diff --git a/Documentation/ABI/testing/sysfs-class-net-phydev b/Documentation/ABI/testing/sysfs-class-net-phydev
index 40ced0ea4316..ac722dd5e694 100644
--- a/Documentation/ABI/testing/sysfs-class-net-phydev
+++ b/Documentation/ABI/testing/sysfs-class-net-phydev
@@ -51,3 +51,15 @@ Description:
 		Boolean value indicating whether the PHY device is used in
 		standalone mode, without a net_device associated, by PHYLINK.
 		Attribute created only when this is the case.
+
+What:		/sys/class/mdio_bus/<bus>/<device>/phy_dev_flags
+Date:		March 2021
+KernelVersion:	5.13
+Contact:	netdev@vger.kernel.org
+Description:
+		32-bit hexadecimal number representing a bit mask of the
+		configuration bits passed from the consumer of the PHY
+		(Ethernet MAC, switch, etc.) to the PHY driver. The flags are
+		only used internally by the kernel and their placement are
+		not meant to be stable across kernel versions. This is intended
+		for facilitating the debugging of PHY drivers.
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index cc38e326405a..a009d1769b08 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -512,10 +512,21 @@ phy_has_fixups_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(phy_has_fixups);
 
+static ssize_t phy_dev_flags_show(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	struct phy_device *phydev = to_phy_device(dev);
+
+	return sprintf(buf, "0x%08x\n", phydev->dev_flags);
+}
+static DEVICE_ATTR_RO(phy_dev_flags);
+
 static struct attribute *phy_dev_attrs[] = {
 	&dev_attr_phy_id.attr,
 	&dev_attr_phy_interface.attr,
 	&dev_attr_phy_has_fixups.attr,
+	&dev_attr_phy_dev_flags.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(phy_dev);