net: miiphybb: Convert documentation to rst
Convert the current miiphybb documentation to rst. Rename
the README.bitbangMII to bitbangmii.rst in the process.
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/doc/develop/bitbangmii.rst b/doc/develop/bitbangmii.rst
new file mode 100644
index 0000000..35a4a0c
--- /dev/null
+++ b/doc/develop/bitbangmii.rst
@@ -0,0 +1,75 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+.. Luigi 'Comio' Mantellini <luigi.mantellini@idf-hit.com>, Industrie Dial Face S.p.A., 2009
+
+Bit-banged MII bus support
+==========================
+
+The miiphybb ( Bit-banged MII bus driver ) supports an arbitrary number of
+MII buses. This feature is useful when a driver uses different MII buses for
+different PHYs and all (or a part) of these buses are implemented via
+bit-banging mode.
+
+The driver requires that the following macro is defined in the board
+configuration file:
+
+* CONFIG_BITBANGMII - Enable the miiphybb driver
+
+The driver code needs to allocate a regular MDIO device using mdio_alloc()
+and assign .read and .write accessors which wrap bb_miiphy_read() and
+bb_miiphy_write() functions respectively. The bb_miiphy_read() and
+bb_miiphy_write() functions take a pointer to a callback structure,
+struct bb_miiphy_bus_ops. The struct bb_miiphy_bus_ops has the following
+fields/callbacks (see miiphy.h for details):
+
+.. code-block:: c
+
+ int (*mdio_active)() // Activate the MDIO pin as output
+ int (*mdio_tristate)() // Activate the MDIO pin as input/tristate pin
+ int (*set_mdio)() // Write the MDIO pin
+ int (*get_mdio)() // Read the MDIO pin
+ int (*set_mdc)() // Write the MDC pin
+ int (*delay)() // Delay function
+
+The driver code will look like:
+
+.. code-block:: c
+
+ static const struct bb_miiphy_bus_ops ravb_bb_miiphy_bus_ops = {
+ .mdio_active = ravb_bb_mdio_active,
+ .mdio_tristate = ravb_bb_mdio_tristate,
+ .set_mdio = ravb_bb_set_mdio,
+ .get_mdio = ravb_bb_get_mdio,
+ .set_mdc = ravb_bb_set_mdc,
+ .delay = ravb_bb_delay,
+ };
+
+ static int ravb_bb_miiphy_read(struct mii_dev *miidev, int addr,
+ int devad, int reg)
+ {
+ return bb_miiphy_read(miidev, &ravb_bb_miiphy_bus_ops,
+ addr, devad, reg);
+ }
+
+ static int ravb_bb_miiphy_write(struct mii_dev *miidev, int addr,
+ int devad, int reg, u16 value)
+ {
+ return bb_miiphy_write(miidev, &ravb_bb_miiphy_bus_ops,
+ addr, devad, reg, value);
+ }
+
+ static int ravb_probe(struct udevice *dev)
+ {
+ struct mii_dev *mdiodev;
+ ...
+ mdiodev = mdio_alloc();
+ if (!mdiodev)
+ return -ENOMEM;
+
+ mdiodev->read = ravb_bb_miiphy_read;
+ mdiodev->write = ravb_bb_miiphy_write;
+ mdiodev->priv = eth;
+ snprintf(mdiodev->name, sizeof(mdiodev->name), dev->name);
+
+ ret = mdio_register(mdiodev);
+ ...
+ }