doc/README.bitbangMII

This patch rewrites the miiphybb ( Bit-banged MII bus driver ) in order to
support an arbitrary number of mii buses. This feature is useful when your
board 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 macros should be defined into the board
configuration file:

CONFIG_BITBANGMII	- Enable the miiphybb driver

The board code needs to fill the bb_miiphy_buses[] array with a record for
each required bus and declare the bb_miiphy_buses_num variable with the
number of mii buses. The record (struct bb_miiphy_bus) has the following
fields/callbacks (see miiphy.h for details):

char name[]	       - The symbolic name that must be equal to the MII bus
			 registered name
int (*init)()	       - Initialization function called at startup time (just
			 before the Ethernet initialization)
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
void *priv	       - Private data used by board specific code

The board code will look like:

struct bb_miiphy_bus bb_miiphy_buses[] = {
 { .name = "miibus#1", .init = b1_init, .mdio_active = b1_mdio_active, ... },
 { .name = "miibus#2", .init = b2_init, .mdio_active = b2_mdio_active, ... },
 ...
};
int bb_miiphy_buses_num = sizeof(bb_miiphy_buses) /
			  sizeof(bb_miiphy_buses[0]);

2009 Industrie Dial Face S.p.A.
     Luigi 'Comio' Mantellini <luigi.mantellini@idf-hit.com>