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([183.91.15.56]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c85202b91c6sm13929495a12.14.2026.05.27.22.32.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 May 2026 22:32:19 -0700 (PDT) From: phucduc.bui@gmail.com To: Mark Brown , Greg Kroah-Hartman Cc: "Rafael J . Wysocki" , Danilo Krummrich , driver-core@lists.linux.dev, linux-kernel@vger.kernel.org, bui duc phuc Subject: [PATCH] regmap: reject volatile update_bits() in cache-only mode Date: Thu, 28 May 2026 12:32:04 +0700 Message-ID: <20260528053204.46783-1-phucduc.bui@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: driver-core@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: bui duc phuc Prevent _regmap_update_bits() from accessing hardware when the register map is in cache-only mode. Unlike regmap_raw_read() and _regmap_read(), the volatile _regmap_update_bits() fast path bypasses the cache_only check. This can result in unexpected hardware accesses while the device is suspended. Return -EBUSY to ensure behavior is consistent with other cache-only access paths. Signed-off-by: bui duc phuc --- Compile-tested only. drivers/base/regmap/regmap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index b2b26f07f4e3..e6e022b02637 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -3257,6 +3257,9 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg, *change = false; if (regmap_volatile(map, reg) && map->reg_update_bits) { + if (map->cache_only) + return -EBUSY; + reg = regmap_reg_addr(map, reg); ret = map->reg_update_bits(map->bus_context, reg, mask, val); if (ret == 0 && change) -- 2.43.0