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phylib: Add support for board-level PHY fixups

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Sometimes the specific interaction between the platform and the PHY
requires special handling.  For instance, to change where the PHY's
clock input is, or to add a delay to account for latency issues in the
data path.  We add a mechanism for registering a callback with the PHY
Lib to be called on matching PHYs when they are brought up, or reset.

Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Andy Fleming
2008-04-18 17:29:54 -05:00
committed by Jeff Garzik
parent 8ec7226a93
commit f62220d3a9
5 changed files with 182 additions and 16 deletions
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38
Documentation/networking/phy.txt
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@@ -1,7 +1,7 @@
-------
PHY Abstraction Layer
(Updated 2006-11-30)
(Updated 2008-04-08)
Purpose
@@ -291,3 +291,39 @@ Writing a PHY driver
Feel free to look at the Marvell, Cicada, and Davicom drivers in
drivers/net/phy/ for examples (the lxt and qsemi drivers have
not been tested as of this writing)
Board Fixups
Sometimes the specific interaction between the platform and the PHY requires
special handling. For instance, to change where the PHY's clock input is,
or to add a delay to account for latency issues in the data path. In order
to support such contingencies, the PHY Layer allows platform code to register
fixups to be run when the PHY is brought up (or subsequently reset).
When the PHY Layer brings up a PHY it checks to see if there are any fixups
registered for it, matching based on UID (contained in the PHY device's phy_id
field) and the bus identifier (contained in phydev->dev.bus_id). Both must
match, however two constants, PHY_ANY_ID and PHY_ANY_UID, are provided as
wildcards for the bus ID and UID, respectively.
When a match is found, the PHY layer will invoke the run function associated
with the fixup. This function is passed a pointer to the phy_device of
interest. It should therefore only operate on that PHY.
The platform code can either register the fixup using phy_register_fixup():
int phy_register_fixup(const char *phy_id,
u32 phy_uid, u32 phy_uid_mask,
int (*run)(struct phy_device *));
Or using one of the two stubs, phy_register_fixup_for_uid() and
phy_register_fixup_for_id():
int phy_register_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask,
int (*run)(struct phy_device *));
int phy_register_fixup_for_id(const char *phy_id,
int (*run)(struct phy_device *));
The stubs set one of the two matching criteria, and set the other one to
match anything.