X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=Documentation%2Fphy.txt;h=ebff6ee52441edbca95a0ebc8b20cd49ac218d3d;hb=91c6c8dcc7c30ed2d5861c670621a23f3b37e293;hp=0103e4b15b0eadb099b091618d19b5d247dcc906;hpb=9aa28f2b71055d5ae17a2e1daee359d4174bb13e;p=~andy%2Flinux

diff --git a/Documentation/phy.txt b/Documentation/phy.txt
index 0103e4b15b0..ebff6ee5244 100644
--- a/Documentation/phy.txt
+++ b/Documentation/phy.txt
@@ -75,14 +75,26 @@ Before the controller can make use of the PHY, it has to get a reference to
 it. This framework provides the following APIs to get a reference to the PHY.
 
 struct phy *phy_get(struct device *dev, const char *string);
+struct phy *phy_optional_get(struct device *dev, const char *string);
 struct phy *devm_phy_get(struct device *dev, const char *string);
-
-phy_get and devm_phy_get can be used to get the PHY. In the case of dt boot,
-the string arguments should contain the phy name as given in the dt data and
-in the case of non-dt boot, it should contain the label of the PHY.
-The only difference between the two APIs is that devm_phy_get associates the
-device with the PHY using devres on successful PHY get. On driver detach,
-release function is invoked on the the devres data and devres data is freed.
+struct phy *devm_phy_optional_get(struct device *dev, const char *string);
+
+phy_get, phy_optional_get, devm_phy_get and devm_phy_optional_get can
+be used to get the PHY. In the case of dt boot, the string arguments
+should contain the phy name as given in the dt data and in the case of
+non-dt boot, it should contain the label of the PHY.  The two
+devm_phy_get associates the device with the PHY using devres on
+successful PHY get. On driver detach, release function is invoked on
+the the devres data and devres data is freed. phy_optional_get and
+devm_phy_optional_get should be used when the phy is optional. These
+two functions will never return -ENODEV, but instead returns NULL when
+the phy cannot be found.
+
+It should be noted that NULL is a valid phy reference. All phy
+consumer calls on the NULL phy become NOPs. That is the release calls,
+the phy_init() and phy_exit() calls, and phy_power_on() and
+phy_power_off() calls are all NOP when applied to a NULL phy. The NULL
+phy is useful in devices for handling optional phy devices.
 
 5. Releasing a reference to the PHY