is harmful.

Signed-off-by: Richard Weinberger <richard@....at>
---
 drivers/base/regmap/regmap.c | 2 ++
 include/linux/regmap.h       | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index ce9be3989a218..38d7a03aa7637 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -697,6 +697,8 @@ struct regmap *__regmap_init(struct device *dev,
 	if (ret)
 		goto err_map;
 
+	map->debugfs_disable = config->debugfs_disable;
+
 	ret = -EINVAL; /* Later error paths rely on this */
 
 	if (config->disable_locking) {
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 55343795644b9..646501a055eba 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -395,6 +395,7 @@ typedef void (*regmap_unlock)(void *);
  *
  * @ranges: Array of configuration entries for virtual address ranges.
  * @num_ranges: Number of range configuration entries.
+ * @debugfs_disable: Disable debugfs access to this register.
  */
 struct regmap_config {
 	const char *name;
@@ -467,6 +468,8 @@ struct regmap_config {
 
 	const struct regmap_range_cfg *ranges;
 	unsigned int num_ranges;
+
+	bool debugfs_disable;
 };
 
 /**
-- 
2.51.0