[PATCH 2/2] regmap: mdio: Reject invalid clause-22 addresses

[Sander Vanheule]

When an invalid register offset is provided, the upper bits are silently
discarded. Change this to return -ENXIO instead, to help catch potential
bugs.

Signed-off-by: Sander Vanheule <sander@xxxxxxxxxxxxx>
---
 drivers/base/regmap/regmap-mdio.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/base/regmap/regmap-mdio.c b/drivers/base/regmap/regmap-mdio.c
index aee34bf2400e..9adfb82be8f1 100644
--- a/drivers/base/regmap/regmap-mdio.c
+++ b/drivers/base/regmap/regmap-mdio.c
@@ -13,7 +13,10 @@ static int regmap_mdio_read(void *context, unsigned int reg, unsigned int *val)
 	struct mdio_device *mdio_dev = context;
 	int ret;
 
-	ret = mdiobus_read(mdio_dev->bus, mdio_dev->addr, reg & REGNUM_C22_MASK);
+	if (unlikely(reg & ~REGNUM_C22_MASK))
+		return -ENXIO;
+
+	ret = mdiobus_read(mdio_dev->bus, mdio_dev->addr, reg);
 	if (ret < 0)
 		return ret;
 
@@ -25,7 +28,10 @@ static int regmap_mdio_write(void *context, unsigned int reg, unsigned int val)
 {
 	struct mdio_device *mdio_dev = context;
 
-	return mdiobus_write(mdio_dev->bus, mdio_dev->addr, reg & REGNUM_C22_MASK, val);
+	if (unlikely(reg & ~REGNUM_C22_MASK))
+		return -ENXIO;
+
+	return mdiobus_write(mdio_dev->bus, mdio_dev->addr, reg, val);
 }
 
 static const struct regmap_bus regmap_mdio_bus = {
-- 
2.31.1