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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/README.bitbangMII | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/doc/README.bitbangMII b/doc/README.bitbangMII new file mode 100644 index 0000000000..edd085630f --- /dev/null +++ b/doc/README.bitbangMII @@ -0,0 +1,56 @@ +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 +CONFIG_BITBANGMII_MULTI - Enable the multi bus support + +If the CONFIG_BITBANGMII_MULTI is not defined, the board's config file needs +to define at least the following macros: + +MII_INIT - Generic code to enable the MII bus (optional) +MDIO_DECLARE - Declaration needed to access to the MDIO pin (optional) +MDIO_ACTIVE - Activate the MDIO pin as out pin +MDIO_TRISTATE - Activate the MDIO pin as input/tristate pin +MDIO_READ - Read the MDIO pin +MDIO(v) - Write v on the MDIO pin +MDC_DECLARE - Declaration needed to access to the MDC pin (optional) +MDC(v) - Write v on the MDC pin + +The previous macros make the driver compatible with the previous version +(that didn't support the multi-bus). + +When the CONFIG_BITBANGMII_MULTI is also defined, 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> |