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60ea8a94d6
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>
75 lines
2.6 KiB
ReStructuredText
75 lines
2.6 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0-or-later
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.. Luigi 'Comio' Mantellini <luigi.mantellini@idf-hit.com>, Industrie Dial Face S.p.A., 2009
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Bit-banged MII bus support
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==========================
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The miiphybb ( Bit-banged MII bus driver ) supports an arbitrary number of
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MII buses. This feature is useful when a driver uses different MII buses for
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different PHYs and all (or a part) of these buses are implemented via
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bit-banging mode.
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The driver requires that the following macro is defined in the board
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configuration file:
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* CONFIG_BITBANGMII - Enable the miiphybb driver
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The driver code needs to allocate a regular MDIO device using mdio_alloc()
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and assign .read and .write accessors which wrap bb_miiphy_read() and
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bb_miiphy_write() functions respectively. The bb_miiphy_read() and
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bb_miiphy_write() functions take a pointer to a callback structure,
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struct bb_miiphy_bus_ops. The struct bb_miiphy_bus_ops has the following
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fields/callbacks (see miiphy.h for details):
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.. code-block:: c
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int (*mdio_active)() // Activate the MDIO pin as output
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int (*mdio_tristate)() // Activate the MDIO pin as input/tristate pin
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int (*set_mdio)() // Write the MDIO pin
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int (*get_mdio)() // Read the MDIO pin
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int (*set_mdc)() // Write the MDC pin
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int (*delay)() // Delay function
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The driver code will look like:
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.. code-block:: c
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static const struct bb_miiphy_bus_ops ravb_bb_miiphy_bus_ops = {
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.mdio_active = ravb_bb_mdio_active,
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.mdio_tristate = ravb_bb_mdio_tristate,
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.set_mdio = ravb_bb_set_mdio,
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.get_mdio = ravb_bb_get_mdio,
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.set_mdc = ravb_bb_set_mdc,
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.delay = ravb_bb_delay,
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};
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static int ravb_bb_miiphy_read(struct mii_dev *miidev, int addr,
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int devad, int reg)
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{
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return bb_miiphy_read(miidev, &ravb_bb_miiphy_bus_ops,
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addr, devad, reg);
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}
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static int ravb_bb_miiphy_write(struct mii_dev *miidev, int addr,
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int devad, int reg, u16 value)
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{
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return bb_miiphy_write(miidev, &ravb_bb_miiphy_bus_ops,
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addr, devad, reg, value);
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}
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static int ravb_probe(struct udevice *dev)
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{
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struct mii_dev *mdiodev;
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...
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mdiodev = mdio_alloc();
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if (!mdiodev)
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return -ENOMEM;
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mdiodev->read = ravb_bb_miiphy_read;
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mdiodev->write = ravb_bb_miiphy_write;
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mdiodev->priv = eth;
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snprintf(mdiodev->name, sizeof(mdiodev->name), dev->name);
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ret = mdio_register(mdiodev);
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...
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}
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