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PHY Abstraction Layer
-(Updated 2005-07-21)
+(Updated 2008-04-08)
Purpose
Next, you need to know the device name of the PHY connected to this device.
The name will look something like, "phy0:0", where the first number is the
- bus id, and the second is the PHY's address on that bus.
+ bus id, and the second is the PHY's address on that bus. Typically,
+ the bus is responsible for making its ID unique.
Now, to connect, just call this function:
- phydev = phy_connect(dev, phy_name, &adjust_link, flags);
+ phydev = phy_connect(dev, phy_name, &adjust_link, flags, interface);
phydev is a pointer to the phy_device structure which represents the PHY. If
phy_connect is successful, it will return the pointer. dev, here, is the
This is useful if the system has put hardware restrictions on
the PHY/controller, of which the PHY needs to be aware.
+ interface is a u32 which specifies the connection type used
+ between the controller and the PHY. Examples are GMII, MII,
+ RGMII, and SGMII. For a full list, see include/linux/phy.h
+
Now just make sure that phydev->supported and phydev->advertising have any
values pruned from them which don't make sense for your controller (a 10/100
controller may be connected to a gigabit capable PHY, so you would need to
start, or disables then frees them for stop.
struct phy_device * phy_attach(struct net_device *dev, const char *phy_id,
- u32 flags);
+ u32 flags, phy_interface_t interface);
Attaches a network device to a particular PHY, binding the PHY to a generic
driver if none was found during bus initialization. Passes in
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.
+