new file mode 100644
@@ -0,0 +1,29 @@
+What: /sys/kernel/debug/mdio_bus/<MDIO_BUS>/addr
+Date: July 2020
+KernelVersion: 5.9
+Contact: Marek Behún <marek.behun@nic.cz>
+Description: (RW) Address of the PHY device on the MDIO bus which should be
+ read from/written to when accessing the "val" file in this
+ directory.
+ Format: %u
+
+What: /sys/kernel/debug/mdio_bus/<MDIO_BUS>/reg
+Date: July 2020
+KernelVersion: 5.9
+Contact: Marek Behún <marek.behun@nic.cz>
+Description: (RW) Register number of the PHY device selected by the "addr"
+ file in this directory, which should be read from/written to
+ when accessing the "val" file in this directory.
+ To access Clause 45 register do a bitwise or with MII_ADDR_C45
+ (=0x40000000).
+ Format: %u
+
+What: /sys/kernel/debug/mdio_bus/<MDIO_BUS>/val
+Date: July 2020
+KernelVersion: 5.9
+Contact: Marek Behún <marek.behun@nic.cz>
+Description: (RW) Value of the register specified by the "reg" file of the
+ PHY device specified by the "addr" file in this directory.
+ Reading/writing this file calls directly function
+ mdiobus_read/mdiobus_write with arguments from these files.
+ Format: 0x%04x
This adds the documentation for debugfs files residing in /sys/kernel/debug/mdio_bus. These files are created when CONFIG_MDIO_BUS_DEBUGFS option is enabled. Signed-off-by: Marek Behún <marek.behun@nic.cz> --- Documentation/ABI/testing/debugfs-mdio_bus | 29 ++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-mdio_bus